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Date: Thu, 1 Jun 2017 10:19:36 -0500
From: Reza Arbab <arbab@linux.vnet.ibm.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Andrea Arcangeli <aarcange@redhat.com>,
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        Igor Mammedov <imammedo@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] mm, memory_hotplug: support movable_node for
 hotplugable nodes
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On Thu, Jun 01, 2017 at 04:22:28PM +0200, Michal Hocko wrote:
>On Thu 01-06-17 16:11:55, Vlastimil Babka wrote:
>> Simple should work, hopefully.
>> - if memory is hotplugged, it's obviously hotplugable, so we don't have
>> to rely on BIOS description.
>
>Not sure I understand. We do not have any information about the hotplug
>status at the time we do online.

The x86 SRAT (or the dt, on other platforms) can describe memory as 
hotpluggable. See memblock_mark_hotplug(). That's only for memory 
present at boot, though.

He's saying that since the memory was added after boot, it is by 
definition hotpluggable. There's no need to check for that 
marking/description.

-- 
Reza Arbab