Messages in this thread | | | Date | Thu, 25 Aug 2022 15:58:45 +0800 | Subject | Re: [PATCH v2 1/5] mm/hugetlb: fix races when looking up a CONT-PTE size hugetlb page | From | Baolin Wang <> |
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On 8/25/2022 3:10 PM, David Hildenbrand wrote: > >>> + /* >>> + * 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).
Make sense. Thanks for your explanation.
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