linux-kernel - Re: [PATCH v5] sched/deadline: remove useless param from setup_new_dl

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Date:	Fri, 5 Aug 2016 09:56:43 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Juri Lelli <juri.lelli@....com>
Cc:	peterz@...radead.org, linux-kernel@...r.kernel.org,
	mingo@...hat.com, luca.abeni@...tn.it, xpang@...hat.com
Subject: Re: [PATCH v5] sched/deadline: remove useless param from
 setup_new_dl_entity

On Fri,  5 Aug 2016 11:09:59 +0100
Juri Lelli <juri.lelli@....com> wrote:

> @@ -1720,19 +1720,28 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
>   */
>  static void switched_to_dl(struct rq *rq, struct task_struct *p)
>  {
> -	if (dl_time_before(p->dl.deadline, rq_clock(rq)))
> -		setup_new_dl_entity(&p->dl, &p->dl);
>  
> -	if (task_on_rq_queued(p) && rq->curr != p) {
> +	if (task_on_rq_queued(p)) {

I always hated functions totally encapsulated by an if statement. This
can be a bit simpler (and less indented) if you have:

	/* If p is not queued, its parameters will be updated at wakeup */
	if (!task_on_rq_queued(p))
		return;

	[...]

Other than that, it looks good.

Reviewed-by: Steven Rostedt <rostedt@...dmis.org>

-- Steve

> +		/*
> +		 * If p is not queued we will update its parameters at next
> +		 * wakeup. If p is dl_boosted we already updated its params in
> +		 * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH),
> +		 * p's deadline being now already after rq_clock(rq).
> +		 */
> +		if (dl_time_before(p->dl.deadline, rq_clock(rq)))
> +			setup_new_dl_entity(&p->dl);
> +
> +		if (rq->curr != p) {
>  #ifdef CONFIG_SMP
> -		if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
> -			queue_push_tasks(rq);
> +			if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
> +				queue_push_tasks(rq);
>  #else
> -		if (dl_task(rq->curr))
> -			check_preempt_curr_dl(rq, p, 0);
> -		else
> -			resched_curr(rq);
> +			if (dl_task(rq->curr))
> +				check_preempt_curr_dl(rq, p, 0);
> +			else
> +				resched_curr(rq);
>  #endif
> +		}
>  	}
>  }
>