Messages in this thread | | | Date | Thu, 25 Aug 2022 09:10:41 +0200 | Subject | Re: [PATCH v2 1/5] mm/hugetlb: fix races when looking up a CONT-PTE size hugetlb page | From | David Hildenbrand <> |
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>> + /* >> + * try_grab_page() should always succeed here, because we hold >> + * the ptl lock and have verified pte_present(). >> + */ >> + if (WARN_ON_ONCE(!try_grab_page(page, flags))) { >> + page = NULL; >> + goto out; >> + } >> + } else { > > Should add FOLL_MIGRATION validation before waiting a migration entry.
We really only need FOLL_MIGRATION for KSM. As hugetlb pages cannot be KSM pages, we don't need this.
Actually, I do have patches in the works that rip out FOLL_MIGRATION completely by adjusting KSM code.
So let's try to not add dead code (although it would make sense for feature completeness as is -- but then, FOLL_MIGRATION really needs to go).
-- Thanks,
David / dhildenb
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