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 for <linux-nvdimm@lists.01.org>; Wed, 17 Apr 2019 15:03:33 -0700 (PDT)
Date: Wed, 17 Apr 2019 15:03:31 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v6 00/12] mm: Sub-section memory hotplug support
Message-Id: <20190417150331.90219ca42a1c0db8632d0fd5@linux-foundation.org>
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To: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>, David Hildenbrand <david@redhat.com>, linux-nvdimm@lists.01.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, =?ISO-8859-1?Q?J=E9r=F4me?= Glisse <jglisse@redhat.com>, Vlastimil Babka <vbabka@suse.cz>
List-ID: <linux-nvdimm@lists.01.org>

On Wed, 17 Apr 2019 11:38:55 -0700 Dan Williams <dan.j.williams@intel.com> wrote:

> The memory hotplug section is an arbitrary / convenient unit for memory
> hotplug. 'Section-size' units have bled into the user interface
> ('memblock' sysfs) and can not be changed without breaking existing
> userspace. The section-size constraint, while mostly benign for typical
> memory hotplug, has and continues to wreak havoc with 'device-memory'
> use cases, persistent memory (pmem) in particular. Recall that pmem uses
> devm_memremap_pages(), and subsequently arch_add_memory(), to allocate a
> 'struct page' memmap for pmem. However, it does not use the 'bottom
> half' of memory hotplug, i.e. never marks pmem pages online and never
> exposes the userspace memblock interface for pmem. This leaves an
> opening to redress the section-size constraint.

v6 and we're not showing any review activity.  Who would be suitable
people to help out here?
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