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| author |   Mel Gorman <mgorman@suse.de> | 2014-04-03 14:47:24 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-03 16:20:58 -0700 |
| commit | d26914d11751b23ca2e8747725f2cae10c2f2c1b (patch) | |
| tree | 020b606fb9223e29292f54922a11111239e3a3f4 /mm/slab.c | |
| parent | mm, compaction: ignore pageblock skip when manually invoking compaction (diff) | |
| download | linux-dev-d26914d11751b23ca2e8747725f2cae10c2f2c1b.tar.xz linux-dev-d26914d11751b23ca2e8747725f2cae10c2f2c1b.zip | |
mm: optimize put_mems_allowed() usage
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>
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 b264214c77ea..9153c802e2fe 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3073,7 +3073,7 @@ 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: @@ -3131,7 +3131,7 @@ 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; } |