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| author | Mel Gorman <mgorman@techsingularity.net> | 2016-05-19 17:14:10 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-19 19:12:14 -0700 |
| commit | c33d6c06f60f710f0305ae792773e1c2560e1e51 (patch) | |
| tree | 97fc4be2e392b0b5c80f6d7458ab8d3a0e940c48 /include/linux/mmzone.h | |
| parent | 48ee5f3696f62496481a8b6d852bcad9b3ebbe37 (diff) | |
| download | lwn-c33d6c06f60f710f0305ae792773e1c2560e1e51.tar.gz lwn-c33d6c06f60f710f0305ae792773e1c2560e1e51.zip | |
mm, page_alloc: avoid looking up the first zone in a zonelist twice
The allocator fast path looks up the first usable zone in a zonelist and
then get_page_from_freelist does the same job in the zonelist iterator.
This patch preserves the necessary information.
4.6.0-rc2 4.6.0-rc2
fastmark-v1r20 initonce-v1r20
Min alloc-odr0-1 364.00 ( 0.00%) 359.00 ( 1.37%)
Min alloc-odr0-2 262.00 ( 0.00%) 260.00 ( 0.76%)
Min alloc-odr0-4 214.00 ( 0.00%) 214.00 ( 0.00%)
Min alloc-odr0-8 186.00 ( 0.00%) 186.00 ( 0.00%)
Min alloc-odr0-16 173.00 ( 0.00%) 173.00 ( 0.00%)
Min alloc-odr0-32 165.00 ( 0.00%) 165.00 ( 0.00%)
Min alloc-odr0-64 161.00 ( 0.00%) 162.00 ( -0.62%)
Min alloc-odr0-128 159.00 ( 0.00%) 161.00 ( -1.26%)
Min alloc-odr0-256 168.00 ( 0.00%) 170.00 ( -1.19%)
Min alloc-odr0-512 180.00 ( 0.00%) 181.00 ( -0.56%)
Min alloc-odr0-1024 190.00 ( 0.00%) 190.00 ( 0.00%)
Min alloc-odr0-2048 196.00 ( 0.00%) 196.00 ( 0.00%)
Min alloc-odr0-4096 202.00 ( 0.00%) 202.00 ( 0.00%)
Min alloc-odr0-8192 206.00 ( 0.00%) 205.00 ( 0.49%)
Min alloc-odr0-16384 206.00 ( 0.00%) 205.00 ( 0.49%)
The benefit is negligible and the results are within the noise but each
cycle counts.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 327f0fa1e1ce..4b28d2f8125e 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -959,13 +959,10 @@ static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z, */ static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist, enum zone_type highest_zoneidx, - nodemask_t *nodes, - struct zone **zone) + nodemask_t *nodes) { - struct zoneref *z = next_zones_zonelist(zonelist->_zonerefs, + return next_zones_zonelist(zonelist->_zonerefs, highest_zoneidx, nodes); - *zone = zonelist_zone(z); - return z; } /** @@ -980,10 +977,17 @@ static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist, * within a given nodemask */ #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ - for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone); \ + for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \ zone; \ z = next_zones_zonelist(++z, highidx, nodemask), \ - zone = zonelist_zone(z)) \ + zone = zonelist_zone(z)) + +#define for_next_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ + for (zone = z->zone; \ + zone; \ + z = next_zones_zonelist(++z, highidx, nodemask), \ + zone = zonelist_zone(z)) + /** * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index |