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    Subject[PATCH 07/35] autonuma: teach gup_fast about pte_numa
    gup_fast will skip over non present ptes (pte_numa requires the pte to
    be non present). So no explicit check is needed for pte_numa in the
    pte case.

    gup_fast will also automatically skip over THP when the trans huge pmd
    is non present (pmd_numa requires the pmd to be non present).

    But for the special pmd mode scan of knuma_scand
    (/sys/kernel/mm/autonuma/knuma_scand/pmd == 1), the pmd may be of numa
    type (so non present too), the pte may be present. gup_pte_range
    wouldn't notice the pmd is of numa type. So to avoid losing a NUMA
    hinting page fault with gup_fast we need an explicit check for
    pmd_numa() here to be sure it will fault through gup ->

    Signed-off-by: Andrea Arcangeli <>
    arch/x86/mm/gup.c | 2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)

    diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
    index dd74e46..bf36575 100644
    --- a/arch/x86/mm/gup.c
    +++ b/arch/x86/mm/gup.c
    @@ -164,7 +164,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
    * wait_split_huge_page() would never return as the
    * tlb flush IPI wouldn't run.
    - if (pmd_none(pmd) || pmd_trans_splitting(pmd))
    + if (pmd_none(pmd) || pmd_trans_splitting(pmd) || pmd_numa(pmd))
    return 0;
    if (unlikely(pmd_large(pmd))) {
    if (!gup_huge_pmd(pmd, addr, next, write, pages, nr))

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