Redesign the patch for allocation of shmem space and LWLocks for add-on
modules; the first try was not usable in EXEC_BACKEND builds (e.g., Windows). Instead, just provide some entry points to increase the allocation requests during postmaster start, and provide a dedicated LWLock that can be used to synchronize allocation operations performed by backends. Per discussion with Marc Munro.
This commit is contained in:
Tom Lane
parent
a3dff39c53
commit
e0dece127d
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/storage/ipc/ipci.c,v 1.88 2006/10/04 00:29:57 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/storage/ipc/ipci.c,v 1.89 2006/10/15 22:04:07 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -32,6 +32,30 @@
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#include "storage/spin.h"
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static Size total_addin_request = 0;
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static bool addin_request_allowed = true;
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/*
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* RequestAddinShmemSpace
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* Request that extra shmem space be allocated for use by
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* a loadable module.
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*
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* This is only useful if called from the _PG_init hook of a library that
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* is loaded into the postmaster via shared_preload_libraries. Once
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* shared memory has been allocated, calls will be ignored. (We could
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* raise an error, but it seems better to make it a no-op, so that
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* libraries containing such calls can be reloaded if needed.)
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*/
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void
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RequestAddinShmemSpace(Size size)
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{
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if (IsUnderPostmaster || !addin_request_allowed)
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return; /* too late */
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total_addin_request = add_size(total_addin_request, size);
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}
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/*
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* CreateSharedMemoryAndSemaphores
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* Creates and initializes shared memory and semaphores.
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@ -57,7 +81,6 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
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{
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PGShmemHeader *seghdr;
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Size size;
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Size size_b4addins;
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int numSemas;
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/*
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@ -91,16 +114,11 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
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size = add_size(size, ShmemBackendArraySize());
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#endif
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/* might as well round it off to a multiple of a typical page size */
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size = add_size(size, 8192 - (size % 8192));
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/* freeze the addin request size and include it */
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addin_request_allowed = false;
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size = add_size(size, total_addin_request);
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/*
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* The shared memory for add-ins is treated as a separate segment, but
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* in reality it is not.
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*/
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size_b4addins = size;
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size = add_size(size, AddinShmemSize());
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/* round it off again */
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/* might as well round it off to a multiple of a typical page size */
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size = add_size(size, 8192 - (size % 8192));
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elog(DEBUG3, "invoking IpcMemoryCreate(size=%lu)",
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@ -111,16 +129,6 @@ CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
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*/
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seghdr = PGSharedMemoryCreate(size, makePrivate, port);
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/*
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* Modify hdr to show segment size before add-ins
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*/
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seghdr->totalsize = size_b4addins;
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/*
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* Set up segment header sections in each Addin context
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*/
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InitAddinContexts((void *) ((char *) seghdr + size_b4addins));
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InitShmemAccess(seghdr);
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/*
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/storage/ipc/shmem.c,v 1.97 2006/10/04 00:29:57 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/storage/ipc/shmem.c,v 1.98 2006/10/15 22:04:07 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -53,7 +53,7 @@
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* postmaster. However, this does not work in the EXEC_BACKEND case.
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* In ports using EXEC_BACKEND, new backends have to set up their local
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* pointers using the method described in (b) above.
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*
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* (d) memory allocation model: shared memory can never be
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* freed, once allocated. Each hash table has its own free list,
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* so hash buckets can be reused when an item is deleted. However,
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@ -61,15 +61,6 @@
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* cannot be redistributed to other tables. We could build a simple
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* hash bucket garbage collector if need be. Right now, it seems
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* unnecessary.
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*
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* (e) Add-ins can request their own logical shared memory segments
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* by calling RegisterAddinContext() from the preload-libraries hook.
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* Each call establishes a uniquely named add-in shared memopry
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* context which will be set up as part of postgres intialisation.
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* Memory can be allocated from these contexts using
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* ShmemAllocFromContext(), and can be reset to its initial condition
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* using ShmemResetContext(). Also, RegisterAddinLWLock(LWLockid *lock_ptr)
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* can be used to request that a LWLock be allocated, placed into *lock_ptr.
