diff options
Diffstat (limited to 'src/backend/port/sysv_shmem.c')
| -rw-r--r-- | src/backend/port/sysv_shmem.c | 42 |
1 files changed, 16 insertions, 26 deletions
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c index 49b3416640d..1511a61bc56 100644 --- a/src/backend/port/sysv_shmem.c +++ b/src/backend/port/sysv_shmem.c @@ -62,10 +62,11 @@ * to a process after exec(). Since EXEC_BACKEND is intended only for * developer use, this shouldn't be a big problem. Because of this, we do * not worry about supporting anonymous shmem in the EXEC_BACKEND cases below. + * + * As of PostgreSQL 12, we regained the ability to use a large System V shared + * memory region even in non-EXEC_BACKEND builds, if shared_memory_type is set + * to sysv (though this is not the default). */ -#ifndef EXEC_BACKEND -#define USE_ANONYMOUS_SHMEM -#endif typedef key_t IpcMemoryKey; /* shared memory key passed to shmget(2) */ @@ -75,10 +76,8 @@ typedef int IpcMemoryId; /* shared memory ID returned by shmget(2) */ unsigned long UsedShmemSegID = 0; void *UsedShmemSegAddr = NULL; -#ifdef USE_ANONYMOUS_SHMEM static Size AnonymousShmemSize; static void *AnonymousShmem = NULL; -#endif static void *InternalIpcMemoryCreate(IpcMemoryKey memKey, Size size); static void IpcMemoryDetach(int status, Datum shmaddr); @@ -370,8 +369,6 @@ PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) return true; } -#ifdef USE_ANONYMOUS_SHMEM - #ifdef MAP_HUGETLB /* @@ -534,8 +531,6 @@ AnonymousShmemDetach(int status, Datum arg) } } -#endif /* USE_ANONYMOUS_SHMEM */ - /* * PGSharedMemoryCreate * @@ -566,7 +561,7 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port, Size sysvsize; /* Complain if hugepages demanded but we can't possibly support them */ -#if !defined(USE_ANONYMOUS_SHMEM) || !defined(MAP_HUGETLB) +#if !defined(MAP_HUGETLB) if (huge_pages == HUGE_PAGES_ON) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), @@ -576,18 +571,19 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port, /* Room for a header? */ Assert(size > MAXALIGN(sizeof(PGShmemHeader))); -#ifdef USE_ANONYMOUS_SHMEM - AnonymousShmem = CreateAnonymousSegment(&size); - AnonymousShmemSize = size; + if (shared_memory_type == SHMEM_TYPE_MMAP) + { + AnonymousShmem = CreateAnonymousSegment(&size); + AnonymousShmemSize = size; - /* Register on-exit routine to unmap the anonymous segment */ - on_shmem_exit(AnonymousShmemDetach, (Datum) 0); + /* Register on-exit routine to unmap the anonymous segment */ + on_shmem_exit(AnonymousShmemDetach, (Datum) 0); - /* Now we need only allocate a minimal-sized SysV shmem block. */ - sysvsize = sizeof(PGShmemHeader); -#else - sysvsize = size; -#endif + /* Now we need only allocate a minimal-sized SysV shmem block. */ + sysvsize = sizeof(PGShmemHeader); + } + else + sysvsize = size; /* Make sure PGSharedMemoryAttach doesn't fail without need */ UsedShmemSegAddr = NULL; @@ -687,14 +683,10 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port, * block. Otherwise, the System V shared memory block is only a shim, and * we must return a pointer to the real block. */ -#ifdef USE_ANONYMOUS_SHMEM if (AnonymousShmem == NULL) return hdr; memcpy(AnonymousShmem, hdr, sizeof(PGShmemHeader)); return (PGShmemHeader *) AnonymousShmem; -#else - return hdr; -#endif } #ifdef EXEC_BACKEND @@ -801,7 +793,6 @@ PGSharedMemoryDetach(void) UsedShmemSegAddr = NULL; } -#ifdef USE_ANONYMOUS_SHMEM if (AnonymousShmem != NULL) { if (munmap(AnonymousShmem, AnonymousShmemSize) < 0) @@ -809,7 +800,6 @@ PGSharedMemoryDetach(void) AnonymousShmem, AnonymousShmemSize); AnonymousShmem = NULL; } -#endif } |