Re: [PATCH v6 05/10] mm/memory_hotplug: Shrink zones when offlining memory

David Hildenbrand
2019-12-03T15:27:24Z

On 03.12.19 16:10, Oscar Salvador wrote:
> On Sun, Oct 06, 2019 at 10:56:41AM +0200, David Hildenbrand wrote:
>> Fixes: d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug")
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>
> I did not see anything wrong with the taken approach, and makes sense to me.
> The only thing that puzzles me is we seem to not balance spanned_pages
> for ZONE_DEVICE anymore.
> memremap_pages() increments them via move_pfn_range_to_zone, but we skip
> ZONE_DEVICE in remove_pfn_range_from_zone.

Yes, documented e.g., in

commit 7ce700bf11b5e2cb84e4352bbdf2123a7a239c84
Author: David Hildenbrand <david@redhat.com>
Date: Thu Nov 21 17:53:56 2019 -0800

mm/memory_hotplug: don't access uninitialized memmaps in
shrink_zone_span()

Needs some more thought - but is definitely not urgent (well, now it's
at least no longer completely broken).

>
> That is not really related to this patch, so I might be missing something,
> but it caught my eye while reviewing this.
>
> Anyway, for this one:
>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
>

Thanks!

>
> off-topic: I __think__ we really need to trim the CC list.

Yes we should :) - done.

--
Thanks,

David / dhildenb