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Date:   Thu, 15 Nov 2018 17:52:25 +0800
From:   Baoquan He <bhe@redhat.com>
To:     David Hildenbrand <david@redhat.com>
Cc:     Michal Hocko <mhocko@kernel.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
        aarcange@redhat.com
Subject: Re: Memory hotplug softlock issue
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On 11/15/18 at 10:42am, David Hildenbrand wrote:
> I am wondering why it is always the last memory block of that device
> (and even that node). Coincidence?

I remember one or two times it's the last 6G or 4G which stall there,
the size of memory block is 2G. But most of time it's the last memory
block. And from the debug printing added by Michal's patch, it's the
stress program itself which owns the migrating page and loop forvever
there.