Messages in this thread | | | From | James Houghton <> | Date | Thu, 5 Jan 2023 01:50:42 +0000 | Subject | Re: [PATCH 1/3] mm/hugetlb: Pre-allocate pgtable pages for uffd wr-protects |
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On Wed, Jan 4, 2023 at 10:52 PM Peter Xu <peterx@redhat.com> wrote: > > Userfaultfd-wp uses pte markers to mark wr-protected pages for both shmem > and hugetlb. Shmem has pre-allocation ready for markers, but hugetlb path > was overlooked. > > Doing so by calling huge_pte_alloc() if the initial pgtable walk fails to > find the huge ptep. It's possible that huge_pte_alloc() can fail with high > memory pressure, in that case stop the loop immediately and fail silently. > This is not the most ideal solution but it matches with what we do with > shmem meanwhile it avoids the splat in dmesg. > > Cc: linux-stable <stable@vger.kernel.org> # 5.19+ > Fixes: 60dfaad65aa9 ("mm/hugetlb: allow uffd wr-protect none ptes") > Reported-by: James Houghton <jthoughton@google.com> > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > mm/hugetlb.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-)
Acked-by: James Houghton <jthoughton@google.com>
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