diff options
| 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 /mm/vmstat.c | |
| parent | 3484b2de9499df23c4604a513b36f96326ae81ad (diff) | |
| download | lwn-0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd.tar.gz lwn-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 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index 8267f77d1875..e574e883fa70 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -763,6 +763,7 @@ const char * const vmstat_text[] = { "nr_shmem", "nr_dirtied", "nr_written", + "nr_pages_scanned", #ifdef CONFIG_NUMA "numa_hit", @@ -1067,7 +1068,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, min_wmark_pages(zone), low_wmark_pages(zone), high_wmark_pages(zone), - zone->pages_scanned, + zone_page_state(zone, NR_PAGES_SCANNED), zone->spanned_pages, zone->present_pages, zone->managed_pages); |