linux-kernel - Re: [PATCH 3/3] mm: remove unnecessary uses of lock_page

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Message-ID: <20160203092926.GG21016@esperanza>
Date:	Wed, 3 Feb 2016 12:29:26 +0300
From:	Vladimir Davydov <vdavydov@...tuozzo.com>
To:	Johannes Weiner <hannes@...xchg.org>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Michal Hocko <mhocko@...e.cz>, <linux-mm@...ck.org>,
	<cgroups@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<kernel-team@...com>
Subject: Re: [PATCH 3/3] mm: remove unnecessary uses of lock_page_memcg()

On Fri, Jan 29, 2016 at 06:19:33PM -0500, Johannes Weiner wrote:
> There are several users that nest lock_page_memcg() inside lock_page()
> to prevent page->mem_cgroup from changing. But the page lock prevents
> pages from moving between cgroups, so that is unnecessary overhead.
> 
> Remove lock_page_memcg() in contexts with locked contexts and fix the
> debug code in the page stat functions to be okay with the page lock.
> 
> Signed-off-by: Johannes Weiner <hannes@...xchg.org>

Acked-by: Vladimir Davydov <vdavydov@...tuozzo.com>