1997-09-18 16:21:02 +02:00
|
|
|
/*-------------------------------------------------------------------------
|
|
|
|
*
|
|
|
|
* s_lock.h--
|
|
|
|
* This file contains the implementation (if any) for spinlocks.
|
|
|
|
*
|
|
|
|
* Copyright (c) 1994, Regents of the University of California
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* IDENTIFICATION
|
1998-05-04 18:58:59 +02:00
|
|
|
* $Header: /cvsroot/pgsql/src/include/storage/s_lock.h,v 1.32 1998/05/04 16:58:59 scrappy Exp $
|
1997-09-18 16:21:02 +02:00
|
|
|
*
|
|
|
|
*-------------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
/*
|
|
|
|
* DESCRIPTION
|
1998-05-04 18:58:59 +02:00
|
|
|
* The public functions that must be provided are:
|
1998-04-29 14:41:29 +02:00
|
|
|
*
|
1998-05-04 18:58:59 +02:00
|
|
|
* void S_INIT_LOCK(slock_t *lock)
|
1998-04-29 14:41:29 +02:00
|
|
|
*
|
|
|
|
* void S_LOCK(slock_t *lock)
|
|
|
|
*
|
1998-05-04 18:58:59 +02:00
|
|
|
* void S_UNLOCK(slock_t *lock)
|
1998-04-29 14:41:29 +02:00
|
|
|
*
|
1998-05-04 18:58:59 +02:00
|
|
|
* void S_LOCK_FREE(slock_t *lock)
|
|
|
|
* Tests if the lock is free. Returns non-zero if free, 0 if locked.
|
1998-04-29 14:41:29 +02:00
|
|
|
*
|
1998-05-04 18:58:59 +02:00
|
|
|
* The S_LOCK() macro implements a primitive but still useful random
|
|
|
|
* backoff to avoid hordes of busywaiting lockers chewing CPU.
|
1997-09-18 16:21:02 +02:00
|
|
|
*
|
1998-05-04 18:58:59 +02:00
|
|
|
* Effectively:
|
1997-09-18 16:21:02 +02:00
|
|
|
* void
|
1998-04-29 14:41:29 +02:00
|
|
|
* S_LOCK(slock_t *lock)
|
1997-09-18 16:21:02 +02:00
|
|
|
* {
|
1998-05-04 18:58:59 +02:00
|
|
|
* while (TAS(lock))
|
|
|
|
* {
|
1998-04-29 14:41:29 +02:00
|
|
|
* // back off the cpu for a semi-random short time
|
1998-05-04 18:58:59 +02:00
|
|
|
* }
|
1997-09-18 16:21:02 +02:00
|
|
|
* }
|
|
|
|
*
|
1998-05-04 18:58:59 +02:00
|
|
|
* This implementation takes advantage of a tas function written
|
|
|
|
* (in assembly language) on machines that have a native test-and-set
|
|
|
|
* instruction. Alternative mutex implementations may also be used.
|
1998-04-29 14:41:29 +02:00
|
|
|
* This function is hidden under the TAS macro to allow substitutions.
|
1997-09-18 16:21:02 +02:00
|
|
|
*
|
1998-04-29 14:41:29 +02:00
|
|
|
* #define TAS(lock) tas(lock)
|
|
|
|
* int tas(slock_t *lock) // True if lock already set
|
|
|
|
*
|
|
|
|
* If none of this can be done, POSTGRES will default to using
|
|
|
|
* System V semaphores (and take a large performance hit -- around 40%
|
|
|
|
* of its time on a DS5000/240 is spent in semop(3)...).
|
|
|
|
*
|
|
|
|
* NOTES
|
1997-09-18 16:21:02 +02:00
|
|
|
* AIX has a test-and-set but the recommended interface is the cs(3)
|
|
|
|
* system call. This provides an 8-instruction (plus system call
|
|
|
|
* overhead) uninterruptible compare-and-set operation. True
|
|
|
|
* spinlocks might be faster but using cs(3) still speeds up the
|
|
|
|
* regression test suite by about 25%. I don't have an assembler
|
|
|
|
* manual for POWER in any case.
