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Subject[thiscpuops upgrade 06/10] vmstat: Use this_cpu_inc_return for vm statistics
this_cpu_inc_return() saves us a memory access there. Code
size does not change.

Signed-off-by: Christoph Lameter <cl@linux.com>

---
mm/vmstat.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
Index: linux-2.6/mm/vmstat.c
===================================================================
--- linux-2.6.orig/mm/vmstat.c 2010-11-23 16:35:19.000000000 -0600
+++ linux-2.6/mm/vmstat.c 2010-11-23 16:45:24.000000000 -0600
@@ -227,9 +227,7 @@ void __inc_zone_state(struct zone *zone,
s8 * __percpu p = pcp->vm_stat_diff + item;
int 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)) {
int overstep = t / 2;
@@ -251,9 +249,7 @@ void __dec_zone_state(struct zone *zone,
s8 * __percpu p = pcp->vm_stat_diff + item;
int 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)) {
int overstep = t / 2;


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