mm/vmstat: Avoid on each online CPU loops

Both iterations over online cpus can be replaced by the proper node
specific functions.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org
Cc: rt@linutronix.de
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20161129145113.fn3lw5aazjjvdrr3@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 0b63ffb5c407b554d4120f1531fecda2f444a3e7..5152cd1c490f8cff9d3fe129c3adb82b409cc44f 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1720,19 +1720,21 @@ static void __init start_shepherd_timer(void)
 
 static void __init init_cpu_node_state(void)
 {
-       int cpu;
+       int node;
 
-       for_each_online_cpu(cpu)
-               node_set_state(cpu_to_node(cpu), N_CPU);
+       for_each_online_node(node) {
+               if (cpumask_weight(cpumask_of_node(node)) > 0)
+                       node_set_state(node, N_CPU);
+       }
 }
 
 static void vmstat_cpu_dead(int node)
 {
-       int cpu;
+       const struct cpumask *node_cpus;
 
-       for_each_online_cpu(cpu)
-               if (cpu_to_node(cpu) == node)
-                       return;
+       node_cpus = cpumask_of_node(node);
+       if (cpumask_weight(node_cpus) > 0)
+               return;
 
        node_clear_state(node, N_CPU);
 }