|
|
|
|
*
|
1998-04-29 14:41:29 +02:00
|
|
|
* There are default implementations for all these macros at the bottom
|
|
|
|
* of this file. Check if your platform can use these or needs to
|
|
|
|
* override them.
|
|
|
|
*
|
1997-09-18 16:21:02 +02:00
|
|
|
*/
|
1998-05-04 18:58:59 +02:00
|
|
|
#if !defined(S_LOCK_H)
|
1997-09-18 16:21:02 +02:00
|
|
|
#define S_LOCK_H
|
|
|
|
|
|
|
|
#include "storage/ipc.h"
|
|
|
|
|
|
|
|
#if defined(HAS_TEST_AND_SET)
|
|
|
|
|
1998-04-29 14:41:29 +02:00
|
|
|
#if defined(linux)
|
|
|
|
/***************************************************************************
|
|
|
|
* All Linux
|
|
|
|
*/
|
|
|
|
|
|
|
|
#if defined(__alpha__)
|
|
|
|
|
|
|
|
#define S_UNLOCK(lock) { __asm__("mb"); *(lock) = 0; }
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* __alpha__ */
|
1998-04-29 14:41:29 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#else /* linux */
|
1998-04-29 14:41:29 +02:00
|
|
|
/***************************************************************************
|
|
|
|
* All non Linux
|
|
|
|
*/
|
|
|
|
|
1997-09-18 16:21:02 +02:00
|
|
|
#if defined (nextstep)
|
|
|
|
/*
|
|
|
|
* NEXTSTEP (mach)
|
|
|
|
* slock_t is defined as a struct mutex.
|
|
|
|
*/
|
1998-04-29 14:41:29 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_LOCK(lock) mutex_lock(lock)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_UNLOCK(lock) mutex_unlock(lock)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_INIT_LOCK(lock) mutex_init(lock)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
/* For Mach, we have to delve inside the entrails of `struct mutex'. Ick! */
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_LOCK_FREE(alock) ((alock)->lock == 0)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* nextstep */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
1998-02-05 04:31:01 +01:00
|
|
|
#if defined(__sgi)
|
1997-09-18 16:21:02 +02:00
|
|
|
/*
|
|
|
|
* SGI IRIX 5
|
|
|
|
* slock_t is defined as a struct abilock_t, which has a single unsigned long
|
|
|
|
* member.
|
|
|
|
*
|
|
|
|
* This stuff may be supplemented in the future with Masato Kataoka's MIPS-II
|
|
|
|
* assembly from his NECEWS SVR4 port, but we probably ought to retain this
|
|
|
|
* for the R3000 chips out there.
|
|
|
|
*/
|
1998-05-04 18:58:59 +02:00
|
|
|
#define TAS(lock) (!acquire_lock(lock))
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
#define S_UNLOCK(lock) release_lock(lock)
|
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_INIT_LOCK(lock) init_lock(lock)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_LOCK_FREE(lock) (stat_lock(lock) == UNLOCKED)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* __sgi */
|
|
|
|
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if (defined(__alpha__)
|
1997-09-18 16:21:02 +02:00
|
|
|
/*
|
|
|
|
* OSF/1 (Alpha AXP)
|
|
|
|
*
|
|
|
|
* Note that slock_t on the Alpha AXP is msemaphore instead of char
|
|
|
|
* (see storage/ipc.h).
|
|
|
|
*/
|
1998-05-04 18:58:59 +02:00
|
|
|
#define TAS(lock) (msem_lock((lock), MSEM_IF_NOWAIT) < 0)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_UNLOCK(lock) msem_unlock((lock), 0)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_INIT_LOCK(lock) msem_init((lock), MSEM_UNLOCKED)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_LOCK_FREE(lock) (!(lock)->msem_state)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* __alpha__ */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if defined(_AIX)
|
1997-09-18 16:21:02 +02:00
|
|
|
/*
|
|
|
|
* AIX (POWER)
|
|
|
|
*
|
|
|
|
* Note that slock_t on POWER/POWER2/PowerPC is int instead of char
|
|
|
|
* (see storage/ipc.h).
