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epoll: use freezable blocking call 

Avoid waking up every thread sleeping in an epoll_wait call during
suspend and resume by calling a freezable blocking call.  Previous
patches modified the freezer to avoid sending wakeups to threads
that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Colin Cross 2013-05-06 23:50:16 +00:00 committed by Rafael J. Wysocki
parent e2610b268b
commit 1c441e9212
1 changed files with 3 additions and 1 deletions
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4
fs/eventpoll.c
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@ -34,6 +34,7 @@
#include <linux/mutex.h>
#include <linux/anon_inodes.h>
#include <linux/device.h>
#include <linux/freezer.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/mman.h>
@ -1602,7 +1603,8 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
}
spin_unlock_irqrestore(&ep->lock, flags);
if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS))
if (!freezable_schedule_hrtimeout_range(to, slack,
HRTIMER_MODE_ABS))
timed_out = 1;
spin_lock_irqsave(&ep->lock, flags);