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[PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState 209+ messages / 5 participants [nested] [flat]
* [PATCH v2] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState @ 2023-02-25 21:39 Andres Freund <[email protected]> 0 siblings, 0 replies; 209+ 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] 209+ messages in thread
* [PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState @ 2023-02-25 21:39 Andres Freund <[email protected]> 0 siblings, 0 replies; 209+ 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] 209+ messages in thread
* [PATCH v20 5/6] Add CONCURRENTLY option to REPACK command. @ 2025-08-30 17:13 Álvaro Herrera <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Álvaro Herrera @ 2025-08-30 17:13 UTC (permalink / raw) The REPACK command copies the relation data into a new file, creates new indexes and eventually swaps the files. To make sure that the old file does not change during the copying, the relation is locked in an exclusive mode, which prevents applications from both reading and writing. (To keep the data consistent, we'd only need to prevent the applications from writing, but even reading needs to be blocked before we can swap the files - otherwise some applications could continue using the old file. Since we should not request a stronger lock without releasing the weaker one first, we acquire the exclusive lock in the beginning and keep it till the end of the processing.) This patch introduces an alternative workflow, which only requires the exclusive lock when the relation (and index) files are being swapped. (Supposedly, the swapping should be pretty fast.) On the other hand, when we copy the data to the new file, we allow applications to read from the relation and even to write to it. First, we scan the relation using a "historic snapshot", and insert all the tuples satisfying this snapshot into the new file. Second, logical decoding is used to capture the data changes done by applications during the copying (i.e. changes that do not satisfy the historic snapshot mentioned above), and those are applied to the new file before we acquire the exclusive lock that we need to swap the files. (Of course, more data changes can take place while we are waiting for the lock - these will be applied to the new file after we have acquired the lock, before we swap the files.) Since the logical decoding system, during its startup, waits until all the transactions which already have XID assigned have finished, there is a risk of deadlock if a transaction that already changed anything in the database tries to acquire a conflicting lock on the table REPACK CONCURRENTLY is working on. As an example, consider transaction running CREATE INDEX command on the table that is being REPACKed CONCURRENTLY. On the other hand, DML commands (INSERT, UPDATE, DELETE) are not a problem as their lock does not conflict with REPACK CONCURRENTLY. The current approach is that we accept the risk. If we tried to avoid it, it'd be necessary to unlock the table before the logical decoding is setup and lock it again afterwards. Such temporary unlocking would imply re-checking if the table still meets all the requirements for REPACK CONCURRENTLY. Like the existing implementation of REPACK, the variant with the CONCURRENTLY option also requires an extra space for the new relation and index files (which coexist with the old files for some time). In addition, the CONCURRENTLY option might introduce a lag in releasing WAL segments for archiving / recycling. This is due to the decoding of the data changes done by applications concurrently. When copying the table contents into the new file, we check the lag periodically. If it exceeds the size of a WAL segment, we decode all the available WAL before resuming the copying. (Of course, the changes are not applied until the whole table contents is copied.) A background worker might be a better approach for the decoding - let's consider implementing it in the future. The WAL records produced by running DML commands on the new relation do not contain enough information to be processed by the logical decoding system. All we need from the new relation is the file (relfilenode), while the actual relation is eventually dropped. Thus there is no point in replaying the DMLs anywhere. Author: Antonin Houska <[email protected]> --- doc/src/sgml/monitoring.sgml | 37 +- doc/src/sgml/mvcc.sgml | 12 +- doc/src/sgml/ref/repack.sgml | 129 +- src/Makefile | 1 + src/backend/access/heap/heapam.c | 34 +- src/backend/access/heap/heapam_handler.c | 227 ++- src/backend/access/heap/rewriteheap.c | 6 +- src/backend/access/transam/xact.c | 11 +- src/backend/catalog/system_views.sql | 30 +- src/backend/commands/cluster.c | 1677 +++++++++++++++-- src/backend/commands/matview.c | 2 +- src/backend/commands/tablecmds.c | 1 + src/backend/commands/vacuum.c | 12 +- src/backend/meson.build | 1 + src/backend/replication/logical/decode.c | 83 + src/backend/replication/logical/snapbuild.c | 20 + .../replication/pgoutput_repack/Makefile | 32 + .../replication/pgoutput_repack/meson.build | 18 + .../pgoutput_repack/pgoutput_repack.c | 288 +++ src/backend/storage/ipc/ipci.c | 1 + .../storage/lmgr/generate-lwlocknames.pl | 2 +- src/backend/utils/cache/relcache.c | 1 + src/backend/utils/time/snapmgr.c | 3 +- src/bin/psql/tab-complete.in.c | 25 +- src/include/access/heapam.h | 9 +- src/include/access/heapam_xlog.h | 2 + src/include/access/tableam.h | 10 + src/include/commands/cluster.h | 91 +- src/include/commands/progress.h | 23 +- src/include/replication/snapbuild.h | 1 + src/include/storage/lockdefs.h | 4 +- src/include/utils/snapmgr.h | 2 + src/test/modules/injection_points/Makefile | 5 +- .../injection_points/expected/repack.out | 113 ++ .../modules/injection_points/logical.conf | 1 + src/test/modules/injection_points/meson.build | 4 + .../injection_points/specs/repack.spec | 143 ++ src/test/regress/expected/rules.out | 29 +- src/tools/pgindent/typedefs.list | 4 + 39 files changed, 2821 insertions(+), 273 deletions(-) create mode 100644 src/backend/replication/pgoutput_repack/Makefile create mode 100644 src/backend/replication/pgoutput_repack/meson.build create mode 100644 src/backend/replication/pgoutput_repack/pgoutput_repack.c create mode 100644 src/test/modules/injection_points/expected/repack.out create mode 100644 src/test/modules/injection_points/logical.conf create mode 100644 src/test/modules/injection_points/specs/repack.spec diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 12e103d319d..61c0197555f 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -6074,14 +6074,35 @@ FROM pg_stat_get_backend_idset() AS backendid; <row> <entry role="catalog_table_entry"><para role="column_definition"> - <structfield>heap_tuples_written</structfield> <type>bigint</type> + <structfield>heap_tuples_inserted</structfield> <type>bigint</type> </para> <para> - Number of heap tuples written. + Number of heap tuples inserted. This counter only advances when the phase is <literal>seq scanning heap</literal>, - <literal>index scanning heap</literal> - or <literal>writing new heap</literal>. + <literal>index scanning heap</literal>, + <literal>writing new heap</literal> + or <literal>catch-up</literal>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>heap_tuples_updated</structfield> <type>bigint</type> + </para> + <para> + Number of heap tuples updated. + This counter only advances when the phase is <literal>catch-up</literal>. + </para></entry> + </row> + + <row> + <entry role="catalog_table_entry"><para role="column_definition"> + <structfield>heap_tuples_deleted</structfield> <type>bigint</type> + </para> + <para> + Number of heap tuples deleted. + This counter only advances when the phase is <literal>catch-up</literal>. </para></entry> </row> @@ -6162,6 +6183,14 @@ FROM pg_stat_get_backend_idset() AS backendid; <command>REPACK</command> is currently writing the new heap. </entry> </row> + <row> + <entry><literal>catch-up</literal></entry> + <entry> + <command>REPACK CONCURRENTLY</command> is currently processing the DML + commands that other transactions executed during any of the preceding + phase. + </entry> + </row> <row> <entry><literal>swapping relation files</literal></entry> <entry> diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml index 049ee75a4ba..0f5c34af542 100644 --- a/doc/src/sgml/mvcc.sgml +++ b/doc/src/sgml/mvcc.sgml @@ -1833,15 +1833,17 @@ SELECT pg_advisory_lock(q.id) FROM <title>Caveats</title> <para> - Some DDL commands, currently only <link linkend="sql-truncate"><command>TRUNCATE</command></link> and the - table-rewriting forms of <link linkend="sql-altertable"><command>ALTER TABLE</command></link>, are not + Some commands, currently only <link linkend="sql-truncate"><command>TRUNCATE</command></link>, the + table-rewriting forms of <link linkend="sql-altertable"><command>ALTER + TABLE</command></link> and <command>REPACK</command> with + the <literal>CONCURRENTLY</literal> option, are not MVCC-safe. This means that after the truncation or rewrite commits, the table will appear empty to concurrent transactions, if they are using a - snapshot taken before the DDL command committed. This will only be an + snapshot taken before the command committed. This will only be an issue for a transaction that did not access the table in question - before the DDL command started — any transaction that has done so + before the command started — any transaction that has done so would hold at least an <literal>ACCESS SHARE</literal> table lock, - which would block the DDL command until that transaction completes. + which would block the truncating or rewriting command until that transaction completes. So these commands will not cause any apparent inconsistency in the table contents for successive queries on the target table, but they could cause visible inconsistency between the contents of the target diff --git a/doc/src/sgml/ref/repack.sgml b/doc/src/sgml/ref/repack.sgml index fd9d89f8aaa..ff5ce48de55 100644 --- a/doc/src/sgml/ref/repack.sgml +++ b/doc/src/sgml/ref/repack.sgml @@ -27,6 +27,7 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <re VERBOSE [ <replaceable class="parameter">boolean</replaceable> ] ANALYSE | ANALYZE + CONCURRENTLY </synopsis> </refsynopsisdiv> @@ -49,7 +50,8 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <re processes every table and materialized view in the current database that the current user has the <literal>MAINTAIN</literal> privilege on. This form of <command>REPACK</command> cannot be executed inside a transaction - block. + block. Also, this form is not allowed if + the <literal>CONCURRENTLY</literal> option is used. </para> <para> @@ -62,7 +64,8 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <re When a table is being repacked, an <literal>ACCESS EXCLUSIVE</literal> lock is acquired on it. This prevents any other database operations (both reads and writes) from operating on the table until the <command>REPACK</command> - is finished. + is finished. If you want to keep the table accessible during the repacking, + consider using the <literal>CONCURRENTLY</literal> option. </para> <refsect2 id="sql-repack-notes-on-clustering" xreflabel="Notes on Clustering"> @@ -179,6 +182,128 @@ REPACK [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] [ <re </listitem> </varlistentry> + <varlistentry> + <term><literal>CONCURRENTLY</literal></term> + <listitem> + <para> + Allow other transactions to use the table while it is being repacked. + </para> + + <para> + Internally, <command>REPACK</command> copies the contents of the table + (ignoring dead tuples) into a new file, sorted by the specified index, + and also creates a new file for each index. Then it swaps the old and + new files for the table and all the indexes, and deletes the old + files. The <literal>ACCESS EXCLUSIVE</literal> lock is needed to make + sure that the old files do not change during the processing because the + changes would get lost due to the swap. + </para> + + <para> + With the <literal>CONCURRENTLY</literal> option, the <literal>ACCESS + EXCLUSIVE</literal> lock is only acquired to swap the table and index + files. The data changes that took place during the creation of the new + table and index files are captured using logical decoding + (<xref linkend="logicaldecoding"/>) and applied before + the <literal>ACCESS EXCLUSIVE</literal> lock is requested. Thus the lock + is typically held only for the time needed to swap the files, which + should be pretty short. However, the time might still be noticeable if + too many data changes have been done to the table while + <command>REPACK</command> was waiting for the lock: those changes must + be processed just before the files are swapped, while the + <literal>ACCESS EXCLUSIVE</literal> lock is being held. + </para> + + <para> + Note that <command>REPACK</command> with the + the <literal>CONCURRENTLY</literal> option does not try to order the + rows inserted into the table after the repacking started. Also + note <command>REPACK</command> might fail to complete due to DDL + commands executed on the table by other transactions during the + repacking. + </para> + + <note> + <para> + In addition to the temporary space requirements explained in + <xref linkend="sql-repack-notes-on-resources"/>, + the <literal>CONCURRENTLY</literal> option can add to the usage of + temporary space a bit more. The reason is that other transactions can + perform DML operations which cannot be applied to the new file until + <command>REPACK</command> has copied all the tuples from the old + file. Thus the tuples inserted into the old file during the copying are + also stored separately in a temporary file, so they can eventually be + applied to the new file. + </para> + + <para> + Furthermore, the data changes performed during the copying are + extracted from <link linkend="wal">write-ahead log</link> (WAL), and + this extraction (decoding) only takes place when certain amount of WAL + has been written. Therefore, WAL removal can be delayed by this + threshold. Currently the threshold is equal to the value of + the <link linkend="guc-wal-segment-size"><varname>wal_segment_size</varname></link> + configuration parameter. + </para> + </note> + + <para> + The <literal>CONCURRENTLY</literal> option cannot be used in the + following cases: + + <itemizedlist> + <listitem> + <para> + The table is <literal>UNLOGGED</literal>. + </para> + </listitem> + + <listitem> + <para> + The table is partitioned. + </para> + </listitem> + + <listitem> + <para> + The table is a system catalog or a <acronym>TOAST</acronym> table. + </para> + </listitem> + + <listitem> + <para> + <command>REPACK</command> is executed inside a transaction block. + </para> + </listitem> + + <listitem> + <para> + The <link linkend="guc-wal-level"><varname>wal_level</varname></link> + configuration parameter is less than <literal>logical</literal>. + </para> + </listitem> + + <listitem> + <para> + The <link linkend="guc-max-replication-slots"><varname>max_replication_slots</varname></link> + configuration parameter does not allow for creation of an additional + replication slot. + </para> + </listitem> + </itemizedlist> + </para> + + <warning> + <para> + <command>REPACK</command> with the <literal>CONCURRENTLY</literal> + option is not MVCC-safe, see <xref linkend="mvcc-caveats"/> for + details. + </para> + </warning> + + </listitem> + </varlistentry> + <varlistentry> <term><literal>VERBOSE</literal></term> <listitem> diff --git a/src/Makefile b/src/Makefile index 2f31a2f20a7..b18c9a14ffa 100644 --- a/src/Makefile +++ b/src/Makefile @@ -23,6 +23,7 @@ SUBDIRS = \ interfaces \ backend/replication/libpqwalreceiver \ backend/replication/pgoutput \ + backend/replication/pgoutput_repack \ fe_utils \ bin \ pl \ diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index e3e7307ef5f..f9a4fe3faed 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -60,7 +60,8 @@ static HeapTuple heap_prepare_insert(Relation relation, HeapTuple tup, static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf, Buffer newbuf, HeapTuple oldtup, HeapTuple newtup, HeapTuple old_key_tuple, - bool all_visible_cleared, bool new_all_visible_cleared); + bool all_visible_cleared, bool new_all_visible_cleared, + bool wal_logical); #ifdef USE_ASSERT_CHECKING static void check_lock_if_inplace_updateable_rel(Relation relation, ItemPointer otid, @@ -2780,7 +2781,7 @@ xmax_infomask_changed(uint16 new_infomask, uint16 old_infomask) TM_Result heap_delete(Relation relation, ItemPointer tid, CommandId cid, Snapshot crosscheck, bool wait, - TM_FailureData *tmfd, bool changingPart) + TM_FailureData *tmfd, bool changingPart, bool wal_logical) { TM_Result result; TransactionId xid = GetCurrentTransactionId(); @@ -3027,7 +3028,8 @@ l1: * Compute replica identity tuple before entering the critical section so * we don't PANIC upon a memory allocation failure. */ - old_key_tuple = ExtractReplicaIdentity(relation, &tp, true, &old_key_copied); + old_key_tuple = wal_logical ? + ExtractReplicaIdentity(relation, &tp, true, &old_key_copied) : NULL; /* * If this is the first possibly-multixact-able operation in the current @@ -3117,6 +3119,15 @@ l1: xlrec.flags |= XLH_DELETE_CONTAINS_OLD_KEY; } + /* + * Unlike UPDATE, DELETE is decoded even if there is no old key, so it + * does not help to clear both XLH_DELETE_CONTAINS_OLD_TUPLE and + * XLH_DELETE_CONTAINS_OLD_KEY. Thus we need an extra flag. TODO + * Consider not decoding tuples w/o the old tuple/key instead. + */ + if (!wal_logical) + xlrec.flags |= XLH_DELETE_NO_LOGICAL; + XLogBeginInsert(); XLogRegisterData(&xlrec, SizeOfHeapDelete); @@ -3209,7 +3220,8 @@ simple_heap_delete(Relation relation, ItemPointer tid) result = heap_delete(relation, tid, GetCurrentCommandId(true), InvalidSnapshot, true /* wait for commit */ , - &tmfd, false /* changingPart */ ); + &tmfd, false, /* changingPart */ + true /* wal_logical */ ); switch (result) { case TM_SelfModified: @@ -3250,7 +3262,7 @@ TM_Result heap_update(Relation relation, ItemPointer otid, HeapTuple newtup, CommandId cid, Snapshot crosscheck, bool wait, TM_FailureData *tmfd, LockTupleMode *lockmode, - TU_UpdateIndexes *update_indexes) + TU_UpdateIndexes *update_indexes, bool wal_logical) { TM_Result result; TransactionId xid = GetCurrentTransactionId(); @@ -4143,7 +4155,8 @@ l2: newbuf, &oldtup, heaptup, old_key_tuple, all_visible_cleared, - all_visible_cleared_new); + all_visible_cleared_new, + wal_logical); if (newbuf != buffer) { PageSetLSN(BufferGetPage(newbuf), recptr); @@ -4501,7 +4514,8 @@ simple_heap_update(Relation relation, ItemPointer otid, HeapTuple tup, result = heap_update(relation, otid, tup, GetCurrentCommandId(true), InvalidSnapshot, true /* wait for commit */ , - &tmfd, &lockmode, update_indexes); + &tmfd, &lockmode, update_indexes, + true /* wal_logical */ ); switch (result) { case TM_SelfModified: @@ -8842,7 +8856,8 @@ static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf, Buffer newbuf, HeapTuple oldtup, HeapTuple newtup, HeapTuple old_key_tuple, - bool all_visible_cleared, bool new_all_visible_cleared) + bool all_visible_cleared, bool new_all_visible_cleared, + bool wal_logical) { xl_heap_update xlrec; xl_heap_header xlhdr; @@ -8853,7 +8868,8 @@ log_heap_update(Relation reln, Buffer oldbuf, suffixlen = 0; XLogRecPtr recptr; Page page = BufferGetPage(newbuf); - bool need_tuple_data = RelationIsLogicallyLogged(reln); + bool need_tuple_data = RelationIsLogicallyLogged(reln) && + wal_logical; bool init; int bufflags; diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c index 79f9de5d760..d03084768e0 100644 --- a/src/backend/access/heap/heapam_handler.c +++ b/src/backend/access/heap/heapam_handler.c @@ -33,6 +33,7 @@ #include "catalog/index.h" #include "catalog/storage.h" #include "catalog/storage_xlog.h" +#include "commands/cluster.h" #include "commands/progress.h" #include "executor/executor.h" #include "miscadmin.h" @@ -309,7 +310,8 @@ heapam_tuple_delete(Relation relation, ItemPointer tid, CommandId cid, * the storage itself is cleaning the dead tuples by itself, it is the * time to call the index tuple deletion also. */ - return heap_delete(relation, tid, cid, crosscheck, wait, tmfd, changingPart); + return heap_delete(relation, tid, cid, crosscheck, wait, tmfd, changingPart, + true); } @@ -328,7 +330,7 @@ heapam_tuple_update(Relation relation, ItemPointer otid, TupleTableSlot *slot, tuple->t_tableOid = slot->tts_tableOid; result = heap_update(relation, otid, tuple, cid, crosscheck, wait, - tmfd, lockmode, update_indexes); + tmfd, lockmode, update_indexes, true); ItemPointerCopy(&tuple->t_self, &slot->tts_tid); /* @@ -685,13 +687,15 @@ static void heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, Relation OldIndex, bool use_sort, TransactionId OldestXmin, + Snapshot snapshot, + LogicalDecodingContext *decoding_ctx, TransactionId *xid_cutoff, MultiXactId *multi_cutoff, double *num_tuples, double *tups_vacuumed, double *tups_recently_dead) { - RewriteState rwstate; + RewriteState rwstate = NULL; IndexScanDesc indexScan; TableScanDesc tableScan; HeapScanDesc heapScan; @@ -705,6 +709,8 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, bool *isnull; BufferHeapTupleTableSlot *hslot; BlockNumber prev_cblock = InvalidBlockNumber; + bool concurrent = snapshot != NULL; + XLogRecPtr end_of_wal_prev = GetFlushRecPtr(NULL); /* Remember if it's a system catalog */ is_system_catalog = IsSystemRelation(OldHeap); @@ -720,9 +726,12 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, values = (Datum *) palloc(natts * sizeof(Datum)); isnull = (bool *) palloc(natts * sizeof(bool)); - /* Initialize the rewrite operation */ - rwstate = begin_heap_rewrite(OldHeap, NewHeap, OldestXmin, *xid_cutoff, - *multi_cutoff); + /* + * Initialize the rewrite operation. + */ + if (!concurrent) + rwstate = begin_heap_rewrite(OldHeap, NewHeap, OldestXmin, + *xid_cutoff, *multi_cutoff); /* Set up sorting if wanted */ @@ -737,6 +746,9 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, * Prepare to scan the OldHeap. To ensure we see recently-dead tuples * that still need to be copied, we scan with SnapshotAny and use * HeapTupleSatisfiesVacuum for the visibility test. + * + * In the CONCURRENTLY case, we do regular MVCC visibility tests, using + * the snapshot passed by the caller. */ if (OldIndex != NULL && !use_sort) { @@ -753,7 +765,9 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, tableScan = NULL; heapScan = NULL; - indexScan = index_beginscan(OldHeap, OldIndex, SnapshotAny, NULL, 0, 0); + indexScan = index_beginscan(OldHeap, OldIndex, + snapshot ? snapshot : SnapshotAny, + NULL, 0, 0); index_rescan(indexScan, NULL, 0, NULL, 0); } else @@ -762,7 +776,9 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, pgstat_progress_update_param(PROGRESS_REPACK_PHASE, PROGRESS_REPACK_PHASE_SEQ_SCAN_HEAP); - tableScan = table_beginscan(OldHeap, SnapshotAny, 0, (ScanKey) NULL); + tableScan = table_beginscan(OldHeap, + snapshot ? snapshot : SnapshotAny, + 0, (ScanKey) NULL); heapScan = (HeapScanDesc) tableScan; indexScan = NULL; @@ -785,6 +801,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, HeapTuple tuple; Buffer buf; bool isdead; + HTSV_Result vis; CHECK_FOR_INTERRUPTS(); @@ -837,70 +854,84 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, tuple = ExecFetchSlotHeapTuple(slot, false, NULL); buf = hslot->buffer; - LockBuffer(buf, BUFFER_LOCK_SHARE); - - switch (HeapTupleSatisfiesVacuum(tuple, OldestXmin, buf)) + /* + * Regarding CONCURRENTLY, see the comments on MVCC snapshot above. + */ + if (!concurrent) { - case HEAPTUPLE_DEAD: - /* Definitely dead */ - isdead = true; - break; - case HEAPTUPLE_RECENTLY_DEAD: - *tups_recently_dead += 1; - /* fall through */ - case HEAPTUPLE_LIVE: - /* Live or recently dead, must copy it */ - isdead = false; - break; - case HEAPTUPLE_INSERT_IN_PROGRESS: + LockBuffer(buf, BUFFER_LOCK_SHARE); - /* - * Since we hold exclusive lock on the relation, normally the - * only way to see this is if it was inserted earlier in our - * own transaction. However, it can happen in system - * catalogs, since we tend to release write lock before commit - * there. Give a warning if neither case applies; but in any - * case we had better copy it. - */ - if (!is_system_catalog && - !TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple->t_data))) - elog(WARNING, "concurrent insert in progress within table \"%s\"", - RelationGetRelationName(OldHeap)); - /* treat as live */ - isdead = false; - break; - case HEAPTUPLE_DELETE_IN_PROGRESS: - - /* - * Similar situation to INSERT_IN_PROGRESS case. - */ - if (!is_system_catalog && - !TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetUpdateXid(tuple->t_data))) - elog(WARNING, "concurrent delete in progress within table \"%s\"", - RelationGetRelationName(OldHeap)); - /* treat as recently dead */ - *tups_recently_dead += 1; - isdead = false; - break; - default: - elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result"); - isdead = false; /* keep compiler quiet */ - break; - } - - LockBuffer(buf, BUFFER_LOCK_UNLOCK); - - if (isdead) - { - *tups_vacuumed += 1; - /* heap rewrite module still needs to see it... */ - if (rewrite_heap_dead_tuple(rwstate, tuple)) + switch ((vis = HeapTupleSatisfiesVacuum(tuple, OldestXmin, buf))) { - /* A previous recently-dead tuple is now known dead */ - *tups_vacuumed += 1; - *tups_recently_dead -= 1; + case HEAPTUPLE_DEAD: + /* Definitely dead */ + isdead = true; + break; + case HEAPTUPLE_RECENTLY_DEAD: + *tups_recently_dead += 1; + /* fall through */ + case HEAPTUPLE_LIVE: + /* Live or recently dead, must copy it */ + isdead = false; + break; + case HEAPTUPLE_INSERT_IN_PROGRESS: + + /* + * As long as we hold exclusive lock on the relation, + * normally the only way to see this is if it was inserted + * earlier in our own transaction. However, it can happen + * in system catalogs, since we tend to release write lock + * before commit there. Also, there's no exclusive lock + * during concurrent processing. Give a warning if neither + * case applies; but in any case we had better copy it. + */ + if (!is_system_catalog && !concurrent && + !TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmin(tuple->t_data))) + elog(WARNING, "concurrent insert in progress within table \"%s\"", + RelationGetRelationName(OldHeap)); + /* treat as live */ + isdead = false; + break; + case HEAPTUPLE_DELETE_IN_PROGRESS: + + /* + * Similar situation to INSERT_IN_PROGRESS case. + */ + if (!is_system_catalog && !concurrent && + !TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetUpdateXid(tuple->t_data))) + elog(WARNING, "concurrent delete in progress within table \"%s\"", + RelationGetRelationName(OldHeap)); + /* treat as recently dead */ + *tups_recently_dead += 1; + isdead = false; + break; + default: + elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result"); + isdead = false; /* keep compiler quiet */ + break; } - continue; + + if (isdead) + { + *tups_vacuumed += 1; + /* heap rewrite module still needs to see it... */ + if (rewrite_heap_dead_tuple(rwstate, tuple)) + { + /* A previous recently-dead tuple is now known dead */ + *tups_vacuumed += 1; + *tups_recently_dead -= 1; + } + + LockBuffer(buf, BUFFER_LOCK_UNLOCK); + continue; + } + + /* + * In the concurrent case, we have a copy of the tuple, so we + * don't worry whether the source tuple will be deleted / updated + * after we release the lock. + */ + LockBuffer(buf, BUFFER_LOCK_UNLOCK); } *num_tuples += 1; @@ -919,7 +950,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, { const int ct_index[] = { PROGRESS_REPACK_HEAP_TUPLES_SCANNED, - PROGRESS_REPACK_HEAP_TUPLES_WRITTEN + PROGRESS_REPACK_HEAP_TUPLES_INSERTED }; int64 ct_val[2]; @@ -934,6 +965,31 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, ct_val[1] = *num_tuples; pgstat_progress_update_multi_param(2, ct_index, ct_val); } + + /* + * Process the WAL produced by the load, as well as by other + * transactions, so that the replication slot can advance and WAL does + * not pile up. Use wal_segment_size as a threshold so that we do not + * introduce the decoding overhead too often. + * + * Of course, we must not apply the changes until the initial load has + * completed. + * + * Note that our insertions into the new table should not be decoded + * as we (intentionally) do not write the logical decoding specific + * information to WAL. + */ + if (concurrent) + { + XLogRecPtr end_of_wal; + + end_of_wal = GetFlushRecPtr(NULL); + if ((end_of_wal - end_of_wal_prev) > wal_segment_size) + { + repack_decode_concurrent_changes(decoding_ctx, end_of_wal); + end_of_wal_prev = end_of_wal; + } + } } if (indexScan != NULL) @@ -977,7 +1033,7 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, values, isnull, rwstate); /* Report n_tuples */ - pgstat_progress_update_param(PROGRESS_REPACK_HEAP_TUPLES_WRITTEN, + pgstat_progress_update_param(PROGRESS_REPACK_HEAP_TUPLES_INSERTED, n_tuples); } @@ -985,7 +1041,8 @@ heapam_relation_copy_for_cluster(Relation OldHeap, Relation NewHeap, } /* Write out any remaining tuples, and fsync if needed */ - end_heap_rewrite(rwstate); + if (rwstate) + end_heap_rewrite(rwstate); /* Clean up */ pfree(values); @@ -2376,6 +2433,10 @@ heapam_scan_sample_next_tuple(TableScanDesc scan, SampleScanState *scanstate, * SET WITHOUT OIDS. * * So, we must reconstruct the tuple from component Datums. + * + * If rwstate=NULL, use simple_heap_insert() instead of rewriting - in that + * case we still need to deform/form the tuple. TODO Shouldn't we rename the + * function, as might not do any rewrite? */ static void reform_and_rewrite_tuple(HeapTuple tuple, @@ -2398,8 +2459,28 @@ reform_and_rewrite_tuple(HeapTuple tuple, copiedTuple = heap_form_tuple(newTupDesc, values, isnull); - /* The heap rewrite module does the rest */ - rewrite_heap_tuple(rwstate, tuple, copiedTuple); + if (rwstate) + /* The heap rewrite module does the rest */ + rewrite_heap_tuple(rwstate, tuple, copiedTuple); + else + { + /* + * Insert tuple when processing REPACK CONCURRENTLY. + * + * rewriteheap.c is not used in the CONCURRENTLY case because it'd be + * difficult to do the same in the catch-up phase (as the logical + * decoding does not provide us with sufficient visibility + * information). Thus we must use heap_insert() both during the + * catch-up and here. + * + * The following is like simple_heap_insert() except that we pass the + * flag to skip logical decoding: as soon as REPACK CONCURRENTLY swaps + * the relation files, it drops this relation, so no logical + * replication subscription should need the data. + */ + heap_insert(NewHeap, copiedTuple, GetCurrentCommandId(true), + HEAP_INSERT_NO_LOGICAL, NULL); + } heap_freetuple(copiedTuple); } diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c index e6d2b5fced1..6aa2ed214f2 100644 --- a/src/backend/access/heap/rewriteheap.c +++ b/src/backend/access/heap/rewriteheap.c @@ -617,9 +617,9 @@ raw_heap_insert(RewriteState state, HeapTuple tup) int options = HEAP_INSERT_SKIP_FSM; /* - * While rewriting the heap for VACUUM FULL / CLUSTER, make sure data - * for the TOAST table are not logically decoded. The main heap is - * WAL-logged as XLOG FPI records, which are not logically decoded. + * While rewriting the heap for REPACK, make sure data for the TOAST + * table are not logically decoded. The main heap is WAL-logged as + * XLOG FPI records, which are not logically decoded. */ options |= HEAP_INSERT_NO_LOGICAL; diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index b46e7e9c2a6..5670f2bfbde 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -215,6 +215,7 @@ typedef struct TransactionStateData bool parallelChildXact; /* is any parent transaction parallel? */ bool chain; /* start a new block after this one */ bool topXidLogged; /* for a subxact: is top-level XID logged? */ + bool internal; /* for a subxact: launched internally? */ struct TransactionStateData *parent; /* back link to parent */ } TransactionStateData; @@ -4735,6 +4736,7 @@ BeginInternalSubTransaction(const char *name) /* Normal subtransaction start */ PushTransaction(); s = CurrentTransactionState; /* changed by push */ + s->internal = true; /* * Savepoint names, like the TransactionState block itself, live @@ -5251,7 +5253,13 @@ AbortSubTransaction(void) LWLockReleaseAll(); pgstat_report_wait_end(); - pgstat_progress_end_command(); + + /* + * Internal subtransacion might be used by an user command, in which case + * the command outlives the subtransaction. + */ + if (!s->internal) + pgstat_progress_end_command(); pgaio_error_cleanup(); @@ -5468,6 +5476,7 @@ PushTransaction(void) s->parallelModeLevel = 0; s->parallelChildXact = (p->parallelModeLevel != 0 || p->parallelChildXact); s->topXidLogged = false; + s->internal = false; CurrentTransactionState = s; diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index b2b7b10c2be..a92ac78ad9e 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -1266,16 +1266,17 @@ CREATE VIEW pg_stat_progress_cluster AS WHEN 2 THEN 'index scanning heap' WHEN 3 THEN 'sorting tuples' WHEN 4 THEN 'writing new heap' - WHEN 5 THEN 'swapping relation files' - WHEN 6 THEN 'rebuilding index' - WHEN 7 THEN 'performing final cleanup' + -- 5 is 'catch-up', but that should not appear here. + WHEN 6 THEN 'swapping relation files' + WHEN 7 THEN 'rebuilding index' + WHEN 8 THEN 'performing final cleanup' END AS phase, CAST(S.param3 AS oid) AS cluster_index_relid, S.param4 AS heap_tuples_scanned, S.param5 AS heap_tuples_written, - S.param6 AS heap_blks_total, - S.param7 AS heap_blks_scanned, - S.param8 AS index_rebuild_count + S.param8 AS heap_blks_total, + S.param9 AS heap_blks_scanned, + S.param10 AS index_rebuild_count FROM pg_stat_get_progress_info('CLUSTER') AS S LEFT JOIN pg_database D ON S.datid = D.oid; @@ -1291,16 +1292,19 @@ CREATE VIEW pg_stat_progress_repack AS WHEN 2 THEN 'index scanning heap' WHEN 3 THEN 'sorting tuples' WHEN 4 THEN 'writing new heap' - WHEN 5 THEN 'swapping relation files' - WHEN 6 THEN 'rebuilding index' - WHEN 7 THEN 'performing final cleanup' + WHEN 5 THEN 'catch-up' + WHEN 6 THEN 'swapping relation files' + WHEN 7 THEN 'rebuilding index' + WHEN 8 THEN 'performing final cleanup' END AS phase, CAST(S.param3 AS oid) AS repack_index_relid, S.param4 AS heap_tuples_scanned, - S.param5 AS heap_tuples_written, - S.param6 AS heap_blks_total, - S.param7 AS heap_blks_scanned, - S.param8 AS index_rebuild_count + S.param5 AS heap_tuples_inserted, + S.param6 AS heap_tuples_updated, + S.param7 AS heap_tuples_deleted, + S.param8 AS heap_blks_total, + S.param9 AS heap_blks_scanned, + S.param10 AS index_rebuild_count FROM pg_stat_get_progress_info('REPACK') AS S LEFT JOIN pg_database D ON S.datid = D.oid; diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index 8b64f9e6795..511b2bb6c43 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -25,6 +25,10 @@ #include "access/toast_internals.h" #include "access/transam.h" #include "access/xact.h" +#include "access/xlog.h" +#include "access/xlog_internal.h" +#include "access/xloginsert.h" +#include "access/xlogutils.h" #include "catalog/catalog.h" #include "catalog/dependency.h" #include "catalog/heap.h" @@ -32,6 +36,7 @@ #include "catalog/namespace.h" #include "catalog/objectaccess.h" #include "catalog/pg_am.h" +#include "catalog/pg_control.h" #include "catalog/pg_inherits.h" #include "catalog/toasting.h" #include "commands/cluster.h" @@ -39,15 +44,21 @@ #include "commands/progress.h" #include "commands/tablecmds.h" #include "commands/vacuum.h" +#include "executor/executor.h" #include "miscadmin.h" #include "optimizer/optimizer.h" #include "pgstat.h" +#include "replication/decode.h" +#include "replication/logical.h" +#include "replication/snapbuild.h" #include "storage/bufmgr.h" +#include "storage/ipc.h" #include "storage/lmgr.h" #include "storage/predicate.h" #include "utils/acl.h" #include "utils/fmgroids.h" #include "utils/guc.h" +#include "utils/injection_point.h" #include "utils/inval.h" #include "utils/lsyscache.h" #include "utils/memutils.h" @@ -67,13 +78,45 @@ typedef struct Oid indexOid; } RelToCluster; +/* + * The following definitions are used for concurrent processing. + */ + +/* + * The locators are used to avoid logical decoding of data that we do not need + * for our table. + */ +RelFileLocator repacked_rel_locator = {.relNumber = InvalidOid}; +RelFileLocator repacked_rel_toast_locator = {.relNumber = InvalidOid}; + +/* + * Everything we need to call ExecInsertIndexTuples(). + */ +typedef struct IndexInsertState +{ + ResultRelInfo *rri; + EState *estate; + + Relation ident_index; +} IndexInsertState; + +/* The WAL segment being decoded. */ +static XLogSegNo repack_current_segment = 0; + + static bool cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, - Oid indexOid, Oid userid, int options); + Oid indexOid, Oid userid, LOCKMODE lmode, + int options); +static void check_repack_concurrently_requirements(Relation rel); static void rebuild_relation(RepackCommand cmd, bool usingindex, - Relation OldHeap, Relation index, bool verbose); + Relation OldHeap, Relation index, Oid userid, + bool verbose, bool concurrent); static void copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, - bool verbose, bool *pSwapToastByContent, - TransactionId *pFreezeXid, MultiXactId *pCutoffMulti); + Snapshot snapshot, LogicalDecodingContext *decoding_ctx, + bool verbose, + bool *pSwapToastByContent, + TransactionId *pFreezeXid, + MultiXactId *pCutoffMulti); static List *get_tables_to_repack(RepackCommand cmd, bool usingindex, MemoryContext permcxt); static List *get_tables_to_repack_partitioned(RepackCommand cmd, @@ -81,12 +124,61 @@ static List *get_tables_to_repack_partitioned(RepackCommand cmd, Oid relid, bool rel_is_index); static bool cluster_is_permitted_for_relation(RepackCommand cmd, Oid relid, Oid userid); + +static void begin_concurrent_repack(Relation rel); +static void end_concurrent_repack(void); +static LogicalDecodingContext *setup_logical_decoding(Oid relid, + const char *slotname, + TupleDesc tupdesc); +static HeapTuple get_changed_tuple(char *change); +static void apply_concurrent_changes(RepackDecodingState *dstate, + Relation rel, ScanKey key, int nkeys, + IndexInsertState *iistate); +static void apply_concurrent_insert(Relation rel, ConcurrentChange *change, + HeapTuple tup, IndexInsertState *iistate, + TupleTableSlot *index_slot); +static void apply_concurrent_update(Relation rel, HeapTuple tup, + HeapTuple tup_target, + ConcurrentChange *change, + IndexInsertState *iistate, + TupleTableSlot *index_slot); +static void apply_concurrent_delete(Relation rel, HeapTuple tup_target, + ConcurrentChange *change); +static HeapTuple find_target_tuple(Relation rel, ScanKey key, int nkeys, + HeapTuple tup_key, + IndexInsertState *iistate, + TupleTableSlot *ident_slot, + IndexScanDesc *scan_p); +static void process_concurrent_changes(LogicalDecodingContext *ctx, + XLogRecPtr end_of_wal, + Relation rel_dst, + Relation rel_src, + ScanKey ident_key, + int ident_key_nentries, + IndexInsertState *iistate); +static IndexInsertState *get_index_insert_state(Relation relation, + Oid ident_index_id); +static ScanKey build_identity_key(Oid ident_idx_oid, Relation rel_src, + int *nentries); +static void free_index_insert_state(IndexInsertState *iistate); +static void cleanup_logical_decoding(LogicalDecodingContext *ctx); +static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, + Relation cl_index, + LogicalDecodingContext *ctx, + bool swap_toast_by_content, + TransactionId frozenXid, + MultiXactId cutoffMulti); +static List *build_new_indexes(Relation NewHeap, Relation OldHeap, List *OldIndexes); static Relation process_single_relation(RepackStmt *stmt, + LOCKMODE lockmode, + bool isTopLevel, ClusterParams *params); static Oid determine_clustered_index(Relation rel, bool usingindex, const char *indexname); +#define REPL_PLUGIN_NAME "pgoutput_repack" + static const char * RepackCommandAsString(RepackCommand cmd) { @@ -95,7 +187,7 @@ RepackCommandAsString(RepackCommand cmd) case REPACK_COMMAND_REPACK: return "REPACK"; case REPACK_COMMAND_VACUUMFULL: - return "VACUUM"; + return "VACUUM (FULL)"; case REPACK_COMMAND_CLUSTER: return "CLUSTER"; } @@ -132,6 +224,7 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) ClusterParams params = {0}; Relation rel = NULL; MemoryContext repack_context; + LOCKMODE lockmode; List *rtcs; /* Parse option list */ @@ -142,6 +235,16 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) else if (strcmp(opt->defname, "analyze") == 0 || strcmp(opt->defname, "analyse") == 0) params.options |= defGetBoolean(opt) ? CLUOPT_ANALYZE : 0; + else if (strcmp(opt->defname, "concurrently") == 0 && + defGetBoolean(opt)) + { + if (stmt->command != REPACK_COMMAND_REPACK) + ereport(ERROR, + errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("CONCURRENTLY option not supported for %s", + RepackCommandAsString(stmt->command))); + params.options |= CLUOPT_CONCURRENT; + } else ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), @@ -151,13 +254,25 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) parser_errposition(pstate, opt->location))); } + /* + * Determine the lock mode expected by cluster_rel(). + * + * In the exclusive case, we obtain AccessExclusiveLock right away to + * avoid lock-upgrade hazard in the single-transaction case. In the + * CONCURRENTLY case, the AccessExclusiveLock will only be used at the end + * of processing, supposedly for very short time. Until then, we'll have + * to unlock the relation temporarily, so there's no lock-upgrade hazard. + */ + lockmode = (params.options & CLUOPT_CONCURRENT) == 0 ? + AccessExclusiveLock : ShareUpdateExclusiveLock; + /* * If a single relation is specified, process it and we're done ... unless * the relation is a partitioned table, in which case we fall through. */ if (stmt->relation != NULL) { - rel = process_single_relation(stmt, ¶ms); + rel = process_single_relation(stmt, lockmode, isTopLevel, ¶ms); if (rel == NULL) return; } @@ -169,10 +284,29 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) errmsg("cannot ANALYZE multiple tables")); /* - * By here, we know we are in a multi-table situation. In order to avoid - * holding locks for too long, we want to process each table in its own - * transaction. This forces us to disallow running inside a user - * transaction block. + * By here, we know we are in a multi-table situation. + * + * Concurrent processing is currently considered rather special (e.g. in + * terms of resources consumed) so it is not performed in bulk. + */ + if (params.options & CLUOPT_CONCURRENT) + { + if (rel != NULL) + { + Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE); + ereport(ERROR, + errmsg("REPACK CONCURRENTLY not supported for partitioned tables"), + errhint("Consider running the command for individual partitions.")); + } + else + ereport(ERROR, + errmsg("REPACK CONCURRENTLY requires explicit table name")); + } + + /* + * In order to avoid holding locks for too long, we want to process each + * table in its own transaction. This forces us to disallow running + * inside a user transaction block. */ PreventInTransactionBlock(isTopLevel, RepackCommandAsString(stmt->command)); @@ -252,7 +386,7 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) * Open the target table, coping with the case where it has been * dropped. */ - rel = try_table_open(rtc->tableOid, AccessExclusiveLock); + rel = try_table_open(rtc->tableOid, lockmode); if (rel == NULL) { CommitTransactionCommand(); @@ -264,7 +398,7 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) /* Process this table */ cluster_rel(stmt->command, stmt->usingindex, - rel, rtc->indexOid, ¶ms); + rel, rtc->indexOid, ¶ms, isTopLevel); /* cluster_rel closes the relation, but keeps lock */ PopActiveSnapshot(); @@ -293,22 +427,55 @@ ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel) * If indexOid is InvalidOid, the table will be rewritten in physical order * instead of index order. * + * Note that, in the concurrent case, the function releases the lock at some + * point, in order to get AccessExclusiveLock for the final steps (i.e. to + * swap the relation files). To make things simpler, the caller should expect + * OldHeap to be closed on return, regardless CLUOPT_CONCURRENT. (The + * AccessExclusiveLock is kept till the end of the transaction.) + * * 'cmd' indicates which command is being executed, to be used for error * messages. */ void cluster_rel(RepackCommand cmd, bool usingindex, - Relation OldHeap, Oid indexOid, ClusterParams *params) + Relation OldHeap, Oid indexOid, ClusterParams *params, + bool isTopLevel) { Oid tableOid = RelationGetRelid(OldHeap); + Relation index; + LOCKMODE lmode; Oid save_userid; int save_sec_context; int save_nestlevel; bool verbose = ((params->options & CLUOPT_VERBOSE) != 0); bool recheck = ((params->options & CLUOPT_RECHECK) != 0); - Relation index; + bool concurrent = ((params->options & CLUOPT_CONCURRENT) != 0); - Assert(CheckRelationLockedByMe(OldHeap, AccessExclusiveLock, false)); + /* + * Check that the correct lock is held. The lock mode is + * AccessExclusiveLock for normal processing and ShareUpdateExclusiveLock + * for concurrent processing (so that SELECT, INSERT, UPDATE and DELETE + * commands work, but cluster_rel() cannot be called concurrently for the + * same relation). + */ + lmode = !concurrent ? AccessExclusiveLock : ShareUpdateExclusiveLock; + + /* There are specific requirements on concurrent processing. */ + if (concurrent) + { + /* + * Make sure we have no XID assigned, otherwise call of + * setup_logical_decoding() can cause a deadlock. + * + * The existence of transaction block actually does not imply that XID + * was already assigned, but it very likely is. We might want to check + * the result of GetCurrentTransactionIdIfAny() instead, but that + * would be less clear from user's perspective. + */ + PreventInTransactionBlock(isTopLevel, "REPACK (CONCURRENTLY)"); + + check_repack_concurrently_requirements(OldHeap); + } /* Check for user-requested abort. */ CHECK_FOR_INTERRUPTS(); @@ -351,11 +518,13 @@ cluster_rel(RepackCommand cmd, bool usingindex, * If this is a single-transaction CLUSTER, we can skip these tests. We * *must* skip the one on indisclustered since it would reject an attempt * to cluster a not-previously-clustered index. + * + * XXX move [some of] these comments to where the RECHECK flag is + * determined? */ - if (recheck) - if (!cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid, - params->options)) - goto out; + if (recheck && !cluster_rel_recheck(cmd, OldHeap, indexOid, save_userid, + lmode, params->options)) + goto out; /* * We allow repacking shared catalogs only when not using an index. It @@ -369,6 +538,12 @@ cluster_rel(RepackCommand cmd, bool usingindex, errmsg("cannot run \"%s\" on a shared catalog", RepackCommandAsString(cmd)))); + /* + * The CONCURRENTLY case should have been rejected earlier because it does + * not support system catalogs. + */ + Assert(!(OldHeap->rd_rel->relisshared && concurrent)); + /* * Don't process temp tables of other backends ... their local buffer * manager is not going to cope. @@ -404,7 +579,7 @@ cluster_rel(RepackCommand cmd, bool usingindex, if (OidIsValid(indexOid)) { /* verify the index is good and lock it */ - check_index_is_clusterable(OldHeap, indexOid, AccessExclusiveLock); + check_index_is_clusterable(OldHeap, indexOid, lmode); /* also open it */ index = index_open(indexOid, NoLock); } @@ -421,7 +596,9 @@ cluster_rel(RepackCommand cmd, bool usingindex, if (OldHeap->rd_rel->relkind == RELKIND_MATVIEW && !RelationIsPopulated(OldHeap)) { - relation_close(OldHeap, AccessExclusiveLock); + if (index) + index_close(index, lmode); + relation_close(OldHeap, lmode); goto out; } @@ -434,11 +611,35 @@ cluster_rel(RepackCommand cmd, bool usingindex, * invalid, because we move tuples around. Promote them to relation * locks. Predicate locks on indexes will be promoted when they are * reindexed. + * + * During concurrent processing, the heap as well as its indexes stay in + * operation, so we postpone this step until they are locked using + * AccessExclusiveLock near the end of the processing. */ - TransferPredicateLocksToHeapRelation(OldHeap); + if (!concurrent) + TransferPredicateLocksToHeapRelation(OldHeap); /* rebuild_relation does all the dirty work */ - rebuild_relation(cmd, usingindex, OldHeap, index, verbose); + PG_TRY(); + { + /* + * For concurrent processing, make sure that our logical decoding + * ignores data changes of other tables than the one we are + * processing. + */ + if (concurrent) + begin_concurrent_repack(OldHeap); + + rebuild_relation(cmd, usingindex, OldHeap, index, save_userid, + verbose, concurrent); + } + PG_FINALLY(); + { + if (concurrent) + end_concurrent_repack(); + } + PG_END_TRY(); + /* rebuild_relation closes OldHeap, and index if valid */ out: @@ -457,14 +658,14 @@ out: */ static bool cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, Oid indexOid, - Oid userid, int options) + Oid userid, LOCKMODE lmode, int options) { Oid tableOid = RelationGetRelid(OldHeap); /* Check that the user still has privileges for the relation */ if (!cluster_is_permitted_for_relation(cmd, tableOid, userid)) { - relation_close(OldHeap, AccessExclusiveLock); + relation_close(OldHeap, lmode); return false; } @@ -478,7 +679,7 @@ cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, Oid indexOid, */ if (RELATION_IS_OTHER_TEMP(OldHeap)) { - relation_close(OldHeap, AccessExclusiveLock); + relation_close(OldHeap, lmode); return false; } @@ -489,7 +690,7 @@ cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, Oid indexOid, */ if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid))) { - relation_close(OldHeap, AccessExclusiveLock); + relation_close(OldHeap, lmode); return false; } @@ -500,7 +701,7 @@ cluster_rel_recheck(RepackCommand cmd, Relation OldHeap, Oid indexOid, if ((options & CLUOPT_RECHECK_ISCLUSTERED) != 0 && !get_index_isclustered(indexOid)) { - relation_close(OldHeap, AccessExclusiveLock); + relation_close(OldHeap, lmode); return false; } } @@ -641,19 +842,89 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal) table_close(pg_index, RowExclusiveLock); } +/* + * Check if the CONCURRENTLY option is legal for the relation. + */ +static void +check_repack_concurrently_requirements(Relation rel) +{ + char relpersistence, + replident; + Oid ident_idx; + + /* Data changes in system relations are not logically decoded. */ + if (IsCatalogRelation(rel)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot repack relation \"%s\"", + RelationGetRelationName(rel)), + errhint("REPACK CONCURRENTLY is not supported for catalog relations."))); + + /* + * reorderbuffer.c does not seem to handle processing of TOAST relation + * alone. + */ + if (IsToastRelation(rel)) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot repack relation \"%s\"", + RelationGetRelationName(rel)), + errhint("REPACK CONCURRENTLY is not supported for TOAST relations, unless the main relation is repacked too."))); + + relpersistence = rel->rd_rel->relpersistence; + if (relpersistence != RELPERSISTENCE_PERMANENT) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot repack relation \"%s\"", + RelationGetRelationName(rel)), + errhint("REPACK CONCURRENTLY is only allowed for permanent relations."))); + + /* With NOTHING, WAL does not contain the old tuple. */ + replident = rel->rd_rel->relreplident; + if (replident == REPLICA_IDENTITY_NOTHING) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot repack relation \"%s\"", + RelationGetRelationName(rel)), + errhint("Relation \"%s\" has insufficient replication identity.", + RelationGetRelationName(rel)))); + + /* + * Identity index is not set if the replica identity is FULL, but PK might + * exist in such a case. + */ + ident_idx = RelationGetReplicaIndex(rel); + if (!OidIsValid(ident_idx) && OidIsValid(rel->rd_pkindex)) + ident_idx = rel->rd_pkindex; + if (!OidIsValid(ident_idx)) + ereport(ERROR, + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot process relation \"%s\"", + RelationGetRelationName(rel)), + (errhint("Relation \"%s\" has no identity index.", + RelationGetRelationName(rel))))); +} + + /* * rebuild_relation: rebuild an existing relation in index or physical order * - * OldHeap: table to rebuild. + * OldHeap: table to rebuild. See cluster_rel() for comments on the required + * lock strength. + * * index: index to cluster by, or NULL to rewrite in physical order. * - * On entry, heap and index (if one is given) must be open, and - * AccessExclusiveLock held on them. - * On exit, they are closed, but locks on them are not released. + * On entry, heap and index (if one is given) must be open, and the + * appropriate lock held on them -- AccessExclusiveLock for exclusive + * processing and ShareUpdateExclusiveLock for concurrent processing. + * + * On exit, they are closed, but still locked with AccessExclusiveLock. (The + * function handles the lock upgrade if 'concurrent' is true.) */ static void rebuild_relation(RepackCommand cmd, bool usingindex, - Relation OldHeap, Relation index, bool verbose) + Relation OldHeap, Relation index, Oid userid, + bool verbose, bool concurrent) { Oid tableOid = RelationGetRelid(OldHeap); Oid accessMethod = OldHeap->rd_rel->relam; @@ -661,13 +932,55 @@ rebuild_relation(RepackCommand cmd, bool usingindex, Oid OIDNewHeap; Relation NewHeap; char relpersistence; - bool is_system_catalog; bool swap_toast_by_content; TransactionId frozenXid; MultiXactId cutoffMulti; + NameData slotname; + LogicalDecodingContext *ctx = NULL; + Snapshot snapshot = NULL; +#if USE_ASSERT_CHECKING + LOCKMODE lmode; - Assert(CheckRelationLockedByMe(OldHeap, AccessExclusiveLock, false) && - (index == NULL || CheckRelationLockedByMe(index, AccessExclusiveLock, false))); + lmode = concurrent ? ShareUpdateExclusiveLock : AccessExclusiveLock; + + Assert(CheckRelationLockedByMe(OldHeap, lmode, false)); + Assert(!usingindex || CheckRelationLockedByMe(index, lmode, false)); +#endif + + if (concurrent) + { + TupleDesc tupdesc; + + /* + * REPACK CONCURRENTLY is not allowed in a transaction block, so this + * should never fire. + */ + Assert(GetTopTransactionIdIfAny() == InvalidTransactionId); + + /* + * A single backend should not execute multiple REPACK commands at a + * time, so use PID to make the slot unique. + */ + snprintf(NameStr(slotname), NAMEDATALEN, "repack_%d", MyProcPid); + + tupdesc = CreateTupleDescCopy(RelationGetDescr(OldHeap)); + + /* + * Prepare to capture the concurrent data changes. + * + * Note that this call waits for all transactions with XID already + * assigned to finish. If some of those transactions is waiting for a + * lock conflicting with ShareUpdateExclusiveLock on our table (e.g. + * it runs CREATE INDEX), we can end up in a deadlock. Not sure this + * risk is worth unlocking/locking the table (and its clustering + * index) and checking again if its still eligible for REPACK + * CONCURRENTLY. + */ + ctx = setup_logical_decoding(tableOid, NameStr(slotname), tupdesc); + + snapshot = SnapBuildInitialSnapshotForRepack(ctx->snapshot_builder); + PushActiveSnapshot(snapshot); + } /* for CLUSTER or REPACK USING INDEX, mark the index as the one to use */ if (usingindex) @@ -675,7 +988,6 @@ rebuild_relation(RepackCommand cmd, bool usingindex, /* Remember info about rel before closing OldHeap */ relpersistence = OldHeap->rd_rel->relpersistence; - is_system_catalog = IsSystemRelation(OldHeap); /* * Create the transient table that will receive the re-ordered data. @@ -691,30 +1003,67 @@ rebuild_relation(RepackCommand cmd, bool usingindex, NewHeap = table_open(OIDNewHeap, NoLock); /* Copy the heap data into the new table in the desired order */ - copy_table_data(NewHeap, OldHeap, index, verbose, + copy_table_data(NewHeap, OldHeap, index, snapshot, ctx, verbose, &swap_toast_by_content, &frozenXid, &cutoffMulti); + /* The historic snapshot won't be needed anymore. */ + if (snapshot) + PopActiveSnapshot(); - /* Close relcache entries, but keep lock until transaction commit */ - table_close(OldHeap, NoLock); - if (index) - index_close(index, NoLock); + if (concurrent) + { + /* + * Push a snapshot that we will use to find old versions of rows when + * processing concurrent UPDATE and DELETE commands. (That snapshot + * should also be used by index expressions.) + */ + PushActiveSnapshot(GetTransactionSnapshot()); - /* - * Close the new relation so it can be dropped as soon as the storage is - * swapped. The relation is not visible to others, so no need to unlock it - * explicitly. - */ - table_close(NewHeap, NoLock); + /* + * Make sure we can find the tuples just inserted when applying DML + * commands on top of those. + */ + CommandCounterIncrement(); + UpdateActiveSnapshotCommandId(); - /* - * Swap the physical files of the target and transient tables, then - * rebuild the target's indexes and throw away the transient table. - */ - finish_heap_swap(tableOid, OIDNewHeap, is_system_catalog, - swap_toast_by_content, false, true, - frozenXid, cutoffMulti, - relpersistence); + rebuild_relation_finish_concurrent(NewHeap, OldHeap, index, + ctx, swap_toast_by_content, + frozenXid, cutoffMulti); + PopActiveSnapshot(); + + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_FINAL_CLEANUP); + + /* Done with decoding. */ + cleanup_logical_decoding(ctx); + ReplicationSlotRelease(); + ReplicationSlotDrop(NameStr(slotname), false); + } + else + { + bool is_system_catalog = IsSystemRelation(OldHeap); + + /* Close relcache entries, but keep lock until transaction commit */ + table_close(OldHeap, NoLock); + if (index) + index_close(index, NoLock); + + /* + * Close the new relation so it can be dropped as soon as the storage + * is swapped. The relation is not visible to others, so no need to + * unlock it explicitly. + */ + table_close(NewHeap, NoLock); + + /* + * Swap the physical files of the target and transient tables, then + * rebuild the target's indexes and throw away the transient table. + */ + finish_heap_swap(tableOid, OIDNewHeap, is_system_catalog, + swap_toast_by_content, false, true, true, + frozenXid, cutoffMulti, + relpersistence); + } } @@ -849,15 +1198,19 @@ make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, Oid