From: Mel Gorman <mgorman@xxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== commit 07a427884348d38a6fd56fa4d78249c407196650 upstream. shmem_getpage_gfp uses an atomic operation to set the SwapBacked field before it's even added to the LRU or visible. This is unnecessary as what could it possible race against? Use an unlocked variant. Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Rik van Riel <riel@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- include/linux/page-flags.h | 1 + mm/shmem.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 67fc8a246a07..0d1b0357ca85 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -208,6 +208,7 @@ PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ PAGEFLAG(SavePinned, savepinned); /* Xen */ PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) + __SETPAGEFLAG(SwapBacked, swapbacked) __PAGEFLAG(SlobFree, slob_free) diff --git a/mm/shmem.c b/mm/shmem.c index 15e5527934ad..8572e8e39afb 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1142,7 +1142,7 @@ repeat: goto decused; } - SetPageSwapBacked(page); + __SetPageSwapBacked(page); __set_page_locked(page); error = mem_cgroup_cache_charge(page, current->mm, gfp & GFP_RECLAIM_MASK); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html