From e7aaaa6934636d7a6cadd9e2a05250fbb6a34f65 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 16 Jul 2009 15:44:29 +0200 Subject: [PATCH] sched: Drop the need_resched() loop from cond_resched() The schedule() function is a loop that reschedules the current task while the TIF_NEED_RESCHED flag is set: void schedule(void) { need_resched: /* schedule code */ if (need_resched()) goto need_resched; } And cond_resched() repeat this loop: do { add_preempt_count(PREEMPT_ACTIVE); schedule(); sub_preempt_count(PREEMPT_ACTIVE); } while(need_resched()); This loop is needless because schedule() already did the check and nothing can set TIF_NEED_RESCHED between schedule() exit and the loop check in need_resched(). Then remove this needless loop. Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra Signed-off-by: Peter Zijlstra LKML-Reference: <1247725694-6082-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 03f7e3fd80b..4c5ee843d57 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6618,11 +6618,9 @@ static void __cond_resched(void) * PREEMPT_ACTIVE, which could trigger a second * cond_resched() call. */ - do { - add_preempt_count(PREEMPT_ACTIVE); - schedule(); - sub_preempt_count(PREEMPT_ACTIVE); - } while (need_resched()); + add_preempt_count(PREEMPT_ACTIVE); + schedule(); + sub_preempt_count(PREEMPT_ACTIVE); } int __sched _cond_resched(void) -- 2.11.4.GIT