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From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: mingo@redhat.com, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
	kprateek.nayak@amd.com, linux-kernel@vger.kernel.org,
	qyousef@layalina.io
Subject: Re: [PATCH 3/6 v3] sched/eevdf: Update slice protection even when resched is already set
Date: Fri, 26 Jun 2026 09:21:28 +0200	[thread overview]
Message-ID: <20260626072128.GI1181229@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20260624151229.1710703-4-vincent.guittot@linaro.org>

On Wed, Jun 24, 2026 at 05:12:26PM +0200, Vincent Guittot wrote:
> Even if resched is already set, we might want to update or even cancel
> the slice protection and ensure that the newly waking task will be the
> next one to run.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 8639086e5d9e..854f3a9f1d80 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9804,7 +9804,7 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f
>  	 * prevents us from potentially nominating it as a false LAST_BUDDY
>  	 * below.
>  	 */
> -	if (test_tsk_need_resched(rq->curr))
> +	if (!sched_feat(PREEMPT_SHORT) && test_tsk_need_resched(rq->curr))
>  		return;
>  
>  	if (!sched_feat(WAKEUP_PREEMPTION))

This one is leading to boot splats for me -- let me try and figure out
why.

  reply	other threads:[~2026-06-26  7:21 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-24 15:12 [PATCH 0/6 v3] sched/eevdf: Improve scheduling latency of short slice task Vincent Guittot
2026-06-24 15:12 ` [PATCH 1/6 v3] sched/fair: Set next buddy for preempt short Vincent Guittot
2026-06-25  6:24   ` K Prateek Nayak
2026-06-25 12:40     ` Vincent Guittot
2026-06-25 12:43       ` Peter Zijlstra
2026-06-26  6:54       ` Peter Zijlstra
2026-06-26  7:02         ` Vincent Guittot
2026-06-26  8:08           ` Peter Zijlstra
2026-06-26  8:55             ` Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 2/6 v3] sched/eevdf: Take into account current's lag when updating slice protection Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 3/6 v3] sched/eevdf: Update slice protection even when resched is already set Vincent Guittot
2026-06-26  7:21   ` Peter Zijlstra [this message]
2026-06-26  7:46     ` Peter Zijlstra
2026-06-30  9:03       ` [tip: sched/core] sched/core: Fix inter-class wakeup_preempt() tip-bot2 for Peter Zijlstra
2026-06-30  9:03   ` [tip: sched/core] sched/eevdf: Update slice protection even when resched is already set tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 4/6 v3] sched/eevdf: Cancel slice protection if short slice task is eligible Vincent Guittot
2026-06-25  6:00   ` K Prateek Nayak
2026-06-25 12:40     ` Vincent Guittot
2026-06-26  5:51       ` Shubhang Kaushik
2026-06-26  7:39         ` Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 5/6 v3] sched/eevdf: Always update slice protection Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 6/6 v3] sched/eevdf: Speedup short slice task scheduling Vincent Guittot
2026-06-25  7:37   ` K Prateek Nayak
2026-06-25  8:37     ` Peter Zijlstra
2026-06-25 10:09       ` Peter Zijlstra
2026-06-25 12:57         ` Vincent Guittot
2026-06-25 12:59           ` Vincent Guittot
2026-06-25 22:28             ` Peter Zijlstra
2026-06-26  3:57               ` K Prateek Nayak
2026-06-26  6:41                 ` Peter Zijlstra
2026-06-26  7:05                 ` Vincent Guittot
2026-06-26  7:18                   ` Peter Zijlstra
2026-06-26  7:54                     ` Peter Zijlstra
2026-06-26  8:55                       ` Vincent Guittot
2026-06-26 13:55                         ` Vincent Guittot
2026-06-29 14:25                           ` Vincent Guittot
2026-06-25 14:55       ` Vincent Guittot
2026-06-25 12:51     ` Vincent Guittot
2026-06-25  8:33   ` Peter Zijlstra
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot

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