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[PATCH] doc review: COPY progress: 8a4f618e7ae3cb11b0b37d0f06f05c8ff905833f
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* [PATCH] doc review: COPY progress: 8a4f618e7ae3cb11b0b37d0f06f05c8ff905833f
@ 2021-01-07 01:08  Justin Pryzby <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Justin Pryzby @ 2021-01-07 01:08 UTC (permalink / raw)

---
 doc/src/sgml/monitoring.sgml | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 43fe8ae383..3cdb1aff3c 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -6414,9 +6414,9 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
   <para>
    Whenever <command>COPY</command> is running, the
    <structname>pg_stat_progress_copy</structname> view will contain one row
-   for each backend that is currently running <command>COPY</command> command.
-   The table bellow describes the information that will be reported and provide
-   information how to interpret it.
+   for each backend that is currently running a <command>COPY</command> command.
+   The table below describes the information that will be reported and provides
+   information about how to interpret it.
   </para>
 
   <table id="pg-stat-progress-copy-view" xreflabel="pg_stat_progress_copy">
@@ -6445,7 +6445,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>datid</structfield> <type>text</type>
+       <structfield>datid</structfield> <type>oid</type>
       </para>
       <para>
        OID of the database to which this backend is connected.
@@ -6467,7 +6467,7 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
       </para>
       <para>
        OID of the table on which the <command>COPY</command> command is executed.
-       It is set to 0 if <command>SELECT</command> query is provided.
+       It is set to 0 if copying from a <command>SELECT</command> query.
       </para></entry>
      </row>
 
-- 
2.17.0


--aM3YZ0Iwxop3KEKx
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="0001-doc-review-COPY-progress-8a4f618e7ae3cb11b0b37d0f06f.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v4 1/2] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 176 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  23 +++
 src/include/storage/lwlock.h                  |   2 +
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 +++
 .../expected/test_dsm_registry.out            |  14 ++
 .../modules/test_dsm_registry/meson.build     |  33 ++++
 .../sql/test_dsm_registry.sql                 |   4 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  75 ++++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 20 files changed, 386 insertions(+)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..2b2be4bb99
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,176 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		key[64];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+static void init_dsm_registry(void);
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Initialize or attach a DSM entry.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+dsm_registry_init_or_attach(const char *key, size_t size,
+							void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(key);
+	Assert(size);
+	Assert(found);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find_or_insert(dsm_registry_table, key_padded, found);
+	if (!(*found))
+	{
+		/* Initialize DSM registry entry. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing DSM registry entry. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of already-attached DSM registry entry. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 706140eb9f..44d6a243e5 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 79a16d077f..88fef448be 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 315a78cda9..f3faa991d1 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index f61ec3e59d..f13077bd8c 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -325,6 +325,7 @@ WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consu
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
 WALSummarizer	"Waiting to read or update WAL summarization state."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 XactBuffer	"Waiting for I/O on a transaction status SLRU buffer."
 CommitTsBuffer	"Waiting for I/O on a commit timestamp SLRU buffer."
@@ -355,6 +356,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..247ac0acc1
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,23 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern void *dsm_registry_init_or_attach(const char *key, size_t size,
+										 void (*init_callback) (void *ptr),
+										 bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index b038e599c0..e0e7b3b765 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,6 +207,8 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
 	LWTRANCHE_FIRST_USER_DEFINED,
 }			BuiltinTrancheIds;
 
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index b76f588559..bd53d52a3f 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..8ffbd343a0
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..4a7992109b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2023, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..b3351be0a1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..068f47ed02
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,75 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+init_state(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+dsm_registry_attach(void)
+{
+	bool		found;
+
+	tdr_state = dsm_registry_init_or_attach("test_dsm_registry",
+											sizeof(TestDSMRegistryStruct),
+											init_state, &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 5fd46b7bd1..469f7570f5 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2799,6 +2801,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--BOKacYhQ+x31HxR3
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v4-0002-use-dsm-registry-for-pg_prewarm.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v5 1/2] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 176 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  23 +++
 src/include/storage/lwlock.h                  |   2 +
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 +++
 .../expected/test_dsm_registry.out            |  14 ++
 .../modules/test_dsm_registry/meson.build     |  33 ++++
 .../sql/test_dsm_registry.sql                 |   4 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  75 ++++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 20 files changed, 386 insertions(+)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..3a32dcfe40
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,176 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		key[64];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+static void init_dsm_registry(void);
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Initialize or attach a DSM entry.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+dsm_registry_init_or_attach(const char *key, size_t size,
+							void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(key);
+	Assert(size);
+	Assert(found);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find_or_insert(dsm_registry_table, key_padded, found);
+	if (!(*found))
+	{
+		/* Initialize DSM registry entry. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing DSM registry entry. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of an already-attached DSM registry entry. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index e5119ed55d..fbc62b1563 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 08bdc718b8..5a936171f7 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index b4b989ac56..2f2de5a562 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 088eb977d4..33c4c645b8 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -325,6 +325,7 @@ WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consu
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
 WALSummarizer	"Waiting to read or update WAL summarization state."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 XactBuffer	"Waiting for I/O on a transaction status SLRU buffer."
 CommitTsBuffer	"Waiting for I/O on a commit timestamp SLRU buffer."
@@ -355,6 +356,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..5d4cf9ca49
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,23 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern void *dsm_registry_init_or_attach(const char *key, size_t size,
+										 void (*init_callback) (void *ptr),
+										 bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 167ae34208..50a65e046d 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,6 +207,8 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
 	LWTRANCHE_FIRST_USER_DEFINED,
 }			BuiltinTrancheIds;
 
