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    mm: numa: Support NUMA hinting page faults from gup/gup_fast · 0b9d7052
    Andrea Arcangeli 提交于
    Introduce FOLL_NUMA to tell follow_page to check
    pte/pmd_numa. get_user_pages must use FOLL_NUMA, and it's safe to do
    so because it always invokes handle_mm_fault and retries the
    follow_page later.
    
    KVM secondary MMU page faults will trigger the NUMA hinting page
    faults through gup_fast -> get_user_pages -> follow_page ->
    handle_mm_fault.
    
    Other follow_page callers like KSM should not use FOLL_NUMA, or they
    would fail to get the pages if they use follow_page instead of
    get_user_pages.
    
    [ This patch was picked up from the AutoNUMA tree. ]
    Originally-by: NAndrea Arcangeli <aarcange@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Rik van Riel <riel@redhat.com>
    [ ported to this tree. ]
    Signed-off-by: NIngo Molnar <mingo@kernel.org>
    Reviewed-by: NRik van Riel <riel@redhat.com>
    0b9d7052
mm.h 56.4 KB