NewAccessMethod, /* * Do the physical copying of table data. * + * 'snapshot' and 'decoding_ctx': see table_relation_copy_for_cluster(). Pass + * iff concurrent processing is required. + * * There are three output parameters: * *pSwapToastByContent is set true if toast tables must be swapped by content. * *pFreezeXid receives the TransactionId used as freeze cutoff point. * *pCutoffMulti receives the MultiXactId used as a cutoff point. */ static void -copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, bool verbose, - bool *pSwapToastByContent, TransactionId *pFreezeXid, - MultiXactId *pCutoffMulti) +copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, + Snapshot snapshot, LogicalDecodingContext *decoding_ctx, + bool verbose, bool *pSwapToastByContent, + TransactionId *pFreezeXid, MultiXactId *pCutoffMulti) { Relation relRelation; HeapTuple reltup; @@ -875,6 +1228,8 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, bool verb PGRUsage ru0; char *nspname; + bool concurrent = snapshot != NULL; + pg_rusage_init(&ru0); /* Store a copy of the namespace name for logging purposes */ @@ -977,8 +1332,48 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, bool verb * provided, else plain seqscan. */ if (OldIndex != NULL && OldIndex->rd_rel->relam == BTREE_AM_OID) + { + ResourceOwner oldowner = NULL; + ResourceOwner resowner = NULL; + + /* + * In the CONCURRENT case, use a dedicated resource owner so we don't + * leave any additional locks behind us that we cannot release easily. + */ + if (concurrent) + { + Assert(CheckRelationLockedByMe(OldHeap, ShareUpdateExclusiveLock, + false)); + Assert(CheckRelationLockedByMe(OldIndex, ShareUpdateExclusiveLock, + false)); + + resowner = ResourceOwnerCreate(CurrentResourceOwner, + "plan_cluster_use_sort"); + oldowner = CurrentResourceOwner; + CurrentResourceOwner = resowner; + } + use_sort = plan_cluster_use_sort(RelationGetRelid(OldHeap), RelationGetRelid(OldIndex)); + + if (concurrent) + { + CurrentResourceOwner = oldowner; + + /* + * We are primarily concerned about locks, but if the planner + * happened to allocate any other resources, we should release + * them too because we're going to delete the whole resowner. + */ + ResourceOwnerRelease(resowner, RESOURCE_RELEASE_BEFORE_LOCKS, + false, false); + ResourceOwnerRelease(resowner, RESOURCE_RELEASE_LOCKS, + false, false); + ResourceOwnerRelease(resowner, RESOURCE_RELEASE_AFTER_LOCKS, + false, false); + ResourceOwnerDelete(resowner); + } + } else use_sort = false; @@ -1007,7 +1402,9 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, bool verb * values (e.g. because the AM doesn't use freezing). */ table_relation_copy_for_cluster(OldHeap, NewHeap, OldIndex, use_sort, - cutoffs.OldestXmin, &cutoffs.FreezeLimit, + cutoffs.OldestXmin, snapshot, + decoding_ctx, + &cutoffs.FreezeLimit, &cutoffs.MultiXactCutoff, &num_tuples, &tups_vacuumed, &tups_recently_dead); @@ -1016,7 +1413,11 @@ copy_table_data(Relation NewHeap, Relation OldHeap, Relation OldIndex, bool verb *pFreezeXid = cutoffs.FreezeLimit; *pCutoffMulti = cutoffs.MultiXactCutoff; - /* Reset rd_toastoid just to be tidy --- it shouldn't be looked at again */ + /* + * Reset rd_toastoid just to be tidy --- it shouldn't be looked at again. + * In the CONCURRENTLY case, we need to set it again before applying the + * concurrent changes. + */ NewHeap->rd_toastoid = InvalidOid; num_pages = RelationGetNumberOfBlocks(NewHeap); @@ -1474,14 +1875,13 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, bool swap_toast_by_content, bool check_constraints, bool is_internal, + bool reindex, TransactionId frozenXid, MultiXactId cutoffMulti, char newrelpersistence) { ObjectAddress object; Oid mapped_tables[4]; - int reindex_flags; - ReindexParams reindex_params = {0}; int i; /* Report that we are now swapping relation files */ @@ -1507,39 +1907,47 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, if (is_system_catalog) CacheInvalidateCatalog(OIDOldHeap); - /* - * Rebuild each index on the relation (but not the toast table, which is - * all-new at this point). It is important to do this before the DROP - * step because if we are processing a system catalog that will be used - * during DROP, we want to have its indexes available. There is no - * advantage to the other order anyway because this is all transactional, - * so no chance to reclaim disk space before commit. We do not need a - * final CommandCounterIncrement() because reindex_relation does it. - * - * Note: because index_build is called via reindex_relation, it will never - * set indcheckxmin true for the indexes. This is OK even though in some - * sense we are building new indexes rather than rebuilding existing ones, - * because the new heap won't contain any HOT chains at all, let alone - * broken ones, so it can't be necessary to set indcheckxmin. - */ - reindex_flags = REINDEX_REL_SUPPRESS_INDEX_USE; - if (check_constraints) - reindex_flags |= REINDEX_REL_CHECK_CONSTRAINTS; + if (reindex) + { + int reindex_flags; + ReindexParams reindex_params = {0}; - /* - * Ensure that the indexes have the same persistence as the parent - * relation. - */ - if (newrelpersistence == RELPERSISTENCE_UNLOGGED) - reindex_flags |= REINDEX_REL_FORCE_INDEXES_UNLOGGED; - else if (newrelpersistence == RELPERSISTENCE_PERMANENT) - reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT; + /* + * Rebuild each index on the relation (but not the toast table, which + * is all-new at this point). It is important to do this before the + * DROP step because if we are processing a system catalog that will + * be used during DROP, we want to have its indexes available. There + * is no advantage to the other order anyway because this is all + * transactional, so no chance to reclaim disk space before commit. We + * do not need a final CommandCounterIncrement() because + * reindex_relation does it. + * + * Note: because index_build is called via reindex_relation, it will + * never set indcheckxmin true for the indexes. This is OK even + * though in some sense we are building new indexes rather than + * rebuilding existing ones, because the new heap won't contain any + * HOT chains at all, let alone broken ones, so it can't be necessary + * to set indcheckxmin. + */ + reindex_flags = REINDEX_REL_SUPPRESS_INDEX_USE; + if (check_constraints) + reindex_flags |= REINDEX_REL_CHECK_CONSTRAINTS; - /* Report that we are now reindexing relations */ - pgstat_progress_update_param(PROGRESS_REPACK_PHASE, - PROGRESS_REPACK_PHASE_REBUILD_INDEX); + /* + * Ensure that the indexes have the same persistence as the parent + * relation. + */ + if (newrelpersistence == RELPERSISTENCE_UNLOGGED) + reindex_flags |= REINDEX_REL_FORCE_INDEXES_UNLOGGED; + else if (newrelpersistence == RELPERSISTENCE_PERMANENT) + reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT; - reindex_relation(NULL, OIDOldHeap, reindex_flags, &reindex_params); + /* Report that we are now reindexing relations */ + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_REBUILD_INDEX); + + reindex_relation(NULL, OIDOldHeap, reindex_flags, &reindex_params); + } /* Report that we are now doing clean up */ pgstat_progress_update_param(PROGRESS_REPACK_PHASE, @@ -1881,7 +2289,8 @@ cluster_is_permitted_for_relation(RepackCommand cmd, Oid relid, Oid userid) * resolve in this case. */ static Relation -process_single_relation(RepackStmt *stmt, ClusterParams *params) +process_single_relation(RepackStmt *stmt, LOCKMODE lockmode, bool isTopLevel, + ClusterParams *params) { Relation rel; Oid tableOid; @@ -1890,13 +2299,9 @@ process_single_relation(RepackStmt *stmt, ClusterParams *params) Assert(stmt->command == REPACK_COMMAND_CLUSTER || stmt->command == REPACK_COMMAND_REPACK); - /* - * Find, lock, and check permissions on the table. We obtain - * AccessExclusiveLock right away to avoid lock-upgrade hazard in the - * single-transaction case. - */ + /* Find, lock, and check permissions on the table. */ tableOid = RangeVarGetRelidExtended(stmt->relation, - AccessExclusiveLock, + lockmode, 0, RangeVarCallbackMaintainsTable, NULL); @@ -1922,26 +2327,17 @@ process_single_relation(RepackStmt *stmt, ClusterParams *params) return rel; else { - Oid indexOid; + Oid indexOid = InvalidOid; - indexOid = determine_clustered_index(rel, stmt->usingindex, - stmt->indexname); - if (OidIsValid(indexOid)) - check_index_is_clusterable(rel, indexOid, AccessExclusiveLock); - cluster_rel(stmt->command, stmt->usingindex, rel, indexOid, params); - - /* Do an analyze, if requested */ - if (params->options & CLUOPT_ANALYZE) + if (stmt->usingindex) { - VacuumParams vac_params = {0}; - - vac_params.options |= VACOPT_ANALYZE; - if (params->options & CLUOPT_VERBOSE) - vac_params.options |= VACOPT_VERBOSE; - analyze_rel(RelationGetRelid(rel), NULL, vac_params, NIL, true, - NULL); + indexOid = determine_clustered_index(rel, stmt->usingindex, + stmt->indexname); + check_index_is_clusterable(rel, indexOid, lockmode); } + cluster_rel(stmt->command, stmt->usingindex, rel, indexOid, + params, isTopLevel); return NULL; } } @@ -1998,3 +2394,1052 @@ determine_clustered_index(Relation rel, bool usingindex, const char *indexname) return indexOid; } + + +/* + * Call this function before REPACK CONCURRENTLY starts to setup logical + * decoding. It makes sure that other users of the table put enough + * information into WAL. + * + * The point is that at various places we expect that the table we're + * processing is treated like a system catalog. For example, we need to be + * able to scan it using a "historic snapshot" anytime during the processing + * (as opposed to scanning only at the start point of the decoding, as logical + * replication does during initial table synchronization), in order to apply + * concurrent UPDATE / DELETE commands. + * + * Note that TOAST table needs no attention here as it's not scanned using + * historic snapshot. + */ +static void +begin_concurrent_repack(Relation rel) +{ + Oid toastrelid; + + /* Avoid logical decoding of other relations by this backend. */ + repacked_rel_locator = rel->rd_locator; + toastrelid = rel->rd_rel->reltoastrelid; + if (OidIsValid(toastrelid)) + { + Relation toastrel; + + /* Avoid logical decoding of other TOAST relations. */ + toastrel = table_open(toastrelid, AccessShareLock); + repacked_rel_toast_locator = toastrel->rd_locator; + table_close(toastrel, AccessShareLock); + } +} + +/* + * Call this when done with REPACK CONCURRENTLY. + */ +static void +end_concurrent_repack(void) +{ + /* + * Restore normal function of (future) logical decoding for this backend. + */ + repacked_rel_locator.relNumber = InvalidOid; + repacked_rel_toast_locator.relNumber = InvalidOid; +} + +/* + * This function is much like pg_create_logical_replication_slot() except that + * the new slot is neither released (if anyone else could read changes from + * our slot, we could miss changes other backends do while we copy the + * existing data into temporary table), nor persisted (it's easier to handle + * crash by restarting all the work from scratch). + */ +static LogicalDecodingContext * +setup_logical_decoding(Oid relid, const char *slotname, TupleDesc tupdesc) +{ + LogicalDecodingContext *ctx; + RepackDecodingState *dstate; + + /* + * Check if we can use logical decoding. + */ + CheckSlotPermissions(); + CheckLogicalDecodingRequirements(); + + /* RS_TEMPORARY so that the slot gets cleaned up on ERROR. */ + ReplicationSlotCreate(slotname, true, RS_TEMPORARY, false, false, false); + + /* + * Neither prepare_write nor do_write callback nor update_progress is + * useful for us. + * + * Regarding the value of need_full_snapshot, we pass false because the + * table we are processing is present in RepackedRelsHash and therefore, + * regarding logical decoding, treated like a catalog. + */ + ctx = CreateInitDecodingContext(REPL_PLUGIN_NAME, + NIL, + false, + InvalidXLogRecPtr, + XL_ROUTINE(.page_read = read_local_xlog_page, + .segment_open = wal_segment_open, + .segment_close = wal_segment_close), + NULL, NULL, NULL); + + /* + * We don't have control on setting fast_forward, so at least check it. + */ + Assert(!ctx->fast_forward); + + DecodingContextFindStartpoint(ctx); + + /* Some WAL records should have been read. */ + Assert(ctx->reader->EndRecPtr != InvalidXLogRecPtr); + + XLByteToSeg(ctx->reader->EndRecPtr, repack_current_segment, + wal_segment_size); + + /* + * Setup structures to store decoded changes. + */ + dstate = palloc0(sizeof(RepackDecodingState)); + dstate->relid = relid; + dstate->tstore = tuplestore_begin_heap(false, false, + maintenance_work_mem); + + dstate->tupdesc = tupdesc; + + /* Initialize the descriptor to store the changes ... */ + dstate->tupdesc_change = CreateTemplateTupleDesc(1); + + TupleDescInitEntry(dstate->tupdesc_change, 1, NULL, BYTEAOID, -1, 0); + /* ... as well as the corresponding slot. */ + dstate->tsslot = MakeSingleTupleTableSlot(dstate->tupdesc_change, + &TTSOpsMinimalTuple); + + dstate->resowner = ResourceOwnerCreate(CurrentResourceOwner, + "logical decoding"); + + ctx->output_writer_private = dstate; + return ctx; +} + +/* + * Retrieve tuple from ConcurrentChange structure. + * + * The input data starts with the structure but it might not be appropriately + * aligned. + */ +static HeapTuple +get_changed_tuple(char *change) +{ + HeapTupleData tup_data; + HeapTuple result; + char *src; + + /* + * Ensure alignment before accessing the fields. (This is why we can't use + * heap_copytuple() instead of this function.) + */ + src = change + offsetof(ConcurrentChange, tup_data); + memcpy(&tup_data, src, sizeof(HeapTupleData)); + + result = (HeapTuple) palloc(HEAPTUPLESIZE + tup_data.t_len); + memcpy(result, &tup_data, sizeof(HeapTupleData)); + result->t_data = (HeapTupleHeader) ((char *) result + HEAPTUPLESIZE); + src = change + SizeOfConcurrentChange; + memcpy(result->t_data, src, result->t_len); + + return result; +} + +/* + * Decode logical changes from the WAL sequence up to end_of_wal. + */ +void +repack_decode_concurrent_changes(LogicalDecodingContext *ctx, + XLogRecPtr end_of_wal) +{ + RepackDecodingState *dstate; + ResourceOwner resowner_old; + + /* + * Invalidate the "present" cache before moving to "(recent) history". + */ + InvalidateSystemCaches(); + + dstate = (RepackDecodingState *) ctx->output_writer_private; + resowner_old = CurrentResourceOwner; + CurrentResourceOwner = dstate->resowner; + + PG_TRY(); + { + while (ctx->reader->EndRecPtr < end_of_wal) + { + XLogRecord *record; + XLogSegNo segno_new; + char *errm = NULL; + XLogRecPtr end_lsn; + + record = XLogReadRecord(ctx->reader, &errm); + if (errm) + elog(ERROR, "%s", errm); + + if (record != NULL) + LogicalDecodingProcessRecord(ctx, ctx->reader); + + /* + * If WAL segment boundary has been crossed, inform the decoding + * system that the catalog_xmin can advance. (We can confirm more + * often, but a filling a single WAL segment should not take much + * time.) + */ + end_lsn = ctx->reader->EndRecPtr; + XLByteToSeg(end_lsn, segno_new, wal_segment_size); + if (segno_new != repack_current_segment) + { + LogicalConfirmReceivedLocation(end_lsn); + elog(DEBUG1, "REPACK: confirmed receive location %X/%X", + (uint32) (end_lsn >> 32), (uint32) end_lsn); + repack_current_segment = segno_new; + } + + CHECK_FOR_INTERRUPTS(); + } + InvalidateSystemCaches(); + CurrentResourceOwner = resowner_old; + } + PG_CATCH(); + { + /* clear all timetravel entries */ + InvalidateSystemCaches(); + CurrentResourceOwner = resowner_old; + PG_RE_THROW(); + } + PG_END_TRY(); +} + +/* + * Apply changes that happened during the initial load. + * + * Scan key is passed by caller, so it does not have to be constructed + * multiple times. Key entries have all fields initialized, except for + * sk_argument. + */ +static void +apply_concurrent_changes(RepackDecodingState *dstate, Relation rel, + ScanKey key, int nkeys, IndexInsertState *iistate) +{ + TupleTableSlot *index_slot, + *ident_slot; + HeapTuple tup_old = NULL; + + if (dstate->nchanges == 0) + return; + + /* TupleTableSlot is needed to pass the tuple to ExecInsertIndexTuples(). */ + index_slot = MakeSingleTupleTableSlot(dstate->tupdesc, &TTSOpsHeapTuple); + + /* A slot to fetch tuples from identity index. */ + ident_slot = table_slot_create(rel, NULL); + + while (tuplestore_gettupleslot(dstate->tstore, true, false, + dstate->tsslot)) + { + bool shouldFree; + HeapTuple tup_change, + tup, + tup_exist; + char *change_raw, + *src; + ConcurrentChange change; + bool isnull[1]; + Datum values[1]; + + CHECK_FOR_INTERRUPTS(); + + /* Get the change from the single-column tuple. */ + tup_change = ExecFetchSlotHeapTuple(dstate->tsslot, false, &shouldFree); + heap_deform_tuple(tup_change, dstate->tupdesc_change, values, isnull); + Assert(!isnull[0]); + + /* Make sure we access aligned data. */ + change_raw = (char *) DatumGetByteaP(values[0]); + src = (char *) VARDATA(change_raw); + memcpy(&change, src, SizeOfConcurrentChange); + + /* TRUNCATE change contains no tuple, so process it separately. */ + if (change.kind == CHANGE_TRUNCATE) + { + /* + * All the things that ExecuteTruncateGuts() does (such as firing + * triggers or handling the DROP_CASCADE behavior) should have + * taken place on the source relation. Thus we only do the actual + * truncation of the new relation (and its indexes). + */ + heap_truncate_one_rel(rel); + + pfree(tup_change); + continue; + } + + /* + * Extract the tuple from the change. The tuple is copied here because + * it might be assigned to 'tup_old', in which case it needs to + * survive into the next iteration. + */ + tup = get_changed_tuple(src); + + if (change.kind == CHANGE_UPDATE_OLD) + { + Assert(tup_old == NULL); + tup_old = tup; + } + else if (change.kind == CHANGE_INSERT) + { + Assert(tup_old == NULL); + + apply_concurrent_insert(rel, &change, tup, iistate, index_slot); + + pfree(tup); + } + else if (change.kind == CHANGE_UPDATE_NEW || + change.kind == CHANGE_DELETE) + { + IndexScanDesc ind_scan = NULL; + HeapTuple tup_key; + + if (change.kind == CHANGE_UPDATE_NEW) + { + tup_key = tup_old != NULL ? tup_old : tup; + } + else + { + Assert(tup_old == NULL); + tup_key = tup; + } + + /* + * Find the tuple to be updated or deleted. + */ + tup_exist = find_target_tuple(rel, key, nkeys, tup_key, + iistate, ident_slot, &ind_scan); + if (tup_exist == NULL) + elog(ERROR, "Failed to find target tuple"); + + if (change.kind == CHANGE_UPDATE_NEW) + apply_concurrent_update(rel, tup, tup_exist, &change, iistate, + index_slot); + else + apply_concurrent_delete(rel, tup_exist, &change); + + if (tup_old != NULL) + { + pfree(tup_old); + tup_old = NULL; + } + + pfree(tup); + index_endscan(ind_scan); + } + else + elog(ERROR, "Unrecognized kind of change: %d", change.kind); + + /* + * If a change was applied now, increment CID for next writes and + * update the snapshot so it sees the changes we've applied so far. + */ + if (change.kind != CHANGE_UPDATE_OLD) + { + CommandCounterIncrement(); + UpdateActiveSnapshotCommandId(); + } + + /* TTSOpsMinimalTuple has .get_heap_tuple==NULL. */ + Assert(shouldFree); + pfree(tup_change); + } + + tuplestore_clear(dstate->tstore); + dstate->nchanges = 0; + + /* Cleanup. */ + ExecDropSingleTupleTableSlot(index_slot); + ExecDropSingleTupleTableSlot(ident_slot); +} + +static void +apply_concurrent_insert(Relation rel, ConcurrentChange *change, HeapTuple tup, + IndexInsertState *iistate, TupleTableSlot *index_slot) +{ + List *recheck; + + + /* + * Like simple_heap_insert(), but make sure that the INSERT is not + * logically decoded - see reform_and_rewrite_tuple() for more + * information. + */ + heap_insert(rel, tup, GetCurrentCommandId(true), HEAP_INSERT_NO_LOGICAL, + NULL); + + /* + * Update indexes. + * + * In case functions in the index need the active snapshot and caller + * hasn't set one. + */ + ExecStoreHeapTuple(tup, index_slot, false); + recheck = ExecInsertIndexTuples(iistate->rri, + index_slot, + iistate->estate, + false, /* update */ + false, /* noDupErr */ + NULL, /* specConflict */ + NIL, /* arbiterIndexes */ + false /* onlySummarizing */ + ); + + /* + * If recheck is required, it must have been preformed on the source + * relation by now. (All the logical changes we process here are already + * committed.) + */ + list_free(recheck); + + pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_INSERTED, 1); +} + +static void +apply_concurrent_update(Relation rel, HeapTuple tup, HeapTuple tup_target, + ConcurrentChange *change, IndexInsertState *iistate, + TupleTableSlot *index_slot) +{ + LockTupleMode lockmode; + TM_FailureData tmfd; + TU_UpdateIndexes update_indexes; + TM_Result res; + List *recheck; + + /* + * Write the new tuple into the new heap. ('tup' gets the TID assigned + * here.) + * + * Do it like in simple_heap_update(), except for 'wal_logical' (and + * except for 'wait'). + */ + res = heap_update(rel, &tup_target->t_self, tup, + GetCurrentCommandId(true), + InvalidSnapshot, + false, /* no wait - only we are doing changes */ + &tmfd, &lockmode, &update_indexes, + false /* wal_logical */ ); + if (res != TM_Ok) + ereport(ERROR, (errmsg("failed to apply concurrent UPDATE"))); + + ExecStoreHeapTuple(tup, index_slot, false); + + if (update_indexes != TU_None) + { + recheck = ExecInsertIndexTuples(iistate->rri, + index_slot, + iistate->estate, + true, /* update */ + false, /* noDupErr */ + NULL, /* specConflict */ + NIL, /* arbiterIndexes */ + /* onlySummarizing */ + update_indexes == TU_Summarizing); + list_free(recheck); + } + + pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_UPDATED, 1); +} + +static void +apply_concurrent_delete(Relation rel, HeapTuple tup_target, + ConcurrentChange *change) +{ + TM_Result res; + TM_FailureData tmfd; + + /* + * Delete tuple from the new heap. + * + * Do it like in simple_heap_delete(), except for 'wal_logical' (and + * except for 'wait'). + */ + res = heap_delete(rel, &tup_target->t_self, GetCurrentCommandId(true), + InvalidSnapshot, false, + &tmfd, + false, /* no wait - only we are doing changes */ + false /* wal_logical */ ); + + if (res != TM_Ok) + ereport(ERROR, (errmsg("failed to apply concurrent DELETE"))); + + pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_DELETED, 1); +} + +/* + * Find the tuple to be updated or deleted. + * + * 'key' is a pre-initialized scan key, into which the function will put the + * key values. + * + * 'tup_key' is a tuple containing the key values for the scan. + * + * On exit,'*scan_p' contains the scan descriptor used. The caller must close + * it when he no longer needs the tuple returned. + */ +static HeapTuple +find_target_tuple(Relation rel, ScanKey key, int nkeys, HeapTuple tup_key, + IndexInsertState *iistate, + TupleTableSlot *ident_slot, IndexScanDesc *scan_p) +{ + IndexScanDesc scan; + Form_pg_index ident_form; + int2vector *ident_indkey; + HeapTuple result = NULL; + + /* XXX no instrumentation for now */ + scan = index_beginscan(rel, iistate->ident_index, GetActiveSnapshot(), + NULL, nkeys, 0); + *scan_p = scan; + index_rescan(scan, key, nkeys, NULL, 0); + + /* Info needed to retrieve key values from heap tuple. */ + ident_form = iistate->ident_index->rd_index; + ident_indkey = &ident_form->indkey; + + /* Use the incoming tuple to finalize the scan key. */ + for (int i = 0; i < scan->numberOfKeys; i++) + { + ScanKey entry; + bool isnull; + int16 attno_heap; + + entry = &scan->keyData[i]; + attno_heap = ident_indkey->values[i]; + entry->sk_argument = heap_getattr(tup_key, + attno_heap, + rel->rd_att, + &isnull); + Assert(!isnull); + } + if (index_getnext_slot(scan, ForwardScanDirection, ident_slot)) + { + bool shouldFree; + + result = ExecFetchSlotHeapTuple(ident_slot, false, &shouldFree); + /* TTSOpsBufferHeapTuple has .get_heap_tuple != NULL. */ + Assert(!shouldFree); + } + + return result; +} + +/* + * Decode and apply concurrent changes. + * + * Pass rel_src iff its reltoastrelid is needed. + */ +static void +process_concurrent_changes(LogicalDecodingContext *ctx, XLogRecPtr end_of_wal, + Relation rel_dst, Relation rel_src, ScanKey ident_key, + int ident_key_nentries, IndexInsertState *iistate) +{ + RepackDecodingState *dstate; + + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_CATCH_UP); + + dstate = (RepackDecodingState *) ctx->output_writer_private; + + repack_decode_concurrent_changes(ctx, end_of_wal); + + if (dstate->nchanges == 0) + return; + + PG_TRY(); + { + /* + * Make sure that TOAST values can eventually be accessed via the old + * relation - see comment in copy_table_data(). + */ + if (rel_src) + rel_dst->rd_toastoid = rel_src->rd_rel->reltoastrelid; + + apply_concurrent_changes(dstate, rel_dst, ident_key, + ident_key_nentries, iistate); + } + PG_FINALLY(); + { + if (rel_src) + rel_dst->rd_toastoid = InvalidOid; + } + PG_END_TRY(); +} + +static IndexInsertState * +get_index_insert_state(Relation relation, Oid ident_index_id) +{ + EState *estate; + int i; + IndexInsertState *result; + + result = (IndexInsertState *) palloc0(sizeof(IndexInsertState)); + estate = CreateExecutorState(); + + result->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo)); + InitResultRelInfo(result->rri, relation, 0, 0, 0); + ExecOpenIndices(result->rri, false); + + /* + * Find the relcache entry of the identity index so that we spend no extra + * effort to open / close it. + */ + for (i = 0; i < result->rri->ri_NumIndices; i++) + { + Relation ind_rel; + + ind_rel = result->rri->ri_IndexRelationDescs[i]; + if (ind_rel->rd_id == ident_index_id) + result->ident_index = ind_rel; + } + if (result->ident_index == NULL) + elog(ERROR, "Failed to open identity index"); + + /* Only initialize fields needed by ExecInsertIndexTuples(). */ + result->estate = estate; + + return result; +} + +/* + * Build scan key to process logical changes. + */ +static ScanKey +build_identity_key(Oid ident_idx_oid, Relation rel_src, int *nentries) +{ + Relation ident_idx_rel; + Form_pg_index ident_idx; + int n, + i; + ScanKey result; + + Assert(OidIsValid(ident_idx_oid)); + ident_idx_rel = index_open(ident_idx_oid, AccessShareLock); + ident_idx = ident_idx_rel->rd_index; + n = ident_idx->indnatts; + result = (ScanKey) palloc(sizeof(ScanKeyData) * n); + for (i = 0; i < n; i++) + { + ScanKey entry; + int16 relattno; + Form_pg_attribute att; + Oid opfamily, + opcintype, + opno, + opcode; + + entry = &result[i]; + relattno = ident_idx->indkey.values[i]; + if (relattno >= 1) + { + TupleDesc desc; + + desc = rel_src->rd_att; + att = TupleDescAttr(desc, relattno - 1); + } + else + elog(ERROR, "Unexpected attribute number %d in index", relattno); + + opfamily = ident_idx_rel->rd_opfamily[i]; + opcintype = ident_idx_rel->rd_opcintype[i]; + opno = get_opfamily_member(opfamily, opcintype, opcintype, + BTEqualStrategyNumber); + + if (!OidIsValid(opno)) + elog(ERROR, "Failed to find = operator for type %u", opcintype); + + opcode = get_opcode(opno); + if (!OidIsValid(opcode)) + elog(ERROR, "Failed to find = operator for operator %u", opno); + + /* Initialize everything but argument. */ + ScanKeyInit(entry, + i + 1, + BTEqualStrategyNumber, opcode, + (Datum) NULL); + entry->sk_collation = att->attcollation; + } + index_close(ident_idx_rel, AccessShareLock); + + *nentries = n; + return result; +} + +static void +free_index_insert_state(IndexInsertState *iistate) +{ + ExecCloseIndices(iistate->rri); + FreeExecutorState(iistate->estate); + pfree(iistate->rri); + pfree(iistate); +} + +static void +cleanup_logical_decoding(LogicalDecodingContext *ctx) +{ + RepackDecodingState *dstate; + + dstate = (RepackDecodingState *) ctx->output_writer_private; + + ExecDropSingleTupleTableSlot(dstate->tsslot); + FreeTupleDesc(dstate->tupdesc_change); + FreeTupleDesc(dstate->tupdesc); + tuplestore_end(dstate->tstore); + + FreeDecodingContext(ctx); +} + +/* + * The final steps of rebuild_relation() for concurrent processing. + * + * On entry, NewHeap is locked in AccessExclusiveLock mode. OldHeap and its + * clustering index (if one is passed) are still locked in a mode that allows + * concurrent data changes. On exit, both tables and their indexes are closed, + * but locked in AccessExclusiveLock mode. + */ +static void +rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap, + Relation cl_index, + LogicalDecodingContext *ctx, + bool swap_toast_by_content, + TransactionId frozenXid, + MultiXactId cutoffMulti) +{ + LOCKMODE lockmode_old PG_USED_FOR_ASSERTS_ONLY; + List *ind_oids_new; + Oid old_table_oid = RelationGetRelid(OldHeap); + Oid new_table_oid = RelationGetRelid(NewHeap); + List *ind_oids_old = RelationGetIndexList(OldHeap); + ListCell *lc, + *lc2; + char relpersistence; + bool is_system_catalog; + Oid ident_idx_old, + ident_idx_new; + IndexInsertState *iistate; + ScanKey ident_key; + int ident_key_nentries; + XLogRecPtr wal_insert_ptr, + end_of_wal; + char dummy_rec_data = '\0'; + Relation *ind_refs, + *ind_refs_p; + int nind; + + /* Like in cluster_rel(). */ + lockmode_old = ShareUpdateExclusiveLock; + Assert(CheckRelationLockedByMe(OldHeap, lockmode_old, false)); + Assert(cl_index == NULL || + CheckRelationLockedByMe(cl_index, lockmode_old, false)); + /* This is expected from the caller. */ + Assert(CheckRelationLockedByMe(NewHeap, AccessExclusiveLock, false)); + + ident_idx_old = RelationGetReplicaIndex(OldHeap); + + /* + * Unlike the exclusive case, we build new indexes for the new relation + * rather than swapping the storage and reindexing the old relation. The + * point is that the index build can take some time, so we do it before we + * get AccessExclusiveLock on the old heap and therefore we cannot swap + * the heap storage yet. + * + * index_create() will lock the new indexes using AccessExclusiveLock - no + * need to change that. + * + * We assume that ShareUpdateExclusiveLock on the table prevents anyone + * from dropping the existing indexes or adding new ones, so the lists of + * old and new indexes should match at the swap time. On the other hand we + * do not block ALTER INDEX commands that do not require table lock (e.g. + * ALTER INDEX ... SET ...). + * + * XXX Should we check a the end of our work if another transaction + * executed such a command and issue a NOTICE that we might have discarded + * its effects? (For example, someone changes storage parameter after we + * have created the new index, the new value of that parameter is lost.) + * Alternatively, we can lock all the indexes now in a mode that blocks + * all the ALTER INDEX commands (ShareUpdateExclusiveLock ?), and keep + * them locked till the end of the transactions. That might increase the + * risk of deadlock during the lock upgrade below, however SELECT / DML + * queries should not be involved in such a deadlock. + */ + ind_oids_new = build_new_indexes(NewHeap, OldHeap, ind_oids_old); + + /* + * Processing shouldn't start w/o valid identity index. + */ + Assert(OidIsValid(ident_idx_old)); + + /* Find "identity index" on the new relation. */ + ident_idx_new = InvalidOid; + forboth(lc, ind_oids_old, lc2, ind_oids_new) + { + Oid ind_old = lfirst_oid(lc); + Oid ind_new = lfirst_oid(lc2); + + if (ident_idx_old == ind_old) + { + ident_idx_new = ind_new; + break; + } + } + if (!OidIsValid(ident_idx_new)) + + /* + * Should not happen, given our lock on the old relation. + */ + ereport(ERROR, + (errmsg("Identity index missing on the new relation"))); + + /* Executor state to update indexes. */ + iistate = get_index_insert_state(NewHeap, ident_idx_new); + + /* + * Build scan key that we'll use to look for rows to be updated / deleted + * during logical decoding. + */ + ident_key = build_identity_key(ident_idx_new, OldHeap, &ident_key_nentries); + + /* + * During testing, wait for another backend to perform concurrent data + * changes which we will process below. + */ + INJECTION_POINT("repack-concurrently-before-lock", NULL); + + /* + * Flush all WAL records inserted so far (possibly except for the last + * incomplete page, see GetInsertRecPtr), to minimize the amount of data + * we need to flush while holding exclusive lock on the source table. + */ + wal_insert_ptr = GetInsertRecPtr(); + XLogFlush(wal_insert_ptr); + end_of_wal = GetFlushRecPtr(NULL); + + /* + * Apply concurrent changes first time, to minimize the time we need to + * hold AccessExclusiveLock. (Quite some amount of WAL could have been + * written during the data copying and index creation.) + */ + process_concurrent_changes(ctx, end_of_wal, NewHeap, + swap_toast_by_content ? OldHeap : NULL, + ident_key, ident_key_nentries, iistate); + + /* + * Acquire AccessExclusiveLock on the table, its TOAST relation (if there + * is one), all its indexes, so that we can swap the files. + * + * Before that, unlock the index temporarily to avoid deadlock in case + * another transaction is trying to lock it while holding the lock on the + * table. + */ + if (cl_index) + { + index_close(cl_index, ShareUpdateExclusiveLock); + cl_index = NULL; + } + /* For the same reason, unlock TOAST relation. */ + if (OldHeap->rd_rel->reltoastrelid) + LockRelationOid(OldHeap->rd_rel->reltoastrelid, AccessExclusiveLock); + /* Finally lock the table */ + LockRelationOid(old_table_oid, AccessExclusiveLock); + + /* + * Lock all indexes now, not only the clustering one: all indexes need to + * have their files swapped. While doing that, store their relation + * references in an array, to handle predicate locks below. + */ + ind_refs_p = ind_refs = palloc_array(Relation, list_length(ind_oids_old)); + nind = 0; + foreach(lc, ind_oids_old) + { + Oid ind_oid; + Relation index; + + ind_oid = lfirst_oid(lc); + index = index_open(ind_oid, AccessExclusiveLock); + + /* + * TODO 1) Do we need to check if ALTER INDEX was executed since the + * new index was created in build_new_indexes()? 2) Specifically for + * the clustering index, should check_index_is_clusterable() be called + * here? (Not sure about the latter: ShareUpdateExclusiveLock on the + * table probably blocks all commands that affect the result of + * check_index_is_clusterable().) + */ + *ind_refs_p = index; + ind_refs_p++; + nind++; + } + + /* + * In addition, lock the OldHeap's TOAST relation exclusively - again, the + * lock is needed to swap the files. + */ + if (OidIsValid(OldHeap->rd_rel->reltoastrelid)) + LockRelationOid(OldHeap->rd_rel->reltoastrelid, AccessExclusiveLock); + + /* + * Tuples and pages of the old heap will be gone, but the heap will stay. + */ + TransferPredicateLocksToHeapRelation(OldHeap); + /* The same for indexes. */ + for (int i = 0; i < nind; i++) + { + Relation index = ind_refs[i]; + + TransferPredicateLocksToHeapRelation(index); + + /* + * References to indexes on the old relation are not needed anymore, + * however locks stay till the end of the transaction. + */ + index_close(index, NoLock); + } + pfree(ind_refs); + + /* + * Flush anything we see in WAL, to make sure that all changes committed + * while we were waiting for the exclusive lock are available for + * decoding. This should not be necessary if all backends had + * synchronous_commit set, but we can't rely on this setting. + * + * Unfortunately, GetInsertRecPtr() may lag behind the actual insert + * position, and GetLastImportantRecPtr() points at the start of the last + * record rather than at the end. Thus the simplest way to determine the + * insert position is to insert a dummy record and use its LSN. + * + * XXX Consider using GetLastImportantRecPtr() and adding the size of the + * last record (plus the total size of all the page headers the record + * spans)? + */ + XLogBeginInsert(); + XLogRegisterData(&dummy_rec_data, 1); + wal_insert_ptr = XLogInsert(RM_XLOG_ID, XLOG_NOOP); + XLogFlush(wal_insert_ptr); + end_of_wal = GetFlushRecPtr(NULL); + + /* Apply the concurrent changes again. */ + process_concurrent_changes(ctx, end_of_wal, NewHeap, + swap_toast_by_content ? OldHeap : NULL, + ident_key, ident_key_nentries, iistate); + + /* Remember info about rel before closing OldHeap */ + relpersistence = OldHeap->rd_rel->relpersistence; + is_system_catalog = IsSystemRelation(OldHeap); + + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_SWAP_REL_FILES); + + /* + * Even ShareUpdateExclusiveLock should have prevented others from + * creating / dropping indexes (even using the CONCURRENTLY option), so we + * do not need to check whether the lists match. + */ + forboth(lc, ind_oids_old, lc2, ind_oids_new) + { + Oid ind_old = lfirst_oid(lc); + Oid ind_new = lfirst_oid(lc2); + Oid mapped_tables[4]; + + /* Zero out possible results from swapped_relation_files */ + memset(mapped_tables, 0, sizeof(mapped_tables)); + + swap_relation_files(ind_old, ind_new, + (old_table_oid == RelationRelationId), + swap_toast_by_content, + true, + InvalidTransactionId, + InvalidMultiXactId, + mapped_tables); + +#ifdef USE_ASSERT_CHECKING + + /* + * Concurrent processing is not supported for system relations, so + * there should be no mapped tables. + */ + for (int i = 0; i < 4; i++) + Assert(mapped_tables[i] == 0); +#endif + } + + /* The new indexes must be visible for deletion. */ + CommandCounterIncrement(); + + /* Close the old heap but keep lock until transaction commit. */ + table_close(OldHeap, NoLock); + /* Close the new heap. (We didn't have to open its indexes). */ + table_close(NewHeap, NoLock); + + /* Cleanup what we don't need anymore. (And close the identity index.) */ + pfree(ident_key); + free_index_insert_state(iistate); + + /* + * Swap the relations and their TOAST relations and TOAST indexes. This + * also drops the new relation and its indexes. + * + * (System catalogs are currently not supported.) + */ + Assert(!is_system_catalog); + finish_heap_swap(old_table_oid, new_table_oid, + is_system_catalog, + swap_toast_by_content, + false, true, false, + frozenXid, cutoffMulti, + relpersistence); +} + +/* + * Build indexes on NewHeap according to those on OldHeap. + * + * OldIndexes is the list of index OIDs on OldHeap. + * + * A list of OIDs of the corresponding indexes created on NewHeap is + * returned. The order of items does match, so we can use these arrays to swap + * index storage. + */ +static List * +build_new_indexes(Relation NewHeap, Relation OldHeap, List *OldIndexes) +{ + ListCell *lc; + List *result = NIL; + + pgstat_progress_update_param(PROGRESS_REPACK_PHASE, + PROGRESS_REPACK_PHASE_REBUILD_INDEX); + + foreach(lc, OldIndexes) + { + Oid ind_oid, + ind_oid_new; + char *newName; + Relation ind; + + ind_oid = lfirst_oid(lc); + ind = index_open(ind_oid, AccessShareLock); + + newName = ChooseRelationName(get_rel_name(ind_oid), + NULL, + "repacknew", + get_rel_namespace(ind->rd_index->indrelid), + false); + ind_oid_new = index_create_copy(NewHeap, ind_oid, + ind->rd_rel->reltablespace, newName, + false); + result = lappend_oid(result, ind_oid_new); + + index_close(ind, AccessShareLock); + } + + return result; +} diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c index 