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Date: Fri, 21 Sep 2012 13:16:02 -0700
From: Tejun Heo <tj@kernel.org>
To: Pekka Enberg <penberg@kernel.org>
Cc: Glauber Costa <glommer@parallels.com>, Christoph Lameter <cl@linux.com>,
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Subject: Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page
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On Fri, Sep 21, 2012 at 11:14:45PM +0300, Pekka Enberg wrote:
> On Fri, Sep 21, 2012 at 11:07 PM, Tejun Heo <tj@kernel.org> wrote:
> > Not necessarily disagreeing, but I don't think it's helpful to set the
> > bar impossibly high.  Even static_key doesn't have "exactly *zero*"
> > impact.  Let's stick to as minimal as possible when not in use and
> > reasonable in use.
> 
> For !CONFIG_MEMCG_KMEM, it should be exactly zero. No need to play
> games with static_key.

Ah, misread, though you were talking about MEMCG_KMEM && not in use.
Yeap, if turned off in Kconfig, it shouldn't have any performance
overhead.

Thanks.

-- 
tejun