linux-kernel - Re: [PATCH v16 6/7] sched: Fix proxy/current (push,pull)ability

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Message-ID: <CANDhNCrb4CB5=3fkFAjC-OK=DfDmRtOavEk=8wYyK6BEk7-r5Q@mail.gmail.com>
Date: Wed, 16 Apr 2025 14:18:36 -0700
From: John Stultz <jstultz@...gle.com>
To: K Prateek Nayak <kprateek.nayak@....com>
Cc: LKML <linux-kernel@...r.kernel.org>, 
	Valentin Schneider <valentin.schneider@....com>, Joel Fernandes <joelagnelf@...dia.com>, 
	Qais Yousef <qyousef@...alina.io>, 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>, 
	Valentin Schneider <vschneid@...hat.com>, Steven Rostedt <rostedt@...dmis.org>, 
	Ben Segall <bsegall@...gle.com>, Zimuzo Ezeozue <zezeozue@...gle.com>, Mel Gorman <mgorman@...e.de>, 
	Will Deacon <will@...nel.org>, Waiman Long <longman@...hat.com>, Boqun Feng <boqun.feng@...il.com>, 
	"Paul E. McKenney" <paulmck@...nel.org>, Metin Kaya <Metin.Kaya@....com>, 
	Xuewen Yan <xuewen.yan94@...il.com>, Thomas Gleixner <tglx@...utronix.de>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, Suleiman Souhlal <suleiman@...gle.com>, kernel-team@...roid.com, 
	"Connor O'Brien" <connoro@...gle.com>
Subject: Re: [PATCH v16 6/7] sched: Fix proxy/current (push,pull)ability

On Sun, Apr 13, 2025 at 8:29 PM K Prateek Nayak <kprateek.nayak@....com> wrote:
>
> Hello John,
>
> On 4/12/2025 11:32 AM, John Stultz wrote:
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index ad45a8fea245e..eb07c3a1b8fa4 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -2166,6 +2166,9 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
> >       if (dl_server(&p->dl))
> >               return;
> >
> > +     if (task_is_blocked(p))
> > +             return;
> > +
> >       if (!task_current(rq, p) && !p->dl.dl_throttled && p->nr_cpus_allowed > 1)
> >               enqueue_pushable_dl_task(rq, p);
> >   }
>
> Do we need an early return in put_prev_task_dl() similar to the one in
> put_prev_task_rt()?

Indeed, that does look like something I've overlooked (and suggests I
need to do more deadline testing). Thank you so much for pointing this
out!
-john