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| author | Mel Gorman <mgorman@suse.de> | 2014-08-06 16:07:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-06 18:01:20 -0700 |
| commit | 0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd (patch) | |
| tree | 7b9d8f7625e45c28ad626c7b5419e8e33c59788e /include/linux/mmzone.h | |
| parent | 3484b2de9499df23c4604a513b36f96326ae81ad (diff) | |
| download | linux-0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd.tar.gz linux-0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd.tar.bz2 linux-0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd.zip | |
mm: move zone->pages_scanned into a vmstat counter
zone->pages_scanned is a write-intensive cache line during page reclaim
and it's also updated during page free. Move the counter into vmstat to
take advantage of the per-cpu updates and do not update it in the free
paths unless necessary.
On a small UMA machine running tiobench the difference is marginal. On
a 4-node machine the overhead is more noticable. Note that automatic
NUMA balancing was disabled for this test as otherwise the system CPU
overhead is unpredictable.
3.16.0-rc3 3.16.0-rc3 3.16.0-rc3
vanillarearrange-v5 vmstat-v5
User 746.94 759.78 774.56
System 65336.22 58350.98 32847.27
Elapsed 27553.52 27282.02 27415.04
Note that the overhead reduction will vary depending on where exactly
pages are allocated and freed.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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 | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ed0876bb902c..0bd77f730b38 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -143,6 +143,7 @@ enum zone_stat_item { NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */ NR_DIRTIED, /* page dirtyings since bootup */ NR_WRITTEN, /* page writings since bootup */ + NR_PAGES_SCANNED, /* pages scanned since last reclaim */ #ifdef CONFIG_NUMA NUMA_HIT, /* allocated in intended node */ NUMA_MISS, /* allocated in non intended node */ @@ -480,7 +481,6 @@ struct zone { /* Fields commonly accessed by the page reclaim scanner */ spinlock_t lru_lock; - unsigned long pages_scanned; /* since last reclaim */ struct lruvec lruvec; /* Evictions & activations on the inactive file list */ |