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Commit ee940d8d authored by Mike Frysinger's avatar Mike Frysinger Committed by Rafael J. Wysocki
Browse files

Freezer: Use SMP barriers 



The freezer processes are dealing with multiple threads running
simultaneously, and on a UP system, the memory reads/writes do
not need barriers to keep things in sync.  These are only needed
on SMP systems, so use SMP barriers instead.

Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent 3c431936

kernel/freezer.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -17,7 +17,7 @@ static inline void frozen_process(void) 
{

{

	if (!unlikely(current->flags & PF_NOFREEZE)) {

	if (!unlikely(current->flags & PF_NOFREEZE)) {

		current->flags |= PF_FROZEN;

		current->flags |= PF_FROZEN;

		wmb();

		smp_wmb();

	}

	}

	clear_freeze_flag(current);

	clear_freeze_flag(current);

}

}
@@ -93,7 +93,7 @@ bool freeze_task(struct task_struct *p, bool sig_only) 
	 * the task as frozen and next clears its TIF_FREEZE.

	 * the task as frozen and next clears its TIF_FREEZE.

	 */

	 */

	if (!freezing(p)) {

	if (!freezing(p)) {

		rmb();

		smp_rmb();

		if (frozen(p))

		if (frozen(p))

			return false;

			return false;