diff options
| author | Davidlohr Bueso <dave@stgolabs.net> | 2019-01-03 15:27:19 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-01-04 13:13:46 -0800 |
| commit | abc610e01c663e25c41a3bdcbc4115cd7fbb047b (patch) | |
| tree | bf1652615120062bc27a0dc5b6250974a81664cd /fs | |
| parent | c5a282e9635e9c7382821565083db5d260085e3e (diff) | |
| download | lwn-abc610e01c663e25c41a3bdcbc4115cd7fbb047b.tar.gz lwn-abc610e01c663e25c41a3bdcbc4115cd7fbb047b.zip | |
fs/epoll: avoid barrier after an epoll_wait(2) timeout
Upon timeout, we can just exit out of the loop, without the cost of the
changing the task's state with an smp_store_mb call. Just exit out of
the loop and be done - setting the task state afterwards will be, of
course, redundant.
[dave@stgolabs.net: forgotten fixlets]
Link: http://lkml.kernel.org/r/20181109155258.jxcr4t2pnz6zqct3@linux-r8p5
Link: http://lkml.kernel.org/r/20181108051006.18751-7-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/eventpoll.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index b42f53d64d11..9beb166b7264 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1820,15 +1820,19 @@ fetch_events: res = -EINTR; break; } - if (ep_events_available(ep) || timed_out) + + eavail = ep_events_available(ep); + if (eavail) break; if (signal_pending(current)) { res = -EINTR; break; } - if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) + if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) { timed_out = 1; + break; + } } __set_current_state(TASK_RUNNING); |