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*/
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#include "postgres.h"
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@ -95,19 +86,6 @@ slock_t *ShmemLock; /* spinlock for shared memory and LWLock
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static HTAB *ShmemIndex = NULL; /* primary index hashtable for shmem */
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/* Structures and globals for managing add-in shared memory contexts */
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typedef struct context
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{
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char *name;
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Size size;
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PGShmemHeader *seg_hdr;
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struct context *next;
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} ContextNode;
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static ContextNode *addin_contexts = NULL;
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static Size addin_contexts_size = 0;
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/*
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* InitShmemAccess() --- set up basic pointers to shared memory.
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@ -162,99 +140,7 @@ InitShmemAllocation(void)
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}
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/*
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* RegisterAddinContext -- Register the requirement for a named shared
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* memory context.
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*/
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void
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RegisterAddinContext(const char *name, Size size)
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{
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char *newstr = malloc(strlen(name) + 1);
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ContextNode *node = malloc(sizeof(ContextNode));
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strcpy(newstr, name);
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node->name = newstr;
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/* Round up to typical page size */
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node->size = add_size(size, 8192 - (size % 8192));
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node->next = addin_contexts;
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addin_contexts = node;
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addin_contexts_size = add_size(addin_contexts_size, node->size);
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}
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/*
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* ContextFromName -- Return the ContextNode for the given named
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* context, or NULL if not found.
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*/
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static ContextNode *
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ContextFromName(const char *name)
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{
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ContextNode *context = addin_contexts;
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while (context)
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{
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if (strcmp(name, context->name) == 0)
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return context;
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context = context->next;
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}
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return NULL;
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}
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/*
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* InitAddinContexts -- Initialise the registered addin shared memory
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* contexts.
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*/
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void
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InitAddinContexts(void *start)
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{
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PGShmemHeader *next_segment = (PGShmemHeader *) start;
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ContextNode *context = addin_contexts;
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while (context)
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{
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context->seg_hdr = next_segment;
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next_segment->totalsize = context->size;
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next_segment->freeoffset = MAXALIGN(sizeof(PGShmemHeader));
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next_segment = (PGShmemHeader *)
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((char *) next_segment + context->size);
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context = context->next;
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}
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}
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/*
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* ShmemResetContext -- Re-initialise the named addin shared memory context.
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*/
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void
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ShmemResetContext(const char *name)
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{
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PGShmemHeader *segment;
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ContextNode *context = ContextFromName(name);
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if (!context)
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("cannot reset unknown shared memory context %s",
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name)));
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segment = context->seg_hdr;
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segment->freeoffset = MAXALIGN(sizeof(PGShmemHeader));
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}
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/*
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* AddinShmemSize -- Report how much shared memory has been registered
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* for add-ins.
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*/
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Size
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AddinShmemSize(void)
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{
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return addin_contexts_size;
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}
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/*
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* ShmemAllocFromContext -- allocate max-aligned chunk from shared memory
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* ShmemAlloc -- allocate max-aligned chunk from shared memory
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*
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* Assumes ShmemLock and ShmemSegHdr are initialized.
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*
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@ -263,30 +149,15 @@ AddinShmemSize(void)
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* to be compatible with malloc().
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*/
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void *
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ShmemAllocFromContext(Size size, const char *context_name)
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ShmemAlloc(Size size)
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{
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Size newStart;
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Size newFree;
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void *newSpace;
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ContextNode *context;
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/* use volatile pointer to prevent code rearrangement */
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volatile PGShmemHeader *shmemseghdr = ShmemSegHdr;
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/*
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* if context_name is provided, allocate from the named context
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*/
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if (context_name)
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{
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context = ContextFromName(context_name);
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if (!context)
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ereport(ERROR,
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(errcode(ERRCODE_INTERNAL_ERROR),
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errmsg("cannot reset unknown shared memory context %s",
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context_name)));
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shmemseghdr = context->seg_hdr;
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}
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/*
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* ensure all space is adequately aligned.
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*/
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@ -305,7 +176,7 @@ ShmemAllocFromContext(Size size, const char *context_name)
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newFree = newStart + size;
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if (newFree <= shmemseghdr->totalsize)
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{
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newSpace = (void *) MAKE_PTRFROM((SHMEM_OFFSET) shmemseghdr, newStart);
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newSpace = (void *) MAKE_PTR(newStart);
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shmemseghdr->freeoffset = newFree;
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}
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else
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@ -321,22 +192,6 @@ ShmemAllocFromContext(Size size, const char *context_name)
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return newSpace;
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}
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/*
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* ShmemAlloc -- allocate max-aligned chunk from shared memory
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*
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* Assumes ShmemLock and ShmemSegHdr are initialized.
