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Date: Sat, 20 Sep 2008 01:02:09 +0300
From: "Pekka Enberg" <penberg@cs.helsinki.fi>
To: "Christoph Lameter" <cl@linux-foundation.org>
Subject: Re: [patch 3/3] Increase default reserve percpu area
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, jeremy@goop.org, ebiederm@xmission.com,
       travis@sgi.com, herbert@gondor.apana.org.au, xemul@openvz.org
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On Fri, Sep 19, 2008 at 11:37 PM, Christoph Lameter
<cl@linux-foundation.org> wrote:
> SLUB now requires a portion of the per cpu reserve. There are on average
> about 70 real slabs on a system (aliases do not count) and each needs 12 bytes
> of per cpu space. Thats 840 bytes. In debug mode all slabs will be real slabs
> which will make us end up with 150 -> 1800. Give it some slack and add 2000
> bytes to the default size.
>
> Things work fine without this patch but then slub will reduce the percpu reserve
> for modules.

Hmm, shouldn't this be dynamically configured at runtime by
multiplying the number of possible CPUs with some constant?