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authorIngo Molnar <mingo@elte.hu>2007-10-15 17:00:13 +0200
committerIngo Molnar <mingo@elte.hu>2007-10-15 17:00:13 +0200
commit1e819950660e6a811b549422ffb652273257e45e (patch)
tree86bd6a49002d97de371c7e89a184a8b44c02b8d7
parent08ec3df5109e0555da5b9deb4382fd29733c852c (diff)
sched: optimize schedule() a bit on SMP
optimize schedule() a bit on SMP, by moving the rq-clock update outside the rq lock. code size is the same: text data bss dec hex filename 25725 2666 96 28487 6f47 sched.o.before 25725 2666 96 28487 6f47 sched.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--kernel/sched.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index e717047be5c..4f13d379bea 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3481,9 +3481,13 @@ need_resched_nonpreemptible:
schedule_debug(prev);
- spin_lock_irq(&rq->lock);
- clear_tsk_need_resched(prev);
+ /*
+ * Do the rq-clock update outside the rq lock:
+ */
+ local_irq_disable();
__update_rq_clock(rq);
+ spin_lock(&rq->lock);
+ clear_tsk_need_resched(prev);
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&