Messages in this thread | | | Subject | Re: [PATCH v2] mm/page_isolation: do not isolate the max order page | From | David Hildenbrand <> | Date | Thu, 3 Dec 2020 17:28:00 +0100 |
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On 03.12.20 17:22, Muchun Song wrote: > The max order page has no buddy page and never merge to other order. > So isolating and then freeing it is pointless. And if order == MAX_ORDER > - 1, then the buddy can actually be a !pfn_valid() in some corner case? > pfn_valid_within(buddy_pfn) that follows would only catch it on archs > with holes in zone. Then is_migrate_isolate_page(buddy) might access an > invalid buddy. So this is also a bug fix. > > Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
As just replied to v1, I don't think this is required and the patch description can be simplified - e.g., stating that we have/had not such users.
-- Thanks,
David / dhildenb
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