188e26f0e6e..71b73c21ebf 100644 --- a/src/backend/commands/matview.c +++ b/src/backend/commands/matview.c @@ -904,7 +904,7 @@ refresh_by_match_merge(Oid matviewOid, Oid tempOid, Oid relowner, static void refresh_by_heap_swap(Oid matviewOid, Oid OIDNewHeap, char relpersistence) { - finish_heap_swap(matviewOid, OIDNewHeap, false, false, true, true, + finish_heap_swap(matviewOid, OIDNewHeap, false, false, true, true, true, RecentXmin, ReadNextMultiXactId(), relpersistence); } diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 082a3575d62..c79f5b1dc0f 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -5989,6 +5989,7 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode, finish_heap_swap(tab->relid, OIDNewHeap, false, false, true, !OidIsValid(tab->newTableSpace), + true, RecentXmin, ReadNextMultiXactId(), persistence); diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 8863ad0e8bd..6de9d0ba39d 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -125,7 +125,7 @@ static void vac_truncate_clog(TransactionId frozenXID, TransactionId lastSaneFrozenXid, MultiXactId lastSaneMinMulti); static bool vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params, - BufferAccessStrategy bstrategy); + BufferAccessStrategy bstrategy, bool isTopLevel); static double compute_parallel_delay(void); static VacOptValue get_vacoptval_from_boolean(DefElem *def); static bool vac_tid_reaped(ItemPointer itemptr, void *state); @@ -633,7 +633,8 @@ vacuum(List *relations, const VacuumParams params, BufferAccessStrategy bstrateg if (params.options & VACOPT_VACUUM) { - if (!vacuum_rel(vrel->oid, vrel->relation, params, bstrategy)) + if (!vacuum_rel(vrel->oid, vrel->relation, params, bstrategy, + isTopLevel)) continue; } @@ -1997,7 +1998,7 @@ vac_truncate_clog(TransactionId frozenXID, */ static bool vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params, - BufferAccessStrategy bstrategy) + BufferAccessStrategy bstrategy, bool isTopLevel) { LOCKMODE lmode; Relation rel; @@ -2288,7 +2289,7 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params, /* VACUUM FULL is now a variant of CLUSTER; see cluster.c */ cluster_rel(REPACK_COMMAND_VACUUMFULL, false, rel, InvalidOid, - &cluster_params); + &cluster_params, isTopLevel); /* cluster_rel closes the relation, but keeps lock */ rel = NULL; @@ -2331,7 +2332,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params, toast_vacuum_params.options |= VACOPT_PROCESS_MAIN; toast_vacuum_params.toast_parent = relid; - vacuum_rel(toast_relid, NULL, toast_vacuum_params, bstrategy); + vacuum_rel(toast_relid, NULL, toast_vacuum_params, bstrategy, + isTopLevel); } /* diff --git a/src/backend/meson.build b/src/backend/meson.build index b831a541652..5c148131217 100644 --- a/src/backend/meson.build +++ b/src/backend/meson.build @@ -194,5 +194,6 @@ pg_test_mod_args = pg_mod_args + { subdir('jit/llvm') subdir('replication/libpqwalreceiver') subdir('replication/pgoutput') +subdir('replication/pgoutput_repack') subdir('snowball') subdir('utils/mb/conversion_procs') diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c index cc03f0706e9..5dc4ae58ffe 100644 --- a/src/backend/replication/logical/decode.c +++ b/src/backend/replication/logical/decode.c @@ -33,6 +33,7 @@ #include "access/xlogreader.h" #include "access/xlogrecord.h" #include "catalog/pg_control.h" +#include "commands/cluster.h" #include "replication/decode.h" #include "replication/logical.h" #include "replication/message.h" @@ -472,6 +473,88 @@ heap_decode(LogicalDecodingContext *ctx, XLogRecordBuffer *buf) TransactionId xid = XLogRecGetXid(buf->record); SnapBuild *builder = ctx->snapshot_builder; + /* + * If the change is not intended for logical decoding, do not even + * establish transaction for it - REPACK CONCURRENTLY is the typical use + * case. + * + * First, check if REPACK CONCURRENTLY is being performed by this backend. + * If so, only decode data changes of the table that it is processing, and + * the changes of its TOAST relation. + * + * (TOAST locator should not be set unless the main is.) + */ + Assert(!OidIsValid(repacked_rel_toast_locator.relNumber) || + OidIsValid(repacked_rel_locator.relNumber)); + + if (OidIsValid(repacked_rel_locator.relNumber)) + { + XLogReaderState *r = buf->record; + RelFileLocator locator; + + /* Not all records contain the block. */ + if (XLogRecGetBlockTagExtended(r, 0, &locator, NULL, NULL, NULL) && + !RelFileLocatorEquals(locator, repacked_rel_locator) && + (!OidIsValid(repacked_rel_toast_locator.relNumber) || + !RelFileLocatorEquals(locator, repacked_rel_toast_locator))) + return; + } + + /* + * Second, skip records which do not contain sufficient information for + * the decoding. + * + * The problem we solve here is that REPACK CONCURRENTLY generates WAL + * when doing changes in the new table. Those changes should not be useful + * for any other user (such as logical replication subscription) because + * the new table will eventually be dropped (after REPACK CONCURRENTLY has + * assigned its file to the "old table"). + */ + switch (info) + { + case XLOG_HEAP_INSERT: + { + xl_heap_insert *rec; + + rec = (xl_heap_insert *) XLogRecGetData(buf->record); + + /* + * This does happen when 1) raw_heap_insert marks the TOAST + * record as HEAP_INSERT_NO_LOGICAL, 2) REPACK CONCURRENTLY + * replays inserts performed by other backends. + */ + if ((rec->flags & XLH_INSERT_CONTAINS_NEW_TUPLE) == 0) + return; + + break; + } + + case XLOG_HEAP_HOT_UPDATE: + case XLOG_HEAP_UPDATE: + { + xl_heap_update *rec; + + rec = (xl_heap_update *) XLogRecGetData(buf->record); + if ((rec->flags & + (XLH_UPDATE_CONTAINS_NEW_TUPLE | + XLH_UPDATE_CONTAINS_OLD_TUPLE | + XLH_UPDATE_CONTAINS_OLD_KEY)) == 0) + return; + + break; + } + + case XLOG_HEAP_DELETE: + { + xl_heap_delete *rec; + + rec = (xl_heap_delete *) XLogRecGetData(buf->record); + if (rec->flags & XLH_DELETE_NO_LOGICAL) + return; + break; + } + } + ReorderBufferProcessXid(ctx->reorder, xid, buf->origptr); /* diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c index a2f1803622c..8e5116a9cab 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -486,6 +486,26 @@ SnapBuildInitialSnapshot(SnapBuild *builder) return SnapBuildMVCCFromHistoric(snap, true); } +/* + * Build an MVCC snapshot for the initial data load performed by REPACK + * CONCURRENTLY command. + * + * The snapshot will only be used to scan one particular relation, which is + * treated like a catalog (therefore ->building_full_snapshot is not + * important), and the caller should already have a replication slot setup (so + * we do not set MyProc->xmin). XXX Do we yet need to add some restrictions? + */ +Snapshot +SnapBuildInitialSnapshotForRepack(SnapBuild *builder) +{ + Snapshot snap; + + Assert(builder->state == SNAPBUILD_CONSISTENT); + + snap = SnapBuildBuildSnapshot(builder); + return SnapBuildMVCCFromHistoric(snap, false); +} + /* * Turn a historic MVCC snapshot into an ordinary MVCC snapshot. * diff --git a/src/backend/replication/pgoutput_repack/Makefile b/src/backend/replication/pgoutput_repack/Makefile new file mode 100644 index 00000000000..4efeb713b70 --- /dev/null +++ b/src/backend/replication/pgoutput_repack/Makefile @@ -0,0 +1,32 @@ +#------------------------------------------------------------------------- +# +# Makefile-- +# Makefile for src/backend/replication/pgoutput_repack +# +# IDENTIFICATION +# src/backend/replication/pgoutput_repack +# +#------------------------------------------------------------------------- + +subdir = src/backend/replication/pgoutput_repack +top_builddir = ../../../.. +include $(top_builddir)/src/Makefile.global + +OBJS = \ + $(WIN32RES) \ + pgoutput_repack.o +PGFILEDESC = "pgoutput_repack - logical replication output plugin for REPACK command" +NAME = pgoutput_repack + +all: all-shared-lib + +include $(top_srcdir)/src/Makefile.shlib + +install: all installdirs install-lib + +installdirs: installdirs-lib + +uninstall: uninstall-lib + +clean distclean: clean-lib + rm -f $(OBJS) diff --git a/src/backend/replication/pgoutput_repack/meson.build b/src/backend/replication/pgoutput_repack/meson.build new file mode 100644 index 00000000000..133e865a4a0 --- /dev/null +++ b/src/backend/replication/pgoutput_repack/meson.build @@ -0,0 +1,18 @@ +# Copyright (c) 2022-2024, PostgreSQL Global Development Group + +pgoutput_repack_sources = files( + 'pgoutput_repack.c', +) + +if host_system == 'windows' + pgoutput_repack_sources += rc_lib_gen.process(win32ver_rc, extra_args: [ + '--NAME', 'pgoutput_repack', + '--FILEDESC', 'pgoutput_repack - logical replication output plugin for REPACK command',]) +endif + +pgoutput_repack = shared_module('pgoutput_repack', + pgoutput_repack_sources, + kwargs: pg_mod_args, +) + +backend_targets += pgoutput_repack diff --git a/src/backend/replication/pgoutput_repack/pgoutput_repack.c b/src/backend/replication/pgoutput_repack/pgoutput_repack.c new file mode 100644 index 00000000000..687fbbc59bb --- /dev/null +++ b/src/backend/replication/pgoutput_repack/pgoutput_repack.c @@ -0,0 +1,288 @@ +/*------------------------------------------------------------------------- + * + * pgoutput_cluster.c + * Logical Replication output plugin for REPACK command + * + * Copyright (c) 2012-2024, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/backend/replication/pgoutput_cluster/pgoutput_cluster.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "access/heaptoast.h" +#include "commands/cluster.h" +#include "replication/snapbuild.h" + +PG_MODULE_MAGIC; + +static void plugin_startup(LogicalDecodingContext *ctx, + OutputPluginOptions *opt, bool is_init); +static void plugin_shutdown(LogicalDecodingContext *ctx); +static void plugin_begin_txn(LogicalDecodingContext *ctx, + ReorderBufferTXN *txn); +static void plugin_commit_txn(LogicalDecodingContext *ctx, + ReorderBufferTXN *txn, XLogRecPtr commit_lsn); +static void plugin_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, + Relation rel, ReorderBufferChange *change); +static void plugin_truncate(struct LogicalDecodingContext *ctx, + ReorderBufferTXN *txn, int nrelations, + Relation relations[], + ReorderBufferChange *change); +static void store_change(LogicalDecodingContext *ctx, + ConcurrentChangeKind kind, HeapTuple tuple); + +void +_PG_output_plugin_init(OutputPluginCallbacks *cb) +{ + AssertVariableIsOfType(&_PG_output_plugin_init, LogicalOutputPluginInit); + + cb->startup_cb = plugin_startup; + cb->begin_cb = plugin_begin_txn; + cb->change_cb = plugin_change; + cb->truncate_cb = plugin_truncate; + cb->commit_cb = plugin_commit_txn; + cb->shutdown_cb = plugin_shutdown; +} + + +/* initialize this plugin */ +static void +plugin_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt, + bool is_init) +{ + ctx->output_plugin_private = NULL; + + /* Probably unnecessary, as we don't use the SQL interface ... */ + opt->output_type = OUTPUT_PLUGIN_BINARY_OUTPUT; + + if (ctx->output_plugin_options != NIL) + { + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("This plugin does not expect any options"))); + } +} + +static void +plugin_shutdown(LogicalDecodingContext *ctx) +{ +} + +/* + * As we don't release the slot during processing of particular table, there's + * no room for SQL interface, even for debugging purposes. Therefore we need + * neither OutputPluginPrepareWrite() nor OutputPluginWrite() in the plugin + * callbacks. (Although we might want to write custom callbacks, this API + * seems to be unnecessarily generic for our purposes.) + */ + +/* BEGIN callback */ +static void +plugin_begin_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn) +{ +} + +/* COMMIT callback */ +static void +plugin_commit_txn(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, + XLogRecPtr commit_lsn) +{ +} + +/* + * Callback for individual changed tuples + */ +static void +plugin_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn, + Relation relation, ReorderBufferChange *change) +{ + RepackDecodingState *dstate; + + dstate = (RepackDecodingState *) ctx->output_writer_private; + + /* Only interested in one particular relation. */ + if (relation->rd_id != dstate->relid) + return; + + /* Decode entry depending on its type */ + switch (change->action) + { + case REORDER_BUFFER_CHANGE_INSERT: + { + HeapTuple newtuple; + + newtuple = change->data.tp.newtuple != NULL ? + change->data.tp.newtuple : NULL; + + /* + * Identity checks in the main function should have made this + * impossible. + */ + if (newtuple == NULL) + elog(ERROR, "Incomplete insert info."); + + store_change(ctx, CHANGE_INSERT, newtuple); + } + break; + case REORDER_BUFFER_CHANGE_UPDATE: + { + HeapTuple oldtuple, + newtuple; + + oldtuple = change->data.tp.oldtuple != NULL ? + change->data.tp.oldtuple : NULL; + newtuple = change->data.tp.newtuple != NULL ? + change->data.tp.newtuple : NULL; + + if (newtuple == NULL) + elog(ERROR, "Incomplete update info."); + + if (oldtuple != NULL) + store_change(ctx, CHANGE_UPDATE_OLD, oldtuple); + + store_change(ctx, CHANGE_UPDATE_NEW, newtuple); + } + break; + case REORDER_BUFFER_CHANGE_DELETE: + { + HeapTuple oldtuple; + + oldtuple = change->data.tp.oldtuple ? + change->data.tp.oldtuple : NULL; + + if (oldtuple == NULL) + elog(ERROR, "Incomplete delete info."); + + store_change(ctx, CHANGE_DELETE, oldtuple); + } + break; + default: + /* Should not come here */ + Assert(false); + break; + } +} + +static void +plugin_truncate(struct LogicalDecodingContext *ctx, ReorderBufferTXN *txn, + int nrelations, Relation relations[], + ReorderBufferChange *change) +{ + RepackDecodingState *dstate; + int i; + Relation relation = NULL; + + dstate = (RepackDecodingState *) ctx->output_writer_private; + + /* Find the relation we are processing. */ + for (i = 0; i < nrelations; i++) + { + relation = relations[i]; + + if (RelationGetRelid(relation) == dstate->relid) + break; + } + + /* Is this truncation of another relation? */ + if (i == nrelations) + return; + + store_change(ctx, CHANGE_TRUNCATE, NULL); +} + +/* Store concurrent data change. */ +static void +store_change(LogicalDecodingContext *ctx, ConcurrentChangeKind kind, + HeapTuple tuple) +{ + RepackDecodingState *dstate; + char *change_raw; + ConcurrentChange change; + bool flattened = false; + Size size; + Datum values[1]; + bool isnull[1]; + char *dst, + *dst_start; + + dstate = (RepackDecodingState *) ctx->output_writer_private; + + size = MAXALIGN(VARHDRSZ) + SizeOfConcurrentChange; + + if (tuple) + { + /* + * ReorderBufferCommit() stores the TOAST chunks in its private memory + * context and frees them after having called apply_change(). + * Therefore we need flat copy (including TOAST) that we eventually + * copy into the memory context which is available to + * decode_concurrent_changes(). + */ + if (HeapTupleHasExternal(tuple)) + { + /* + * toast_flatten_tuple_to_datum() might be more convenient but we + * don't want the decompression it does. + */ + tuple = toast_flatten_tuple(tuple, dstate->tupdesc); + flattened = true; + } + + size += tuple->t_len; + } + + /* XXX Isn't there any function / macro to do this? */ + if (size >= 0x3FFFFFFF) + elog(ERROR, "Change is too big."); + + /* Construct the change. */ + change_raw = (char *) palloc0(size); + SET_VARSIZE(change_raw, size); + + /* + * Since the varlena alignment might not be sufficient for the structure, + * set the fields in a local instance and remember where it should + * eventually be copied. + */ + change.kind = kind; + dst_start = (char *) VARDATA(change_raw); + + /* No other information is needed for TRUNCATE. */ + if (change.kind == CHANGE_TRUNCATE) + { + memcpy(dst_start, &change, SizeOfConcurrentChange); + goto store; + } + + /* + * Copy the tuple. + * + * CAUTION: change->tup_data.t_data must be fixed on retrieval! + */ + memcpy(&change.tup_data, tuple, sizeof(HeapTupleData)); + dst = dst_start + SizeOfConcurrentChange; + memcpy(dst, tuple->t_data, tuple->t_len); + + /* The data has been copied. */ + if (flattened) + pfree(tuple); + +store: + /* Copy the structure so it can be stored. */ + memcpy(dst_start, &change, SizeOfConcurrentChange); + + /* Store as tuple of 1 bytea column. */ + values[0] = PointerGetDatum(change_raw); + isnull[0] = false; + tuplestore_putvalues(dstate->tstore, dstate->tupdesc_change, + values, isnull); + + /* Accounting. */ + dstate->nchanges++; + + /* Cleanup. */ + pfree(change_raw); +} diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c index 2fa045e6b0f..e9ddf39500c 100644 --- a/src/backend/storage/ipc/ipci.c +++ b/src/backend/storage/ipc/ipci.c @@ -25,6 +25,7 @@ #include "access/xlogprefetcher.h" #include "access/xlogrecovery.h" #include "commands/async.h" +#include "commands/cluster.h" #include "miscadmin.h" #include "pgstat.h" #include "postmaster/autovacuum.h" diff --git a/src/backend/storage/lmgr/generate-lwlocknames.pl b/src/backend/storage/lmgr/generate-lwlocknames.pl index cd3e43c448a..519f3953638 100644 --- a/src/backend/storage/lmgr/generate-lwlocknames.pl +++ b/src/backend/storage/lmgr/generate-lwlocknames.pl @@ -162,7 +162,7 @@ while (<$lwlocklist>) die "$wait_event_lwlocks[$lwlock_count] defined in wait_event_names.txt but " - . " missing from lwlocklist.h" + . "missing from lwlocklist.h" if $lwlock_count < scalar @wait_event_lwlocks; die diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c index 6fe268a8eec..d27a4c30548 100644 --- a/src/backend/utils/cache/relcache.c +++ b/src/backend/utils/cache/relcache.c @@ -64,6 +64,7 @@ #include "catalog/pg_type.h" #include "catalog/schemapg.h" #include "catalog/storage.h" +#include "commands/cluster.h" #include "commands/policy.h" #include "commands/publicationcmds.h" #include "commands/trigger.h" diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c index bc7840052fe..6d46537cbe8 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -213,7 +213,6 @@ static List *exportedSnapshots = NIL; /* Prototypes for local functions */ static void UnregisterSnapshotNoOwner(Snapshot snapshot); -static void FreeSnapshot(Snapshot snapshot); static void SnapshotResetXmin(void); /* ResourceOwner callbacks to track snapshot references */ @@ -657,7 +656,7 @@ CopySnapshot(Snapshot snapshot) * FreeSnapshot * Free the memory associated with a snapshot. */ -static void +void FreeSnapshot(Snapshot snapshot) { Assert(snapshot->regd_count == 0); diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c index 59ff6e0923b..528fb08154a 100644 --- a/src/bin/psql/tab-complete.in.c +++ b/src/bin/psql/tab-complete.in.c @@ -4998,18 +4998,27 @@ match_previous_words(int pattern_id, } /* REPACK */ - else if (Matches("REPACK")) + else if (Matches("REPACK") || Matches("REPACK", "(*)")) + COMPLETE_WITH_SCHEMA_QUERY_PLUS(Query_for_list_of_clusterables, + "CONCURRENTLY"); + else if (Matches("REPACK", "CONCURRENTLY")) COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_clusterables); - else if (Matches("REPACK", "(*)")) + else if (Matches("REPACK", "(*)", "CONCURRENTLY")) COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_clusterables); - /* If we have REPACK <sth>, then add "USING INDEX" */ - else if (Matches("REPACK", MatchAnyExcept("("))) + /* If we have REPACK [ CONCURRENTLY ] <sth>, then add "USING INDEX" */ + else if (Matches("REPACK", MatchAnyExcept("(|CONCURRENTLY")) || + Matches("REPACK", "CONCURRENTLY", MatchAnyExcept("("))) COMPLETE_WITH("USING INDEX"); - /* If we have REPACK (*) <sth>, then add "USING INDEX" */ - else if (Matches("REPACK", "(*)", MatchAny)) + /* If we have REPACK (*) [ CONCURRENTLY ] <sth>, then