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authorMel Gorman <mgorman@techsingularity.net>2016-05-19 17:14:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-19 19:12:14 -0700
commitc33d6c06f60f710f0305ae792773e1c2560e1e51 (patch)
tree97fc4be2e392b0b5c80f6d7458ab8d3a0e940c48 /include
parent48ee5f3696f62496481a8b6d852bcad9b3ebbe37 (diff)
downloadlinux-c33d6c06f60f710f0305ae792773e1c2560e1e51.tar.bz2
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')
-rw-r--r--include/linux/mmzone.h18
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