mm: remove SWAP_MLOCK check for SWAP_SUCCESS in ttu

If the page is mapped and rescue in try_to_unmap_one, the
page_mapcount() of a page cannot be zero, so the page_mapcount check in
try_to_unmap is enough to return SWAP_SUCCESS.  IOW, SWAP_MLOCK check is
redundant so remove it.

Link: http://lkml.kernel.org/r/1489555493-14659-4-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/rmap.c b/mm/rmap.c
index f6aa18d8a420d492b11a0ded1b0e695dfec0e3ec..dfe40557ea29f55c00999e6c5bd0a252f43a3d73 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1535,7 +1535,7 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
        else
                ret = rmap_walk(page, &rwc);
 
-       if (ret != SWAP_MLOCK && !page_mapcount(page))
+       if (!page_mapcount(page))
                ret = SWAP_SUCCESS;
        return ret;
 }