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[PATCH v8 3/5] instr_time: Add INSTR_TIME_SET_SECONDS(), INSTR_TIME_IS_LT()
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* [PATCH v8 3/5] instr_time: Add INSTR_TIME_SET_SECONDS(), INSTR_TIME_IS_LT()
@ 2023-01-20 23:31  Andres Freund <andres@anarazel.de>
  0 siblings, 0 replies; 500+ messages in thread

From: Andres Freund @ 2023-01-20 23:31 UTC (permalink / raw)

INSTR_TIME_SET_SECONDS() is useful to calculate the end of a time-bound loop
without having to convert into time units (which is
costly). INSTR_TIME_IS_LT() can be used to check the loop condition.

Author:
Reviewed-by:
Discussion: https://postgr.es/m/
Backpatch:
---
 src/include/portability/instr_time.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/include/portability/instr_time.h b/src/include/portability/instr_time.h
index c0ed491395d..af2ab6ec887 100644
--- a/src/include/portability/instr_time.h
+++ b/src/include/portability/instr_time.h
@@ -15,6 +15,8 @@
  *
  * INSTR_TIME_IS_ZERO(t)			is t equal to zero?
  *
+ * INSTR_TIME_IS_LT(x, y)			x < y
+ *
  * INSTR_TIME_SET_ZERO(t)			set t to zero (memset is acceptable too)
  *
  * INSTR_TIME_SET_CURRENT(t)		set t to current time
@@ -22,6 +24,8 @@
  * INSTR_TIME_SET_CURRENT_LAZY(t)	set t to current time if t is zero,
  *									evaluates to whether t changed
  *
+ * INSTR_TIME_SET_SECONDS(t, s)		set t to s seconds
+ *
  * INSTR_TIME_ADD(x, y)				x += y
  *
  * INSTR_TIME_SUBTRACT(x, y)		x -= y
@@ -122,6 +126,9 @@ pg_clock_gettime_ns(void)
 #define INSTR_TIME_SET_CURRENT(t) \
 	((t) = pg_clock_gettime_ns())
 
+#define INSTR_TIME_SET_SECONDS(t, s) \
+	((t).ticks = NS_PER_S * (s))
+
 #define INSTR_TIME_GET_NANOSEC(t) \
 	((int64) (t).ticks)
 
@@ -156,6 +163,9 @@ GetTimerFrequency(void)
 #define INSTR_TIME_SET_CURRENT(t) \
 	((t) = pg_query_performance_counter())
 
+#define INSTR_TIME_SET_SECONDS(t, s) \
+	((t).ticks = s * GetTimerFrequency())
+
 #define INSTR_TIME_GET_NANOSEC(t) \
 	((int64) (((double) (t).ticks * NS_PER_S) / GetTimerFrequency()))
 
@@ -168,6 +178,8 @@ GetTimerFrequency(void)
 
 #define INSTR_TIME_IS_ZERO(t)	((t).ticks == 0)
 
+#define INSTR_TIME_IS_LT(x, y)	((x).ticks < (y).ticks)
+
 
 #define INSTR_TIME_SET_ZERO(t)	((t).ticks = 0)
 
-- 
2.38.0


--vt42kbp2j7rjcapp
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v8-0004-wip-report-nanoseconds-in-pg_test_timing.patch"



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v2 7/9] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Xf36GNcW+0xZNily
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v2-0008-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread

* [PATCH v1 6/8] convert SharedFileSet->refcnt to an atomic
@ 2026-07-09 19:53  Nathan Bossart <nathan@postgresql.org>
  0 siblings, 0 replies; 500+ messages in thread

From: Nathan Bossart @ 2026-07-09 19:53 UTC (permalink / raw)

---
 src/backend/storage/file/sharedfileset.c | 27 +++++++++---------------
 src/include/storage/sharedfileset.h      |  5 ++---
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index d76bd72dc63..4f12f92beae 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -38,8 +38,7 @@ void
 SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 {
 	/* Initialize the shared fileset specific members. */
-	SpinLockInit(&fileset->mutex);
-	fileset->refcnt = 1;
+	pg_atomic_init_u32(&fileset->refcnt, 1);
 
 	/* Initialize the fileset. */
 	FileSetInit(&fileset->fs);
@@ -55,19 +54,15 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 void
 SharedFileSetAttach(SharedFileSet *fileset, dsm_segment *seg)
 {
-	bool		success;
+	uint32		refcnt;
 
-	SpinLockAcquire(&fileset->mutex);
-	if (fileset->refcnt == 0)
-		success = false;
-	else
-	{
-		++fileset->refcnt;
-		success = true;
-	}
-	SpinLockRelease(&fileset->mutex);
+	refcnt = pg_atomic_read_u32(&fileset->refcnt);
+	while (refcnt != 0 &&
+		   !pg_atomic_compare_exchange_u32(&fileset->refcnt, &refcnt,
+										   refcnt + 1))
+		;
 
-	if (!success)
+	if (refcnt == 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("could not attach to a SharedFileSet that is already destroyed")));
@@ -98,11 +93,9 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 	bool		unlink_all = false;
 	SharedFileSet *fileset = (SharedFileSet *) DatumGetPointer(datum);
 
-	SpinLockAcquire(&fileset->mutex);
-	Assert(fileset->refcnt > 0);
-	if (--fileset->refcnt == 0)
+	Assert(pg_atomic_read_u32(&fileset->refcnt) > 0);
+	if (pg_atomic_sub_fetch_u32(&fileset->refcnt, 1) == 0)
 		unlink_all = true;
-	SpinLockRelease(&fileset->mutex);
 
 	/*
 	 * If we are the last to detach, we delete the directory in all
diff --git a/src/include/storage/sharedfileset.h b/src/include/storage/sharedfileset.h
index 904396e7173..d89626ae64b 100644
--- a/src/include/storage/sharedfileset.h
+++ b/src/include/storage/sharedfileset.h
@@ -15,10 +15,10 @@
 #ifndef SHAREDFILESET_H
 #define SHAREDFILESET_H
 
+#include "port/atomics.h"
 #include "storage/dsm.h"
 #include "storage/fd.h"
 #include "storage/fileset.h"
-#include "storage/spin.h"
 
 /*
  * A set of temporary files that can be shared by multiple backends.
@@ -26,8 +26,7 @@
 typedef struct SharedFileSet
 {
 	FileSet		fs;
-	slock_t		mutex;			/* mutex protecting the reference count */
-	int			refcnt;			/* number of attached backends */
+	pg_atomic_uint32 refcnt;	/* number of attached backends */
 } SharedFileSet;
 
 extern void SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg);
-- 
2.50.1 (Apple Git-155)


--Ot5x3ffkWEuxilWO
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
	filename=v1-0007-convert-ParallelBlockTableScanDescData-phs_-start.patch



^ permalink  raw  reply  [nested|flat] 500+ messages in thread