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 <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>
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 3ad909d..f9a7bc8 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -227,9 +227,7 @@
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 @@
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;