diff options
Diffstat (limited to 'src/include/storage/spin.h')
| -rw-r--r-- | src/include/storage/spin.h | 36 |
1 files changed, 11 insertions, 25 deletions
diff --git a/src/include/storage/spin.h b/src/include/storage/spin.h index bd01d4ae0c1..cdfd43a06a1 100644 --- a/src/include/storage/spin.h +++ b/src/include/storage/spin.h @@ -14,17 +14,9 @@ * Acquire a spinlock, waiting if necessary. * Time out and abort() if unable to acquire the lock in a * "reasonable" amount of time --- typically ~ 1 minute. - * Cancel/die interrupts are held off until the lock is released. * * void SpinLockRelease(volatile slock_t *lock) * Unlock a previously acquired lock. - * Release the cancel/die interrupt holdoff. - * - * void SpinLockAcquire_NoHoldoff(volatile slock_t *lock) - * void SpinLockRelease_NoHoldoff(volatile slock_t *lock) - * Same as above, except no interrupt holdoff processing is done. - * This pair of macros may be used when there is a surrounding - * interrupt holdoff. * * bool SpinLockFree(slock_t *lock) * Tests if the lock is free. Returns TRUE if free, FALSE if locked. @@ -43,14 +35,21 @@ * protects shared data with a spinlock MUST reference that shared * data through a volatile pointer. * + * Keep in mind the coding rule that spinlocks must not be held for more + * than a few instructions. In particular, we assume it is not possible + * for a CHECK_FOR_INTERRUPTS() to occur while holding a spinlock, and so + * it is not necessary to do HOLD/RESUME_INTERRUPTS() in these macros. + * * These macros are implemented in terms of hardware-dependent macros - * supplied by s_lock.h. + * supplied by s_lock.h. There is not currently any extra functionality + * added by this header, but there has been in the past and may someday + * be again. * * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/spin.h,v 1.26 2005/10/13 06:17:34 neilc Exp $ + * $PostgreSQL: pgsql/src/include/storage/spin.h,v 1.27 2005/12/29 18:08:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -58,26 +57,13 @@ #define SPIN_H #include "storage/s_lock.h" -#include "miscadmin.h" #define SpinLockInit(lock) S_INIT_LOCK(lock) -#define SpinLockAcquire(lock) \ - do { \ - HOLD_INTERRUPTS(); \ - S_LOCK(lock); \ - } while (0) - -#define SpinLockAcquire_NoHoldoff(lock) S_LOCK(lock) - -#define SpinLockRelease(lock) \ - do { \ - S_UNLOCK(lock); \ - RESUME_INTERRUPTS(); \ - } while (0) +#define SpinLockAcquire(lock) S_LOCK(lock) -#define SpinLockRelease_NoHoldoff(lock) S_UNLOCK(lock) +#define SpinLockRelease(lock) S_UNLOCK(lock) #define SpinLockFree(lock) S_LOCK_FREE(lock) |