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[PATCH v1] WIP: Evaluate arguments of correlated SubPlans in the referencing ExprState
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* [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; 377+ 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] 377+ messages in thread

* [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; 377+ 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] 377+ messages in thread

* [PATCH v1 1/3] Remove unnecessary volatile qualifiers.
@ 2026-02-18 16:31  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ 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] 377+ messages in thread

* [PATCH v21 2/3] Lock referenced objects before permission checks in DDL commands
@ 2026-04-27 14:19  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Bertrand Drouvot @ 2026-04-27 14:19 UTC (permalink / raw)

Add LockNotPinnedObjectById() calls before object_aclcheck() at all caller
sites where a permission check on a referenced object occurs before the
dependency on that object is recorded. This converts permission check before
lock to lock before permission check. It closes the TOCTOU window that could
allow a REVOKE to succeed between the permission check and the dependency
recording.

Author: Bertrand Drouvot <[email protected]>
Reviewed-by:
Discussion: https://postgr.es/m/[email protected]
---
 src/backend/catalog/dependency.c        | 22 ++++++++++++++++++++++
 src/backend/catalog/namespace.c         |  1 +
 src/backend/catalog/pg_aggregate.c      |  5 +++++
 src/backend/catalog/pg_cast.c           |  1 +
 src/backend/catalog/pg_operator.c       |  2 ++
 src/backend/commands/aggregatecmds.c    |  2 ++
 src/backend/commands/alter.c            |  3 +++
 src/backend/commands/collationcmds.c    |  2 ++
 src/backend/commands/conversioncmds.c   |  3 +++
 src/backend/commands/extension.c        |  1 +
 src/backend/commands/foreigncmds.c      |  5 +++++
 src/backend/commands/functioncmds.c     | 11 +++++++++++
 src/backend/commands/indexcmds.c        |  2 ++
 src/backend/commands/opclasscmds.c      |  2 ++
 src/backend/commands/operatorcmds.c     |  8 ++++++++
 src/backend/commands/statscmds.c        |  1 +
 src/backend/commands/subscriptioncmds.c |  4 ++++
 src/backend/commands/tablecmds.c        |  7 +++++++
 src/backend/commands/trigger.c          |  2 ++
 src/backend/commands/tsearchcmds.c      |  2 ++
 src/backend/commands/typecmds.c         |  9 +++++++++
 src/include/catalog/dependency.h        |  1 +
 22 files changed, 96 insertions(+)
  22.5% src/backend/catalog/
  76.2% src/backend/commands/

diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 7e26691393d..a41e6ee2175 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -1678,6 +1678,24 @@ LockNotPinnedObject(const ObjectAddress *object)
 	}
 }
 
+/*
+ * LockNotPinnedObjectById
+ *
+ * Lock the object if it is not pinned.  This is a convenience wrapper
+ * for callers that need to lock a referenced object before a permission
+ * check, converting permission check before lock to lock before permission
+ * check.
+ */
+void
+LockNotPinnedObjectById(Oid classid, Oid objid)
+{
+	ObjectAddress object;
+
+	ObjectAddressSet(object, classid, objid);
+
+	LockNotPinnedObject(&object);
+}
+
 /*
  * recordDependencyOnExpr - find expression dependencies
  *
@@ -1960,8 +1978,11 @@ find_expr_references_walker(Node *node,
 					objoid = DatumGetObjectId(con->constvalue);
 					if (SearchSysCacheExists1(PROCOID,
 											  ObjectIdGetDatum(objoid)))
+					{
+						LockNotPinnedObjectById(ProcedureRelationId, objoid);
 						add_object_address(ProcedureRelationId, objoid, 0,
 										   context->addrs);
+					}
 					break;
 				case REGOPEROID:
 				case REGOPERATOROID:
@@ -2057,6 +2078,7 @@ find_expr_references_walker(Node *node,
 	{
 		FuncExpr   *funcexpr = (FuncExpr *) node;
 
+		LockNotPinnedObjectById(ProcedureRelationId, funcexpr->funcid);
 		add_object_address(ProcedureRelationId, funcexpr->funcid, 0,
 						   context->addrs);
 		/* fall through to examine arguments */
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index 56b87d878e8..7dec076e111 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -3512,6 +3512,7 @@ LookupCreationNamespace(const char *nspname)
 
 	namespaceId = get_namespace_oid(nspname, false);
 
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceId, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
diff --git a/src/backend/catalog/pg_aggregate.c b/src/backend/catalog/pg_aggregate.c
index 243b952b9cc..41b390e8d96 100644
--- a/src/backend/catalog/pg_aggregate.c
+++ b/src/backend/catalog/pg_aggregate.c
@@ -586,22 +586,26 @@ AggregateCreate(const char *aggName,
 	 */
 	for (i = 0; i < numArgs; i++)
 	{
+		LockNotPinnedObjectById(TypeRelationId, aggArgTypes[i]);
 		aclresult = object_aclcheck(TypeRelationId, aggArgTypes[i], GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, aggArgTypes[i]);
 	}
 
+	LockNotPinnedObjectById(TypeRelationId, aggTransType);
 	aclresult = object_aclcheck(TypeRelationId, aggTransType, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, aggTransType);
 
 	if (OidIsValid(aggmTransType))
 	{
+		LockNotPinnedObjectById(TypeRelationId, aggmTransType);
 		aclresult = object_aclcheck(TypeRelationId, aggmTransType, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, aggmTransType);
 	}
 
+	LockNotPinnedObjectById(TypeRelationId, finaltype);
 	aclresult = object_aclcheck(TypeRelationId, finaltype, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, finaltype);
@@ -909,6 +913,7 @@ lookup_agg_function(List *fnName,
 	}
 
