Commit-ID: fdab649b1aa732cd6e79654349088465cdff49af Gitweb: http://git.kernel.org/tip/fdab649b1aa732cd6e79654349088465cdff49af Author: Paul E. McKenney <paul.mckenney@xxxxxxxxxx> AuthorDate: Mon, 13 Aug 2012 16:34:12 -0700 Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> CommitDate: Sun, 23 Sep 2012 07:42:51 -0700 rcu: Remove redundant memory barrier from __call_rcu() The first memory barrier in __call_rcu() is supposed to order any updates done beforehand by the caller against the actual queuing of the callback. However, the second memory barrier (which is intended to order incrementing the queue lengths before queuing the callback) is also between the caller's updates and the queuing of the callback. The second memory barrier can therefore serve both purposes. This commit therefore removes the first memory barrier. Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx> --- kernel/rcutree.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 98f2752..ba4f4b4 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1922,8 +1922,6 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), head->func = func; head->next = NULL; - smp_mb(); /* Ensure RCU update seen before callback registry. */ - /* * Opportunistically note grace-period endings and beginnings. * Note that we might see a beginning right after we see an -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|