diff options
Diffstat (limited to 'src/backend/storage/ipc/spin.c')
| -rw-r--r-- | src/backend/storage/ipc/spin.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/src/backend/storage/ipc/spin.c b/src/backend/storage/ipc/spin.c index 554eeba797e..ed71d79ad9f 100644 --- a/src/backend/storage/ipc/spin.c +++ b/src/backend/storage/ipc/spin.c @@ -14,7 +14,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/ipc/Attic/spin.c,v 1.27 2000/12/11 00:49:52 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/ipc/Attic/spin.c,v 1.28 2001/01/12 21:53:59 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -144,8 +144,21 @@ SpinAcquire(SPINLOCK lockid) SLock *slckP = &(SLockArray[lockid]); PRINT_SLDEBUG("SpinAcquire", lockid, slckP); + /* + * Lock out die() until we exit the critical section protected by the + * spinlock. This ensures that die() will not interrupt manipulations + * of data structures in shared memory. We don't want die() to + * interrupt this routine between S_LOCK and PROC_INCR_SLOCK, either, + * so must do it before acquiring the lock, not after. + */ + START_CRIT_SECTION(); + /* + * Acquire the lock, then record that we have done so (for recovery + * in case of elog(ERROR) during the critical section). + */ S_LOCK(&(slckP->shlock)); PROC_INCR_SLOCK(lockid); + PRINT_SLDEBUG("SpinAcquire/done", lockid, slckP); } @@ -154,15 +167,22 @@ SpinRelease(SPINLOCK lockid) { SLock *slckP = &(SLockArray[lockid]); + PRINT_SLDEBUG("SpinRelease", lockid, slckP); /* * Check that we are actually holding the lock we are releasing. This * can be done only after MyProc has been initialized. */ Assert(!MyProc || MyProc->sLocks[lockid] > 0); - + /* + * Record that we no longer hold the spinlock, and release it. + */ PROC_DECR_SLOCK(lockid); - PRINT_SLDEBUG("SpinRelease", lockid, slckP); S_UNLOCK(&(slckP->shlock)); + /* + * Exit the critical section entered in SpinAcquire(). + */ + END_CRIT_SECTION(); + PRINT_SLDEBUG("SpinRelease/done", lockid, slckP); } @@ -187,7 +207,7 @@ SpinRelease(SPINLOCK lockid) * * Note that the SpinLockIds array is not in shared memory; it is filled * by the postmaster and then inherited through fork() by backends. This - * is OK because its contents do not change after system startup. + * is OK because its contents do not change after shmem initialization. */ #define SPINLOCKS_PER_SET PROC_NSEMS_PER_SET @@ -285,6 +305,8 @@ SpinFreeAllSemaphores(void) if (SpinLockIds[i] >= 0) IpcSemaphoreKill(SpinLockIds[i]); } + free(SpinLockIds); + SpinLockIds = NULL; } /* @@ -295,6 +317,8 @@ SpinFreeAllSemaphores(void) void SpinAcquire(SPINLOCK lock) { + /* See the TAS() version of this routine for commentary */ + START_CRIT_SECTION(); IpcSemaphoreLock(SpinLockIds[0], lock); PROC_INCR_SLOCK(lock); } @@ -307,15 +331,18 @@ SpinAcquire(SPINLOCK lock) void SpinRelease(SPINLOCK lock) { + /* See the TAS() version of this routine for commentary */ #ifdef USE_ASSERT_CHECKING /* Check it's locked */ int semval; semval = IpcSemaphoreGetValue(SpinLockIds[0], lock); Assert(semval < 1); + Assert(!MyProc || MyProc->sLocks[lockid] > 0); #endif PROC_DECR_SLOCK(lock); IpcSemaphoreUnlock(SpinLockIds[0], lock); + END_CRIT_SECTION(); } /* |