 	/* Check aggregate creator has permission to call the function */
+	LockNotPinnedObjectById(ProcedureRelationId, fnOid);
 	aclresult = object_aclcheck(ProcedureRelationId, fnOid, GetUserId(), ACL_EXECUTE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(fnOid));
diff --git a/src/backend/catalog/pg_cast.c b/src/backend/catalog/pg_cast.c
index 5119c2acda2..bb48e686f83 100644
--- a/src/backend/catalog/pg_cast.c
+++ b/src/backend/catalog/pg_cast.c
@@ -105,6 +105,7 @@ CastCreate(Oid sourcetypeid, Oid targettypeid,
 	/* dependency on function */
 	if (OidIsValid(funcid))
 	{
+		LockNotPinnedObjectById(ProcedureRelationId, funcid);
 		ObjectAddressSet(referenced, ProcedureRelationId, funcid);
 		add_exact_object_address(&referenced, addrs);
 	}
diff --git a/src/backend/catalog/pg_operator.c b/src/backend/catalog/pg_operator.c
index 6b90c774c18..a222358d081 100644
--- a/src/backend/catalog/pg_operator.c
+++ b/src/backend/catalog/pg_operator.c
@@ -654,6 +654,7 @@ get_other_operator(List *otherOp, Oid otherLeftTypeId, Oid otherRightTypeId,
 
 	/* not in catalogs, different from operator, so make shell */
 
+	LockNotPinnedObjectById(NamespaceRelationId, otherNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, otherNamespace, GetUserId(),
 								ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
@@ -876,6 +877,7 @@ makeOperatorDependencies(HeapTuple tuple,
 	/* Dependency on namespace */
 	if (OidIsValid(oper->oprnamespace))
 	{
+		LockNotPinnedObjectById(NamespaceRelationId, oper->oprnamespace);
 		ObjectAddressSet(referenced, NamespaceRelationId, oper->oprnamespace);
 		add_exact_object_address(&referenced, addrs);
 	}
diff --git a/src/backend/commands/aggregatecmds.c b/src/backend/commands/aggregatecmds.c
index 41b45dc6402..c2fb111daf3 100644
--- a/src/backend/commands/aggregatecmds.c
+++ b/src/backend/commands/aggregatecmds.c
@@ -22,6 +22,7 @@
  */
 #include "postgres.h"
 
+#include "catalog/dependency.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_aggregate.h"
 #include "catalog/pg_namespace.h"
@@ -101,6 +102,7 @@ DefineAggregate(ParseState *pstate,
 	aggNamespace = QualifiedNameGetCreationNamespace(name, &aggName);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, aggNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, aggNamespace, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
diff --git a/src/backend/commands/alter.c b/src/backend/commands/alter.c
index 74ceb5fe20d..03516cb0d2e 100644
--- a/src/backend/commands/alter.c
+++ b/src/backend/commands/alter.c
@@ -221,6 +221,7 @@ AlterObjectRename_internal(Relation rel, Oid objectId, const char *new_name)
 		/* User must have CREATE privilege on the namespace */
 		if (OidIsValid(namespaceId))
 		{
+			LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 			aclresult = object_aclcheck(NamespaceRelationId, namespaceId, GetUserId(),
 										ACL_CREATE);
 			if (aclresult != ACLCHECK_OK)
@@ -752,6 +753,7 @@ AlterObjectNamespace_internal(Relation rel, Oid objid, Oid nspOid)
 						   NameStr(*(DatumGetName(name))));
 
 		/* User must have CREATE privilege on new namespace */
+		LockNotPinnedObjectById(NamespaceRelationId, nspOid);
 		aclresult = object_aclcheck(NamespaceRelationId, nspOid, GetUserId(), ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -1014,6 +1016,7 @@ AlterObjectOwner_internal(Oid classId, Oid objectId, Oid new_ownerId)
 			{
 				AclResult	aclresult;
 
+				LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 				aclresult = object_aclcheck(NamespaceRelationId, namespaceId, new_ownerId,
 											ACL_CREATE);
 				if (aclresult != ACLCHECK_OK)
diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 0bc31ec2b6f..fa5dad1aa1f 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -21,6 +21,7 @@
 #include "access/htup_details.h"
 #include "access/table.h"
 #include "access/xact.h"
+#include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
@@ -82,6 +83,7 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 
 	collNamespace = QualifiedNameGetCreationNamespace(names, &collName);
 
+	LockNotPinnedObjectById(NamespaceRelationId, collNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, collNamespace, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
diff --git a/src/backend/commands/conversioncmds.c b/src/backend/commands/conversioncmds.c
index 5f2022d3072..d60ecdb711a 100644
--- a/src/backend/commands/conversioncmds.c
+++ b/src/backend/commands/conversioncmds.c
@@ -14,6 +14,7 @@
  */
 #include "postgres.h"
 
+#include "catalog/dependency.h"
 #include "catalog/pg_conversion.h"
 #include "catalog/pg_namespace.h"
 #include "catalog/pg_proc.h"
@@ -50,6 +51,7 @@ CreateConversionCommand(CreateConversionStmt *stmt)
 													&conversion_name);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceId, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -97,6 +99,7 @@ CreateConversionCommand(CreateConversionStmt *stmt)
 						NameListToString(func_name), "integer")));
 
 	/* Check we have EXECUTE rights for the function */
+	LockNotPinnedObjectById(ProcedureRelationId, funcoid);
 	aclresult = object_aclcheck(ProcedureRelationId, funcoid, GetUserId(), ACL_EXECUTE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FUNCTION,
diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index a330b5fd6ce..4e82a010788 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -3283,6 +3283,7 @@ AlterExtensionNamespace(const char *extensionName, const char *newschema, Oid *o
 					   extensionName);
 
