linux-kernel - Re: [PATCH 1/2] sched/fair: Do not let idle entities preempt others

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Message-ID: <CABk29Ns=Jqb2c5gcEMr7uBnDZ7S_xWp5tUmrX=T8pHrg5RmeDQ@mail.gmail.com>
Date: Fri, 21 Feb 2025 11:54:30 -0800
From: Josh Don <joshdon@...gle.com>
To: Abel Wu <wuyun.abel@...edance.com>
Cc: Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Juri Lelli <juri.lelli@...hat.com>, Vincent Guittot <vincent.guittot@...aro.org>, 
	Dietmar Eggemann <dietmar.eggemann@....com>, Steven Rostedt <rostedt@...dmis.org>, 
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>, 
	Valentin Schneider <vschneid@...hat.com>, Tianchen Ding <dtcccc@...ux.alibaba.com>, 
	"open list:SCHEDULER" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] sched/fair: Do not let idle entities preempt others

On Fri, Feb 21, 2025 at 3:12 AM Abel Wu <wuyun.abel@...edance.com> wrote:
>
> A task with SCHED_IDLE policy doesn't preempt others by definition, and
> the semantics are intended to be preserved when extending to cgroups
> introduced in commit 304000390f88 ("sched: Cgroup SCHED_IDLE support").
>
> But current implementation allows idle entities to preempt each other
> on wakeup, which seems not behave as expected especially after
> commit faa42d29419d ("sched/fair: Make SCHED_IDLE entity be preempted in strict hierarchy")
> so fix this by explicitly skip wakeup preemption for idle entities.

Thanks, looks good to me.

Reviewed-by: Josh Don <joshdon@...gle.com>