Messages in this thread | | | Subject | Re: [External] Re: [PATCH v2] mm/page_isolation: do not isolate the max order page | From | David Hildenbrand <> | Date | Fri, 4 Dec 2020 18:12:55 +0100 |
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On 04.12.20 17:12, Muchun Song wrote: > On Fri, Dec 4, 2020 at 12:28 AM David Hildenbrand <david@redhat.com> wrote: >> >> 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 > > You mean we should remove the Fixes tag? Thanks.
As discussed in v1, I don't think we really have systems where this applies, but could be in corner cases on MIPS or with FLATMEM. Let's just leave it like that. :)
Reviewed-by: David Hildenbrand <david@redhat.com>
-- Thanks,
David / dhildenb
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