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SubjectRe: [PATCH v7 2/6] userfaultfd: disable huge PMD sharing for MINOR registered VMAs
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On 2/18/21 4:48 PM, Axel Rasmussen wrote:
> As the comment says: for the MINOR fault use case, although the page
> might be present and populated in the other (non-UFFD-registered) half
> of the mapping, it may be out of date, and we explicitly want userspace
> to get a minor fault so it can check and potentially update the page's
> contents.
>
> Huge PMD sharing would prevent these faults from occurring for
> suitably aligned areas, so disable it upon UFFD registration.
>
> Reviewed-by: Peter Xu <peterx@redhat.com>
> Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>

Thanks,

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
--
Mike Kravetz

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