 	/* Permission check: must have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, nspOid);
 	aclresult = object_aclcheck(NamespaceRelationId, nspOid, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA, newschema);
diff --git a/src/backend/commands/foreigncmds.c b/src/backend/commands/foreigncmds.c
index c4852be2eb2..dd31e260739 100644
--- a/src/backend/commands/foreigncmds.c
+++ b/src/backend/commands/foreigncmds.c
@@ -377,6 +377,7 @@ AlterForeignServerOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId)
 			check_can_set_role(GetUserId(), newOwnerId);
 
 			/* New owner must have USAGE privilege on foreign-data wrapper */
+			LockNotPinnedObjectById(ForeignDataWrapperRelationId, form->srvfdw);
 			aclresult = object_aclcheck(ForeignDataWrapperRelationId, form->srvfdw, newOwnerId, ACL_USAGE);
 			if (aclresult != ACLCHECK_OK)
 			{
@@ -997,6 +998,7 @@ CreateForeignServer(CreateForeignServerStmt *stmt)
 	 */
 	fdw = GetForeignDataWrapperByName(stmt->fdwname, false);
 
+	LockNotPinnedObjectById(ForeignDataWrapperRelationId, fdw->fdwid);
 	aclresult = object_aclcheck(ForeignDataWrapperRelationId, fdw->fdwid, ownerId, ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FDW, fdw->fdwname);
@@ -1188,6 +1190,7 @@ user_mapping_ddl_aclcheck(Oid umuserid, Oid serverid, const char *servername)
 		{
 			AclResult	aclresult;
 
+			LockNotPinnedObjectById(ForeignServerRelationId, serverid);
 			aclresult = object_aclcheck(ForeignServerRelationId, serverid, curuserid, ACL_USAGE);
 			if (aclresult != ACLCHECK_OK)
 				aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, servername);
@@ -1539,6 +1542,7 @@ CreateForeignTable(CreateForeignTableStmt *stmt, Oid relid)
 	 * get the actual FDW for option validation etc.
 	 */
 	server = GetForeignServerByName(stmt->servername, false);
+	LockNotPinnedObjectById(ForeignServerRelationId, server->serverid);
 	aclresult = object_aclcheck(ForeignServerRelationId, server->serverid, ownerId, ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, server->servername);
@@ -1598,6 +1602,7 @@ ImportForeignSchema(ImportForeignSchemaStmt *stmt)
 
 	/* Check that the foreign server exists and that we have USAGE on it */
 	server = GetForeignServerByName(stmt->server_name, false);
+	LockNotPinnedObjectById(ForeignServerRelationId, server->serverid);
 	aclresult = object_aclcheck(ForeignServerRelationId, server->serverid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, server->servername);
diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index 3afd762e9dc..9aec534c390 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -146,6 +146,7 @@ compute_return_type(TypeName *returnType, Oid languageOid,
 				 errdetail("Creating a shell type definition.")));
 		namespaceId = QualifiedNameGetCreationNamespace(returnType->names,
 														&typname);
+		LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 		aclresult = object_aclcheck(NamespaceRelationId, namespaceId, GetUserId(),
 									ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
@@ -158,6 +159,7 @@ compute_return_type(TypeName *returnType, Oid languageOid,
 		CommandCounterIncrement();
 	}
 
+	LockNotPinnedObjectById(TypeRelationId, rettype);
 	aclresult = object_aclcheck(TypeRelationId, rettype, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, rettype);
@@ -274,6 +276,7 @@ interpret_function_parameter_list(ParseState *pstate,
 			toid = InvalidOid;	/* keep compiler quiet */
 		}
 
+		LockNotPinnedObjectById(TypeRelationId, toid);
 		aclresult = object_aclcheck(TypeRelationId, toid, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, toid);
@@ -1071,6 +1074,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 													&funcname);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceId, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -1125,6 +1129,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 	if (languageStruct->lanpltrusted)
 	{
 		/* if trusted language, need USAGE privilege */
+		LockNotPinnedObjectById(LanguageRelationId, languageOid);
 		aclresult = object_aclcheck(LanguageRelationId, languageOid, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, OBJECT_LANGUAGE,
@@ -1582,10 +1587,12 @@ CreateCast(CreateCastStmt *stmt)
 						format_type_be(sourcetypeid),
 						format_type_be(targettypeid))));
 
+	LockNotPinnedObjectById(TypeRelationId, sourcetypeid);
 	aclresult = object_aclcheck(TypeRelationId, sourcetypeid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, sourcetypeid);
 
+	LockNotPinnedObjectById(TypeRelationId, targettypeid);
 	aclresult = object_aclcheck(TypeRelationId, targettypeid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, targettypeid);
@@ -1874,6 +1881,7 @@ CreateTransform(CreateTransformStmt *stmt)
 	if (!object_ownercheck(TypeRelationId, typeid, GetUserId()))
 		aclcheck_error_type(ACLCHECK_NOT_OWNER, typeid);
 
+	LockNotPinnedObjectById(TypeRelationId, typeid);
 	aclresult = object_aclcheck(TypeRelationId, typeid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, typeid);
@@ -1883,6 +1891,7 @@ CreateTransform(CreateTransformStmt *stmt)
 	 */
 	langid = get_language_oid(stmt->lang, false);
 
+	LockNotPinnedObjectById(LanguageRelationId, langid);
 	aclresult = object_aclcheck(LanguageRelationId, langid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_LANGUAGE, stmt->lang);
@@ -1897,6 +1906,7 @@ CreateTransform(CreateTransformStmt *stmt)
 		if (!object_ownercheck(ProcedureRelationId, fromsqlfuncid, GetUserId()))
 			aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_FUNCTION, NameListToString(stmt->fromsql->objname));
 
