From: Davidlohr Bueso <dave@stgolabs.net>
To: Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Davidlohr Bueso <dave@stgolabs.net>
Subject: epoll: optimize setting task running after blocking
Date: Fri, 06 Feb 2015 17:40:52 -0800 [thread overview]
Message-ID: <1423273252.1057.11.camel@stgolabs.net> (raw)
After waking up a task waiting for an event, we explicitly
mark it as TASK_RUNNING (which is necessary as we do the
checks for wakeups as TASK_INTERRUPTABLE). Once running
and dealing with actually delivering the events, we're
obviously not planning on calling schedule, thus we can
relax the implied barrier and simply update the state with
__set_current_state().
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
fs/eventpoll.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index d77f944..1e009ca 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1639,9 +1639,9 @@ fetch_events:
spin_lock_irqsave(&ep->lock, flags);
}
- __remove_wait_queue(&ep->wq, &wait);
- set_current_state(TASK_RUNNING);
+ __remove_wait_queue(&ep->wq, &wait);
+ __set_current_state(TASK_RUNNING);
}
check_events:
/* Is it worth to try to dig for events ? */
--
2.1.4
reply other threads:[~2015-02-07 1:40 UTC|newest]
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