Messages in this thread | | | Date | Mon, 2 Oct 2023 16:42:50 +0200 | Subject | Re: [PATCH v2 1/3] userfaultfd: UFFDIO_REMAP: rmap preparation | From | David Hildenbrand <> |
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On 23.09.23 03:31, Suren Baghdasaryan wrote: > From: Andrea Arcangeli <aarcange@redhat.com> > > As far as the rmap code is concerned, UFFDIO_REMAP only alters the > page->mapping and page->index. It does it while holding the page > lock. However folio_referenced() is doing rmap walks without taking the > folio lock first, so folio_lock_anon_vma_read() must be updated to > re-check that the folio->mapping didn't change after we obtained the > anon_vma read lock.
I'm curious: why don't we need this for existing users of page_move_anon_rmap()? What's special about UFFDIO_REMAP?
-- Cheers,
David / dhildenb
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