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index 00ff1d77d1..2c3b8d73bc 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..8ffbd343a0
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..a4045fea37
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..b3351be0a1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..b57f13cebb
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,75 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+init_state(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+dsm_registry_attach(void)
+{
+	bool		found;
+
+	tdr_state = dsm_registry_init_or_attach("test_dsm_registry",
+											sizeof(TestDSMRegistryStruct),
+											init_state, &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 5fd46b7bd1..469f7570f5 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2799,6 +2801,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--dTy3Mrz/UPE2dbVg
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v5-0002-use-dsm-registry-for-pg_prewarm.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v6 2/3] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 doc/src/sgml/xfunc.sgml                       |  49 ++++-
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 174 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  23 +++
 src/include/storage/lwlock.h                  |   2 +
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 +++
 .../expected/test_dsm_registry.out            |  14 ++
 .../modules/test_dsm_registry/meson.build     |  33 ++++
 .../sql/test_dsm_registry.sql                 |   4 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  76 ++++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 21 files changed, 431 insertions(+), 3 deletions(-)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index 0ba52b41d4..9d305000f9 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -3460,6 +3460,45 @@ LWLockRelease(AddinShmemInitLock);
       the <productname>PostgreSQL</productname> source tree.
      </para>
     </sect3>
+
+    <sect3 id="xfunc-shared-addin-after-startup">
+     <title>Requesting Shared Memory After Startup</title>
+
+     <para>
+      There is another, more flexible method of reserving shared memory that
+      can be done after server startup and outside a
+      <literal>shmem_request_hook</literal>.  To do so, each backend that will
+      use the shared memory should obtain a pointer to it by calling:
+<programlisting>
+void *GetNamedDSMSegment(const char *name, size_t size,
+                         void (*init_callback) (void *ptr),
+                         bool *found)
+</programlisting>
+      If a dynamic shared memory segment with the given name does not yet
+      exist, this function will allocate it and initialize it with the provided
+      <function>init_callback</function> callback function.  If the segment has
+      already been allocated and initialized by another backend, this function
+      simply attaches the existing dynamic shared memory segment to the current
+      backend.
+     </para>
+
+     <para>
+      Unlike shared memory reserved at server startup, there is no need to
+      acquire <function>AddinShmemInitLock</function> or otherwise take action
+      to avoid race conditions when reserving shared memory with
+      <function>GetNamedDSMSegment</function>.  This function ensures that only
+      one backend allocates and initializes the segment and that all other
+      backends receive a pointer to the fully allocated and initialized
+      segment.
+     </para>
+
+     <para>
+      A complete usage example of <function>GetNamedDSMSegment</function> can
+      be found in
+      <filename>src/test/modules/test_dsm_registry/test_dsm_registry.c</filename>
+      in the <productname>PostgreSQL</productname> source tree.
+     </para>
+    </sect3>
    </sect2>
 
    <sect2 id="xfunc-addin-lwlocks">
@@ -3469,8 +3508,9 @@ LWLockRelease(AddinShmemInitLock);
      <title>Requesting LWLocks at Startup</title>
 
      <para>
-      Add-ins can reserve LWLocks on server startup.  Like with shared memory,
-      the add-in's shared library must be preloaded by specifying it in
+      Add-ins can reserve LWLocks on server startup.  Like with shared memory
+      reserved at server startup, the add-in's shared library must be preloaded
+      by specifying it in
       <xref linkend="guc-shared-preload-libraries"/><indexterm><primary>shared_preload_libraries</primary></indexterm>,
       and the shared library should register a
       <literal>shmem_request_hook</literal> in its
@@ -3508,7 +3548,10 @@ void LWLockInitialize(LWLock *lock, int tranche_id)
       process allocates a new <literal>tranche_id</literal> and initializes
       each new LWLock.  One way to do this is to only call these functions in
       your shared memory initialization code with the
-      <function>AddinShmemInitLock</function> held exclusively.
+      <function>AddinShmemInitLock</function> held exclusively.  If using
+      <function>GetNamedDSMSegment</function>, calling these functions in the
+      <function>init_callback</function> callback function is sufficient to
+      avoid race conditions.
      </para>
 
      <para>
diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..7deaa0d6c5
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,174 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		name[64];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Initialize or attach a named DSM segment.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+GetNamedDSMSegment(const char *name, size_t size,
+				   void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		name_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(name);
+	Assert(size);
+	Assert(found);
+
+	if (strlen(name) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM segment name too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(name_padded, name);
+	entry = dshash_find_or_insert(dsm_registry_table, name_padded, found);
+	if (!(*found))
+	{
+		/* Initialize the segment. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing segment. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of an already-attached segment. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index e5119ed55d..fbc62b1563 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 08bdc718b8..5a936171f7 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index b4b989ac56..2f2de5a562 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index f625473ad4..6bcb1cca0c 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -329,6 +329,7 @@ WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consu
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
 WALSummarizer	"Waiting to read or update WAL summarization state."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 #
 # END OF PREDEFINED LWLOCKS (DO NOT CHANGE THIS LINE)
@@ -367,6 +368,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..8e8a23ba60
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,23 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern void *GetNamedDSMSegment(const char *name, size_t size,
+								void (*init_callback) (void *ptr),
+								bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 167ae34208..50a65e046d 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,6 +207,8 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
 	LWTRANCHE_FIRST_USER_DEFINED,
 }			BuiltinTrancheIds;
 
