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>

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>
Mel Gorman · Linus Torvalds · Eric Lee · Eric Lee · Eric Lee · Eric Lee
1 parent 0d5d823ab4
Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff
mm/vmstat.c
@@ -200,7 +200,7 @@
 			continue;
  
 		threshold = (*calculate_pressure)(zone);
-		for_each_possible_cpu(cpu)
+		for_each_online_cpu(cpu)
 			per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 							= threshold;
 	}
...	...	@@ -200,7 +200,7 @@
200	200	continue;
201	201
202	202	threshold = (*calculate_pressure)(zone);
203		- for_each_possible_cpu(cpu)
	203	+ for_each_online_cpu(cpu)
204	204	per_cpu_ptr(zone->pageset, cpu)->stat_threshold
205	205	= threshold;
206	206	}