+		LockNotPinnedObjectById(ProcedureRelationId, fromsqlfuncid);
 		aclresult = object_aclcheck(ProcedureRelationId, fromsqlfuncid, GetUserId(), ACL_EXECUTE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, OBJECT_FUNCTION, NameListToString(stmt->fromsql->objname));
@@ -1923,6 +1933,7 @@ CreateTransform(CreateTransformStmt *stmt)
 		if (!object_ownercheck(ProcedureRelationId, tosqlfuncid, GetUserId()))
 			aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_FUNCTION, NameListToString(stmt->tosql->objname));
 
+		LockNotPinnedObjectById(ProcedureRelationId, tosqlfuncid);
 		aclresult = object_aclcheck(ProcedureRelationId, tosqlfuncid, GetUserId(), ACL_EXECUTE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, OBJECT_FUNCTION, NameListToString(stmt->tosql->objname));
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..6216ab2a5f5 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "access/tableam.h"
 #include "access/xact.h"
 #include "catalog/catalog.h"
+#include "catalog/dependency.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"
@@ -770,6 +771,7 @@ DefineIndex(ParseState *pstate,
 	{
 		AclResult	aclresult;
 
+		LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 		aclresult = object_aclcheck(NamespaceRelationId, namespaceId, root_save_userid,
 									ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
diff --git a/src/backend/commands/opclasscmds.c b/src/backend/commands/opclasscmds.c
index 7493a9ccc06..ad71ee53cb2 100644
--- a/src/backend/commands/opclasscmds.c
+++ b/src/backend/commands/opclasscmds.c
@@ -363,6 +363,7 @@ DefineOpClass(CreateOpClassStmt *stmt)
 													 &opcname);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceoid);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceoid, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -801,6 +802,7 @@ DefineOpFamily(CreateOpFamilyStmt *stmt)
 													 &opfname);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceoid);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceoid, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
diff --git a/src/backend/commands/operatorcmds.c b/src/backend/commands/operatorcmds.c
index 3e7b09b3494..bb2ce833bdd 100644
--- a/src/backend/commands/operatorcmds.c
+++ b/src/backend/commands/operatorcmds.c
@@ -33,6 +33,7 @@
 
 #include "access/htup_details.h"
 #include "access/table.h"
+#include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/objectaccess.h"
 #include "catalog/pg_namespace.h"
@@ -92,6 +93,7 @@ DefineOperator(List *names, List *parameters)
 	oprNamespace = QualifiedNameGetCreationNamespace(names, &oprName);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, oprNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, oprNamespace, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -189,6 +191,7 @@ DefineOperator(List *names, List *parameters)
 
 	if (typeName1)
 	{
+		LockNotPinnedObjectById(TypeRelationId, typeId1);
 		aclresult = object_aclcheck(TypeRelationId, typeId1, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, typeId1);
@@ -196,6 +199,7 @@ DefineOperator(List *names, List *parameters)
 
 	if (typeName2)
 	{
+		LockNotPinnedObjectById(TypeRelationId, typeId2);
 		aclresult = object_aclcheck(TypeRelationId, typeId2, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, typeId2);
@@ -227,12 +231,14 @@ DefineOperator(List *names, List *parameters)
 	 * necessary, since EXECUTE will be checked at any attempted use of the
 	 * operator, but it seems like a good idea anyway.
 	 */
+	LockNotPinnedObjectById(ProcedureRelationId, functionOid);
 	aclresult = object_aclcheck(ProcedureRelationId, functionOid, GetUserId(), ACL_EXECUTE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FUNCTION,
 					   NameListToString(functionName));
 
 	rettype = get_func_rettype(functionOid);
+	LockNotPinnedObjectById(TypeRelationId, rettype);
 	aclresult = object_aclcheck(TypeRelationId, rettype, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, rettype);
@@ -312,6 +318,7 @@ ValidateRestrictionEstimator(List *restrictionName)
 	{
 		AclResult	aclresult;
 
+		LockNotPinnedObjectById(ProcedureRelationId, restrictionOid);
 		aclresult = object_aclcheck(ProcedureRelationId, restrictionOid,
 									GetUserId(), ACL_EXECUTE);
 		if (aclresult != ACLCHECK_OK)
@@ -382,6 +389,7 @@ ValidateJoinEstimator(List *joinName)
 	{
 		AclResult	aclresult;
 
+		LockNotPinnedObjectById(ProcedureRelationId, joinOid);
 		aclresult = object_aclcheck(ProcedureRelationId, joinOid,
 									GetUserId(), ACL_EXECUTE);
 		if (aclresult != ACLCHECK_OK)
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index b354723be44..6afef0f55c4 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -185,6 +185,7 @@ CreateStatistics(CreateStatsStmt *stmt, bool check_rights)
 	{
 		AclResult	aclresult;
 
