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From: Andi Kleen <ak@linux.intel.com>
To: Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH v5 3/3] mm/page_alloc: Keep memoryless cpuless node 0
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 <linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org>

> > What's the point of this indirection other than another way of avoiding
> > empty node 0?
> 
> Honestly, I do not have any idea. I've traced it down to
> Author: Andi Kleen <ak@suse.de>
> Date:   Tue Jan 11 15:35:48 2005 -0800

I don't remember all the details, and I can't even find the commit
(is it in linux-historic?).

But AFAIK there's no guarantee PXMs are small and continuous, so it
seemed better to have a clean zero based space.

Back then we had a lot of problems with buggy SRAT tables in BIOS,
so we really tried to avoid trusting the BIOS as much as possible.

-Andi