linux-kernel - Re: [PATCH v2 0/2] Fix SCHED_IDLE behavior on wakeup preemption

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Message-ID: <3ce5065e-8b9b-46a8-b7c1-5f9b8f118b06@amd.com>
Date: Fri, 28 Feb 2025 13:35:46 +0530
From: K Prateek Nayak <kprateek.nayak@....com>
To: Abel Wu <wuyun.abel@...edance.com>, Madadi Vineeth Reddy
	<vineethr@...ux.ibm.com>, Phil Auld <pauld@...hat.com>, 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>, Josh Don
	<joshdon@...gle.com>, Tianchen Ding <dtcccc@...ux.alibaba.com>
CC: "open list:SCHEDULER" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 0/2] Fix SCHED_IDLE behavior on wakeup preemption

Hello Abel,

On 2/27/2025 2:28 PM, Abel Wu wrote:
> The commit 6bc912b71b6f ("sched: SCHED_OTHER vs SCHED_IDLE isolation")
> defines the behavior of SCHED_IDLE as following:
> 
>   - no SCHED_IDLE buddies
>   - never let SCHED_IDLE preempt on wakeup
>   - always preempt SCHED_IDLE on wakeup
>   - limit SLEEPER fairness for SCHED_IDLE
> 
> and the middle two of them are broken now.

Feel free to include:

Tested-by: K Prateek Nayak <kprateek.nayak@....com>
-- 
Thanks and Regards,
Prateek

> 
> v2:
>   - Collect Reviewed-by tags from Vincent, Josh and Madadi, thanks!
>   - Rebased to up-to-date tip. (Madadi)
>   - Folded some discussion with Vincent into commit log.
> 
> Abel Wu (2):
>    sched/fair: Do not let idle entities preempt others
>    sched/fair: Fix premature check of WAKEUP_PREEMPTION
> 
>   kernel/sched/fair.c | 14 ++++++++------
>   1 file changed, 8 insertions(+), 6 deletions(-)
>