Re: [PATCH v2 02/10] mm/memory_hotplug: enforce section granularity when onlining/offlining

From: Wei Yang
Date: Mon Aug 24 2020 - 22:11:36 EST


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?
>

Seems you are right.

>>
>> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Michal Hocko <mhocko@xxxxxxxx>
>> Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
>> Cc: Baoquan He <bhe@xxxxxxxxxx>
>> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
>> Cc: Oscar Salvador <osalvador@xxxxxxx>
>> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
>
>Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
>
>
>--
>Oscar Salvador
>SUSE L3

--
Wei Yang
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