From: Michal Hocko <mhocko@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>, linux-mm@kvack.org
Subject: Re: [PATCH] mm,oom: Reduce needless dereference.
Date: Wed, 9 Mar 2016 15:55:12 +0100 [thread overview]
Message-ID: <20160309145512.GA27011@dhcp22.suse.cz> (raw)
In-Reply-To: <20160308183032.GA9571@cmpxchg.org>
On Tue 08-03-16 13:30:32, Johannes Weiner wrote:
> On Tue, Mar 08, 2016 at 08:02:31PM +0900, Tetsuo Handa wrote:
> > Since we assigned mm = victim->mm before pr_err(),
> > we don't need to dereference victim->mm again at pr_err().
> > This saves a few instructions.
> >
> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
>
> Yes. Once we introduce a local variable for something, we should use
> it consistently to refer to that thing. Anything else is confusing.
The victim->mm association is stable here because of the task_lock but I
agree that this might be not obvious and reusing the local variable is
easier to read and understand. I doubt we care about the change in the
generated code as an argument though. So just for the sake of clean up
Acked-by: Michal Hocko <mhocko@suse.com>
>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
>
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--
Michal Hocko
SUSE Labs
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prev parent reply other threads:[~2016-03-09 14:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 11:02 [PATCH] mm,oom: Reduce needless dereference Tetsuo Handa
2016-03-08 13:32 ` Vlastimil Babka
2016-03-08 18:30 ` Johannes Weiner
2016-03-09 14:55 ` Michal Hocko [this message]
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