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[PATCH v21 3/8] Row pattern recognition patch (rewriter).
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* [PATCH v21 3/8] Row pattern recognition patch (rewriter).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)

---
 src/backend/utils/adt/ruleutils.c | 103 ++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 00eda1b34c..dff7e169e7 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -426,6 +426,10 @@ static void get_rule_groupingset(GroupingSet *gset, List *targetlist,
 								 bool omit_parens, deparse_context *context);
 static void get_rule_orderby(List *orderList, List *targetList,
 							 bool force_colno, deparse_context *context);
+static void get_rule_pattern(List *patternVariable, List *patternRegexp,
+							 bool force_colno, deparse_context *context);
+static void get_rule_define(List *defineClause, List *patternVariables,
+							bool force_colno, deparse_context *context);
 static void get_rule_windowclause(Query *query, deparse_context *context);
 static void get_rule_windowspec(WindowClause *wc, List *targetList,
 								deparse_context *context);
@@ -6460,6 +6464,67 @@ get_rule_orderby(List *orderList, List *targetList,
 	}
 }
 
+/*
+ * Display a PATTERN clause.
+ */
+static void
+get_rule_pattern(List *patternVariable, List *patternRegexp,
+				 bool force_colno, deparse_context *context)
+{
+	StringInfo	buf = context->buf;
+	const char *sep;
+	ListCell   *lc_var,
+			   *lc_reg = list_head(patternRegexp);
+
+	sep = "";
+	appendStringInfoChar(buf, '(');
+	foreach(lc_var, patternVariable)
+	{
+		char	   *variable = strVal((String *) lfirst(lc_var));
+		char	   *regexp = NULL;
+
+		if (lc_reg != NULL)
+		{
+			regexp = strVal((String *) lfirst(lc_reg));
+
+			lc_reg = lnext(patternRegexp, lc_reg);
+		}
+
+		appendStringInfo(buf, "%s%s", sep, variable);
+		if (regexp !=NULL)
+			appendStringInfoString(buf, regexp);
+
+		sep = " ";
+	}
+	appendStringInfoChar(buf, ')');
+}
+
+/*
+ * Display a DEFINE clause.
+ */
+static void
+get_rule_define(List *defineClause, List *patternVariables,
+				bool force_colno, deparse_context *context)
+{
+	StringInfo	buf = context->buf;
+	const char *sep;
+	ListCell   *lc_var,
+			   *lc_def;
+
+	sep = "  ";
+	Assert(list_length(patternVariables) == list_length(defineClause));
+
+	forboth(lc_var, patternVariables, lc_def, defineClause)
+	{
+		char	   *varName = strVal(lfirst(lc_var));
+		TargetEntry *te = (TargetEntry *) lfirst(lc_def);
+
+		appendStringInfo(buf, "%s%s AS ", sep, varName);
+		get_rule_expr((Node *) te->expr, context, false);
+		sep = ",\n  ";
+	}
+}
+
 /*
  * Display a WINDOW clause.
  *
@@ -6597,6 +6662,44 @@ get_rule_windowspec(WindowClause *wc, List *targetList,
 			appendStringInfoString(buf, "EXCLUDE GROUP ");
 		else if (wc->frameOptions & FRAMEOPTION_EXCLUDE_TIES)
 			appendStringInfoString(buf, "EXCLUDE TIES ");
+		/* RPR */
+		if (wc->rpSkipTo == ST_NEXT_ROW)
+			appendStringInfoString(buf,
+								   "\n  AFTER MATCH SKIP TO NEXT ROW ");
+		else if (wc->rpSkipTo == ST_PAST_LAST_ROW)
+			appendStringInfoString(buf,
+								   "\n  AFTER MATCH SKIP PAST LAST ROW ");
+		else if (wc->rpSkipTo == ST_FIRST_VARIABLE)
+			appendStringInfo(buf,
+							 "\n  AFTER MATCH SKIP TO FIRST %s ",
+							 wc->rpSkipVariable);
+		else if (wc->rpSkipTo == ST_LAST_VARIABLE)
+			appendStringInfo(buf,
+							 "\n  AFTER MATCH SKIP TO LAST %s ",
+							 wc->rpSkipVariable);
+		else if (wc->rpSkipTo == ST_VARIABLE)
+			appendStringInfo(buf,
+							 "\n  AFTER MATCH SKIP TO %s ",
+							 wc->rpSkipVariable);
+
+		if (wc->initial)
+			appendStringInfoString(buf, "\n  INITIAL");
+
+		if (wc->patternVariable)
+		{
+			appendStringInfoString(buf, "\n  PATTERN ");
+			get_rule_pattern(wc->patternVariable, wc->patternRegexp,
+							 false, context);
+		}
+
+		if (wc->defineClause)
+		{
+			appendStringInfoString(buf, "\n  DEFINE\n");
+			get_rule_define(wc->defineClause, wc->patternVariable,
+							false, context);
+			appendStringInfoChar(buf, ' ');
+		}
+
 		/* we will now have a trailing space; remove it */
 		buf->len--;
 	}
-- 
2.25.1