add "USING INDEX" */ + else if (Matches("REPACK", "(*)", MatchAnyExcept("CONCURRENTLY")) || + Matches("REPACK", "(*)", "CONCURRENTLY", MatchAnyExcept("("))) COMPLETE_WITH("USING INDEX"); - /* If we have REPACK <sth> USING, then add the index as well */ - else if (Matches("REPACK", MatchAny, "USING", "INDEX")) + + /* + * Complete ... [ (*) ] [ CONCURRENTLY ] <sth> USING INDEX, with a list of + * indexes for <sth>. + */ + else if (TailMatches(MatchAnyExcept("(|CONCURRENTLY"), "USING", "INDEX")) { set_completion_reference(prev3_wd); COMPLETE_WITH_SCHEMA_QUERY(Query_for_index_of_table); diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h index a2bd5a897f8..b82dd17a966 100644 --- a/src/include/access/heapam.h +++ b/src/include/access/heapam.h @@ -323,14 +323,15 @@ extern void heap_multi_insert(Relation relation, struct TupleTableSlot **slots, BulkInsertState bistate); extern TM_Result heap_delete(Relation relation, ItemPointer tid, CommandId cid, Snapshot crosscheck, bool wait, - struct TM_FailureData *tmfd, bool changingPart); + struct TM_FailureData *tmfd, bool changingPart, + bool wal_logical); extern void heap_finish_speculative(Relation relation, ItemPointer tid); extern void heap_abort_speculative(Relation relation, ItemPointer tid); extern TM_Result heap_update(Relation relation, ItemPointer otid, HeapTuple newtup, CommandId cid, Snapshot crosscheck, bool wait, struct TM_FailureData *tmfd, LockTupleMode *lockmode, - TU_UpdateIndexes *update_indexes); + TU_UpdateIndexes *update_indexes, bool wal_logical); extern TM_Result heap_lock_tuple(Relation relation, HeapTuple tuple, CommandId cid, LockTupleMode mode, LockWaitPolicy wait_policy, bool follow_updates, @@ -411,6 +412,10 @@ extern HTSV_Result HeapTupleSatisfiesVacuumHorizon(HeapTuple htup, Buffer buffer TransactionId *dead_after); extern void HeapTupleSetHintBits(HeapTupleHeader tuple, Buffer buffer, uint16 infomask, TransactionId xid); +extern bool HeapTupleMVCCInserted(HeapTuple htup, Snapshot snapshot, + Buffer buffer); +extern bool HeapTupleMVCCNotDeleted(HeapTuple htup, Snapshot snapshot, + Buffer buffer); extern bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple); extern bool HeapTupleIsSurelyDead(HeapTuple htup, struct GlobalVisState *vistest); diff --git a/src/include/access/heapam_xlog.h b/src/include/access/heapam_xlog.h index 277df6b3cf0..8d4af07f840 100644 --- a/src/include/access/heapam_xlog.h +++ b/src/include/access/heapam_xlog.h @@ -104,6 +104,8 @@ #define XLH_DELETE_CONTAINS_OLD_KEY (1<<2) #define XLH_DELETE_IS_SUPER (1<<3) #define XLH_DELETE_IS_PARTITION_MOVE (1<<4) +/* See heap_delete() */ +#define XLH_DELETE_NO_LOGICAL (1<<5) /* convenience macro for checking whether any form of old tuple was logged */ #define XLH_DELETE_CONTAINS_OLD \ diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h index 1c9e802a6b1..289b64edfd9 100644 --- a/src/include/access/tableam.h +++ b/src/include/access/tableam.h @@ -22,6 +22,7 @@ #include "access/xact.h" #include "commands/vacuum.h" #include "executor/tuptable.h" +#include "replication/logical.h" #include "storage/read_stream.h" #include "utils/rel.h" #include "utils/snapshot.h" @@ -623,6 +624,8 @@ typedef struct TableAmRoutine Relation OldIndex, bool use_sort, TransactionId OldestXmin, + Snapshot snapshot, + LogicalDecodingContext *decoding_ctx, TransactionId *xid_cutoff, MultiXactId *multi_cutoff, double *num_tuples, @@ -1627,6 +1630,10 @@ table_relation_copy_data(Relation rel, const RelFileLocator *newrlocator) * not needed for the relation's AM * - *xid_cutoff - ditto * - *multi_cutoff - ditto + * - snapshot - if != NULL, ignore data changes done by transactions that this + * (MVCC) snapshot considers still in-progress or in the future. + * - decoding_ctx - logical decoding context, to capture concurrent data + * changes. * * Output parameters: * - *xid_cutoff - rel's new relfrozenxid value, may be invalid @@ -1639,6 +1646,8 @@ table_relation_copy_for_cluster(Relation OldTable, Relation NewTable, Relation OldIndex, bool use_sort, TransactionId OldestXmin, + Snapshot snapshot, + LogicalDecodingContext *decoding_ctx, TransactionId *xid_cutoff, MultiXactId *multi_cutoff, double *num_tuples, @@ -1647,6 +1656,7 @@ table_relation_copy_for_cluster(Relation OldTable, Relation NewTable, { OldTable->rd_tableam->relation_copy_for_cluster(OldTable, NewTable, OldIndex, use_sort, OldestXmin, + snapshot, decoding_ctx, xid_cutoff, multi_cutoff, num_tuples, tups_vacuumed, tups_recently_dead); diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h index 890998d84bb..4a508c57a50 100644 --- a/src/include/commands/cluster.h +++ b/src/include/commands/cluster.h @@ -13,10 +13,15 @@ #ifndef CLUSTER_H #define CLUSTER_H +#include "nodes/execnodes.h" #include "nodes/parsenodes.h" #include "parser/parse_node.h" +#include "replication/logical.h" #include "storage/lock.h" +#include "storage/relfilelocator.h" #include "utils/relcache.h" +#include "utils/resowner.h" +#include "utils/tuplestore.h" /* flag bits for ClusterParams->options */ @@ -25,6 +30,8 @@ #define CLUOPT_RECHECK_ISCLUSTERED 0x04 /* recheck relation state for * indisclustered */ #define CLUOPT_ANALYZE 0x08 /* do an ANALYZE */ +#define CLUOPT_CONCURRENT 0x08 /* allow concurrent data changes */ + /* options for CLUSTER */ typedef struct ClusterParams @@ -33,14 +40,95 @@ typedef struct ClusterParams } ClusterParams; +/* + * The following definitions are used by REPACK CONCURRENTLY. + */ + +extern RelFileLocator repacked_rel_locator; +extern RelFileLocator repacked_rel_toast_locator; + +typedef enum +{ + CHANGE_INSERT, + CHANGE_UPDATE_OLD, + CHANGE_UPDATE_NEW, + CHANGE_DELETE, + CHANGE_TRUNCATE +} ConcurrentChangeKind; + +typedef struct ConcurrentChange +{ + /* See the enum above. */ + ConcurrentChangeKind kind; + + /* + * The actual tuple. + * + * The tuple data follows the ConcurrentChange structure. Before use make + * sure the tuple is correctly aligned (ConcurrentChange can be stored as + * bytea) and that tuple->t_data is fixed. + */ + HeapTupleData tup_data; +} ConcurrentChange; + +#define SizeOfConcurrentChange (offsetof(ConcurrentChange, tup_data) + \ + sizeof(HeapTupleData)) + +/* + * Logical decoding state. + * + * Here we store the data changes that we decode from WAL while the table + * contents is being copied to a new storage. Also the necessary metadata + * needed to apply these changes to the table is stored here. + */ +typedef struct RepackDecodingState +{ + /* The relation whose changes we're decoding. */ + Oid relid; + + /* + * Decoded changes are stored here. Although we try to avoid excessive + * batches, it can happen that the changes need to be stored to disk. The + * tuplestore does this transparently. + */ + Tuplestorestate *tstore; + + /* The current number of changes in tstore. */ + double nchanges; + + /* + * Descriptor to store the ConcurrentChange structure serialized (bytea). + * We can't store the tuple directly because tuplestore only supports + * minimum tuple and we may need to transfer OID system column from the + * output plugin. Also we need to transfer the change kind, so it's better + * to put everything in the structure than to use 2 tuplestores "in + * parallel". + */ + TupleDesc tupdesc_change; + + /* Tuple descriptor needed to update indexes. */ + TupleDesc tupdesc; + + /* Slot to retrieve data from tstore. */ + TupleTableSlot *tsslot; + + ResourceOwner resowner; +} RepackDecodingState; + + + extern void ExecRepack(ParseState *pstate, RepackStmt *stmt, bool isTopLevel); extern void cluster_rel(RepackCommand command, bool usingindex, - Relation OldHeap, Oid indexOid, ClusterParams *params); + Relation OldHeap, Oid indexOid, ClusterParams *params, + bool isTopLevel); extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid, LOCKMODE lockmode); extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal); +extern void repack_decode_concurrent_changes(LogicalDecodingContext *ctx, + XLogRecPtr end_of_wal); + extern Oid make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, Oid NewAccessMethod, char relpersistence, LOCKMODE lockmode); extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, @@ -48,6 +136,7 @@ extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap, bool swap_toast_by_content, bool check_constraints, bool is_internal, + bool reindex, TransactionId frozenXid, MultiXactId cutoffMulti, char newrelpersistence); diff --git a/src/include/commands/progress.h b/src/include/commands/progress.h index 5b6639c114c..93917ad5544 100644 --- a/src/include/commands/progress.h +++ b/src/include/commands/progress.h @@ -59,18 +59,20 @@ /* * Progress parameters for REPACK. * - * Note: Since REPACK shares some code with CLUSTER, these values are also - * used by CLUSTER. (CLUSTER is now deprecated, so it makes little sense to - * introduce a separate set of constants.) + * Note: Since REPACK shares some code with CLUSTER, (some of) these values + * are also used by CLUSTER. (CLUSTER is now deprecated, so it makes little + * sense to introduce a separate set of constants.) */ #define PROGRESS_REPACK_COMMAND 0 #define PROGRESS_REPACK_PHASE 1 #define PROGRESS_REPACK_INDEX_RELID 2 #define PROGRESS_REPACK_HEAP_TUPLES_SCANNED 3 -#define PROGRESS_REPACK_HEAP_TUPLES_WRITTEN 4 -#define PROGRESS_REPACK_TOTAL_HEAP_BLKS 5 -#define PROGRESS_REPACK_HEAP_BLKS_SCANNED 6 -#define PROGRESS_REPACK_INDEX_REBUILD_COUNT 7 +#define PROGRESS_REPACK_HEAP_TUPLES_INSERTED 4 +#define PROGRESS_REPACK_HEAP_TUPLES_UPDATED 5 +#define PROGRESS_REPACK_HEAP_TUPLES_DELETED 6 +#define PROGRESS_REPACK_TOTAL_HEAP_BLKS 7 +#define PROGRESS_REPACK_HEAP_BLKS_SCANNED 8 +#define PROGRESS_REPACK_INDEX_REBUILD_COUNT 9 /* * Phases of repack (as advertised via PROGRESS_REPACK_PHASE). @@ -79,9 +81,10 @@ #define PROGRESS_REPACK_PHASE_INDEX_SCAN_HEAP 2 #define PROGRESS_REPACK_PHASE_SORT_TUPLES 3 #define PROGRESS_REPACK_PHASE_WRITE_NEW_HEAP 4 -#define PROGRESS_REPACK_PHASE_SWAP_REL_FILES 5 -#define PROGRESS_REPACK_PHASE_REBUILD_INDEX 6 -#define PROGRESS_REPACK_PHASE_FINAL_CLEANUP 7 +#define PROGRESS_REPACK_PHASE_CATCH_UP 5 +#define PROGRESS_REPACK_PHASE_SWAP_REL_FILES 6 +#define PROGRESS_REPACK_PHASE_REBUILD_INDEX 7 +#define PROGRESS_REPACK_PHASE_FINAL_CLEANUP 8 /* * Commands of PROGRESS_REPACK diff --git a/src/include/replication/snapbuild.h b/src/include/replication/snapbuild.h index 6d4d2d1814c..802fc4b0823 100644 --- a/src/include/replication/snapbuild.h +++ b/src/include/replication/snapbuild.h @@ -73,6 +73,7 @@ extern void FreeSnapshotBuilder(SnapBuild *builder); extern void SnapBuildSnapDecRefcount(Snapshot snap); extern Snapshot SnapBuildInitialSnapshot(SnapBuild *builder); +extern Snapshot SnapBuildInitialSnapshotForRepack(SnapBuild *builder); extern Snapshot SnapBuildMVCCFromHistoric(Snapshot snapshot, bool in_place); extern const char *SnapBuildExportSnapshot(SnapBuild *builder); extern void SnapBuildClearExportedSnapshot(void); diff --git a/src/include/storage/lockdefs.h b/src/include/storage/lockdefs.h index 7f3ba0352f6..2739327b0da 100644 --- a/src/include/storage/lockdefs.h +++ b/src/include/storage/lockdefs.h @@ -36,8 +36,8 @@ typedef int LOCKMODE; #define AccessShareLock 1 /* SELECT */ #define RowShareLock 2 /* SELECT FOR UPDATE/FOR SHARE */ #define RowExclusiveLock 3 /* INSERT, UPDATE, DELETE */ -#define ShareUpdateExclusiveLock 4 /* VACUUM (non-FULL), ANALYZE, CREATE - * INDEX CONCURRENTLY */ +#define ShareUpdateExclusiveLock 4 /* VACUUM (non-exclusive), ANALYZE, CREATE + * INDEX CONCURRENTLY, REPACK CONCURRENTLY */ #define ShareLock 5 /* CREATE INDEX (WITHOUT CONCURRENTLY) */ #define ShareRowExclusiveLock 6 /* like EXCLUSIVE MODE, but allows ROW * SHARE */ diff --git a/src/include/utils/snapmgr.h b/src/include/utils/snapmgr.h index f65f83c85cd..1f821fd2ccd 100644 --- a/src/include/utils/snapmgr.h +++ b/src/include/utils/snapmgr.h @@ -64,6 +64,8 @@ extern Snapshot GetLatestSnapshot(void); extern void SnapshotSetCommandId(CommandId curcid); extern Snapshot CopySnapshot(Snapshot snapshot); +extern void FreeSnapshot(Snapshot snapshot); + extern Snapshot GetCatalogSnapshot(Oid relid); extern Snapshot GetNonHistoricCatalogSnapshot(Oid relid); extern void InvalidateCatalogSnapshot(void); diff --git a/src/test/modules/injection_points/Makefile b/src/test/modules/injection_points/Makefile index fc82cd67f6c..f16422175f8 100644 --- a/src/test/modules/injection_points/Makefile +++ b/src/test/modules/injection_points/Makefile @@ -11,10 +11,11 @@ EXTENSION = injection_points DATA = injection_points--1.0.sql PGFILEDESC = "injection_points - facility for injection points" -REGRESS = injection_points hashagg reindex_conc vacuum +# REGRESS = injection_points hashagg reindex_conc vacuum REGRESS_OPTS = --dlpath=$(top_builddir)/src/test/regress -ISOLATION = basic inplace syscache-update-pruned +ISOLATION = basic inplace syscache-update-pruned repack +ISOLATION_OPTS = --temp-config $(top_srcdir)/src/test/modules/injection_points/logical.conf TAP_TESTS = 1 diff --git a/src/test/modules/injection_points/expected/repack.out b/src/test/modules/injection_points/expected/repack.out new file mode 100644 index 00000000000..b575e9052ee --- /dev/null +++ b/src/test/modules/injection_points/expected/repack.out @@ -0,0 +1,113 @@ +Parsed test spec with 2 sessions + +starting permutation: wait_before_lock change_existing change_new change_subxact1 change_subxact2 check2 wakeup_before_lock check1 +injection_points_attach +----------------------- + +(1 row) + +step wait_before_lock: + REPACK (CONCURRENTLY) repack_test USING INDEX repack_test_pkey; + <waiting ...> +step change_existing: + UPDATE repack_test SET i=10 where i=1; + UPDATE repack_test SET j=20 where i=2; + UPDATE repack_test SET i=30 where i=3; + UPDATE repack_test SET i=40 where i=30; + DELETE FROM repack_test WHERE i=4; + +step change_new: + INSERT INTO repack_test(i, j) VALUES (5, 5), (6, 6), (7, 7), (8, 8); + UPDATE repack_test SET i=50 where i=5; + UPDATE repack_test SET j=60 where i=6; + DELETE FROM repack_test WHERE i=7; + +step change_subxact1: + BEGIN; + INSERT INTO repack_test(i, j) VALUES (100, 100); + SAVEPOINT s1; + UPDATE repack_test SET i=101 where i=100; + SAVEPOINT s2; + UPDATE repack_test SET i=102 where i=101; + COMMIT; + +step change_subxact2: + BEGIN; + SAVEPOINT s1; + INSERT INTO repack_test(i, j) VALUES (110, 110); + ROLLBACK TO SAVEPOINT s1; + INSERT INTO repack_test(i, j) VALUES (110, 111); + COMMIT; + +step check2: + INSERT INTO relfilenodes(node) + SELECT relfilenode FROM pg_class WHERE relname='repack_test'; + + SELECT i, j FROM repack_test ORDER BY i, j; + + INSERT INTO data_s2(i, j) + SELECT i, j FROM repack_test; + + i| j +---+--- + 2| 20 + 6| 60 + 8| 8 + 10| 1 + 40| 3 + 50| 5 +102|100 +110|111 +(8 rows) + +step wakeup_before_lock: + SELECT injection_points_wakeup('repack-concurrently-before-lock'); + +injection_points_wakeup +----------------------- + +(1 row) + +step wait_before_lock: <... completed> +step check1: + INSERT INTO relfilenodes(node) + SELECT relfilenode FROM pg_class WHERE relname='repack_test'; + + SELECT count(DISTINCT node) FROM relfilenodes; + + SELECT i, j FROM repack_test ORDER BY i, j; + + INSERT INTO data_s1(i, j) + SELECT i, j FROM repack_test; + + SELECT count(*) + FROM data_s1 d1 FULL JOIN data_s2 d2 USING (i, j) + WHERE d1.i ISNULL OR d2.i ISNULL; + +count +----- + 2 +(1 row) + + i| j +---+--- + 2| 20 + 6| 60 + 8| 8 + 10| 1 + 40| 3 + 50| 5 +102|100 +110|111 +(8 rows) + +count +----- + 0 +(1 row) + +injection_points_detach +----------------------- + +(1 row) + diff --git a/src/test/modules/injection_points/logical.conf b/src/test/modules/injection_points/logical.conf new file mode 100644 index 00000000000..c8f264bc6cb --- /dev/null +++ b/src/test/modules/injection_points/logical.conf @@ -0,0 +1 @@ +wal_level = logical \ No newline at end of file diff --git a/src/test/modules/injection_points/meson.build b/src/test/modules/injection_points/meson.build index 20390d6b4bf..29561103bbf 100644 --- a/src/test/modules/injection_points/meson.build +++ b/src/test/modules/injection_points/meson.build @@ -47,9 +47,13 @@ tests += { 'specs': [ 'basic', 'inplace', + 'repack', 'syscache-update-pruned', ], 'runningcheck': false, # see syscache-update-pruned + # 'repack' requires wal_level = 'logical'. + 'regress_args': ['--temp-config', files('logical.conf')], + }, 'tap': { 'env': { diff --git a/src/test/modules/injection_points/specs/repack.spec b/src/test/modules/injection_points/specs/repack.spec new file mode 100644 index 00000000000..75850334986 --- /dev/null +++ b/src/test/modules/injection_points/specs/repack.spec @@ -0,0 +1,143 @@ +# Prefix the system columns with underscore as they are not allowed as column +# names. +setup +{ + CREATE EXTENSION injection_points; + + CREATE TABLE repack_test(i int PRIMARY KEY, j int); + INSERT INTO repack_test(i, j) VALUES (1, 1), (2, 2), (3, 3), (4, 4); + + CREATE TABLE relfilenodes(node oid); + + CREATE TABLE data_s1(i int, j int); + CREATE TABLE data_s2(i int, j int); +} + +teardown +{ + DROP TABLE repack_test; + DROP EXTENSION injection_points; + + DROP TABLE relfilenodes; + DROP TABLE data_s1; + DROP TABLE data_s2; +} + +session s1 +setup +{ + SELECT injection_points_set_local(); + SELECT injection_points_attach('repack-concurrently-before-lock', 'wait'); +} +# Perform the initial load and wait for s2 to do some data changes. +step wait_before_lock +{ + REPACK (CONCURRENTLY) repack_test USING INDEX repack_test_pkey; +} +# Check the table from the perspective of s1. +# +# Besides the contents, we also check that relfilenode has changed. + +# Have each session write the contents into a table and use FULL JOIN to check +# if the outputs are identical. +step check1 +{ + INSERT INTO relfilenodes(node) + SELECT relfilenode FROM pg_class WHERE relname='repack_test'; + + SELECT count(DISTINCT node) FROM relfilenodes; + + SELECT i, j FROM repack_test ORDER BY i, j; + + INSERT INTO data_s1(i, j) + SELECT i, j FROM repack_test; + + SELECT count(*) + FROM data_s1 d1 FULL JOIN data_s2 d2 USING (i, j) + WHERE d1.i ISNULL OR d2.i ISNULL; +} +teardown +{ + SELECT injection_points_detach('repack-concurrently-before-lock'); +} + +session s2 +# Change the existing data. UPDATE changes both key and non-key columns. Also +# update one row twice to test whether tuple version generated by this session +# can be found. +step change_existing +{ + UPDATE repack_test SET i=10 where i=1; + UPDATE repack_test SET j=20 where i=2; + UPDATE repack_test SET i=30 where i=3; + UPDATE repack_test SET i=40 where i=30; + DELETE FROM repack_test WHERE i=4; +} +# Insert new rows and UPDATE / DELETE some of them. Again, update both key and +# non-key column. +step change_new +{ + INSERT INTO repack_test(i, j) VALUES (5, 5), (6, 6), (7, 7), (8, 8); + UPDATE repack_test SET i=50 where i=5; + UPDATE repack_test SET j=60 where i=6; + DELETE FROM repack_test WHERE i=7; +} + +# When applying concurrent data changes, we should see the effects of an +# in-progress subtransaction. +# +# XXX Not sure this test is useful now - it was designed for the patch that +# preserves tuple visibility and which therefore modifies +# TransactionIdIsCurrentTransactionId(). +step change_subxact1 +{ + BEGIN; + INSERT INTO repack_test(i, j) VALUES (100, 100); + SAVEPOINT s1; + UPDATE repack_test SET i=101 where i=100; + SAVEPOINT s2; + UPDATE repack_test SET i=102 where i=101; + COMMIT; +} + +# When applying concurrent data changes, we should not see the effects of a +# rolled back subtransaction. +# +# XXX Is this test useful? See above. +step change_subxact2 +{ + BEGIN; + SAVEPOINT s1; + INSERT INTO repack_test(i, j) VALUES (110, 110); + ROLLBACK TO SAVEPOINT s1; + INSERT INTO repack_test(i, j) VALUES (110, 111); + COMMIT; +} + +# Check the table from the perspective of s2. +step check2 +{ + INSERT INTO relfilenodes(node) + SELECT relfilenode FROM pg_class WHERE relname='repack_test'; + + SELECT i, j FROM repack_test ORDER BY i, j; + + INSERT INTO data_s2(i, j) + SELECT i, j FROM repack_test; +} +step wakeup_before_lock +{ + SELECT injection_points_wakeup('repack-concurrently-before-lock'); +} + +# Test if data changes introduced while one session is performing REPACK +# CONCURRENTLY find their way into the table. +permutation + wait_before_lock + change_existing + change_new + change_subxact1 + change_subxact2 + check2 + wakeup_before_lock + check1 diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 3a1d1d28282..fe227bd8a30 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1999,17 +1999,17 @@ pg_stat_progress_cluster| SELECT s.pid, WHEN 2 THEN 'index scanning heap'::text WHEN 3 THEN 'sorting tuples'::text WHEN 4 THEN 'writing new heap'::text - WHEN 5 THEN 'swapping relation files'::text - WHEN 6 THEN 'rebuilding index'::text - WHEN 7 THEN 'performing final cleanup'::text + WHEN 6 THEN 'swapping relation files'::text + WHEN 7 THEN 'rebuilding index'::text + WHEN 8 THEN 'performing final cleanup'::text ELSE NULL::text END AS phase, (s.param3)::oid AS cluster_index_relid, s.param4 AS heap_tuples_scanned, s.param5 AS heap_tuples_written, - s.param6 AS heap_blks_total, - s.param7 AS heap_blks_scanned, - s.param8 AS index_rebuild_count + s.param8 AS heap_blks_total, + s.param9 AS heap_blks_scanned, + s.param10 AS index_rebuild_count FROM (pg_stat_get_progress_info('CLUSTER'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20) LEFT JOIN pg_database d ON ((s.datid = d.oid))); pg_stat_progress_copy| SELECT s.pid, @@ -2081,17 +2081,20 @@ pg_stat_progress_repack| SELECT s.pid, WHEN 2 THEN 'index scanning heap'::text WHEN 3 THEN 'sorting tuples'::text WHEN 4 THEN 'writing new heap'::text - WHEN 5 THEN 'swapping relation files'::text - WHEN 6 THEN 'rebuilding index'::text - WHEN 7 THEN 'performing final cleanup'::text + WHEN 5 THEN 'catch-up'::text + WHEN 6 THEN 'swapping relation files'::text + WHEN 7 THEN 'rebuilding index'::text + WHEN 8 THEN 'performing final cleanup'::text ELSE NULL::text END AS phase, (s.param3)::oid AS repack_index_relid, s.param4 AS heap_tuples_scanned, - s.param5 AS heap_tuples_written, - s.param6 AS heap_blks_total, - s.param7 AS heap_blks_scanned, - s.param8 AS index_rebuild_count + s.param5 AS heap_tuples_inserted, + s.param6 AS heap_tuples_updated, + s.param7 AS heap_tuples_deleted, + s.param8 AS heap_blks_total, + s.param9 AS heap_blks_scanned, + s.param10 AS index_rebuild_count FROM (pg_stat_get_progress_info('REPACK'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20) LEFT JOIN pg_database d ON ((s.datid = d.oid))); pg_stat_progress_vacuum| SELECT s.pid, diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 98242e25432..b64ab8dfab4 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -485,6 +485,8 @@ CompressFileHandle CompressionLocation CompressorState ComputeXidHorizonsResult +ConcurrentChange +ConcurrentChangeKind ConditionVariable ConditionVariableMinimallyPadded ConditionalStack @@ -1257,6 +1259,7 @@ IndexElem IndexFetchHeapData IndexFetchTableData IndexInfo +IndexInsertState IndexList IndexOnlyScan IndexOnlyScanState @@ -2538,6 +2541,7 @@ ReorderBufferUpdateProgressTxnCB ReorderTuple RepOriginId RepackCommand +RepackDecodingState RepackStmt ReparameterizeForeignPathByChild_function ReplaceVarsFromTargetList_context -- 2.39.5 --3q6txozlgl6t37td Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="v20-0006-Preserve-visibility-information-of-the-concurren.patch" ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/3] Remove unnecessary volatile qualifiers. @ 2026-02-18 16:31 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ 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] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v1 1/1] Remove unnecessary volatile qualifiers. @ 2026-06-30 21:41 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers to pg_atomic_* variables or local variables that hold a value returned by a pg_atomic_* function. The pointer arguments for the pg_atomic_* functions are volatile-qualified, so there's no need to mark the pointer volatile. Likewise, a local variable that just holds the result of a pg_atomic_* function gains nothing from volatile. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile when they were modified inside a PG_TRY block and used afterward, but the PG_TRY was later removed. --- src/backend/access/transam/clog.c | 2 +- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 10 ++++----- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 36 insertions(+), 43 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..47975ba892f 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,7 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; + PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..4acef19e563 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void) { uint64 local_gen; uint64 shared_gen; - volatile uint32 flags; + uint32 flags; Assert(MyProcSignalSlot); @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --hE8tq9meMVMcgUcn-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* remove unnecessary volatile qualifiers @ 2026-06-30 21:47 Nathan Bossart <[email protected]> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <[email protected]> 0 siblings, 1 reply; 209+ 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] 209+ messages in thread
* Re: remove unnecessary volatile qualifiers 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> @ 2026-07-06 11:58 ` Heikki Linnakangas <[email protected]> 2026-07-06 15:47 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 0 siblings, 1 reply; 209+ messages in thread From: Heikki Linnakangas @ 2026-07-06 11:58 UTC (permalink / raw) To: Nathan Bossart <[email protected]>; 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] 209+ messages in thread
* Re: remove unnecessary volatile qualifiers 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <[email protected]> @ 2026-07-06 15:47 ` Nathan Bossart <[email protected]> 2026-07-07 16:03 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 0 siblings, 1 reply; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:47 UTC (permalink / raw) To: Heikki Linnakangas <[email protected]>; +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] 209+ messages in thread
* Re: remove unnecessary volatile qualifiers 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <[email protected]> 2026-07-06 15:47 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> @ 2026-07-07 16:03 ` Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-07 16:03 UTC (permalink / raw) To: Heikki Linnakangas <[email protected]>; +Cc: pgsql-hackers Committed. -- nathan ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
* [PATCH v2 1/1] Remove unnecessary volatile qualifiers. @ 2026-07-06 15:24 Nathan Bossart <[email protected]> 0 siblings, 0 replies; 209+ messages in thread From: Nathan Bossart @ 2026-07-06 15:24 UTC (permalink / raw) This commit cleans up volatile qualifiers that fit the below criteria: * Accesses to shared memory protected by a spinlock or LWLock. Before commit 0709b7ee72, callers had to use volatile when accessing spinlock-protected shared memory. Since spinlock acquire/release became compiler barriers, and because LWLocks provide the same guarantee, that is no longer necessary. These either predate that change or were cargo-culted from code that did. * Pointers used only to find the address of a member. The volatile qualifier only affects accesses made by dereferencing the pointer, so it is unnecessary there. * Accesses to struct members that are marked volatile in the struct definition. There's no need to mark these pointers volatile, either. * Leftovers from removed PG_TRY blocks. These were marked volatile to protect a value that is modified inside a PG_TRY block and used afterward, but the PG_TRY has since been removed. --- src/backend/access/transam/clog.c | 7 +++--- src/backend/catalog/index.c | 2 +- src/backend/commands/async.c | 4 ++-- src/backend/replication/syncrep.c | 19 +++++++--------- src/backend/storage/ipc/procsignal.c | 8 +++---- src/backend/storage/ipc/shm_toc.c | 31 ++++++++++++--------------- src/backend/storage/lmgr/lock.c | 2 +- src/backend/storage/lmgr/proc.c | 3 +-- src/test/modules/test_shm_mq/setup.c | 4 ++-- src/test/modules/test_shm_mq/worker.c | 2 +- 10 files changed, 37 insertions(+), 45 deletions(-) diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c index 75012d4b8f0..6f7f6b86eb6 100644 --- a/src/backend/access/transam/clog.c +++ b/src/backend/access/transam/clog.c @@ -450,7 +450,6 @@ static bool TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, XLogRecPtr lsn, int64 pageno) { - volatile PROC_HDR *procglobal = ProcGlobal; PGPROC *proc = MyProc; uint32 nextidx; uint32 wakeidx; @@ -493,7 +492,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * different from ours. If another group starts to update a page in the * same bank as ours, they wait until we release the lock. */ - nextidx = pg_atomic_read_u32(&procglobal->clogGroupFirst); + nextidx = pg_atomic_read_u32(&ProcGlobal->clogGroupFirst); while (true) { @@ -524,7 +523,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, pg_atomic_write_u32(&proc->clogGroupNext, nextidx); - if (pg_atomic_compare_exchange_u32(&procglobal->clogGroupFirst, + if (pg_atomic_compare_exchange_u32(&ProcGlobal->clogGroupFirst, &nextidx, (uint32) MyProcNumber)) break; @@ -576,7 +575,7 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status, * At this point, any processes trying to do this would create a separate * group. */ - nextidx = pg_atomic_exchange_u32(&procglobal->clogGroupFirst, + nextidx = pg_atomic_exchange_u32(&ProcGlobal->clogGroupFirst, INVALID_PROC_NUMBER); /* Remember head of list so we can perform wakeups after dropping lock. */ diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 9407c357f27..81bba4beac7 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId, int save_sec_context; int save_nestlevel; IndexInfo *indexInfo; - volatile bool skipped_constraint = false; + bool skipped_constraint = false; PGRUsage ru0; bool progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0); bool set_tablespace = false; diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index eee8bc29f38..2799f989b96 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void); static bool IsListeningOn(const char *channel); static void asyncQueueUnregister(void); static bool asyncQueueIsFull(void); -static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength); +static bool asyncQueueAdvance(QueuePosition *position, int entryLength); static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe); static ListCell *asyncQueueAddEntries(ListCell *nextNotify); static double asyncQueueUsage(void); @@ -1968,7 +1968,7 @@ asyncQueueIsFull(void) * returns true, else false. */ static bool -asyncQueueAdvance(volatile QueuePosition *position, int entryLength) +asyncQueueAdvance(QueuePosition *position, int entryLength) { int64 pageno = QUEUE_POS_PAGE(*position); int offset = QUEUE_POS_OFFSET(*position); diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c index e0e30579c59..d870f09e0a0 100644 --- a/src/backend/replication/syncrep.c +++ b/src/backend/replication/syncrep.c @@ -483,7 +483,6 @@ SyncRepInitConfig(void) void SyncRepReleaseWaiters(void) { - volatile WalSndCtlData *walsndctl = WalSndCtl; XLogRecPtr writePtr; XLogRecPtr flushPtr; XLogRecPtr applyPtr; @@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void) * Set the lsn first so that when we wake backends they will release up to * this location. */ - if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr) { - walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; + WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr; numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE); } - if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr) { - walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr; numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH); } - if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) + if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr) { - walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; + WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr; numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY); } @@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys) n = 0; for (i = 0; i < max_wal_senders; i++) { - volatile WalSnd *walsnd; /* Use volatile pointer to prevent code - * rearrangement */ + WalSnd *walsnd; SyncRepStandbyData *stby; WalSndState state; /* not included in SyncRepStandbyData */ @@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void) static int SyncRepWakeQueue(bool all, int mode) { - volatile WalSndCtlData *walsndctl = WalSndCtl; int numprocs = 0; dlist_mutable_iter iter; @@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode) /* * Assume the queue is ordered by LSN */ - if (!all && walsndctl->lsn[mode] < proc->waitLSN) + if (!all && WalSndCtl->lsn[mode] < proc->waitLSN) return numprocs; /* diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c index 1397f65f67b..21a77f98c1d 100644 --- a/src/backend/storage/ipc/procsignal.c +++ b/src/backend/storage/ipc/procsignal.c @@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg) int SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber) { - volatile ProcSignalSlot *slot; + ProcSignalSlot *slot; if (procNumber != INVALID_PROC_NUMBER) { @@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = 0; i < NumProcSignalSlots; i++) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit); } @@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type) */ for (int i = NumProcSignalSlots - 1; i >= 0; i--) { - volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; + ProcSignalSlot *slot = &ProcSignal->psh_slot[i]; pid_t pid = pg_atomic_read_u32(&slot->pss_pid); if (pid != 0) @@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags) static bool CheckProcSignal(ProcSignalReason reason) { - volatile ProcSignalSlot *slot = MyProcSignalSlot; + ProcSignalSlot *slot = MyProcSignalSlot; if (slot != NULL) { diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 2f9fbb0a519..2217d48c3d9 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address) void * shm_toc_allocate(shm_toc *toc, Size nbytes) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) + allocated_bytes; @@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of shared memory"))); } - vtoc->toc_allocated_bytes += nbytes; + toc->toc_allocated_bytes += nbytes; SpinLockRelease(&toc->toc_mutex); @@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) Size shm_toc_freespace(shm_toc *toc) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; Size toc_bytes; SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; SpinLockRelease(&toc->toc_mutex); toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); @@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc) void shm_toc_insert(shm_toc *toc, uint64 key, void *address) { - volatile shm_toc *vtoc = toc; Size total_bytes; Size allocated_bytes; Size nentry; @@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; + total_bytes = toc->toc_total_bytes; + allocated_bytes = toc->toc_allocated_bytes; + nentry = toc->toc_nentry; #ifdef USE_ASSERT_CHECKING /* Verify no duplicate keys */ for (Size i = 0; i < nentry; i++) - Assert(vtoc->toc_entry[i].key != key); + Assert(toc->toc_entry[i].key != key); #endif toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry) @@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) } Assert(offset < total_bytes); - vtoc->toc_entry[nentry].key = key; - vtoc->toc_entry[nentry].offset = offset; + toc->toc_entry[nentry].key = key; + toc->toc_entry[nentry].offset = offset; /* * By placing a write barrier after filling in the entry and before @@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) */ pg_write_barrier(); - vtoc->toc_nentry++; + toc->toc_nentry++; SpinLockRelease(&toc->toc_mutex); } diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 8d246ed5a4e..5ee80c7632e 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -312,7 +312,7 @@ typedef struct uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; } FastPathStrongRelationLockData; -static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static FastPathStrongRelationLockData *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 7d01c981a1f..87dd289f626 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -660,8 +660,7 @@ InitAuxiliaryProcess(void) } /* Mark auxiliary proc as in use by me */ - /* use volatile pointer to prevent code rearrangement */ - ((volatile PGPROC *) auxproc)->pid = MyProcPid; + auxproc->pid = MyProcPid; SpinLockRelease(&ProcGlobal->freeProcsLock); diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c index 4f40a61e3d9..991fe27a7fa 100644 --- a/src/test/modules/test_shm_mq/setup.c +++ b/src/test/modules/test_shm_mq/setup.c @@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers, dsm_segment *seg); static void cleanup_background_workers(dsm_segment *seg, Datum arg); static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr); + test_shm_mq_header *hdr); static bool check_worker_status(worker_state *wstate); /* value cached, fetched from shared memory */ @@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg) static void wait_for_workers_to_become_ready(worker_state *wstate, - volatile test_shm_mq_header *hdr) + test_shm_mq_header *hdr) { bool result = false; diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c index e13c05ae5c7..0ba1cfcac47 100644 --- a/src/test/modules/test_shm_mq/worker.c +++ b/src/test/modules/test_shm_mq/worker.c @@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg) shm_toc *toc; shm_mq_handle *inqh; shm_mq_handle *outqh; - volatile test_shm_mq_header *hdr; + test_shm_mq_header *hdr; int myworkernumber; PGPROC *registrant; -- 2.50.1 (Apple Git-155) --z39t9WErpHrlykOW-- ^ permalink raw reply [nested|flat] 209+ messages in thread
end of thread, other threads:[~2026-07-07 16:03 UTC | newest] Thread overview: 209+ 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 <[email protected]> 2023-02-25 21:39 [PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState Andres Freund <[email protected]> 2025-08-30 17:13 [PATCH v20 5/6] Add CONCURRENTLY option to REPACK command. Álvaro Herrera <[email protected]> 2026-02-18 16:31 [PATCH v1 1/3] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:41 [PATCH v1 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-06-30 21:47 remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 2026-07-06 11:58 ` Re: remove unnecessary volatile qualifiers Heikki Linnakangas <[email protected]> 2026-07-06 15:47 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 2026-07-07 16:03 ` Re: remove unnecessary volatile qualifiers Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]> 2026-07-06 15:24 [PATCH v2 1/1] Remove unnecessary volatile qualifiers. Nathan Bossart <[email protected]>
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