linux-kernel - Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in push_rt

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Message-ID: <a37baf01-b9eb-c631-75f1-bdd058362350@redhat.com>
Date:   Thu, 16 Feb 2017 18:36:19 +0100
From:   Daniel Bristot de Oliveira <bristot@...hat.com>
To:     Byungchul Park <byungchul.park@....com>, peterz@...radead.org,
        mingo@...nel.org
Cc:     linux-kernel@...r.kernel.org, juri.lelli@...il.com,
        rostedt@...dmis.org, kernel-team@....com
Subject: Re: [PATCH v3 2/2] sched/rt: Remove unnecessary condition in
 push_rt_task()

On 02/16/2017 03:34 AM, Byungchul Park wrote:
> pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when
> it returns a task other than NULL, which means that task_cpu(task) must
> be rq->cpu. So if task == next_task, then task_cpu(next_task) must be
> rq->cpu as well. Remove the redundant condition and make code simpler.
> 
> By this patch, unnecessary one branch and two LOAD operations in 'if'
> statement can be avoided.
> 
> Signed-off-by: Byungchul Park <byungchul.park@....com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
> Reviewed-by: Juri Lelli <juri.lelli@....com>

+1

Reviewed-by: Daniel Bristot de Oliveira <bristot@...hat.com>

-- Daniel