mm: vmscan: only update per-cpu thresholds for online CPU

When kswapd is awake reclaiming, the per-cpu stat thresholds are lowered
to get more accurate counts to avoid breaching watermarks.  This
threshold update iterates over all possible CPUs which is unnecessary.
Only online CPUs need to be updated.  If a new CPU is onlined,
refresh_zone_stat_thresholds() will set the thresholds correctly.

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>
This commit is contained in:
Mel Gorman 2014-08-06 16:07:18 -07:00 committed by Linus Torvalds
parent 0d5d823ab4
commit bb0b6dffa2

View File

@ -200,7 +200,7 @@ void set_pgdat_percpu_threshold(pg_data_t *pgdat,
continue;
threshold = (*calculate_pressure)(zone);
for_each_possible_cpu(cpu)
for_each_online_cpu(cpu)
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= threshold;
}