From: David Hildenbrand <david@redhat.com>
To: Oscar Salvador <osalvador@suse.de>, Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, dan.j.williams@intel.com,
Jonathan.Cameron@huawei.com, anshuman.khandual@arm.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 0/4] mm,memory_hotplug: allocate memmap from hotadded memory
Date: Tue, 2 Apr 2019 10:39:22 +0200 [thread overview]
Message-ID: <40a84fa8-c1b0-185e-8c6d-230a381099a2@redhat.com> (raw)
In-Reply-To: <20190402082812.fefamf7qlzulb7t2@d104.suse.de>
On 02.04.19 10:28, Oscar Salvador wrote:
> On Mon, Apr 01, 2019 at 01:53:06PM +0200, Michal Hocko wrote:
>> On Mon 01-04-19 09:59:36, Oscar Salvador wrote:
>>> On Fri, Mar 29, 2019 at 02:42:43PM +0100, Michal Hocko wrote:
>>>> Having a larger contiguous area is definitely nice to have but you also
>>>> have to consider the other side of the thing. If we have a movable
>>>> memblock with unmovable memory then we are breaking the movable
>>>> property. So there should be some flexibility for caller to tell whether
>>>> to allocate on per device or per memblock. Or we need something to move
>>>> memmaps during the hotremove.
>>>
>>> By movable memblock you mean a memblock whose pages can be migrated over when
>>> this memblock is offlined, right?
>>
>> I am mostly thinking about movable_node kernel parameter which makes
>> newly hotpluged memory go into ZONE_MOVABLE and people do use that to
>> make sure such a memory can be later hotremoved.
>
> Uhm, I might be missing your point, but hot-added memory that makes use of
> vmemmap pages can be hot-removed as any other memory.
>
> Vmemmap pages do not account as unmovable memory, they just stick around
> until all sections they referred to have been removed, and then, we proceed
> with removing them.
> So, to put it in another way: vmemmap pages are left in the system until the
> whole memory device (DIMM, virt mem-device or whatever) is completely
> hot-removed.
Indeed, separate memblocks can be offlined, but vmemmap is removed along
with remove_memory().
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-04-02 8:39 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-28 13:43 [PATCH 0/4] mm,memory_hotplug: allocate memmap from hotadded memory Oscar Salvador
2019-03-28 13:43 ` [PATCH 1/4] mm, memory_hotplug: cleanup memory offline path Oscar Salvador
2019-04-03 8:43 ` Michal Hocko
2019-03-28 13:43 ` [PATCH 2/4] mm, memory_hotplug: provide a more generic restrictions for memory hotplug Oscar Salvador
2019-04-03 8:46 ` Michal Hocko
2019-04-03 8:48 ` David Hildenbrand
2019-04-04 10:04 ` Oscar Salvador
2019-04-04 10:06 ` David Hildenbrand
2019-04-04 10:31 ` Michal Hocko
2019-04-04 12:04 ` Oscar Salvador
2019-03-28 13:43 ` [PATCH 3/4] mm, memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap Oscar Salvador
2019-03-28 13:43 ` [PATCH 4/4] mm, sparse: rename kmalloc_section_memmap, __kfree_section_memmap Oscar Salvador
2019-03-28 15:09 ` [PATCH 0/4] mm,memory_hotplug: allocate memmap from hotadded memory David Hildenbrand
2019-03-28 15:31 ` David Hildenbrand
2019-03-29 8:45 ` Oscar Salvador
2019-03-29 8:56 ` David Hildenbrand
2019-03-29 9:01 ` David Hildenbrand
2019-03-29 9:20 ` Oscar Salvador
2019-03-29 13:42 ` Michal Hocko
2019-04-01 7:59 ` Oscar Salvador
2019-04-01 11:53 ` Michal Hocko
2019-04-02 8:28 ` Oscar Salvador
2019-04-02 8:39 ` David Hildenbrand [this message]
2019-04-02 12:48 ` Michal Hocko
2019-04-03 8:01 ` Oscar Salvador
2019-04-03 8:12 ` Michal Hocko
2019-04-03 8:17 ` David Hildenbrand
2019-04-03 8:37 ` Michal Hocko
2019-04-03 8:41 ` David Hildenbrand
2019-04-03 8:49 ` Michal Hocko
2019-04-03 8:53 ` David Hildenbrand
2019-04-03 8:50 ` Oscar Salvador
2019-04-03 8:54 ` David Hildenbrand
2019-04-03 9:40 ` Oscar Salvador
2019-04-03 10:46 ` Michal Hocko
2019-04-04 10:25 ` Vlastimil Babka
2019-04-03 8:34 ` Oscar Salvador
2019-04-03 8:36 ` David Hildenbrand
2019-03-29 8:30 ` Oscar Salvador
2019-03-29 8:51 ` David Hildenbrand
2019-03-29 22:23 ` John Hubbard
2019-04-01 7:52 ` Oscar Salvador
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