+		LockNotPinnedObjectById(NamespaceRelationId, namespaceId);
 		aclresult = object_aclcheck(NamespaceRelationId, namespaceId,
 									GetUserId(), ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index 523959ba0ce..08dea4b67b3 100644
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -745,6 +745,7 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
 		conninfo = NULL;
 
 		server = GetForeignServerByName(stmt->servername, false);
+		LockNotPinnedObjectById(ForeignServerRelationId, server->serverid);
 		aclresult = object_aclcheck(ForeignServerRelationId, server->serverid, owner, ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, server->servername);
@@ -1833,6 +1834,7 @@ AlterSubscription(ParseState *pstate, AlterSubscriptionStmt *stmt,
 				 * the server.
 				 */
 				new_server = GetForeignServerByName(stmt->servername, false);
+				LockNotPinnedObjectById(ForeignServerRelationId, new_server->serverid);
 				aclresult = object_aclcheck(ForeignServerRelationId,
 											new_server->serverid,
 											form->subowner, ACL_USAGE);
@@ -2262,6 +2264,7 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		ForeignServer *server;
 
 		server = GetForeignServer(form->subserver);
+		LockNotPinnedObjectById(ForeignServerRelationId, form->subserver);
 		aclresult = object_aclcheck(ForeignServerRelationId, form->subserver,
 									form->subowner, ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
@@ -2606,6 +2609,7 @@ AlterSubscriptionOwner_internal(Relation rel, HeapTuple tup, Oid newOwnerId)
 	{
 		ForeignServer *server = GetForeignServer(form->subserver);
 
+		LockNotPinnedObjectById(ForeignServerRelationId, server->serverid);
 		aclresult = object_aclcheck(ForeignServerRelationId, server->serverid, newOwnerId, ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			ereport(ERROR,
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 92b0f38c353..d95ef23a53f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -30,6 +30,7 @@
 #include "access/xlog.h"
 #include "access/xloginsert.h"
 #include "catalog/catalog.h"
+#include "catalog/dependency.h"
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/namespace.h"
@@ -997,6 +998,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 
 		ofTypeId = typenameTypeId(NULL, stmt->ofTypename);
 
+		LockNotPinnedObjectById(TypeRelationId, ofTypeId);
 		aclresult = object_aclcheck(TypeRelationId, ofTypeId, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, ofTypeId);
@@ -1462,6 +1464,7 @@ BuildDescForRelation(const List *columns)
 		attname = entry->colname;
 		typenameTypeIdAndMod(NULL, entry->typeName, &atttypid, &atttypmod);
 
+		LockNotPinnedObjectById(TypeRelationId, atttypid);
 		aclresult = object_aclcheck(TypeRelationId, atttypid, GetUserId(), ACL_USAGE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error_type(aclresult, atttypid);
@@ -13941,6 +13944,7 @@ checkFkeyPermissions(Relation rel, int16 *attnums, int natts)
 	int			i;
 
 	/* Okay if we have relation-level REFERENCES permission */
+	LockNotPinnedObjectById(RelationRelationId, RelationGetRelid(rel));
 	aclresult = pg_class_aclcheck(RelationGetRelid(rel), roleid,
 								  ACL_REFERENCES);
 	if (aclresult == ACLCHECK_OK)
@@ -14724,6 +14728,7 @@ ATPrepAlterColumnType(List **wqueue,
 	/* Look up the target type */
 	typenameTypeIdAndMod(pstate, typeName, &targettype, &targettypmod);
 
+	LockNotPinnedObjectById(TypeRelationId, targettype);
 	aclresult = object_aclcheck(TypeRelationId, targettype, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, targettype);
@@ -16476,6 +16481,7 @@ ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing, LOCKMODE lock
 				check_can_set_role(GetUserId(), newOwnerId);
 
 				/* New owner must have CREATE privilege on namespace */
+				LockNotPinnedObjectById(NamespaceRelationId, namespaceOid);
 				aclresult = object_aclcheck(NamespaceRelationId, namespaceOid, newOwnerId,
 											ACL_CREATE);
 				if (aclresult != ACLCHECK_OK)
@@ -19882,6 +19888,7 @@ RangeVarCallbackForAlterRelation(const RangeVar *rv, Oid relid, Oid oldrelid,
 	 */
 	if (IsA(stmt, RenameStmt))
 	{
+		LockNotPinnedObjectById(NamespaceRelationId, classform->relnamespace);
 		aclresult = object_aclcheck(NamespaceRelationId, classform->relnamespace,
 									GetUserId(), ACL_CREATE);
 		if (aclresult != ACLCHECK_OK)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index b87b4b40d07..3c5ca8fe7e3 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -350,6 +350,7 @@ CreateTriggerFiringOn(const CreateTrigStmt *stmt, const char *queryString,
 
 		if (OidIsValid(constrrelid))
 		{
+			LockNotPinnedObjectById(RelationRelationId, constrrelid);
 			aclresult = pg_class_aclcheck(constrrelid, GetUserId(),
 										  ACL_TRIGGER);
 			if (aclresult != ACLCHECK_OK)
@@ -695,6 +696,7 @@ CreateTriggerFiringOn(const CreateTrigStmt *stmt, const char *queryString,
 		funcoid = LookupFuncName(stmt->funcname, 0, NULL, false);
 	if (!isInternal)
 	{
+		LockNotPinnedObjectById(ProcedureRelationId, funcoid);
 		aclresult = object_aclcheck(ProcedureRelationId, funcoid, GetUserId(), ACL_EXECUTE);
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult, OBJECT_FUNCTION,
diff --git a/src/backend/commands/tsearchcmds.c b/src/backend/commands/tsearchcmds.c
index a12ce33bae4..eb9e68bbb91 100644
--- a/src/backend/commands/tsearchcmds.c
+++ b/src/backend/commands/tsearchcmds.c
@@ -414,6 +414,7 @@ DefineTSDictionary(List *names, List *parameters)
 	namespaceoid = QualifiedNameGetCreationNamespace(names, &dictname);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceoid);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceoid, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -917,6 +918,7 @@ DefineTSConfiguration(List *names, List *parameters, ObjectAddress *copied)
 	namespaceoid = QualifiedNameGetCreationNamespace(names, &cfgname);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, namespaceoid);
 	aclresult = object_aclcheck(NamespaceRelationId, namespaceoid, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index c4c3cdb5461..0e01dda90ba 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -39,6 +39,7 @@
 #include "access/xact.h"
 #include "catalog/binary_upgrade.h"
 #include "catalog/catalog.h"
+#include "catalog/dependency.h"
 #include "catalog/heap.h"
 #include "catalog/objectaccess.h"
 #include "catalog/pg_am.h"
@@ -739,6 +740,7 @@ DefineDomain(ParseState *pstate, CreateDomainStmt *stmt)
 														&domainName);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, domainNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, domainNamespace, GetUserId(),
 								ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
@@ -788,6 +790,7 @@ DefineDomain(ParseState *pstate, CreateDomainStmt *stmt)
 						TypeNameToString(stmt->typeName)),
 				 parser_errposition(pstate, stmt->typeName->location)));
 
