[thiscpuops upgrade 06/10] vmstat: Use this_cpu_inc_return for vm statistics

[Christoph Lameter <cl@linux.com>]

[-- Attachment #1: this_cpu_add_vmstat --]
[-- Type: text/plain, Size: 1041 bytes --]

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;