Messages in this thread Patch in this message | | | Date | Mon, 06 Dec 2010 11:40:02 -0600 | From | Christoph Lameter <> | Subject | [cpuops inc_return V1 4/9] 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> 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 2010-11-29 10:36:16.000000000 -0600 +++ linux-2.6/mm/vmstat.c 2010-11-29 10:38:50.000000000 -0600 @@ -227,9 +227,7 @@ void __inc_zone_state(struct zone *zone, 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, 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;
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