+	LockNotPinnedObjectById(TypeRelationId, basetypeoid);
 	aclresult = object_aclcheck(TypeRelationId, basetypeoid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error_type(aclresult, basetypeoid);
@@ -1195,6 +1198,7 @@ DefineEnum(CreateEnumStmt *stmt)
 													  &enumName);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, enumNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, enumNamespace, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -1420,6 +1424,7 @@ DefineRange(ParseState *pstate, CreateRangeStmt *stmt)
 													  &typeName);
 
 	/* Check we have creation rights in target namespace */
+	LockNotPinnedObjectById(NamespaceRelationId, typeNamespace);
 	aclresult = object_aclcheck(NamespaceRelationId, typeNamespace, GetUserId(), ACL_CREATE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_SCHEMA,
@@ -1496,6 +1501,7 @@ DefineRange(ParseState *pstate, CreateRangeStmt *stmt)
 																	&multirangeTypeName);
 
 			/* Check we have creation rights in target namespace */
+			LockNotPinnedObjectById(NamespaceRelationId, multirangeNamespace);
 			aclresult = object_aclcheck(NamespaceRelationId, multirangeNamespace,
 										GetUserId(), ACL_CREATE);
 			if (aclresult != ACLCHECK_OK)
@@ -2421,6 +2427,7 @@ findRangeCanonicalFunction(List *procname, Oid typeOid)
 						func_signature_string(procname, 1, NIL, argList))));
 
 	/* Also, range type's creator must have permission to call function */
+	LockNotPinnedObjectById(ProcedureRelationId, procOid);
 	aclresult = object_aclcheck(ProcedureRelationId, procOid, GetUserId(), ACL_EXECUTE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(procOid));
@@ -2464,6 +2471,7 @@ findRangeSubtypeDiffFunction(List *procname, Oid subtype)
 						func_signature_string(procname, 2, NIL, argList))));
 
 	/* Also, range type's creator must have permission to call function */
+	LockNotPinnedObjectById(ProcedureRelationId, procOid);
 	aclresult = object_aclcheck(ProcedureRelationId, procOid, GetUserId(), ACL_EXECUTE);
 	if (aclresult != ACLCHECK_OK)
 		aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(procOid));
@@ -3963,6 +3971,7 @@ AlterTypeOwner(List *names, Oid newOwnerId, ObjectType objecttype)
 			check_can_set_role(GetUserId(), newOwnerId);
 
 			/* New owner must have CREATE privilege on namespace */
+			LockNotPinnedObjectById(NamespaceRelationId, typTup->typnamespace);
 			aclresult = object_aclcheck(NamespaceRelationId, typTup->typnamespace,
 										newOwnerId,
 										ACL_CREATE);
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index fa508ea70c6..ac1d902e912 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -102,6 +102,7 @@ typedef struct ObjectAddresses ObjectAddresses;
 
 extern void AcquireDeletionLock(const ObjectAddress *object, int flags);
 extern void LockNotPinnedObject(const ObjectAddress *object);
+extern void LockNotPinnedObjectById(Oid classid, Oid objid);
 extern bool isObjectPinned(const ObjectAddress *object);
 
 extern void ReleaseDeletionLock(const ObjectAddress *object);
-- 
2.34.1


--FjYZKkuBdH+F20sI
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
	filename="v21-0003-Add-Assert-guard-to-detect-permission-check-befo.patch"
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^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


--hE8tq9meMVMcgUcn--





^ permalink  raw  reply  [nested|flat] 377+ messages in thread

* [PATCH v1 1/1] Remove unnecessary volatile qualifiers.
@ 2026-06-30 21:41  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 377+ messages in thread

From: Nathan Bossart @ 2026-06-30 21:41 UTC (permalink / raw)

This commit cleans up volatile qualifiers that fit the below
criteria:

* Accesses to shared memory protected by a spinlock or LWLock.
Before commit 0709b7ee72, callers had to use volatile when
accessing spinlock-protected shared memory.  Since spinlock
acquire/release became compiler barriers, and because LWLocks
provide the same guarantee, that is no longer necessary.  These
either predate that change or were cargo-culted from code that did.

* Pointers to pg_atomic_* variables or local variables that hold a
value returned by a pg_atomic_* function.  The pointer arguments
for the pg_atomic_* functions are volatile-qualified, so there's no
need to mark the pointer volatile.  Likewise, a local variable that
just holds the result of a pg_atomic_* function gains nothing from
volatile.

* Accesses to struct members that are marked volatile in the struct
definition.  There's no need to mark these pointers volatile,
either.