----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="v21-0004-Row-pattern-recognition-patch-planner.patch"



^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c  | 57 ++++++++++----------------------
 src/tools/pgindent/typedefs.list |  1 -
 2 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 0608eee9eb2..c5943d7fc74 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 56c1f997f88..f4c989c8c30 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -846,7 +846,6 @@ FSMPageData
 FakeRelCacheEntry
 FakeRelCacheEntryData
 FastPathMeta
-FastPathStrongRelationLockData
 FdwInfo
 FdwRoutine
 FetchDirection
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--






^ permalink  raw  reply  [nested|flat] 491+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38 Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 491+ messages in thread

From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw)

---
 src/backend/storage/lmgr/lock.c | 57 ++++++++++-----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5ee80c7632e..035932197a4 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -40,11 +40,11 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/atomics.h"
 #include "storage/lmgr.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/shmem.h"
-#include "storage/spin.h"
 #include "storage/standby.h"
 #include "storage/subsystems.h"
 #include "utils/memutils.h"
@@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
 #define FastPathStrongLockHashPartition(hashcode) \
 	((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
 
-typedef struct
-{
-	slock_t		mutex;
-	uint32		count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
-} FastPathStrongRelationLockData;
-
-static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
+static pg_atomic_uint32 *FastPathStrongRelationLocks;
 
 static void LockManagerShmemRequest(void *arg);
 static void LockManagerShmemInit(void *arg);
@@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg)
 		);
 
 	ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
-					   .size = sizeof(FastPathStrongRelationLockData),
+					   .size = mul_size(sizeof(pg_atomic_uint32),
+										FAST_PATH_STRONG_LOCK_HASH_PARTITIONS),
 					   .ptr = (void **) (void *) &FastPathStrongRelationLocks,
 		);
 }
@@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg)
 static void
 LockManagerShmemInit(void *arg)
 {
-	SpinLockInit(&FastPathStrongRelationLocks->mutex);
+	for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++)
+		pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0);
 }
 
 /*
@@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 			/*
 			 * LWLockAcquire acts as a memory sequencing point, so it's safe
 			 * to assume that any strong locker whose increment to
-			 * FastPathStrongRelationLocks->counts becomes visible after we
-			 * test it has yet to begin to transfer fast-path locks.
+			 * FastPathStrongRelationLocks becomes visible after we test it
+			 * has yet to begin to transfer fast-path locks.
 			 */
 			LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
-			if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
+			if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0)
 				acquired = false;
 			else
 				acquired = FastPathGrantRelationLock(locktag->locktag_field2,
@@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 
 		fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 		locallock->holdsStrongLockCount = false;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 	}
 
 	if (!hash_search(LockMethodLocalHash,
@@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
 	Assert(StrongLockInProgress == NULL);
 	Assert(locallock->holdsStrongLockCount == false);
 
-	/*
-	 * Adding to a memory location is not atomic, so we take a spinlock to
-	 * ensure we don't collide with someone else trying to bump the count at
-	 * the same time.
-	 *
-	 * XXX: It might be worth considering using an atomic fetch-and-add
-	 * instruction here, on architectures where that is supported.
-	 */
-
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	FastPathStrongRelationLocks->count[fasthashcode]++;
+	pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = true;
 	StrongLockInProgress = locallock;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void)
 
 	fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
 	Assert(locallock->holdsStrongLockCount == true);
-	SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-	Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-	FastPathStrongRelationLocks->count[fasthashcode]--;
+	Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+	pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	locallock->holdsStrongLockCount = false;
 	StrongLockInProgress = NULL;
-	SpinLockRelease(&FastPathStrongRelationLocks->mutex);
 }
 
 /*
@@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
-		FastPathStrongRelationLocks->count[fasthashcode]--;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0);
+		pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 }
 
@@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info,
 	{
 		uint32		fasthashcode = FastPathStrongLockHashPartition(hashcode);
 
-		SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
-		FastPathStrongRelationLocks->count[fasthashcode]++;
-		SpinLockRelease(&FastPathStrongRelationLocks->mutex);
+		pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1);
 	}
 
 	LWLockRelease(partitionLock);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO--





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