From aec0a5142cb52aaa152d962d84a838e25d520742 Mon Sep 17 00:00:00 2001 From: Bharata B Rao Date: Thu, 28 Aug 2008 14:42:49 +0530 Subject: sched: call resched_task() conditionally from new task wake up path - During wake up of a new task, task_new_fair() can do a resched_task() on the current task. Later in the code path, check_preempt_curr() also ends up doing the same, which can be avoided. Check if TIF_NEED_RESCHED is already set for the current task. - task_new_fair() does a resched_task() on the current task unconditionally. This can be done only in case when child runs before the parent. So this is a small speedup. Signed-off-by: Bharata B Rao Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index fb8994c6d4bb..8264bb5dbd51 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1348,6 +1348,13 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p) if (unlikely(se == pse)) return; + /* + * We can come here with TIF_NEED_RESCHED already set from new task + * wake up path. + */ + if (test_tsk_need_resched(curr)) + return; + cfs_rq_of(pse)->next = pse; /* @@ -1620,10 +1627,10 @@ static void task_new_fair(struct rq *rq, struct task_struct *p) * 'current' within the tree based on its new key value. */ swap(curr->vruntime, se->vruntime); + resched_task(rq->curr); } enqueue_task_fair(rq, p, 0); - resched_task(rq->curr); } /* -- cgit v1.2.3