From 8d48a3436dd83f7d6e3cde2d76f91f49f27ba16d Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Fri, 9 Jul 2021 17:51:48 +1200 Subject: [PATCH] Remove more obsolete comments about semaphores. Commit 6753333f stopped using semaphores as the sleep/wake mechanism for heavyweight locks, but some obsolete references to that scheme remained in comments. As with similar commit 25b93a29, back-patch all the way. Reviewed-by: Daniel Gustafsson Discussion: https://postgr.es/m/CA%2BhUKGLafjB1uzXcy%3D%3D2L3cy7rjHkqOVn7qRYGBjk%3D%3DtMJE7Yg%40mail.gmail.com --- src/backend/storage/lmgr/lwlock.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c index 55b9d7970e..da67e62255 100644 --- a/src/backend/storage/lmgr/lwlock.c +++ b/src/backend/storage/lmgr/lwlock.c @@ -1302,14 +1302,10 @@ LWLockAcquire(LWLock *lock, LWLockMode mode) /* * Wait until awakened. * - * Since we share the process wait semaphore with the regular lock - * manager and ProcWaitForSignal, and we may need to acquire an LWLock - * while one of those is pending, it is possible that we get awakened - * for a reason other than being signaled by LWLockRelease. If so, - * loop back and wait again. Once we've gotten the LWLock, - * re-increment the sema by the number of additional signals received, - * so that the lock manager or signal manager will see the received - * signal when it next waits. + * It is possible that we get awakened for a reason other than being + * signaled by LWLockRelease. If so, loop back and wait again. Once + * we've gotten the LWLock, re-increment the sema by the number of + * additional signals received. */ LOG_LWDEBUG("LWLockAcquire", lock, "waiting"); @@ -1474,8 +1470,7 @@ LWLockAcquireOrWait(LWLock *lock, LWLockMode mode) { /* * Wait until awakened. Like in LWLockAcquire, be prepared for - * bogus wakeups, because we share the semaphore with - * ProcWaitForSignal. + * bogus wakeups. */ LOG_LWDEBUG("LWLockAcquireOrWait", lock, "waiting"); @@ -1688,14 +1683,10 @@ LWLockWaitForVar(LWLock *lock, uint64 *valptr, uint64 oldval, uint64 *newval) /* * Wait until awakened. * - * Since we share the process wait semaphore with the regular lock - * manager and ProcWaitForSignal, and we may need to acquire an LWLock - * while one of those is pending, it is possible that we get awakened - * for a reason other than being signaled by LWLockRelease. If so, - * loop back and wait again. Once we've gotten the LWLock, - * re-increment the sema by the number of additional signals received, - * so that the lock manager or signal manager will see the received - * signal when it next waits. + * It is possible that we get awakened for a reason other than being + * signaled by LWLockRelease. If so, loop back and wait again. Once + * we've gotten the LWLock, re-increment the sema by the number of + * additional signals received. */ LOG_LWDEBUG("LWLockWaitForVar", lock, "waiting");