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Allow dynamic allocation of shared memory segments.

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Patch by myself and Amit Kapila.  Design help from Noah Misch.  Review
by Andres Freund.
This commit is contained in:
Robert Haas
2013-10-09 21:05:02 -04:00
parent f566515192
commit 0ac5e5a7e1
18 changed files with 2470 additions and 29 deletions
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26
src/backend/port/sysv_shmem.c
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@ -29,6 +29,7 @@
#endif
#include "miscadmin.h"
#include "portability/mem.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
@ -36,31 +37,6 @@
typedef key_t IpcMemoryKey; /* shared memory key passed to shmget(2) */
typedef int IpcMemoryId; /* shared memory ID returned by shmget(2) */
#define IPCProtection (0600) /* access/modify by user only */
#ifdef SHM_SHARE_MMU /* use intimate shared memory on Solaris */
#define PG_SHMAT_FLAGS SHM_SHARE_MMU
#else
#define PG_SHMAT_FLAGS 0
#endif
/* Linux prefers MAP_ANONYMOUS, but the flag is called MAP_ANON on other systems. */
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
/* BSD-derived systems have MAP_HASSEMAPHORE, but it's not present (or needed) on Linux. */
#ifndef MAP_HASSEMAPHORE
#define MAP_HASSEMAPHORE 0
#endif
#define PG_MMAP_FLAGS (MAP_SHARED|MAP_ANONYMOUS|MAP_HASSEMAPHORE)
/* Some really old systems don't define MAP_FAILED. */
#ifndef MAP_FAILED
#define MAP_FAILED ((void *) -1)
#endif
unsigned long UsedShmemSegID = 0;
void *UsedShmemSegAddr = NULL;