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index 00ff1d77d1..2c3b8d73bc 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..8ffbd343a0
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..a4045fea37
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..b3351be0a1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..b46cd6c620
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,76 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+tdr_init_shmem(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+tdr_attach_shmem(void)
+{
+	bool		found;
+
+	tdr_state = GetNamedDSMSegment("test_dsm_registry",
+								   sizeof(TestDSMRegistryStruct),
+								   tdr_init_shmem,
+								   &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f582eb59e7..b7e73736e9 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2799,6 +2801,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--FCuugMFkClbJLl1L
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v6-0003-use-dsm-registry-for-pg_prewarm.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v7 2/3] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 doc/src/sgml/xfunc.sgml                       |  49 ++++-
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 174 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  23 +++
 src/include/storage/lwlock.h                  |   2 +
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 +++
 .../expected/test_dsm_registry.out            |  14 ++
 .../modules/test_dsm_registry/meson.build     |  33 ++++
 .../sql/test_dsm_registry.sql                 |   4 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  76 ++++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 21 files changed, 431 insertions(+), 3 deletions(-)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index 82e1dadcca..fbeac2fd1d 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -3460,6 +3460,45 @@ LWLockRelease(AddinShmemInitLock);
       the <productname>PostgreSQL</productname> source tree.
      </para>
     </sect3>
+
+    <sect3 id="xfunc-shared-addin-after-startup">
+     <title>Requesting Shared Memory After Startup</title>
+
+     <para>
+      There is another, more flexible method of reserving shared memory that
+      can be done after server startup and outside a
+      <literal>shmem_request_hook</literal>.  To do so, each backend that will
+      use the shared memory should obtain a pointer to it by calling:
+<programlisting>
+void *GetNamedDSMSegment(const char *name, size_t size,
+                         void (*init_callback) (void *ptr),
+                         bool *found)
+</programlisting>
+      If a dynamic shared memory segment with the given name does not yet
+      exist, this function will allocate it and initialize it with the provided
+      <function>init_callback</function> callback function.  If the segment has
+      already been allocated and initialized by another backend, this function
+      simply attaches the existing dynamic shared memory segment to the current
+      backend.
+     </para>
+
+     <para>
+      Unlike shared memory reserved at server startup, there is no need to
+      acquire <function>AddinShmemInitLock</function> or otherwise take action
+      to avoid race conditions when reserving shared memory with
+      <function>GetNamedDSMSegment</function>.  This function ensures that only
+      one backend allocates and initializes the segment and that all other
+      backends receive a pointer to the fully allocated and initialized
+      segment.
+     </para>
+
+     <para>
+      A complete usage example of <function>GetNamedDSMSegment</function> can
+      be found in
+      <filename>src/test/modules/test_dsm_registry/test_dsm_registry.c</filename>
+      in the <productname>PostgreSQL</productname> source tree.
+     </para>
+    </sect3>
    </sect2>
 
    <sect2 id="xfunc-addin-lwlocks">
@@ -3469,8 +3508,9 @@ LWLockRelease(AddinShmemInitLock);
      <title>Requesting LWLocks at Startup</title>
 
      <para>
-      Add-ins can reserve LWLocks on server startup.  As with shared memory,
-      the add-in's shared library must be preloaded by specifying it in
+      Add-ins can reserve LWLocks on server startup.  As with shared memory
+      reserved at server startup, the add-in's shared library must be preloaded
+      by specifying it in
       <xref linkend="guc-shared-preload-libraries"/><indexterm><primary>shared_preload_libraries</primary></indexterm>,
       and the shared library should register a
       <literal>shmem_request_hook</literal> in its
@@ -3508,7 +3548,10 @@ void LWLockInitialize(LWLock *lock, int tranche_id)
       process allocates a new <literal>tranche_id</literal> and initializes
       each new LWLock.  One way to do this is to only call these functions in
       your shared memory initialization code with the
-      <function>AddinShmemInitLock</function> held exclusively.
+      <function>AddinShmemInitLock</function> held exclusively.  If using
+      <function>GetNamedDSMSegment</function>, calling these functions in the
+      <function>init_callback</function> callback function is sufficient to
+      avoid race conditions.
      </para>
 
      <para>
diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..7deaa0d6c5
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,174 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		name[64];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Initialize or attach a named DSM segment.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+GetNamedDSMSegment(const char *name, size_t size,
+				   void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		name_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(name);
+	Assert(size);
+	Assert(found);
+
+	if (strlen(name) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM segment name too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(name_padded, name);
+	entry = dshash_find_or_insert(dsm_registry_table, name_padded, found);
+	if (!(*found))
+	{
+		/* Initialize the segment. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing segment. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of an already-attached segment. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index e5119ed55d..fbc62b1563 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 08bdc718b8..5a936171f7 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index b4b989ac56..2f2de5a562 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index f625473ad4..6bcb1cca0c 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -329,6 +329,7 @@ WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consu
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
 WALSummarizer	"Waiting to read or update WAL summarization state."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 #
 # END OF PREDEFINED LWLOCKS (DO NOT CHANGE THIS LINE)
@@ -367,6 +368,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..8e8a23ba60
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,23 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern void *GetNamedDSMSegment(const char *name, size_t size,
+								void (*init_callback) (void *ptr),
+								bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 167ae34208..50a65e046d 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,6 +207,8 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
 	LWTRANCHE_FIRST_USER_DEFINED,
 }			BuiltinTrancheIds;
 
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index 00ff1d77d1..2c3b8d73bc 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..8ffbd343a0
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..a4045fea37
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..b3351be0a1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..b46cd6c620
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,76 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+tdr_init_shmem(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+tdr_attach_shmem(void)
+{
+	bool		found;
+
+	tdr_state = GetNamedDSMSegment("test_dsm_registry",
+								   sizeof(TestDSMRegistryStruct),
+								   tdr_init_shmem,
+								   &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f582eb59e7..b7e73736e9 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2799,6 +2801,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--huq684BweRXVnRxX
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v7-0003-use-dsm-registry-for-pg_prewarm.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v8 2/3] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 doc/src/sgml/xfunc.sgml                       |  49 ++++-
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 178 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  23 +++
 src/include/storage/lwlock.h                  |   2 +
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 +++
 .../expected/test_dsm_registry.out            |  14 ++
 .../modules/test_dsm_registry/meson.build     |  33 ++++
 .../sql/test_dsm_registry.sql                 |   4 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  76 ++++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 21 files changed, 435 insertions(+), 3 deletions(-)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml
index ede2a5dea6..0ad9f38e90 100644
--- a/doc/src/sgml/xfunc.sgml
+++ b/doc/src/sgml/xfunc.sgml
@@ -3460,6 +3460,45 @@ LWLockRelease(AddinShmemInitLock);
       the <productname>PostgreSQL</productname> source tree.
      </para>
     </sect3>
+
+    <sect3 id="xfunc-shared-addin-after-startup">
+     <title>Requesting Shared Memory After Startup</title>
+
+     <para>
+      There is another, more flexible method of reserving shared memory that
+      can be done after server startup and outside a
+      <literal>shmem_request_hook</literal>.  To do so, each backend that will
+      use the shared memory should obtain a pointer to it by calling:
+<programlisting>
+void *GetNamedDSMSegment(const char *name, size_t size,
+                         void (*init_callback) (void *ptr),
+                         bool *found)
+</programlisting>
+      If a dynamic shared memory segment with the given name does not yet
+      exist, this function will allocate it and initialize it with the provided
+      <function>init_callback</function> callback function.  If the segment has
+      already been allocated and initialized by another backend, this function
+      simply attaches the existing dynamic shared memory segment to the current
+      backend.
+     </para>
+
+     <para>
+      Unlike shared memory reserved at server startup, there is no need to
+      acquire <function>AddinShmemInitLock</function> or otherwise take action
+      to avoid race conditions when reserving shared memory with
+      <function>GetNamedDSMSegment</function>.  This function ensures that only
+      one backend allocates and initializes the segment and that all other
+      backends receive a pointer to the fully allocated and initialized
+      segment.
+     </para>
+
+     <para>
+      A complete usage example of <function>GetNamedDSMSegment</function> can
+      be found in
+      <filename>src/test/modules/test_dsm_registry/test_dsm_registry.c</filename>
+      in the <productname>PostgreSQL</productname> source tree.
+     </para>
+    </sect3>
    </sect2>
 
