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Date: Thu, 4 Dec 2014 15:45:34 -0500
From: Tejun Heo <tj@kernel.org>
Subject: Re: [RFC v2] percpu: Add a separate function to merge free areas
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To: Christoph Lameter <cl@linux.com>
Cc: Leonard Crestez <lcrestez@ixiacom.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sorin Dumitru <sdumitru@ixiacom.com>

Hello, Christoph.

On Thu, Dec 04, 2014 at 02:28:10PM -0600, Christoph Lameter wrote:
> Well this is not a common use case and that is not what the per cpu
> allocator was designed for. There is bound to be signifcant fragmentation
> with the current design. The design was for rare allocations when
> structures are initialized.

My unverified gut feeling is that fragmentation prolly is a lot less
of a problem for percpu allocator given that most percpu allocations
are fairly small.  On the other hand, we do wanna pack them tight as
percpu memory is really expensive space-wise.  I could be wrong tho.

Thanks.

-- 
tejun

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