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    Subject[PATCH v4 0/4] mm: Rework zap ptes on swap entries
    Date
    v4:
    - Rebase to v5.17-rc4
    - Add r-b, and suggested-by on patch 2 [David]
    - Fix spelling (s/Quotting/Quoting/) [David]

    RFC V1: https://lore.kernel.org/lkml/20211110082952.19266-1-peterx@redhat.com
    RFC V2: https://lore.kernel.org/lkml/20211115134951.85286-1-peterx@redhat.com
    V3: https://lore.kernel.org/lkml/20220128045412.18695-1-peterx@redhat.com

    Patch 1 should fix a long standing bug for zap_pte_range() on zap_details
    usage. The risk is we could have some swap entries skipped while we should
    have zapped them.

    Migration entries are not the major concern because file backed memory always
    zap in the pattern that "first time without page lock, then re-zap with page
    lock" hence the 2nd zap will always make sure all migration entries are already
    recovered.

    However there can be issues with real swap entries got skipped errornoously.
    There's a reproducer provided in commit message of patch 1 for that.

    Patch 2-4 are cleanups that are based on patch 1. After the whole patchset
    applied, we should have a very clean view of zap_pte_range().

    Only patch 1 needs to be backported to stable if necessary.

    Please review, thanks.

    Peter Xu (4):
    mm: Don't skip swap entry even if zap_details specified
    mm: Rename zap_skip_check_mapping() to should_zap_page()
    mm: Change zap_details.zap_mapping into even_cows
    mm: Rework swap handling of zap_pte_range

    mm/memory.c | 85 +++++++++++++++++++++++++++++++----------------------
    1 file changed, 50 insertions(+), 35 deletions(-)

    --
    2.32.0

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