linux-kernel - Re: [PATCH 1/6] sched/ext: Fix scx vs sched

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Message-ID: <20241030155403.GO14555@noisy.programming.kicks-ass.net>
Date: Wed, 30 Oct 2024 16:54:03 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Christian Loehle <christian.loehle@....com>
Cc: mingo@...nel.org, juri.lelli@...hat.com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
	mgorman@...e.de, vschneid@...hat.com, tj@...nel.org,
	void@...ifault.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/6] sched/ext: Fix scx vs sched_delayed

On Wed, Oct 30, 2024 at 03:50:05PM +0000, Christian Loehle wrote:
> On 10/30/24 15:12, Peter Zijlstra wrote:
> > Commit 98442f0ccd82 ("sched: Fix delayed_dequeue vs
> > switched_from_fair()") forgot about scx :/
> > 
> > Fixes: 98442f0ccd82 ("sched: Fix delayed_dequeue vs switched_from_fair()")
> > Reported-by: Tejun Heo <tj@...nel.org>
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> > Link: https://lkml.kernel.org/r/20241030104934.GK14555@noisy.programming.kicks-ass.net
> > ---
> >  kernel/sched/ext.c |   14 ++++++++++++--
> >  1 file changed, 12 insertions(+), 2 deletions(-)
> > 
> > --- a/kernel/sched/ext.c
> > +++ b/kernel/sched/ext.c
> > @@ -4489,11 +4489,16 @@ static void scx_ops_disable_workfn(struc
> >  	scx_task_iter_start(&sti);
> >  	while ((p = scx_task_iter_next_locked(&sti))) {
> >  		const struct sched_class *old_class = p->sched_class;
> > +		const struct sched_class *new_class =
> > +			__setscheduler_class(p->policy, p->prio);
> >  		struct sched_enq_and_set_ctx ctx;
> >  
> > +		if (old_class != new_class && p->se.sched_delayed)
> > +			dequeue_task(task_rq(p), p, DEQUEUE_SLEEP | DEQUEUE_DELAYED);
> > +
> >  		sched_deq_and_put_task(p, DEQUEUE_SAVE | DEQUEUE_MOVE, &ctx);
> >  
> > -		p->sched_class = __setscheduler_class(p->policy, p->prio);
> > +		p->sched_class = new_class;
> >  		check_class_changing(task_rq(p), p, old_class);
> >  
> >  		sched_enq_and_set_task(&ctx);
> > @@ -5199,12 +5204,17 @@ static int scx_ops_enable(struct sched_e
> >  	scx_task_iter_start(&sti);
> >  	while ((p = scx_task_iter_next_locked(&sti))) {
> >  		const struct sched_class *old_class = p->sched_class;
> > +		const struct sched_class *new_class =
> > +			__setscheduler_class(p->policy, p->prio);
> >  		struct sched_enq_and_set_ctx ctx;
> >  
> > +		if (old_class != new_class && p->se.sched_delayed)
> > +			dequeue_task(task_rq(p), p, DEQUEUE_SLEEP | DEQUEE_DELAYED);
> > +
> 
> s/DEQUEE_DELAYED/DEQUEUE_DELAYED

Bah, typing so hard..

> Anyway, no luck for me applying the series onto sched/core scx's for-next or rc5.
> Any hint or do you mind supplying a branch?

I think I did it on top of tip/master..