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

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Date:   Fri, 26 Jul 2019 15:30:02 +0200
From:   luca abeni <luca.abeni@...tannapisa.it>
To:     Dietmar Eggemann <dietmar.eggemann@....com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        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()

Hi,

On Fri, 26 Jul 2019 09:27:52 +0100
Dietmar Eggemann <dietmar.eggemann@....com> wrote:
[...]
> @@ -2121,17 +2121,13 @@ static int push_dl_task(struct rq *rq)
>  	}
>  
>  	deactivate_task(rq, next_task, 0);
> -	sub_running_bw(&next_task->dl, &rq->dl);
> -	sub_rq_bw(&next_task->dl, &rq->dl);
>  	set_task_cpu(next_task, later_rq->cpu);
> -	add_rq_bw(&next_task->dl, &later_rq->dl);
>  
>  	/*
>  	 * Update the later_rq clock here, because the clock is used
>  	 * by the cpufreq_update_util() inside __add_running_bw().
>  	 */
>  	update_rq_clock(later_rq);
> -	add_running_bw(&next_task->dl, &later_rq->dl);

Looking at the code again and thinking a little bit more about this
issue, I suspect a similar change is needed in pull_dl_task() too, no?



			Luca