vmstat: Use this_cpu_inc_return for vm statistics

this_cpu_inc_return() saves us a memory access there. Code size does not change. V1->V2: - Fixed the location of the __per_cpu pointer attributes - Sparse checked V2->V3: - Move fixes to __percpu attribute usage to earlier patch Reviewed-by: Pekka Enberg <[email protected]> Acked-by: H. Peter Anvin <[email protected]> Signed-off-by: Christoph Lameter <[email protected]> Signed-off-by: Tejun Heo <[email protected]>
CamonZ · Dec 17, 2010 · 908ee0f · 908ee0f
1 parent 275c8b9
commit 908ee0f
Showing 1 changed file with 2 additions and 6 deletions.
diff --git a/mm/vmstat.c b/mm/vmstat.c
@@ -227,9 +227,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 	s8 __percpu *p = pcp->vm_stat_diff + item;
 	s8 v, t;
 
-	__this_cpu_inc(*p);
-
-	v = __this_cpu_read(*p);
+	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
 		s8 overstep = t >> 1;
@@ -251,9 +249,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 	s8 __percpu *p = pcp->vm_stat_diff + item;
 	s8 v, t;
 
-	__this_cpu_dec(*p);
-
-	v = __this_cpu_read(*p);
+	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
 		s8 overstep = t >> 1;