From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kamezawa Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
Subject: Re: [PATCH v3 3/4] memcg: optimize memcg_get_hierarchical_limit
Date: Mon, 25 Jun 2012 18:52:25 +0900
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To: Wanpeng Li <liwp.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Balbir Singh <bsingharora-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Eric Dumazet <eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>, Arun Sharma <asharma-b10kYP2dOMg@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

(2012/06/25 17:44), Wanpeng Li wrote:
> From: Wanpeng Li <liwp-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> 
> Optimize memcg_get_hierarchical_limit to save cpu cycle.
> 
> Signed-off-by: Wanpeng Li <liwp.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

I can't understand the benefit of this patch to the real world...

So, if you wrote the patch description as "clean up" rather than optimize,
ok, I'll agree.

Thanks,
-Kame

> ---
>   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;
>