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*
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* Returns: real pointer to memory or NULL if we are out
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* of space. Has to return a real pointer in order
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* to be compatible with malloc().
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*/
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void *
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ShmemAlloc(Size size)
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{
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return ShmemAllocFromContext(size, NULL);
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}
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/*
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* ShmemIsValid -- test if an offset refers to valid shared memory
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*
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@ -15,7 +15,7 @@
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.46 2006/10/04 00:29:57 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/storage/lmgr/lwlock.c,v 1.47 2006/10/15 22:04:07 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -30,10 +30,6 @@
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#include "storage/spin.h"
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static int NumAddinLWLocks(void);
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static void AssignAddinLWLocks(void);
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/* We use the ShmemLock spinlock to protect LWLockAssign */
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extern slock_t *ShmemLock;
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@ -88,6 +84,9 @@ NON_EXEC_STATIC LWLockPadded *LWLockArray = NULL;
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static int num_held_lwlocks = 0;
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static LWLockId held_lwlocks[MAX_SIMUL_LWLOCKS];
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static int lock_addin_request = 0;
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static bool lock_addin_request_allowed = true;
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#ifdef LWLOCK_STATS
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static int counts_for_pid = 0;
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static int *sh_acquire_counts;
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@ -95,63 +94,6 @@ static int *ex_acquire_counts;
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static int *block_counts;
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#endif
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/*
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* Structures and globals to allow add-ins to register for their own
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* lwlocks from the preload-libraries hook.
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*/
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typedef struct LWLockNode
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{
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LWLockId *lock;
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struct LWLockNode *next;
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} LWLockNode;
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static LWLockNode *addin_locks = NULL;
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static int num_addin_locks = 0;
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/*
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* RegisterAddinLWLock() --- Allow an andd-in to request a LWLock
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* from the preload-libraries hook.
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*/
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void
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RegisterAddinLWLock(LWLockId *lock)
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{
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LWLockNode *locknode = malloc(sizeof(LWLockNode));
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locknode->next = addin_locks;
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locknode->lock = lock;
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addin_locks = locknode;
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num_addin_locks++;
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}
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/*
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* NumAddinLWLocks() --- Return the number of LWLocks requested by add-ins.
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*/
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static int
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NumAddinLWLocks()
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{
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return num_addin_locks;
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}
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/*
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* AssignAddinLWLocks() --- Assign LWLocks previously requested by add-ins.
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*/
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static void
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AssignAddinLWLocks()
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{
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LWLockNode *node = addin_locks;
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while (node)
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{
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*(node->lock) = LWLockAssign();
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node = node->next;
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}
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}
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#ifdef LOCK_DEBUG
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bool Trace_lwlocks = false;
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@ -231,16 +173,38 @@ NumLWLocks(void)
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/* multixact.c needs two SLRU areas */
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numLocks += NUM_MXACTOFFSET_BUFFERS + NUM_MXACTMEMBER_BUFFERS;
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/* Leave a few extra for use by user-defined modules. */
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numLocks += NUM_USER_DEFINED_LWLOCKS;
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/* Add the number that have been explicitly requested by add-ins. */
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numLocks += NumAddinLWLocks();
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/*
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* Add any requested by loadable modules; for backwards-compatibility
|
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* reasons, allocate at least NUM_USER_DEFINED_LWLOCKS of them even
|
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* if there are no explicit requests.
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*/
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lock_addin_request_allowed = false;
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numLocks += Max(lock_addin_request, NUM_USER_DEFINED_LWLOCKS);
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return numLocks;
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}
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|
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/*
|
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* RequestAddinLWLocks
|
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* Request that extra LWLocks be allocated for use by
|
||||
* a loadable module.
|
||||
*
|
||||
* This is only useful if called from the _PG_init hook of a library that
|
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* is loaded into the postmaster via shared_preload_libraries. Once
|
||||
* shared memory has been allocated, calls will be ignored. (We could
|
||||
* raise an error, but it seems better to make it a no-op, so that
|
||||
* libraries containing such calls can be reloaded if needed.)
|
||||
*/
|
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void
|
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RequestAddinLWLocks(int n)
|
||||
{
|
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if (IsUnderPostmaster || !lock_addin_request_allowed)
|
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return; /* too late */
|
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lock_addin_request += n;
|
||||
}
|
||||
|
||||
|
||||
/*
|
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* Compute shmem space needed for LWLocks.
