diff options
author | Mel Gorman <mgorman@suse.de> | 2014-04-03 14:47:24 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-09 12:21:28 -0700 |
commit | 29c2a88157819d1e68ffea8b7d80117b332c8efe (patch) | |
tree | ff14ff01a247ca8813070ca8a3cb3b95419b9541 /mm/slab.c | |
parent | d4995db1ea96e5f357b92469c9b6c3ecc6bdfbaa (diff) |
mm: optimize put_mems_allowed() usage
commit d26914d11751b23ca2e8747725f2cae10c2f2c1b upstream.
Since put_mems_allowed() is strictly optional, its a seqcount retry, we
don't need to evaluate the function if the allocation was in fact
successful, saving a smp_rmb some loads and comparisons on some relative
fast-paths.
Since the naming, get/put_mems_allowed() does suggest a mandatory
pairing, rename the interface, as suggested by Mel, to resemble the
seqcount interface.
This gives us: read_mems_allowed_begin() and read_mems_allowed_retry(),
where it is important to note that the return value of the latter call
is inverted from its previous incarnation.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r-- | mm/slab.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/slab.c b/mm/slab.c index ea854eb2388c..0b1c2a58559d 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3122,7 +3122,7 @@ static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); retry_cpuset: - cpuset_mems_cookie = get_mems_allowed(); + cpuset_mems_cookie = read_mems_allowed_begin(); zonelist = node_zonelist(slab_node(), flags); retry: @@ -3180,7 +3180,7 @@ retry: } } - if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj)) + if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie))) goto retry_cpuset; return obj; } |