Date: Tue, 15 Dec 2009 08:46:37 -0600 (CST)
From: Christoph Lameter <cl@linux-foundation.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
cc: Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org,
       Pekka Enberg <penberg@cs.helsinki.fi>, Mel Gorman <mel@csn.ul.ie>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: [this_cpu_xx V7 6/8] Make slub statistics use this_cpu_inc
In-Reply-To: <4B272BAC.3080502@gmail.com>
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References: <20091214220320.665065925@quilx.com> <20091214220341.901590053@quilx.com> <4B272BAC.3080502@gmail.com>
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On Tue, 15 Dec 2009, Eric Dumazet wrote:

> Le 14/12/2009 23:03, Christoph Lameter a =E9crit :
> > this_cpu_inc() translates into a single instruction on x86 and does not
> > need any register. So use it in stat(). We also want to avoid the
> > calculation of the per cpu kmem_cache_cpu structure pointer. So pass
> > a kmem_cache pointer instead of a kmem_cache_cpu pointer.
> >
>
> Hmm, last time I checked, [__]this_cpu_inc were not using "inc" on x86,
> but the default [__]this_cpu_add((pcp), 1)

Well the add 1 is still a single instruction so its okay. We can easily
add support for inc on x86 if makes a difference?


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