mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-09-12 19:07:59 +02:00
499abb0c0f
existing lock manager and spinlocks: it understands exclusive vs shared lock but has few other fancy features. Replace most uses of spinlocks with lightweight locks. All remaining uses of spinlocks have very short lock hold times (a few dozen instructions), so tweak spinlock backoff code to work efficiently given this assumption. All per my proposal on pghackers 26-Sep-01.
94 lines
2.8 KiB
C
94 lines
2.8 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* ipc.h
|
|
* POSTGRES inter-process communication definitions.
|
|
*
|
|
*
|
|
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* $Id: ipc.h,v 1.51 2001/09/29 04:02:26 tgl Exp $
|
|
*
|
|
* Some files that would normally need to include only sys/ipc.h must
|
|
* instead include this file because on Ultrix, sys/ipc.h is not designed
|
|
* to be included multiple times. This file (by virtue of the ifndef IPC_H)
|
|
* is.
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#ifndef IPC_H
|
|
#define IPC_H
|
|
|
|
#include <sys/types.h>
|
|
#ifdef HAVE_SYS_IPC_H
|
|
#include <sys/ipc.h>
|
|
#endif /* HAVE_SYS_IPC_H */
|
|
|
|
#ifndef HAVE_UNION_SEMUN
|
|
union semun
|
|
{
|
|
int val;
|
|
struct semid_ds *buf;
|
|
unsigned short *array;
|
|
};
|
|
#endif
|
|
|
|
|
|
/* generic IPC definitions */
|
|
|
|
#define IPCProtection (0600) /* access/modify by user only */
|
|
|
|
/* semaphore definitions */
|
|
|
|
typedef uint32 IpcSemaphoreKey; /* semaphore key passed to semget(2) */
|
|
typedef int IpcSemaphoreId; /* semaphore ID returned by semget(2) */
|
|
|
|
#define IPC_NMAXSEM 32 /* maximum number of semaphores per semID */
|
|
|
|
#define PGSemaMagic 537 /* must be less than SEMVMX */
|
|
|
|
/* shared memory definitions */
|
|
|
|
typedef uint32 IpcMemoryKey; /* shared memory key passed to shmget(2) */
|
|
typedef int IpcMemoryId; /* shared memory ID returned by shmget(2) */
|
|
|
|
typedef struct PGShmemHeader /* standard header for all Postgres shmem */
|
|
{
|
|
int32 magic; /* magic # to identify Postgres segments */
|
|
#define PGShmemMagic 679834892
|
|
pid_t creatorPID; /* PID of creating process */
|
|
uint32 totalsize; /* total size of segment */
|
|
uint32 freeoffset; /* offset to first free space */
|
|
} PGShmemHeader;
|
|
|
|
|
|
/* ipc.c */
|
|
extern bool proc_exit_inprogress;
|
|
|
|
extern void proc_exit(int code);
|
|
extern void shmem_exit(int code);
|
|
extern void on_proc_exit(void (*function) (), Datum arg);
|
|
extern void on_shmem_exit(void (*function) (), Datum arg);
|
|
extern void on_exit_reset(void);
|
|
|
|
extern void IpcInitKeyAssignment(int port);
|
|
|
|
extern IpcSemaphoreId IpcSemaphoreCreate(int numSems, int permission,
|
|
int semStartValue,
|
|
bool removeOnExit);
|
|
extern void IpcSemaphoreKill(IpcSemaphoreId semId);
|
|
extern void IpcSemaphoreLock(IpcSemaphoreId semId, int sem, bool interruptOK);
|
|
extern void IpcSemaphoreUnlock(IpcSemaphoreId semId, int sem);
|
|
extern bool IpcSemaphoreTryLock(IpcSemaphoreId semId, int sem);
|
|
extern int IpcSemaphoreGetValue(IpcSemaphoreId semId, int sem);
|
|
|
|
extern PGShmemHeader *IpcMemoryCreate(uint32 size, bool makePrivate,
|
|
int permission);
|
|
|
|
extern bool SharedMemoryIsInUse(IpcMemoryKey shmKey, IpcMemoryId shmId);
|
|
|
|
/* ipci.c */
|
|
extern void CreateSharedMemoryAndSemaphores(bool makePrivate,
|
|
int maxBackends);
|
|
|
|
#endif /* IPC_H */
|