Commit 9745cdb3 authored May 06, 2013 by Colin Cross Committed by Rafael J. Wysocki May 12, 2013

select: use freezable blocking call



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.

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>

parent 1c441e92

fs/select.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <linux/rcupdate.h>
		#include <linux/hrtimer.h>
		#include <linux/sched/rt.h>
		#include <linux/freezer.h>

		#include <asm/uaccess.h>

		@@ -236,7 +237,8 @@ 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);

		/*