From: Michal Hocko <mhocko@kernel.org>
To: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>,
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: Wed, 3 Apr 2019 10:12:32 +0200 [thread overview]
Message-ID: <20190403081232.GB15605@dhcp22.suse.cz> (raw)
In-Reply-To: <20190403080113.adj2m3szhhnvzu56@d104.suse.de>
On Wed 03-04-19 10:01:16, Oscar Salvador wrote:
> On Tue, Apr 02, 2019 at 02:48:45PM +0200, Michal Hocko wrote:
> > So what is going to happen when you hotadd two memblocks. The first one
> > holds memmaps and then you want to hotremove (not just offline) it?
>
> If you hot-add two memblocks, this means that either:
>
> a) you hot-add a 256MB-memory-device (128MB per memblock)
> b) you hot-add two 128MB-memory-device
>
> Either way, hot-removing only works for memory-device as a whole, so
> there is no problem.
>
> Vmemmaps are created per hot-added operations, this means that
> vmemmaps will be created for the hot-added range.
> And since hot-add/hot-remove operations works with the same granularity,
> there is no problem.
What does prevent calling somebody arch_add_memory for a range spanning
multiple memblocks from a driver directly. In other words aren't you
making assumptions about a future usage based on the qemu usecase?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-04-03 8:12 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-28 13:43 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
2019-04-02 12:48 ` Michal Hocko
2019-04-03 8:01 ` Oscar Salvador
2019-04-03 8:12 ` Michal Hocko [this message]
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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