* [PATCH -tip] locking/pvqspinlock: replace xchg() by the more descriptive set_mb()
@ 2015-05-11 1:17 Waiman Long
0 siblings, 0 replies; only message in thread
From: Waiman Long @ 2015-05-11 1:17 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar
Cc: linux-kernel, Linus Torvalds, Scott J Norton, Douglas Hatch, Waiman Long
The xchg() function was used in pv_wait_node() to set a certain value
and provide a memory barrier which is what the set_mb() function
is for. This patch replaces the xchg() call by set_mb().
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
---
kernel/locking/qspinlock_paravirt.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index b5758a9..27ab96d 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -175,7 +175,7 @@ static void pv_wait_node(struct mcs_spinlock *node)
*
* Matches the xchg() from pv_kick_node().
*/
- (void)xchg(&pn->state, vcpu_halted);
+ set_mb(pn->state, vcpu_halted);
if (!READ_ONCE(node->locked))
pv_wait(&pn->state, vcpu_halted);
--
1.7.1
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2015-05-11 1:17 [PATCH -tip] locking/pvqspinlock: replace xchg() by the more descriptive set_mb() Waiman Long
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