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author | Bharata B Rao <bharata@linux.vnet.ibm.com> | 2008-08-28 14:42:49 +0530 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-08-28 11:35:51 +0200 |
commit | aec0a5142cb52aaa152d962d84a838e25d520742 (patch) | |
tree | 8cf21e8fd5c5bc513923fd38acfc562ae0ab39d1 /kernel/sched_fair.c | |
parent | 65eb3dc609dec17deea48dcd4de2e549d29a9824 (diff) | |
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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 <bharata@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r-- | kernel/sched_fair.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index fb8994c..8264bb5 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); } /* |