Messages in this thread | | | Date | Tue, 15 Dec 2020 09:32:38 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched: don't check rq after newidle_balance return positive |
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On Tue, Dec 15, 2020 at 02:48:50PM +0800, chenxg1x@gmail.com wrote: > From: Chen Xiaoguang <xiaoggchen@tencent.com> > > In pick_next_task_fair, if CPU is going to idle newidle_balance > is called first trying to pull some tasks. > When newidle_balance returns positive which means it does > pulls tasks or some tasks enqueued then there is no need to check > sched_fair_runnable again.
No, I think it actually does need to, because while it counts the number of tasks it pulled, it doesn't verify it still has them after it re-acquires rq->lock. That is, someone could've come along and stolen them right from under our noses.
> > Signed-off-by: He Chen <heddchen@tencent.com> > Signed-off-by: Xiaoguang Chen <xiaoggchen@tencent.com>
This SoB chain is broken. The first SoB should be the author, but From does not match.
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