From 58f26c84d9f09a123adca39fd7fbb0b85a8a813f Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Wed, 5 Dec 2018 11:14:08 +1100 Subject: [PATCH] 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. Link: http://lkml.kernel.org/r/20181108051006.18751-7-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Reviewed-by: Andrew Morton Cc: Al Viro Cc: Davidlohr Bueso Cc: Jason Baron Signed-off-by: Andrew Morton Signed-off-by: Stephen Rothwell --- fs/eventpoll.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 6b000ad5cbea..cce334f8e84e 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1820,15 +1820,18 @@ fetch_events: res = -EINTR; break; } - if (ep_events_available(ep) || timed_out) + + if (ep_events_available(ep)) 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); -- 2.50.1