    <sect2 id="xfunc-addin-lwlocks">
@@ -3469,8 +3508,9 @@ LWLockRelease(AddinShmemInitLock);
      <title>Requesting LWLocks at Startup</title>
 
      <para>
-      Add-ins can reserve LWLocks on server startup.  As with shared memory,
-      the add-in's shared library must be preloaded by specifying it in
+      Add-ins can reserve LWLocks on server startup.  As with shared memory
+      reserved at server startup, the add-in's shared library must be preloaded
+      by specifying it in
       <xref linkend="guc-shared-preload-libraries"/><indexterm><primary>shared_preload_libraries</primary></indexterm>,
       and the shared library should register a
       <literal>shmem_request_hook</literal> in its
@@ -3508,7 +3548,10 @@ void LWLockInitialize(LWLock *lock, int tranche_id)
       process allocates a new <literal>tranche_id</literal> and initializes
       each new LWLock.  One way to do this is to only call these functions in
       your shared memory initialization code with the
-      <function>AddinShmemInitLock</function> held exclusively.
+      <function>AddinShmemInitLock</function> held exclusively.  If using
+      <function>GetNamedDSMSegment</function>, calling these functions in the
+      <function>init_callback</function> callback function is sufficient to
+      avoid race conditions.
      </para>
 
      <para>
diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..89f7d670e4
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,178 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		name[64];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Initialize or attach a named DSM segment.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+GetNamedDSMSegment(const char *name, size_t size,
+				   void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		name_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(found);
+
+	if (!name || *name == '\0')
+		elog(ERROR, "DSM segment name cannot be empty");
+
+	if (strlen(name) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM segment name too long");
+
+	if (size == 0)
+		elog(ERROR, "DSM segment size must be nonzero");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(name_padded, name);
+	entry = dshash_find_or_insert(dsm_registry_table, name_padded, found);
+	if (!(*found))
+	{
+		/* Initialize the segment. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing segment. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of an already-attached segment. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index e5119ed55d..fbc62b1563 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 08bdc718b8..5a936171f7 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index b4b989ac56..2f2de5a562 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index f625473ad4..6bcb1cca0c 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -329,6 +329,7 @@ WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consu
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
 WALSummarizer	"Waiting to read or update WAL summarization state."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 #
 # END OF PREDEFINED LWLOCKS (DO NOT CHANGE THIS LINE)
@@ -367,6 +368,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..8e8a23ba60
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,23 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern void *GetNamedDSMSegment(const char *name, size_t size,
+								void (*init_callback) (void *ptr),
+								bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 167ae34208..50a65e046d 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,6 +207,8 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
 	LWTRANCHE_FIRST_USER_DEFINED,
 }			BuiltinTrancheIds;
 
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index 00ff1d77d1..2c3b8d73bc 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..8ffbd343a0
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..a4045fea37
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..b3351be0a1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..b46cd6c620
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,76 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+tdr_init_shmem(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+tdr_attach_shmem(void)
+{
+	bool		found;
+
+	tdr_state = GetNamedDSMSegment("test_dsm_registry",
+								   sizeof(TestDSMRegistryStruct),
+								   tdr_init_shmem,
+								   &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	tdr_attach_shmem();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index f582eb59e7..b7e73736e9 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2799,6 +2801,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--hHWLQfXTYDoKhP50
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v8-0003-use-dsm-registry-for-pg_prewarm.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v1 1/2] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 src/backend/storage/ipc/Makefile         |   1 +
 src/backend/storage/ipc/dsm_registry.c   | 176 +++++++++++++++++++++++
 src/backend/storage/ipc/ipci.c           |   3 +
 src/backend/storage/ipc/meson.build      |   1 +
 src/backend/storage/lmgr/lwlock.c        |   4 +
 src/backend/storage/lmgr/lwlocknames.txt |   1 +
 src/include/storage/dsm_registry.h       |  22 +++
 src/include/storage/lwlock.h             |   4 +-
 src/tools/pgindent/typedefs.list         |   2 +
 9 files changed, 213 insertions(+), 1 deletion(-)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h

diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..ea80f45716
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,176 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		key[256];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+static void init_dsm_registry(void);
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Initialize or attach a DSM entry.
+ *
+ * *ptr should initially be set to NULL.  If it is not NULL, this routine will
+ * assume that the segment has already been attached to the current session.
+ * Otherwise, this routine will set *ptr appropriately.
+ *
+ * init_callback is called to initialize the segment when it is first created.
+ */
+void
+dsm_registry_init_or_attach(const char *key, void **ptr, size_t size,
+							void (*init_callback) (void *ptr))
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	bool		found;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+
+	Assert(key);
+	Assert(ptr);
+	Assert(size);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Quick exit if the value is already set. */
+	if (*ptr)
+		return;
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find_or_insert(dsm_registry_table, key_padded, &found);
+	if (!found)
+	{
+		/* Initialize DSM registry entry. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		*ptr = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (*ptr);
+	}
+	else
+	{
+		/* Attach to existing DSM registry entry. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		*ptr = dsm_segment_address(seg);
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 2225a4a6e6..034b656115 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -38,6 +38,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -113,6 +114,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -285,6 +287,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 79a16d077f..88fef448be 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 315a78cda9..f3faa991d1 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index f72f2906ce..e8f679c8ae 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -54,3 +54,4 @@ XactTruncationLock					44
 WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
+DSMRegistryLock						49
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..8c311e50ae
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,22 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern void dsm_registry_init_or_attach(const char *key, void **ptr, size_t size,
+										void (*init_callback) (void *ptr));
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index b038e599c0..665d471418 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,7 +207,9 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
-	LWTRANCHE_FIRST_USER_DEFINED,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
+	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
 /*
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index d659adbfd6..c89a268d9e 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -606,6 +606,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
-- 
2.25.1


--DocE+STaALJfprDB
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment; filename="v1-0002-test-dsm-registry.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v2 1/2] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 209 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  24 ++
 src/include/storage/lwlock.h                  |   4 +-
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 ++
 .../expected/test_dsm_registry.out            |  16 ++
 .../modules/test_dsm_registry/meson.build     |  33 +++
 .../sql/test_dsm_registry.sql                 |   7 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  75 +++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 20 files changed, 426 insertions(+), 1 deletion(-)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..5fc970001e
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,209 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		key[256];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+static void init_dsm_registry(void);
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Find an existing DSM entry.
+ *
+ * This routine returns whether a segment is registered with the provided key.
+ */
+bool
+dsm_registry_find(const char *key)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+
+	Assert(key);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find(dsm_registry_table, key_padded, false);
+	if (entry)
+		dshash_release_lock(dsm_registry_table, entry);
+
+	MemoryContextSwitchTo(oldcontext);
+
+	return entry != NULL;
+}
+
+/*
+ * Initialize or attach a DSM entry.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+dsm_registry_init_or_attach(const char *key, size_t size,
+							void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(key);
+	Assert(size);
+	Assert(found);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find_or_insert(dsm_registry_table, key_padded, found);
+	if (!(*found))
+	{
+		/* Initialize DSM registry entry. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing DSM registry entry. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of already-attached DSM registry entry. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 706140eb9f..44d6a243e5 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 79a16d077f..88fef448be 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 315a78cda9..f3faa991d1 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7e79163466..de1bc986e1 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -324,6 +324,7 @@ XactTruncation	"Waiting to execute <function>pg_xact_status</function> or update
 WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consumption."
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 XactBuffer	"Waiting for I/O on a transaction status SLRU buffer."
 CommitTsBuffer	"Waiting for I/O on a commit timestamp SLRU buffer."
@@ -354,6 +355,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..5e9c1000bc
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,24 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern bool dsm_registry_find(const char *key);
+extern void *dsm_registry_init_or_attach(const char *key, size_t size,
+										 void (*init_callback) (void *ptr),
+										 bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index b038e599c0..665d471418 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,7 +207,9 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
-	LWTRANCHE_FIRST_USER_DEFINED,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
+	LWTRANCHE_FIRST_USER_DEFINED
 }			BuiltinTrancheIds;
 
 /*
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index b76f588559..bd53d52a3f 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..b9746f8a1e
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,16 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+CREATE DATABASE test;
+\c test
+CREATE EXTENSION test_dsm_registry;
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..4a7992109b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2023, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..bf2f468f10
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,7 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+
+CREATE DATABASE test;
+\c test
+CREATE EXTENSION test_dsm_registry;
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..068f47ed02
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,75 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+init_state(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+dsm_registry_attach(void)
+{
+	bool		found;
+
+	tdr_state = dsm_registry_init_or_attach("test_dsm_registry",
+											sizeof(TestDSMRegistryStruct),
+											init_state, &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e37ef9aa76..4270109fb8 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2796,6 +2798,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--FCuugMFkClbJLl1L
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0002-use-dsm-registry-for-pg_prewarm.patch"



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* [PATCH v3 1/2] add dsm registry
@ 2023-10-12 03:07  Nathan Bossart <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Nathan Bossart @ 2023-10-12 03:07 UTC (permalink / raw)

---
 src/backend/storage/ipc/Makefile              |   1 +
 src/backend/storage/ipc/dsm_registry.c        | 209 ++++++++++++++++++
 src/backend/storage/ipc/ipci.c                |   3 +
 src/backend/storage/ipc/meson.build           |   1 +
 src/backend/storage/lmgr/lwlock.c             |   4 +
 src/backend/storage/lmgr/lwlocknames.txt      |   1 +
 .../utils/activity/wait_event_names.txt       |   3 +
 src/include/storage/dsm_registry.h            |  24 ++
 src/include/storage/lwlock.h                  |   2 +
 src/test/modules/Makefile                     |   1 +
 src/test/modules/meson.build                  |   1 +
 src/test/modules/test_dsm_registry/.gitignore |   4 +
 src/test/modules/test_dsm_registry/Makefile   |  23 ++
 .../expected/test_dsm_registry.out            |  14 ++
 .../modules/test_dsm_registry/meson.build     |  33 +++
 .../sql/test_dsm_registry.sql                 |   4 +
 .../test_dsm_registry--1.0.sql                |  10 +
 .../test_dsm_registry/test_dsm_registry.c     |  75 +++++++
 .../test_dsm_registry.control                 |   4 +
 src/tools/pgindent/typedefs.list              |   3 +
 20 files changed, 420 insertions(+)
 create mode 100644 src/backend/storage/ipc/dsm_registry.c
 create mode 100644 src/include/storage/dsm_registry.h
 create mode 100644 src/test/modules/test_dsm_registry/.gitignore
 create mode 100644 src/test/modules/test_dsm_registry/Makefile
 create mode 100644 src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
 create mode 100644 src/test/modules/test_dsm_registry/meson.build
 create mode 100644 src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.c
 create mode 100644 src/test/modules/test_dsm_registry/test_dsm_registry.control

