• Hugh Dickins's avatar
    mm: use __SetPageSwapBacked and dont ClearPageSwapBacked · fa9949da
    Hugh Dickins authored
    v3.16 commit 07a42788 ("mm: shmem: avoid atomic operation during
    shmem_getpage_gfp") rightly replaced one instance of SetPageSwapBacked
    by __SetPageSwapBacked, pointing out that the newly allocated page is
    not yet visible to other users (except speculative get_page_unless_zero-
    ers, who may not update page flags before their further checks).
    That was part of a series in which Mel was focused on tmpfs profiles:
    but almost all SetPageSwapBacked uses can be so optimized, with the same
    Remove ClearPageSwapBacked from __read_swap_cache_async() error path:
    it's not an error to free a page with PG_swapbacked set.
    Follow a convention of __SetPageLocked, __SetPageSwapBacked instead of
    doing it differently in different places; but that's for tidiness - if
    the ordering actually mattered, we should not be using the __variants.
    There's probably scope for further __SetPageFlags in other places, but
    SwapBacked is the one I'm interested in at the moment.
    Signed-off-by: default avatarHugh Dickins <hughd@google.com>
    Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Andres Lagar-Cavilla <andreslc@google.com>
    Cc: Yang Shi <yang.shi@linaro.org>
    Cc: Ning Qu <quning@gmail.com>
    Reviewed-by: default avatarMel Gorman <mgorman@techsingularity.net>
    Cc: Konstantin Khlebnikov <koct9i@gmail.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
swap_state.c 13 KB