Messages in this thread | | | Date | Mon, 25 Jun 2012 11:46:50 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH v3 3/4] memcg: optimize memcg_get_hierarchical_limit |
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On Mon 25-06-12 16:44:32, Wanpeng Li wrote: > From: Wanpeng Li <liwp@linux.vnet.ibm.com> > > Optimize memcg_get_hierarchical_limit to save cpu cycle.
How did you check that this actually saves some cycles? There are no (compiler) barriers here so it should reordered.
> Signed-off-by: Wanpeng Li <liwp.linux@gmail.com> > --- > mm/memcontrol.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 2e81328..4520b57 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3917,9 +3917,9 @@ static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, > > min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); > min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); > - cgroup = memcg->css.cgroup; > if (!memcg->use_hierarchy) > goto out; > + cgroup = memcg->css.cgroup; > > while (cgroup->parent) { > cgroup = cgroup->parent; > -- > 1.7.9.5 >
-- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic
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