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| author | Omar Sandoval <osandov@fb.com> | 2017-12-06 08:15:31 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-12-06 19:30:34 +0100 |
| commit | c6b9d9a33029014446bd9ed84c1688f6d3d4eab9 (patch) | |
| tree | e7dc6b07c6d578708109f7de8b0ca2520876b2eb /kernel/sched/wait.c | |
| parent | x86: don't hash faulting address in oops printout (diff) | |
| download | linux-c6b9d9a33029014446bd9ed84c1688f6d3d4eab9.tar.xz linux-c6b9d9a33029014446bd9ed84c1688f6d3d4eab9.zip | |
sched/wait: Fix add_wait_queue() behavioral change
The following cleanup commit:
50816c48997a ("sched/wait: Standardize internal naming of wait-queue entries")
... unintentionally changed the behavior of add_wait_queue() from
inserting the wait entry at the head of the wait queue to the tail
of the wait queue.
Beyond a negative performance impact this change in behavior
theoretically also breaks wait queues which mix exclusive and
non-exclusive waiters, as non-exclusive waiters will not be
woken up if they are queued behind enough exclusive waiters.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Fixes: ("sched/wait: Standardize internal naming of wait-queue entries")
Link: http://lkml.kernel.org/r/a16c8ccffd39bd08fdaa45a5192294c784b803a7.1512544324.git.osandov@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/wait.c')
| -rw-r--r-- | kernel/sched/wait.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 98feab7933c7..929ecb7d6b78 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -27,7 +27,7 @@ void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&wq_head->lock, flags); - __add_wait_queue_entry_tail(wq_head, wq_entry); + __add_wait_queue(wq_head, wq_entry); spin_unlock_irqrestore(&wq_head->lock, flags); } EXPORT_SYMBOL(add_wait_queue); |