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Date: Mon, 13 Mar 2017 16:16:04 -0700
From: Andi Kleen <ak@linux.intel.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Igor Mammedov <imammedo@redhat.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
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Subject: Re: WTH is going on with memory hotplug sysf interface (was: Re:
 [RFC PATCH] mm, hotplug: get rid of auto_online_blocks)
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> and ARCH_SPARSEMEM_DEFAULT is enabeld on 64b. So I guess whatever was
> the reason to add this code back in 2006 is not true anymore. So I am
> really wondering. Do we absolutely need to assign pages which are not
> onlined yet to the ZONE_NORMAL unconditionally? Why cannot we put them
> out of any zone and wait for memory online operation to put them where
> requested?

I don't remember any specific reason. May have just been simplification.
Should be fine to use any zone.

-Andi