* Leftovers from removed PG_TRY blocks.  These were marked volatile
when they were modified inside a PG_TRY block and used afterward,
but the PG_TRY was later removed.
---
 src/backend/access/transam/clog.c     |  2 +-
 src/backend/catalog/index.c           |  2 +-
 src/backend/commands/async.c          |  4 ++--
 src/backend/replication/syncrep.c     | 19 +++++++---------
 src/backend/storage/ipc/procsignal.c  | 10 ++++-----
 src/backend/storage/ipc/shm_toc.c     | 31 ++++++++++++---------------
 src/backend/storage/lmgr/lock.c       |  2 +-
 src/backend/storage/lmgr/proc.c       |  3 +--
 src/test/modules/test_shm_mq/setup.c  |  4 ++--
 src/test/modules/test_shm_mq/worker.c |  2 +-
 10 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 75012d4b8f0..47975ba892f 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ static bool
 TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 								XLogRecPtr lsn, int64 pageno)
 {
-	volatile PROC_HDR *procglobal = ProcGlobal;
+	PROC_HDR   *procglobal = ProcGlobal;
 	PGPROC	   *proc = MyProc;
 	uint32		nextidx;
 	uint32		wakeidx;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 9407c357f27..81bba4beac7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -3637,7 +3637,7 @@ reindex_index(const ReindexStmt *stmt, Oid indexId,
 	int			save_sec_context;
 	int			save_nestlevel;
 	IndexInfo  *indexInfo;
-	volatile bool skipped_constraint = false;
+	bool		skipped_constraint = false;
 	PGRUsage	ru0;
 	bool		progress = ((params->options & REINDEXOPT_REPORT_PROGRESS) != 0);
 	bool		set_tablespace = false;
diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c
index eee8bc29f38..2799f989b96 100644
--- a/src/backend/commands/async.c
+++ b/src/backend/commands/async.c
@@ -605,7 +605,7 @@ static void CleanupListenersOnExit(void);
 static bool IsListeningOn(const char *channel);
 static void asyncQueueUnregister(void);
 static bool asyncQueueIsFull(void);
-static bool asyncQueueAdvance(volatile QueuePosition *position, int entryLength);
+static bool asyncQueueAdvance(QueuePosition *position, int entryLength);
 static void asyncQueueNotificationToEntry(Notification *n, AsyncQueueEntry *qe);
 static ListCell *asyncQueueAddEntries(ListCell *nextNotify);
 static double asyncQueueUsage(void);
@@ -1968,7 +1968,7 @@ asyncQueueIsFull(void)
  * returns true, else false.
  */
 static bool
-asyncQueueAdvance(volatile QueuePosition *position, int entryLength)
+asyncQueueAdvance(QueuePosition *position, int entryLength)
 {
 	int64		pageno = QUEUE_POS_PAGE(*position);
 	int			offset = QUEUE_POS_OFFSET(*position);
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index e0e30579c59..d870f09e0a0 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -483,7 +483,6 @@ SyncRepInitConfig(void)
 void
 SyncRepReleaseWaiters(void)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	XLogRecPtr	writePtr;
 	XLogRecPtr	flushPtr;
 	XLogRecPtr	applyPtr;
@@ -558,19 +557,19 @@ SyncRepReleaseWaiters(void)
 	 * Set the lsn first so that when we wake backends they will release up to
 	 * this location.
 	 */
-	if (walsndctl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] < writePtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_WRITE] = writePtr;
 		numwrite = SyncRepWakeQueue(false, SYNC_REP_WAIT_WRITE);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] < flushPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_FLUSH] = flushPtr;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
-	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
+	if (WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] < applyPtr)
 	{
-		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
+		WalSndCtl->lsn[SYNC_REP_WAIT_APPLY] = applyPtr;
 		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
 	}
 
@@ -777,8 +776,7 @@ SyncRepGetCandidateStandbys(SyncRepStandbyData **standbys)
 	n = 0;
 	for (i = 0; i < max_wal_senders; i++)
 	{
-		volatile WalSnd *walsnd;	/* Use volatile pointer to prevent code
-									 * rearrangement */
+		WalSnd	   *walsnd;
 		SyncRepStandbyData *stby;
 		WalSndState state;		/* not included in SyncRepStandbyData */
 
@@ -915,7 +913,6 @@ SyncRepGetStandbyPriority(void)
 static int
 SyncRepWakeQueue(bool all, int mode)
 {
-	volatile WalSndCtlData *walsndctl = WalSndCtl;
 	int			numprocs = 0;
 	dlist_mutable_iter iter;
 
@@ -930,7 +927,7 @@ SyncRepWakeQueue(bool all, int mode)
 		/*
 		 * Assume the queue is ordered by LSN
 		 */
-		if (!all && walsndctl->lsn[mode] < proc->waitLSN)
+		if (!all && WalSndCtl->lsn[mode] < proc->waitLSN)
 			return numprocs;
 
 		/*
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 1397f65f67b..4acef19e563 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -295,7 +295,7 @@ CleanupProcSignalState(int status, Datum arg)
 int
 SendProcSignal(pid_t pid, ProcSignalReason reason, ProcNumber procNumber)
 {
-	volatile ProcSignalSlot *slot;
+	ProcSignalSlot *slot;
 
 	if (procNumber != INVALID_PROC_NUMBER)
 	{
@@ -380,7 +380,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = 0; i < NumProcSignalSlots; i++)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 
 		pg_atomic_fetch_or_u32(&slot->pss_barrierCheckMask, flagbit);
 	}
@@ -406,7 +406,7 @@ EmitProcSignalBarrier(ProcSignalBarrierType type)
 	 */
 	for (int i = NumProcSignalSlots - 1; i >= 0; i--)
 	{
-		volatile ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
+		ProcSignalSlot *slot = &ProcSignal->psh_slot[i];
 		pid_t		pid = pg_atomic_read_u32(&slot->pss_pid);
 
 		if (pid != 0)
@@ -512,7 +512,7 @@ ProcessProcSignalBarrier(void)
 {
 	uint64		local_gen;
 	uint64		shared_gen;
-	volatile uint32 flags;
+	uint32		flags;
 
