Messages in this thread Patch in this message | | | From | Peng Wang <> | Subject | [PATCH v2] sched/fair: Optimize dequeue_task_fair() | Date | Tue, 16 Jun 2020 14:04:07 +0800 |
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While looking at enqueue_task_fair and dequeue_task_fair, it occurred to me that dequeue_task_fair can also be optimized as Vincent described in commit 7d148be69e3a ("sched/fair: Optimize enqueue_task_fair()").
When encountering throttled cfs_rq, dequeue_throttle label can ensure se not to be NULL, and rq->nr_running remains unchanged, so we can also skip the early balance check.
Signed-off-by: Peng Wang <rocking@linux.alibaba.com> --- kernel/sched/fair.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index cbcb2f7..05242b7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5614,14 +5614,14 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) } -dequeue_throttle: - if (!se) - sub_nr_running(rq, 1); + /* At this point se is NULL and we are at root level*/ + sub_nr_running(rq, 1); /* balance early to pull high priority tasks */ if (unlikely(!was_sched_idle && sched_idle_rq(rq))) rq->next_balance = jiffies; +dequeue_throttle: util_est_dequeue(&rq->cfs, p, task_sleep); hrtick_update(rq); } -- 2.9.5
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