[PATCH] small optimization to update_curr_rt

[Dimitri Sivanich <sivanich@sgi.com>]

A very minor improvement, but might it be better to check sched_rt_runtime(rt_rq)
before taking the rt_runtime_lock?

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>

--

 kernel/sched_rt.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux/kernel/sched_rt.c
===================================================================
--- linux.orig/kernel/sched_rt.c	2008-10-22 16:10:03.000000000 -0500
+++ linux/kernel/sched_rt.c	2008-10-31 07:57:19.000000000 -0500
@@ -537,13 +537,13 @@ static void update_curr_rt(struct rq *rq
 	for_each_sched_rt_entity(rt_se) {
 		rt_rq = rt_rq_of_se(rt_se);
 
-		spin_lock(&rt_rq->rt_runtime_lock);
 		if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
+			spin_lock(&rt_rq->rt_runtime_lock);
 			rt_rq->rt_time += delta_exec;
 			if (sched_rt_runtime_exceeded(rt_rq))
 				resched_task(curr);
+			spin_unlock(&rt_rq->rt_runtime_lock);
 		}
-		spin_unlock(&rt_rq->rt_runtime_lock);
 	}
 }