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ANDROID: fs: epoll: use freezable blocking call

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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.

Bug: 77139736
Bug: 120440023
Change-Id: I848d08d28c89302fd42bbbdfa76489a474ab27bf
[ccross: This was upstream (https://lkml.org/lkml/2013/5/6/823), but
         reverted because it reportedly caused memory corruption on
         32-bit x86 (https://patchwork.kernel.org/patch/3162301/).]
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 Todd Kjos
parent 99bafaf6e5
commit 7c6ba364ef
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 <linux/uaccess.h>
#include <asm/io.h>
#include <asm/mman.h>
@ -1816,7 +1817,8 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
}
spin_unlock_irq(&ep->wq.lock);
if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS))
if (!freezable_schedule_hrtimeout_range(to, slack,
HRTIMER_MODE_ABS))
timed_out = 1;
spin_lock_irq(&ep->wq.lock);