From: Peter Zijlstra <peterz@infradead.org>
To: chenxg1x@gmail.com
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
heddchen@tencent.com, xiaoggchen@tencent.com
Subject: Re: [PATCH] sched: don't check rq after newidle_balance return positive
Date: Tue, 15 Dec 2020 09:32:38 +0100 [thread overview]
Message-ID: <20201215083238.GB3040@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1608014930-5144-1-git-send-email-xiaoggchen@tencent.com>
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.
next prev parent reply other threads:[~2020-12-15 8:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-15 6:48 chenxg1x
2020-12-15 8:32 ` Peter Zijlstra [this message]
2020-12-16 9:44 ` 答复: [PATCH] sched: don't check rq after newidle_balance return positive(Internet mail) xiaoggchen(陈小光)
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