diff --git a/src/backend/storage/ipc/Makefile b/src/backend/storage/ipc/Makefile
index 6d5b921038..d8a1653eb6 100644
--- a/src/backend/storage/ipc/Makefile
+++ b/src/backend/storage/ipc/Makefile
@@ -12,6 +12,7 @@ OBJS = \
 	barrier.o \
 	dsm.o \
 	dsm_impl.o \
+	dsm_registry.o \
 	ipc.o \
 	ipci.o \
 	latch.o \
diff --git a/src/backend/storage/ipc/dsm_registry.c b/src/backend/storage/ipc/dsm_registry.c
new file mode 100644
index 0000000000..5fc970001e
--- /dev/null
+++ b/src/backend/storage/ipc/dsm_registry.c
@@ -0,0 +1,209 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.c
+ *
+ * Functions for interfacing with the dynamic shared memory registry.  This
+ * provides a way for libraries to use shared memory without needing to
+ * request it at startup time via a shmem_request_hook.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/storage/ipc/dsm_registry.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "lib/dshash.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
+#include "utils/memutils.h"
+
+typedef struct DSMRegistryCtxStruct
+{
+	dsa_handle	dsah;
+	dshash_table_handle dshh;
+} DSMRegistryCtxStruct;
+
+static DSMRegistryCtxStruct *DSMRegistryCtx;
+
+typedef struct DSMRegistryEntry
+{
+	char		key[256];
+	dsm_handle	handle;
+} DSMRegistryEntry;
+
+static const dshash_parameters dsh_params = {
+	offsetof(DSMRegistryEntry, handle),
+	sizeof(DSMRegistryEntry),
+	dshash_memcmp,
+	dshash_memhash,
+	LWTRANCHE_DSM_REGISTRY_HASH
+};
+
+static dsa_area *dsm_registry_dsa;
+static dshash_table *dsm_registry_table;
+
+static void init_dsm_registry(void);
+
+Size
+DSMRegistryShmemSize(void)
+{
+	return MAXALIGN(sizeof(DSMRegistryCtxStruct));
+}
+
+void
+DSMRegistryShmemInit(void)
+{
+	bool		found;
+
+	DSMRegistryCtx = (DSMRegistryCtxStruct *)
+		ShmemInitStruct("DSM Registry Data",
+						DSMRegistryShmemSize(),
+						&found);
+
+	if (!found)
+	{
+		DSMRegistryCtx->dsah = DSA_HANDLE_INVALID;
+		DSMRegistryCtx->dshh = DSHASH_HANDLE_INVALID;
+	}
+}
+
+/*
+ * Initialize or attach to the dynamic shared hash table that stores the DSM
+ * registry entries, if not already done.  This must be called before accessing
+ * the table.
+ */
+static void
+init_dsm_registry(void)
+{
+	/* Quick exit if we already did this. */
+	if (dsm_registry_table)
+		return;
+
+	/* Otherwise, use a lock to ensure only one process creates the table. */
+	LWLockAcquire(DSMRegistryLock, LW_EXCLUSIVE);
+
+	if (DSMRegistryCtx->dshh == DSHASH_HANDLE_INVALID)
+	{
+		/* Initialize dynamic shared hash table for registry. */
+		dsm_registry_dsa = dsa_create(LWTRANCHE_DSM_REGISTRY_DSA);
+		dsa_pin(dsm_registry_dsa);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_create(dsm_registry_dsa, &dsh_params, 0);
+
+		/* Store handles in shared memory for other backends to use. */
+		DSMRegistryCtx->dsah = dsa_get_handle(dsm_registry_dsa);
+		DSMRegistryCtx->dshh = dshash_get_hash_table_handle(dsm_registry_table);
+	}
+	else
+	{
+		/* Attach to existing dynamic shared hash table. */
+		dsm_registry_dsa = dsa_attach(DSMRegistryCtx->dsah);
+		dsa_pin_mapping(dsm_registry_dsa);
+		dsm_registry_table = dshash_attach(dsm_registry_dsa, &dsh_params,
+										   DSMRegistryCtx->dshh, 0);
+	}
+
+	LWLockRelease(DSMRegistryLock);
+}
+
+/*
+ * Find an existing DSM entry.
+ *
+ * This routine returns whether a segment is registered with the provided key.
+ */
+bool
+dsm_registry_find(const char *key)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+
+	Assert(key);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find(dsm_registry_table, key_padded, false);
+	if (entry)
+		dshash_release_lock(dsm_registry_table, entry);
+
+	MemoryContextSwitchTo(oldcontext);
+
+	return entry != NULL;
+}
+
+/*
+ * Initialize or attach a DSM entry.
+ *
+ * This routine returns the address of the segment.  init_callback is called to
+ * initialize the segment when it is first created.
+ */
+void *
+dsm_registry_init_or_attach(const char *key, size_t size,
+							void (*init_callback) (void *ptr), bool *found)
+{
+	DSMRegistryEntry *entry;
+	MemoryContext oldcontext;
+	char		key_padded[offsetof(DSMRegistryEntry, handle)] = {0};
+	void	   *ret;
+
+	Assert(key);
+	Assert(size);
+	Assert(found);
+
+	if (strlen(key) >= offsetof(DSMRegistryEntry, handle))
+		elog(ERROR, "DSM registry key too long");
+
+	/* Be sure any local memory allocated by DSM/DSA routines is persistent. */
+	oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+
+	/* Connect to the registry. */
+	init_dsm_registry();
+
+	strcpy(key_padded, key);
+	entry = dshash_find_or_insert(dsm_registry_table, key_padded, found);
+	if (!(*found))
+	{
+		/* Initialize DSM registry entry. */
+		dsm_segment *seg = dsm_create(size, 0);
+
+		dsm_pin_segment(seg);
+		dsm_pin_mapping(seg);
+		entry->handle = dsm_segment_handle(seg);
+		ret = dsm_segment_address(seg);
+
+		if (init_callback)
+			(*init_callback) (ret);
+	}
+	else if (!dsm_find_mapping(entry->handle))
+	{
+		/* Attach to existing DSM registry entry. */
+		dsm_segment *seg = dsm_attach(entry->handle);
+
+		dsm_pin_mapping(seg);
+		ret = dsm_segment_address(seg);
+	}
+	else
+	{
+		/* Return address of already-attached DSM registry entry. */
+		ret = dsm_segment_address(dsm_find_mapping(entry->handle));
+	}
+
+	dshash_release_lock(dsm_registry_table, entry);
+	MemoryContextSwitchTo(oldcontext);
+
+	return ret;
+}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 706140eb9f..44d6a243e5 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -40,6 +40,7 @@
 #include "replication/walsender.h"
 #include "storage/bufmgr.h"
 #include "storage/dsm.h"
+#include "storage/dsm_registry.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
 #include "storage/pmsignal.h"
@@ -115,6 +116,7 @@ CalculateShmemSize(int *num_semaphores)
 	size = add_size(size, hash_estimate_size(SHMEM_INDEX_SIZE,
 											 sizeof(ShmemIndexEnt)));
 	size = add_size(size, dsm_estimate_size());
+	size = add_size(size, DSMRegistryShmemSize());
 	size = add_size(size, BufferShmemSize());
 	size = add_size(size, LockShmemSize());
 	size = add_size(size, PredicateLockShmemSize());
@@ -289,6 +291,7 @@ CreateOrAttachShmemStructs(void)
 	InitShmemIndex();
 
