diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2014-08-04 15:31:08 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-08-13 07:51:11 +0200 |
| commit | e708d7ad80737496870fd0b6794704d063fb0cdc (patch) | |
| tree | df4cd87b90efc33e2162c790d07dc4df42faabfd /crypto/lrw.c | |
| parent | 36bbb2f2988a29cdc3f8e0c93478795934553454 (diff) | |
perf: Do poll_wait() before checking condition in perf_poll()
One should first enqueue to the waitqueue and then check for the
condition. If the condition gets true after mutex_unlock() but before
poll_wait() then we lose it and would have wait for another wakeup.
This has been like this since v2.6.31-rc1 commit c7138f37f9 ("perf_counter:
fix perf_poll()"). Before that it was slightly worse. I guess we get enough
wakeups so if we miss here one it doesn't really matter. It is still a
bad example.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1407159068-1478-1-git-send-email-bigeasy@linutronix.de
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'crypto/lrw.c')
0 files changed, 0 insertions, 0 deletions