linux-kernel - Re: [patch] mm, memcg: avoid unnecessary function call when memcg is disabled

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Date:	Tue, 20 Nov 2012 12:27:00 -0500
From:	Johannes Weiner <hannes@...xchg.org>
To:	David Rientjes <rientjes@...gle.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Michal Hocko <mhocko@...e.cz>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [patch] mm, memcg: avoid unnecessary function call when memcg is
 disabled

On Mon, Nov 19, 2012 at 05:44:34PM -0800, David Rientjes wrote:
> While profiling numa/core v16 with cgroup_disable=memory on the command 
> line, I noticed mem_cgroup_count_vm_event() still showed up as high as 
> 0.60% in perftop.
> 
> This occurs because the function is called extremely often even when memcg 
> is disabled.
> 
> To fix this, inline the check for mem_cgroup_disabled() so we avoid the 
> unnecessary function call if memcg is disabled.
> 
> Signed-off-by: David Rientjes <rientjes@...gle.com>

Acked-by: Johannes Weiner <hannes@...xchg.org>
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