diff options
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/storage/buf_internals.h | 20 | ||||
| -rw-r--r-- | src/include/storage/spin.h | 36 |
2 files changed, 17 insertions, 39 deletions
diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h index 3bab9e85b40..71fa0b08d48 100644 --- a/src/include/storage/buf_internals.h +++ b/src/include/storage/buf_internals.h @@ -8,7 +8,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/buf_internals.h,v 1.83 2005/11/22 18:17:31 momjian Exp $ + * $PostgreSQL: pgsql/src/include/storage/buf_internals.h,v 1.84 2005/12/29 18:08:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -138,24 +138,16 @@ typedef struct sbufdesc #define FREENEXT_NOT_IN_LIST (-2) /* - * Macros for acquiring/releasing a buffer header's spinlock. The - * NoHoldoff cases may be used when we know that we hold some LWLock - * and therefore interrupts are already held off. Do not apply these - * to local buffers! + * Macros for acquiring/releasing a shared buffer header's spinlock. + * Do not apply these to local buffers! * * Note: as a general coding rule, if you are using these then you probably - * want to be using a volatile-qualified pointer to the buffer header, to + * need to be using a volatile-qualified pointer to the buffer header, to * ensure that the compiler doesn't rearrange accesses to the header to * occur before or after the spinlock is acquired/released. */ -#define LockBufHdr(bufHdr) \ - SpinLockAcquire(&(bufHdr)->buf_hdr_lock) -#define UnlockBufHdr(bufHdr) \ - SpinLockRelease(&(bufHdr)->buf_hdr_lock) -#define LockBufHdr_NoHoldoff(bufHdr) \ - SpinLockAcquire_NoHoldoff(&(bufHdr)->buf_hdr_lock) -#define UnlockBufHdr_NoHoldoff(bufHdr) \ - SpinLockRelease_NoHoldoff(&(bufHdr)->buf_hdr_lock) +#define LockBufHdr(bufHdr) SpinLockAcquire(&(bufHdr)->buf_hdr_lock) +#define UnlockBufHdr(bufHdr) SpinLockRelease(&(bufHdr)->buf_hdr_lock) /* in buf_init.c */ 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) |