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| author | Mel Gorman <mgorman@suse.de> | 2014-08-28 19:35:28 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-09-26 11:52:04 +0200 |
| commit | 6d3e133532cd49fa925fe5c2a949c5900afd601c (patch) | |
| tree | 0178de5eb7aabc04404f33b71dc6244bfced7686 | |
| parent | f161eedc71da293a9bcfcf3d7f6c1da070a61ef0 (diff) | |
| download | lwn-6d3e133532cd49fa925fe5c2a949c5900afd601c.tar.gz lwn-6d3e133532cd49fa925fe5c2a949c5900afd601c.zip | |
mm: shmem: avoid atomic operation during shmem_getpage_gfp
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@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | include/linux/page-flags.h | 1 | ||||
| -rw-r--r-- | mm/shmem.c | 2 |
2 files changed, 2 insertions, 1 deletions
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); |