|
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*/
|
||||
|
|
@ -304,11 +268,6 @@ CreateLWLocks(void)
|
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LWLockCounter = (int *) ((char *) LWLockArray - 2 * sizeof(int));
|
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LWLockCounter[0] = (int) NumFixedLWLocks;
|
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LWLockCounter[1] = numLocks;
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|
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/*
|
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* Allocate LWLocks for those add-ins that have explicitly requested them.
|
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*/
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AssignAddinLWLocks();
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}
|
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|
||||
|
||||
|
|
|
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|
|
@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
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*
|
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* $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.31 2006/08/01 19:03:11 momjian Exp $
|
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* $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.32 2006/10/15 22:04:07 tgl Exp $
|
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*
|
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*-------------------------------------------------------------------------
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*/
|
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|
|
@ -60,6 +60,7 @@ typedef enum LWLockId
|
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TwoPhaseStateLock,
|
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TablespaceCreateLock,
|
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BtreeVacuumLock,
|
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AddinShmemInitLock,
|
||||
FirstBufMappingLock,
|
||||
FirstLockMgrLock = FirstBufMappingLock + NUM_BUFFER_PARTITIONS,
|
||||
|
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|
|
@ -92,6 +93,6 @@ extern int NumLWLocks(void);
|
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extern Size LWLockShmemSize(void);
|
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extern void CreateLWLocks(void);
|
||||
|
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extern void RegisterAddinLWLock(LWLockId *lock);
|
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extern void RequestAddinLWLocks(int n);
|
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|
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#endif /* LWLOCK_H */
|
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|
|
|
|||
|
|
@ -17,7 +17,7 @@
|
|||
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/storage/pg_shmem.h,v 1.20 2006/10/04 00:30:10 momjian Exp $
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||||
* $PostgreSQL: pgsql/src/include/storage/pg_shmem.h,v 1.21 2006/10/15 22:04:07 tgl Exp $
|
||||
*
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||||
*-------------------------------------------------------------------------
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||||
*/
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||||
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|
@ -51,11 +51,4 @@ extern PGShmemHeader *PGSharedMemoryCreate(Size size, bool makePrivate,
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|||
extern bool PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2);
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||||
extern void PGSharedMemoryDetach(void);
|
||||
|
||||
|
||||
extern void RegisterAddinContext(const char *name, Size size);
|
||||
extern Size AddinShmemSize(void);
|
||||
extern void InitAddinContexts(void *start);
|
||||
extern void *ShmemAllocFromContext(Size size, const char *name);
|
||||
extern void ShmemResetContext(const char *name);
|
||||
|
||||
#endif /* PG_SHMEM_H */
|
||||
|
|
|
|||
|
|
@ -7,7 +7,7 @@
|
|||
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/storage/shmem.h,v 1.48 2006/08/01 19:03:11 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/include/storage/shmem.h,v 1.49 2006/10/15 22:04:08 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
|
@ -38,11 +38,6 @@ typedef unsigned long SHMEM_OFFSET;
|
|||
extern DLLIMPORT SHMEM_OFFSET ShmemBase;
|
||||
|
||||
|
||||
/* coerce an offset into a pointer in a specified address space. This
|
||||
* macro (only) is not confined to the primary shared memory region */
|
||||
#define MAKE_PTRFROM(base,xx_offs)\
|
||||
(base+((unsigned long)(xx_offs)))
|
||||
|
||||
/* coerce an offset into a pointer in this process's address space */
|
||||
#define MAKE_PTR(xx_offs)\
|
||||
(ShmemBase+((unsigned long)(xx_offs)))
|
||||
|
|
@ -77,6 +72,9 @@ extern void *ShmemInitStruct(const char *name, Size size, bool *foundPtr);
|
|||
extern Size add_size(Size s1, Size s2);
|
||||
extern Size mul_size(Size s1, Size s2);
|
||||
|
||||
/* ipci.c */
|
||||
extern void RequestAddinShmemSpace(Size size);
|
||||
|
||||
/* size constants for the shmem index table */
|
||||
/* max size of data structure string name */
|
||||
#define SHMEM_INDEX_KEYSIZE (48)
|
||||
|
|
|
|||
Loading…
Reference in New Issue