Re: [PATCH 3/6 v2] sched/eevdf: Update slice protection even when resched is already set

[Peter Zijlstra]

On Mon, Jun 15, 2026 at 06:24:17PM +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@xxxxxxxxxx>
> ---
>  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 b8d5d9bcc014..b98d67650a98 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9805,7 +9805,7 @@ 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))

Fair enough.

It did get me thinking about what we would want for SCHED_BATCH tasks. I
think we might want to make that RUN_TO_PARITY check (which selects
min_slice) conditional on normal_policy(). But that's another patch for
another day (and much easier after we land that flat thing).