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vmstat: Use this_cpu_inc_return for vm statistics

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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 <penberg@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christoph Lameter 2010-12-06 11:40:02 -06:00 committed by Tejun Heo
parent 275c8b9328
commit 908ee0f122
1 changed files with 2 additions and 6 deletions
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8
mm/vmstat.c
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@ -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 __percpu *p = pcp->vm_stat_diff + item;
s8 v, t; s8 v, t;
__this_cpu_inc(*p); v = __this_cpu_inc_return(*p);
v = __this_cpu_read(*p);
t = __this_cpu_read(pcp->stat_threshold); t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v > t)) { if (unlikely(v > t)) {
s8 overstep = t >> 1; 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 __percpu *p = pcp->vm_stat_diff + item;
s8 v, t; s8 v, t;
__this_cpu_dec(*p); v = __this_cpu_dec_return(*p);
v = __this_cpu_read(*p);
t = __this_cpu_read(pcp->stat_threshold); t = __this_cpu_read(pcp->stat_threshold);
if (unlikely(v < - t)) { if (unlikely(v < - t)) {
s8 overstep = t >> 1; s8 overstep = t >> 1;