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authorThomas Munro <tmunro@postgresql.org>2019-06-21 10:57:07 +1200
committerThomas Munro <tmunro@postgresql.org>2019-06-21 10:57:32 +1200
commitf7aebd7f74117a9b44eb6af575061fc16a728236 (patch)
tree661ac8d143b1ef549582bf72bfedb886cf0ecd5c /src
parent6dfc9464472ec283cf6b13ee67b42afc6346c533 (diff)
downloadpostgresql-f7aebd7f74117a9b44eb6af575061fc16a728236.tar.gz
postgresql-f7aebd7f74117a9b44eb6af575061fc16a728236.zip
Remove obsolete comments about sempahores from proc.c.
Commit 6753333f switched from a semaphore-based wait to a latch-based wait for ProcSleep()/ProcWakeup(), but left behind some stray references to semaphores. Back-patch to 9.5. Reviewed-by: Daniel Gustafsson, Michael Paquier Discussion: https://postgr.es/m/CA+hUKGLs5H6zhmgTijZ1OaJvC1sG0=AFXc1aHuce32tKiQrdEA@mail.gmail.com
Diffstat (limited to 'src')
-rw-r--r--src/backend/storage/lmgr/proc.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 6ad504453b1..94b203f0fbd 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1179,8 +1179,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
/*
* If we detected deadlock, give up without waiting. This must agree with
- * CheckDeadLock's recovery code, except that we shouldn't release the
- * semaphore since we haven't tried to lock it yet.
+ * CheckDeadLock's recovery code.
*/
if (early_deadlock)
{
@@ -1216,9 +1215,9 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
/*
* Set timer so we can wake up after awhile and check for a deadlock. If a
- * deadlock is detected, the handler releases the process's semaphore and
- * sets MyProc->waitStatus = STATUS_ERROR, allowing us to know that we
- * must report failure rather than success.
+ * deadlock is detected, the handler sets MyProc->waitStatus =
+ * STATUS_ERROR, allowing us to know that we must report failure rather
+ * than success.
*
* By delaying the check until we've waited for a bit, we can avoid
* running the rather expensive deadlock-check code in most cases.
@@ -1561,7 +1560,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
/*
- * ProcWakeup -- wake up a process by releasing its private semaphore.
+ * ProcWakeup -- wake up a process by setting its latch.
*
* Also remove the process from the wait queue and set its links invalid.
* RETURN: the next process in the wait queue.
@@ -1696,8 +1695,7 @@ CheckDeadLock(void)
* we know that we don't have to wait anymore.
*
* We check by looking to see if we've been unlinked from the wait queue.
- * This is quicker than checking our semaphore's state, since no kernel
- * call is needed, and it is safe because we hold the lock partition lock.
+ * This is safe because we hold the lock partition lock.
*/
if (MyProc->links.prev == NULL ||
MyProc->links.next == NULL)