 	Assert(MyProcSignalSlot);
 
@@ -670,7 +670,7 @@ ResetProcSignalBarrierBits(uint32 flags)
 static bool
 CheckProcSignal(ProcSignalReason reason)
 {
-	volatile ProcSignalSlot *slot = MyProcSignalSlot;
+	ProcSignalSlot *slot = MyProcSignalSlot;
 
 	if (slot != NULL)
 	{
diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c
index 2f9fbb0a519..2217d48c3d9 100644
--- a/src/backend/storage/ipc/shm_toc.c
+++ b/src/backend/storage/ipc/shm_toc.c
@@ -87,7 +87,6 @@ shm_toc_attach(uint64 magic, void *address)
 void *
 shm_toc_allocate(shm_toc *toc, Size nbytes)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -103,9 +102,9 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
 		+ allocated_bytes;
 
@@ -117,7 +116,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of shared memory")));
 	}
-	vtoc->toc_allocated_bytes += nbytes;
+	toc->toc_allocated_bytes += nbytes;
 
 	SpinLockRelease(&toc->toc_mutex);
 
@@ -130,16 +129,15 @@ shm_toc_allocate(shm_toc *toc, Size nbytes)
 Size
 shm_toc_freespace(shm_toc *toc)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
 	Size		toc_bytes;
 
 	SpinLockAcquire(&toc->toc_mutex);
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 	SpinLockRelease(&toc->toc_mutex);
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry);
@@ -170,7 +168,6 @@ shm_toc_freespace(shm_toc *toc)
 void
 shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 {
-	volatile shm_toc *vtoc = toc;
 	Size		total_bytes;
 	Size		allocated_bytes;
 	Size		nentry;
@@ -183,14 +180,14 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 
 	SpinLockAcquire(&toc->toc_mutex);
 
-	total_bytes = vtoc->toc_total_bytes;
-	allocated_bytes = vtoc->toc_allocated_bytes;
-	nentry = vtoc->toc_nentry;
+	total_bytes = toc->toc_total_bytes;
+	allocated_bytes = toc->toc_allocated_bytes;
+	nentry = toc->toc_nentry;
 
 #ifdef USE_ASSERT_CHECKING
 	/* Verify no duplicate keys */
 	for (Size i = 0; i < nentry; i++)
-		Assert(vtoc->toc_entry[i].key != key);
+		Assert(toc->toc_entry[i].key != key);
 #endif
 
 	toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry)
@@ -208,8 +205,8 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	}
 
 	Assert(offset < total_bytes);
-	vtoc->toc_entry[nentry].key = key;
-	vtoc->toc_entry[nentry].offset = offset;
+	toc->toc_entry[nentry].key = key;
+	toc->toc_entry[nentry].offset = offset;
 
 	/*
 	 * By placing a write barrier after filling in the entry and before
@@ -218,7 +215,7 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address)
 	 */
 	pg_write_barrier();
 
-	vtoc->toc_nentry++;
+	toc->toc_nentry++;
 
 	SpinLockRelease(&toc->toc_mutex);
 }
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8d246ed5a4e..5ee80c7632e 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -312,7 +312,7 @@ typedef struct
 	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
 } FastPathStrongRelationLockData;
 
-static volatile FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 7d01c981a1f..87dd289f626 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -660,8 +660,7 @@ InitAuxiliaryProcess(void)
 	}
 
 	/* Mark auxiliary proc as in use by me */
-	/* use volatile pointer to prevent code rearrangement */
-	((volatile PGPROC *) auxproc)->pid = MyProcPid;
+	auxproc->pid = MyProcPid;
 
 	SpinLockRelease(&ProcGlobal->freeProcsLock);
 
diff --git a/src/test/modules/test_shm_mq/setup.c b/src/test/modules/test_shm_mq/setup.c
index 4f40a61e3d9..991fe27a7fa 100644
--- a/src/test/modules/test_shm_mq/setup.c
+++ b/src/test/modules/test_shm_mq/setup.c
@@ -38,7 +38,7 @@ static worker_state *setup_background_workers(int nworkers,
 											  dsm_segment *seg);
 static void cleanup_background_workers(dsm_segment *seg, Datum arg);
 static void wait_for_workers_to_become_ready(worker_state *wstate,
-											 volatile test_shm_mq_header *hdr);
+											 test_shm_mq_header *hdr);
 static bool check_worker_status(worker_state *wstate);
 
 /* value cached, fetched from shared memory */
@@ -258,7 +258,7 @@ cleanup_background_workers(dsm_segment *seg, Datum arg)
 
 static void
 wait_for_workers_to_become_ready(worker_state *wstate,
-								 volatile test_shm_mq_header *hdr)
+								 test_shm_mq_header *hdr)
 {
 	bool		result = false;
 
diff --git a/src/test/modules/test_shm_mq/worker.c b/src/test/modules/test_shm_mq/worker.c
index e13c05ae5c7..0ba1cfcac47 100644
--- a/src/test/modules/test_shm_mq/worker.c
+++ b/src/test/modules/test_shm_mq/worker.c
@@ -52,7 +52,7 @@ test_shm_mq_main(Datum main_arg)
 	shm_toc    *toc;
 	shm_mq_handle *inqh;
 	shm_mq_handle *outqh;
-	volatile test_shm_mq_header *hdr;
+	test_shm_mq_header *hdr;
 	int			myworkernumber;
 	PGPROC	   *registrant;
 
-- 
2.50.1 (Apple Git-155)


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