From ee940d8dccd899aa1777ea84da3d9cd04b1d2e8e Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@gentoo.org>
Date: Mon, 25 Apr 2011 12:33:15 +0200
Subject: [PATCH] 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: Mike Frysinger <vapier@gentoo.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
kernel/freezer.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/freezer.c b/kernel/freezer.c
index 66ecd2ead215a..7b01de98bb6a9 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -17,7 +17,7 @@ static inline void frozen_process(void)
{
if (!unlikely(current->flags & PF_NOFREEZE)) {
current->flags |= PF_FROZEN;
- wmb();
+ smp_wmb();
}
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.
*/
if (!freezing(p)) {
- rmb();
+ smp_rmb();
if (frozen(p))
return false;
--
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