From: David Hildenbrand <david@redhat.com>
To: Wei Yang <richard.weiyang@linux.alibaba.com>,
Oscar Salvador <osalvador@suse.de>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Baoquan He <bhe@redhat.com>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Subject: Re: [PATCH v2 02/10] mm/memory_hotplug: enforce section granularity when onlining/offlining
Date: Tue, 8 Sep 2020 11:14:58 +0200 [thread overview]
Message-ID: <96fd5d6c-a6e3-648b-6d3e-ebfd2d3969d8@redhat.com> (raw)
In-Reply-To: <20200825021129.GA78808@L-31X9LVDL-1304.local>
On 25.08.20 04:11, Wei Yang wrote:
> On Mon, Aug 24, 2020 at 12:39:18PM +0200, Oscar Salvador wrote:
>> On Wed, Aug 19, 2020 at 07:59:49PM +0200, David Hildenbrand wrote:
>>> Already two people (including me) tried to offline subsections, because
>>> the function looks like it can deal with it. But we really can only
>>> online/offline full sections that are properly aligned (e.g., we can only
>>> mark full sections online/offline via SECTION_IS_ONLINE).
>>>
>>> Add a simple safety net to document the restriction now. Current users
>>> (core and powernv/memtrace) respect these restrictions.
>>
>> It's been a while since I looked at sub-section handling stuff so sorry to ask
>> this, but was it true that we can hot-{remove,add} sub-section granularity, while
>> we can only online /offline on section granularity?
>>
Yes, we can hot-{remove,add} sub-section granularity ZONE_DEVICE memory,
but not memory to be managed by the buddy.
Examples are
- Memory block devices span 1..X sections and can either be
online/offline
- We can only mark full sections to be online/offline in sparsemem
- Besides section handling, current onlining/offlining code could only
work in MAX_ORDER - 1 granularity, not necessarily sub-section
granularity.
Thanks for having a look.
>
> Seems you are right.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-09-08 9:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 17:59 [PATCH v2 00/10] mm/memory_hotplug: online_pages()/offline_pages() cleanups David Hildenbrand
2020-08-19 17:59 ` [PATCH v2 01/10] mm/memory_hotplug: inline __offline_pages() into offline_pages() David Hildenbrand
2020-08-24 10:26 ` Oscar Salvador
2020-08-31 10:05 ` Pankaj Gupta
2020-08-19 17:59 ` [PATCH v2 02/10] mm/memory_hotplug: enforce section granularity when onlining/offlining David Hildenbrand
2020-08-24 10:39 ` Oscar Salvador
2020-08-25 2:11 ` Wei Yang
2020-09-08 9:14 ` David Hildenbrand [this message]
2020-08-19 17:59 ` [PATCH v2 03/10] mm/memory_hotplug: simplify page offlining David Hildenbrand
2020-08-24 10:44 ` Oscar Salvador
2020-09-03 21:58 ` Andrew Morton
2020-09-04 5:47 ` David Hildenbrand
2020-09-04 7:46 ` Michal Hocko
2020-09-04 19:21 ` Andrew Morton
2020-09-07 6:45 ` Michal Hocko
2020-09-08 9:10 ` David Hildenbrand
2020-08-19 17:59 ` [PATCH v2 04/10] mm/page_alloc: simplify __offline_isolated_pages() David Hildenbrand
2020-08-24 10:48 ` Oscar Salvador
2020-08-19 17:59 ` [PATCH v2 05/10] mm/memory_hotplug: drop nr_isolate_pageblock in offline_pages() David Hildenbrand
2020-08-24 10:49 ` Oscar Salvador
2020-08-19 17:59 ` [PATCH v2 06/10] mm/page_isolation: simplify return value of start_isolate_page_range() David Hildenbrand
2020-08-24 10:51 ` Oscar Salvador
2020-08-19 17:59 ` [PATCH v2 07/10] mm/memory_hotplug: simplify page onlining David Hildenbrand
2020-08-24 10:55 ` Oscar Salvador
2020-08-19 17:59 ` [PATCH v2 08/10] mm/page_alloc: drop stale pageblock comment in memmap_init_zone*() David Hildenbrand
2020-08-24 10:58 ` Oscar Salvador
2020-08-19 17:59 ` [PATCH v2 09/10] mm: pass migratetype into memmap_init_zone() and move_pfn_range_to_zone() David Hildenbrand
2020-08-24 11:59 ` Oscar Salvador
2020-08-19 17:59 ` [PATCH v2 10/10] mm/memory_hotplug: mark pageblocks MIGRATE_ISOLATE while onlining memory David Hildenbrand
2020-08-24 12:07 ` Oscar Salvador
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