linux-kernel - Re: [PATCH 1/5] sched/deadline: Fix double accounting of rq/running bw in push_dl

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Message-ID: <20190729161023.GK31398@hirez.programming.kicks-ass.net>
Date:   Mon, 29 Jul 2019 18:10:23 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Dietmar Eggemann <dietmar.eggemann@....com>
Cc:     luca abeni <luca.abeni@...tannapisa.it>,
        Ingo Molnar <mingo@...nel.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Valentin Schneider <Valentin.Schneider@....com>,
        Qais Yousef <Qais.Yousef@....com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] sched/deadline: Fix double accounting of rq/running
 bw in push_dl_task()

On Mon, Jul 29, 2019 at 09:59:28AM +0100, Dietmar Eggemann wrote:
> On 7/26/19 11:11 AM, luca abeni wrote:
> > Hi Dietmar,
> > 
> > On Fri, 26 Jul 2019 09:27:52 +0100
> > Dietmar Eggemann <dietmar.eggemann@....com> wrote:
> > 
> >> push_dl_task() always calls deactivate_task() with flags=0 which sets
> >> p->on_rq=TASK_ON_RQ_MIGRATING.
> > 
> > Uhm... This is a recent change in the deactivate_task() behaviour,
> > right? Because I tested SCHED_DEADLINE a lot, but I've never seen this
> > issue :)
> 
> Looks like it was v5.2 commit 7dd778841164 ("sched/core: Unify p->on_rq
> updates").

Argh, that wasn't intentional (obviously); please post v2 with that as
Fixes and I'll get it in sched/urgent and stable.