From: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
Subject: Re: [PATCH 2/6] add res_counter_uncharge_until()
Date: Mon, 14 May 2012 10:10:39 +0900
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References: <4FACDED0.3020400@jp.fujitsu.com> <4FACE01A.4040405@jp.fujitsu.com> <20120511141945.c487e94c.akpm@linux-foundation.org>
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To: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: "linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org" <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>, "cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Han Ying <yinghan-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, "Aneesh Kumar K.V" <aneesh.kumar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>, Hiroyuki Kamezawa <kamezawa.hiroyuki-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Linux Kernel <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>

(2012/05/12 6:19), Andrew Morton wrote:

> On Fri, 11 May 2012 18:47:06 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org> wrote:
> 
>> From: Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>>
>> At killing res_counter which is a child of other counter,
>> we need to do
>> 	res_counter_uncharge(child, xxx)
>> 	res_counter_charge(parent, xxx)
>>
>> This is not atomic and wasting cpu. This patch adds
>> res_counter_uncharge_until(). This function's uncharge propagates
>> to ancestors until specified res_counter.
>>
>> 	res_counter_uncharge_until(child, parent, xxx)
>>
>> Now, ops is atomic and efficient.
>>
>> