[RFC] [PATCH 7/9] memcg: charge likely success

KAMEZAWA Hiroyuki
2008-09-11T11:15:40Z

In fast path, res_counter_charge() will success.
This annotation 'unlikely' works very well to make footprint shorter.
(And you can see the benefit of this by some benchmarks.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Index: mmtom-2.6.27-rc5+/mm/memcontrol.c
===================================================================
--- mmtom-2.6.27-rc5+.orig/mm/memcontrol.c
+++ mmtom-2.6.27-rc5+/mm/memcontrol.c
@@ -683,7 +683,7 @@ static int mem_cgroup_charge_common(stru
css_get(&memcg->css);
}

- while (res_counter_charge(&mem->res, PAGE_SIZE)) {
+ while (unlikely(res_counter_charge(&mem->res, PAGE_SIZE))) {
if (!(gfp_mask & __GFP_WAIT))
goto out;