linux-kernel - Re: [PATCH v3 1/4] sched: cgroup SCHED

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Message-ID: <20210902012206.cm6flytlp63c2h5v@oracle.com>
Date:   Wed, 1 Sep 2021 21:22:06 -0400
From:   Daniel Jordan <daniel.m.jordan@...cle.com>
To:     Josh Don <joshdon@...gle.com>
Cc:     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>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Paul Turner <pjt@...gle.com>,
        Oleg Rombakh <olegrom@...gle.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Steve Sistare <steven.sistare@...cle.com>,
        Tejun Heo <tj@...nel.org>, Rik van Riel <riel@...riel.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/4] sched: cgroup SCHED_IDLE support

On Thu, Aug 19, 2021 at 06:04:00PM -0700, Josh Don wrote:
> +static int se_is_idle(struct sched_entity *se)
> +{
> +	return 0;
> +}

I'm thinking !FAIR_GROUP_SCHED is a rare thing to behold?  So not a big
deal, but I think this wants to be

        return task_has_idle_policy(task_of(se));

so buddies aren't set for SCHED_IDLE.

>  static void set_last_buddy(struct sched_entity *se)
>  {
> -	if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se))))
> -		return;
> -
>  	for_each_sched_entity(se) {
>  		if (SCHED_WARN_ON(!se->on_rq))
>  			return;
> +		if (se_is_idle(se))
> +			return;
>  		cfs_rq_of(se)->last = se;
>  	}
>  }
>  
>  static void set_next_buddy(struct sched_entity *se)
>  {
> -	if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se))))
> -		return;
> -
>  	for_each_sched_entity(se) {
>  		if (SCHED_WARN_ON(!se->on_rq))
>  			return;
> +		if (se_is_idle(se))
> +			return;
>  		cfs_rq_of(se)->next = se;
>  	}
>  }