From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCHSET] percpu: generalize first chunk allocators and
 improve lpage NUMA support
Date: Wed, 24 Jun 2009 16:55:08 -0700
Message-ID: <20090624165508.30b88343.akpm@linux-foundation.org>
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To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, mingo@elte.hu, andi@firstfloor.org, hpa@zytor.com, tglx@linutronix.de, cl@linux-foundation.org

On Wed, 24 Jun 2009 22:30:06 +0900
Tejun Heo <tj@kernel.org> wrote:

> This patchset is available in the following git tree and will be
> published in for-next if there's no major objection.  It might get
> rebased before going into for-next.
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu.git lpage-numa

<tries to read the patches>

Boy, this stuff is complicated.  Does it all work?

The Impact: lines were useful :)


I assume from the tremendous number of for_each_possible_cpu()s that
CPU hotplug awareness won't be happening.

Do we have a feeling for the amount of wastage here?  If

	num_possible_cpus() - num_online_cpus() == N

and N is large, what did it cost?

And what are reasonable values of N?