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select: use freezable blocking call
authorColin Cross <ccross@android.com>
Mon, 6 May 2013 23:50:17 +0000 (23:50 +0000)
committerChih-Wei Huang <cwhuang@linux.org.tw>
Sat, 13 Dec 2014 15:14:03 +0000 (23:14 +0800)
Avoid waking up every thread sleeping in a select 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.

Change-Id: I0d7565ec0b6bc5d44cb55f958589c56e6bd16348
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>
fs/select.c

index 467bb1c..55278a3 100644 (file)
@@ -238,7 +238,8 @@ int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
 
        set_current_state(state);
        if (!pwq->triggered)
-               rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
+               rc = freezable_schedule_hrtimeout_range(expires, slack,
+                                                       HRTIMER_MODE_ABS);
        __set_current_state(TASK_RUNNING);
 
        /*