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    Subject[PATCH 1/4] mm/rmap: fix comments left over from recent changes
    Parallel developments in mm/rmap.c have left behind some out-of-date
    comments: try_to_migrate_one() also accepts TTU_SYNC (already commented
    in try_to_migrate() itself), and try_to_migrate() returns nothing at all.

    TTU_SPLIT_FREEZE has just been deleted, so reword the comment about it in
    mm/huge_memory.c; and TTU_IGNORE_ACCESS was removed in 5.11, so delete
    the "recently referenced" comment from try_to_unmap_one() (once upon a
    time the comment was near the removed codeblock, but they drifted apart).

    Signed-off-by: Hugh Dickins <hughd@google.com>
    ---
    mm/huge_memory.c | 2 +-
    mm/rmap.c | 7 +------
    2 files changed, 2 insertions(+), 7 deletions(-)

    diff --git a/mm/huge_memory.c b/mm/huge_memory.c
    index 8b731d53e9f4..afff3ac87067 100644
    --- a/mm/huge_memory.c
    +++ b/mm/huge_memory.c
    @@ -2331,7 +2331,7 @@ static void remap_page(struct page *page, unsigned int nr)
    {
    int i;

    - /* If TTU_SPLIT_FREEZE is ever extended to file, remove this check */
    + /* If unmap_page() uses try_to_migrate() on file, remove this check */
    if (!PageAnon(page))
    return;
    if (PageTransHuge(page)) {
    diff --git a/mm/rmap.c b/mm/rmap.c
    index 37c24672125c..746013e282c3 100644
    --- a/mm/rmap.c
    +++ b/mm/rmap.c
    @@ -1439,8 +1439,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
    while (page_vma_mapped_walk(&pvmw)) {
    /*
    * If the page is mlock()d, we cannot swap it out.
    - * If it's recently referenced (perhaps page_referenced
    - * skipped over this mm) then we should reactivate it.
    */
    if (!(flags & TTU_IGNORE_MLOCK)) {
    if (vma->vm_flags & VM_LOCKED) {
    @@ -1687,8 +1685,7 @@ void try_to_unmap(struct page *page, enum ttu_flags flags)
    * @arg: enum ttu_flags will be passed to this argument.
    *
    * If TTU_SPLIT_HUGE_PMD is specified any PMD mappings will be split into PTEs
    - * containing migration entries. This and TTU_RMAP_LOCKED are the only supported
    - * flags.
    + * containing migration entries.
    */
    static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
    unsigned long address, void *arg)
    @@ -1928,8 +1925,6 @@ static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma,
    *
    * Tries to remove all the page table entries which are mapping this page and
    * replace them with special swap entries. Caller must hold the page lock.
    - *
    - * If is successful, return true. Otherwise, false.
    */
    void try_to_migrate(struct page *page, enum ttu_flags flags)
    {
    --
    2.26.2
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