linux-kernel - Re: [PATCH v3 1/2] sched/deadline: Remove unnecessary condition in push_dl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b97cc848-752a-9793-61ce-fe5e4826a013@redhat.com>
Date:   Thu, 16 Feb 2017 18:35:54 +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 1/2] sched/deadline: Remove unnecessary condition in
 push_dl_task()

On 02/16/2017 03:34 AM, Byungchul Park wrote:
> pick_next_pushable_dl_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