|
|
|
|
*/
|
1998-05-04 18:58:59 +02:00
|
|
|
#define TAS(lock) cs((int *) (lock), 0, 1)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* _AIX */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if defined(__hpux)
|
1997-09-18 16:21:02 +02:00
|
|
|
/*
|
|
|
|
* HP-UX (PA-RISC)
|
|
|
|
*
|
|
|
|
* Note that slock_t on PA-RISC is a structure instead of char
|
|
|
|
* (see storage/ipc.h).
|
1998-05-04 18:58:59 +02:00
|
|
|
*
|
|
|
|
* a "set" slock_t has a single word cleared. a "clear" slock_t has
|
|
|
|
* all words set to non-zero. tas() in tas.s
|
1997-09-18 16:21:02 +02:00
|
|
|
*/
|
1998-05-04 18:58:59 +02:00
|
|
|
static slock_t clear_lock =
|
|
|
|
{-1, -1, -1, -1};
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_UNLOCK(lock) (*(lock) = clear_lock) /* struct assignment */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_LOCK_FREE(lock) ( *(int *) (((long) (lock) + 15) & ~15) != 0)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* __hpux */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* else defined(linux) */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
/****************************************************************************
|
|
|
|
* Default Definitions - override these above as needed.
|
1997-09-18 16:21:02 +02:00
|
|
|
*/
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if !defined(S_LOCK)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#include <sys/time.h>
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#define S_NSPINCYCLE 16
|
|
|
|
#define S_MAX_BUSY 1000 * S_NSPINCYCLE
|
1998-02-13 06:10:06 +01:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
extern int s_spincycle[];
|
|
|
|
extern void s_lock_stuck(slock_t *lock, char *file, int line);
|
1998-02-13 06:10:06 +01:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if defined(S_LOCK_DEBUG)
|
1998-02-13 06:10:06 +01:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
extern void s_lock(slock_t *lock);
|
1998-02-13 06:10:06 +01:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#define S_LOCK(lock) s_lock(lock, __FILE__, __LINE__)
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#else /* S_LOCK_DEBUG */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#define S_LOCK(lock) if (1) { \
|
|
|
|
int spins = 0; \
|
|
|
|
while (TAS(lock)) { \
|
|
|
|
struct timeval delay; \
|
|
|
|
delay.tv_sec = 0; \
|
|
|
|
delay.tv_usec = s_spincycle[spins++ % S_NSPINCYCLE]; \
|
|
|
|
(void) select(0, NULL, NULL, NULL, &delay); \
|
|
|
|
if (spins > S_MAX_BUSY) { \
|
|
|
|
/* It's been well over a minute... */ \
|
|
|
|
s_lock_stuck(lock, __FILE__, __LINE__); \
|
|
|
|
} \
|
|
|
|
} \
|
|
|
|
} else
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* S_LOCK_DEBUG */
|
|
|
|
#endif /* S_LOCK */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
|
|
|
|
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if !defined(S_LOCK_FREE)
|
|
|
|
#define S_LOCK_FREE(lock) ((*lock) == 0)
|
|
|
|
#endif /* S_LOCK_FREE */
|
1997-12-30 05:01:28 +01:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if !defined(S_UNLOCK)
|
|
|
|
#define S_UNLOCK(lock) (*(lock) = 0)
|
|
|
|
#endif /* S_UNLOCK */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if !defined(S_INIT_LOCK)
|
1998-02-26 05:46:47 +01:00
|
|
|
#define S_INIT_LOCK(lock) S_UNLOCK(lock)
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* S_INIT_LOCK */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#if !defined(TAS)
|
|
|
|
int tas(slock_t *lock); /* port/.../tas.s, or s_lock.c */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#define TAS(lock) tas(lock)
|
|
|
|
#endif /* TAS */
|
1997-09-25 01:37:26 +02:00
|
|
|
|
1997-09-25 03:48:58 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* HAS_TEST_AND_SET */
|
1997-09-18 16:21:02 +02:00
|
|
|
|
1998-05-04 18:58:59 +02:00
|
|
|
#endif /* S_LOCK_H */
|