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

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Message-ID: <213a5bb3-208a-b8dc-0c80-175ceb4ae1dd@arm.com>
Date:   Mon, 29 Jul 2019 10:00:58 +0100
From:   Dietmar Eggemann <dietmar.eggemann@....com>
To:     luca abeni <luca.abeni@...tannapisa.it>
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()

On 7/26/19 2:30 PM, luca abeni wrote:
> 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?

The code looks the same. Let me try to test it. I will add it in v2 then.