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[PATCH 5/9] document store_change somewhat more
479+ messages / 2 participants
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* [PATCH 5/9] document store_change somewhat more
@ 2026-03-12 15:10  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 479+ messages in thread

From: Álvaro Herrera @ 2026-03-12 15:10 UTC (permalink / raw)

---
 .../replication/pgoutput_repack/pgoutput_repack.c        | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/backend/replication/pgoutput_repack/pgoutput_repack.c b/src/backend/replication/pgoutput_repack/pgoutput_repack.c
index 90f3a8975b9..79fc611b9ff 100644
--- a/src/backend/replication/pgoutput_repack/pgoutput_repack.c
+++ b/src/backend/replication/pgoutput_repack/pgoutput_repack.c
@@ -158,7 +158,14 @@ plugin_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	}
 }
 
-/* Store concurrent data change. */
+/*
+ * For each change affecting the table being repacked, we store enough
+ * information about each tuple in it, so that it can be replayed in the
+ * new copy of the table.
+ *
+ * XXX for DELETE and the UPDATE OLD tuples, we could store just the
+ * replication identity instead of the full tuple.
+ */
 static void
 store_change(LogicalDecodingContext *ctx, Relation relation,
 			 ConcurrentChangeKind kind, HeapTuple tuple)
-- 
2.47.3


--pnppmxqkefjd4hu2
Content-Type: text/plain; charset=utf-8
Content-Disposition: attachment;
	filename*0="0006-use-int-instead-of-uint32-for-the-result-of-list_len.noc";
	filename*1="fbot.txt"



^ permalink  raw  reply  [nested|flat] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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] 479+ messages in thread

* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics
@ 2026-07-09 20:38  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 479+ 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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