Messages in this thread | | | Date | Thu, 21 Jan 2021 13:59:28 -0500 | From | Peter Xu <> | Subject | Re: [PATCH 6/9] userfaultfd: disable huge PMD sharing for MINOR registered VMAs |
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On Fri, Jan 15, 2021 at 11:04:48AM -0800, 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 of the shared mapping, it may be out of date, and we explicitly want 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. > > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
-- Peter Xu
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