Commit bb0b6dff authored Aug 06, 2014 by Mel Gorman Committed by Linus Torvalds Aug 06, 2014

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>

parent 0d5d823a

mm/vmstat.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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