 	dsm_shmem_init();
+	DSMRegistryShmemInit();
 
 	/*
 	 * Set up xlog, clog, and buffers
diff --git a/src/backend/storage/ipc/meson.build b/src/backend/storage/ipc/meson.build
index 79a16d077f..88fef448be 100644
--- a/src/backend/storage/ipc/meson.build
+++ b/src/backend/storage/ipc/meson.build
@@ -4,6 +4,7 @@ backend_sources += files(
   'barrier.c',
   'dsm.c',
   'dsm_impl.c',
+  'dsm_registry.c',
   'ipc.c',
   'ipci.c',
   'latch.c',
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 315a78cda9..f3faa991d1 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -190,6 +190,10 @@ static const char *const BuiltinTrancheNames[] = {
 	"LogicalRepLauncherDSA",
 	/* LWTRANCHE_LAUNCHER_HASH: */
 	"LogicalRepLauncherHash",
+	/* LWTRANCHE_DSM_REGISTRY_DSA: */
+	"DSMRegistryDSA",
+	/* LWTRANCHE_DSM_REGISTRY_HASH: */
+	"DSMRegistryHash",
 };
 
 StaticAssertDecl(lengthof(BuiltinTrancheNames) ==
diff --git a/src/backend/storage/lmgr/lwlocknames.txt b/src/backend/storage/lmgr/lwlocknames.txt
index d621f5507f..ef8542de46 100644
--- a/src/backend/storage/lmgr/lwlocknames.txt
+++ b/src/backend/storage/lmgr/lwlocknames.txt
@@ -55,3 +55,4 @@ WrapLimitsVacuumLock				46
 NotifyQueueTailLock					47
 WaitEventExtensionLock				48
 WALSummarizerLock					49
+DSMRegistryLock						50
diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt
index 7e79163466..de1bc986e1 100644
--- a/src/backend/utils/activity/wait_event_names.txt
+++ b/src/backend/utils/activity/wait_event_names.txt
@@ -324,6 +324,7 @@ XactTruncation	"Waiting to execute <function>pg_xact_status</function> or update
 WrapLimitsVacuum	"Waiting to update limits on transaction id and multixact consumption."
 NotifyQueueTail	"Waiting to update limit on <command>NOTIFY</command> message storage."
 WaitEventExtension	"Waiting to read or update custom wait events information for extensions."
+DSMRegistry	"Waiting to read or update the dynamic shared memory registry."
 
 XactBuffer	"Waiting for I/O on a transaction status SLRU buffer."
 CommitTsBuffer	"Waiting for I/O on a commit timestamp SLRU buffer."
@@ -354,6 +355,8 @@ PgStatsHash	"Waiting for stats shared memory hash table access."
 PgStatsData	"Waiting for shared memory stats data access."
 LogicalRepLauncherDSA	"Waiting to access logical replication launcher's dynamic shared memory allocator."
 LogicalRepLauncherHash	"Waiting to access logical replication launcher's shared hash table."
+DSMRegistryDSA	"Waiting to access dynamic shared memory registry's dynamic shared memory allocator."
+DSMRegistryHash	"Waiting to access dynamic shared memory registry's shared hash table."
 
 #
 # Wait Events - Lock
diff --git a/src/include/storage/dsm_registry.h b/src/include/storage/dsm_registry.h
new file mode 100644
index 0000000000..5e9c1000bc
--- /dev/null
+++ b/src/include/storage/dsm_registry.h
@@ -0,0 +1,24 @@
+/*-------------------------------------------------------------------------
+ *
+ * dsm_registry.h
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/dsm_registry.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef DSM_REGISTRY_H
+#define DSM_REGISTRY_H
+
+extern bool dsm_registry_find(const char *key);
+extern void *dsm_registry_init_or_attach(const char *key, size_t size,
+										 void (*init_callback) (void *ptr),
+										 bool *found);
+
+extern Size DSMRegistryShmemSize(void);
+extern void DSMRegistryShmemInit(void);
+
+#endif							/* DSM_REGISTRY_H */
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index b038e599c0..e0e7b3b765 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -207,6 +207,8 @@ typedef enum BuiltinTrancheIds
 	LWTRANCHE_PGSTATS_DATA,
 	LWTRANCHE_LAUNCHER_DSA,
 	LWTRANCHE_LAUNCHER_HASH,
+	LWTRANCHE_DSM_REGISTRY_DSA,
+	LWTRANCHE_DSM_REGISTRY_HASH,
 	LWTRANCHE_FIRST_USER_DEFINED,
 }			BuiltinTrancheIds;
 
diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 5d33fa6a9a..f656032589 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -18,6 +18,7 @@ SUBDIRS = \
 		  test_custom_rmgrs \
 		  test_ddl_deparse \
 		  test_dsa \
+		  test_dsm_registry \
 		  test_extensions \
 		  test_ginpostinglist \
 		  test_integerset \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index b76f588559..bd53d52a3f 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -15,6 +15,7 @@ subdir('test_copy_callbacks')
 subdir('test_custom_rmgrs')
 subdir('test_ddl_deparse')
 subdir('test_dsa')
+subdir('test_dsm_registry')
 subdir('test_extensions')
 subdir('test_ginpostinglist')
 subdir('test_integerset')
diff --git a/src/test/modules/test_dsm_registry/.gitignore b/src/test/modules/test_dsm_registry/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_dsm_registry/Makefile b/src/test/modules/test_dsm_registry/Makefile
new file mode 100644
index 0000000000..b13e99a354
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_dsm_registry/Makefile
+
+MODULE_big = test_dsm_registry
+OBJS = \
+	$(WIN32RES) \
+	test_dsm_registry.o
+PGFILEDESC = "test_dsm_registry - test code for the DSM registry"
+
+EXTENSION = test_dsm_registry
+DATA = test_dsm_registry--1.0.sql
+
+REGRESS = test_dsm_registry
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_dsm_registry
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
new file mode 100644
index 0000000000..8ffbd343a0
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/expected/test_dsm_registry.out
@@ -0,0 +1,14 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+ set_val_in_shmem 
+------------------
+ 
+(1 row)
+
+\c
+SELECT get_val_in_shmem();
+ get_val_in_shmem 
+------------------
+             1236
+(1 row)
+
diff --git a/src/test/modules/test_dsm_registry/meson.build b/src/test/modules/test_dsm_registry/meson.build
new file mode 100644
index 0000000000..4a7992109b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2023, PostgreSQL Global Development Group
+
+test_dsm_registry_sources = files(
+  'test_dsm_registry.c',
+)
+
+if host_system == 'windows'
+  test_dsm_registry_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_dsm_registry',
+    '--FILEDESC', 'test_dsm_registry - test code for the DSM registry',])
+endif
+
+test_dsm_registry = shared_module('test_dsm_registry',
+  test_dsm_registry_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_dsm_registry
+
+test_install_data += files(
+  'test_dsm_registry.control',
+  'test_dsm_registry--1.0.sql',
+)
+
+tests += {
+  'name': 'test_dsm_registry',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_dsm_registry',
+    ],
+  },
+}
diff --git a/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
new file mode 100644
index 0000000000..b3351be0a1
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/sql/test_dsm_registry.sql
@@ -0,0 +1,4 @@
+CREATE EXTENSION test_dsm_registry;
+SELECT set_val_in_shmem(1236);
+\c
+SELECT get_val_in_shmem();
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
new file mode 100644
index 0000000000..8c55b0919b
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -0,0 +1,10 @@
+/* src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
+
+CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION get_val_in_shmem() RETURNS INT
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
new file mode 100644
index 0000000000..068f47ed02
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -0,0 +1,75 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_dsm_registry.c
+ *		Test the DSM registry
+ *
+ * Copyright (c) 2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_dsm_registry/test_dsm_registry.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
+
+PG_MODULE_MAGIC;
+
+typedef struct TestDSMRegistryStruct
+{
+	int			val;
+	LWLock		lck;
+} TestDSMRegistryStruct;
+
+static TestDSMRegistryStruct *tdr_state;
+
+static void
+init_state(void *ptr)
+{
+	TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
+
+	LWLockInitialize(&state->lck, LWLockNewTrancheId());
+	state->val = 0;
+}
+
+static void
+dsm_registry_attach(void)
+{
+	bool		found;
+
+	tdr_state = dsm_registry_init_or_attach("test_dsm_registry",
+											sizeof(TestDSMRegistryStruct),
+											init_state, &found);
+	LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
+}
+
+PG_FUNCTION_INFO_V1(set_val_in_shmem);
+Datum
+set_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
+	tdr_state->val = PG_GETARG_UINT32(0);
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(get_val_in_shmem);
+Datum
+get_val_in_shmem(PG_FUNCTION_ARGS)
+{
+	int			ret;
+
+	dsm_registry_attach();
+
+	LWLockAcquire(&tdr_state->lck, LW_SHARED);
+	ret = tdr_state->val;
+	LWLockRelease(&tdr_state->lck);
+
+	PG_RETURN_UINT32(ret);
+}
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.control b/src/test/modules/test_dsm_registry/test_dsm_registry.control
new file mode 100644
index 0000000000..813f099889
--- /dev/null
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.control
@@ -0,0 +1,4 @@
+comment = 'Test code for the DSM registry'
+default_version = '1.0'
+module_pathname = '$libdir/test_dsm_registry'
+relocatable = true
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index e37ef9aa76..4270109fb8 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -610,6 +610,8 @@ DropSubscriptionStmt
 DropTableSpaceStmt
 DropUserMappingStmt
 DropdbStmt
+DSMRegistryCtxStruct
+DSMRegistryEntry
 DumpComponents
 DumpId
 DumpOptions
@@ -2796,6 +2798,7 @@ Tcl_NotifierProcs
 Tcl_Obj
 Tcl_Time
 TempNamespaceStatus
+TestDSMRegistryStruct
 TestDecodingData
 TestDecodingTxnData
 TestSpec
-- 
2.25.1


--Dxnq1zWXvFF0Q93v
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v3-0002-use-dsm-registry-for-pg_prewarm.patch"



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2021-01-07 01:08 [PATCH] doc review: COPY progress: 8a4f618e7ae3cb11b0b37d0f06f05c8ff905833f Justin Pryzby <[email protected]>
2023-10-12 03:07 [PATCH v4 1/2] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v5 1/2] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v2 1/2] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v6 2/3] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v7 2/3] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v8 2/3] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v1 1/2] add dsm registry Nathan Bossart <[email protected]>
2023-10-12 03:07 [PATCH v3 1/2] add dsm registry Nathan Bossart <[email protected]>

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