On 29.06.24 03:33, Wei Yang wrote:
Initialize all pages reserved is an ancient behavior.
Since commit 92923ca3aace ("mm: meminit: only set page reserved in the
memblock region"), SetPageReserved is removed from
__init_single_page(). Only those reserved pages are marked PG_reserved.
But we still set PG_reserved on offline and check it on online.
Following two commits removed both of them:
* Commit 0ee5f4f31d36 ("mm/page_alloc.c: don't set pages PageReserved()
when offlining") removed the set on offline.
* Commit 5ecae6359e3a ("mm/memory_hotplug: drop PageReserved() check in
online_pages_range()") removed the check on online.
This means we set PG_reserved for hot-plugged memory at initialization
is not helpful and a little different from bootmem initialization path.
Now we can remove it.
It's not that easy for ZONE_DEVICE.
Also, see mm/mm-stable
commit 3dadec1babf9eee0c67c967df931d6f0cb124a04
Author: David Hildenbrand <david@xxxxxxxxxx>
Date: Fri Jun 7 11:09:36 2024 +0200
mm: pass meminit_context to __free_pages_core()
Patch series "mm/memory_hotplug: use PageOffline() instead of
PageReserved() for !ZONE_DEVICE".
commit b873faaa609ab44c223b2327f55d2b6a2ba4ca9c
Author: David Hildenbrand <david@xxxxxxxxxx>
Date: Fri Jun 7 11:09:37 2024 +0200
mm/memory_hotplug: initialize memmap of !ZONE_DEVICE with
PageOffline() instead of PageReserved()
If you want to work on removing it for ZONE_DEVICE, one idea
is to replace all relevant PageReserved() checks by a
more generic function that would check PageReserved() and the zone
--
Cheers,
David / dhildenb
