Commit b0f8c44f authored May 06, 2013 by Colin Cross Committed by Rafael J. Wysocki May 12, 2013

nanosleep: use freezable blocking call



Avoid waking up every thread sleeping in a nanosleep 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>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 56467c76

kernel/hrtimer.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -47,6 +47,7 @@
	#include <linux/sched/sysctl.h>		#include <linux/sched/sysctl.h>
	#include <linux/sched/rt.h>		#include <linux/sched/rt.h>
	#include <linux/timer.h>		#include <linux/timer.h>
			#include <linux/freezer.h>

	#include <asm/uaccess.h>		#include <asm/uaccess.h>

	@@ -1545,7 +1546,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
	t->task = NULL;		t->task = NULL;

	if (likely(t->task))		if (likely(t->task))
	schedule();		freezable_schedule();

	hrtimer_cancel(&t->timer);		hrtimer_cancel(&t->timer);
	mode = HRTIMER_MODE_ABS;		mode = HRTIMER_MODE_ABS;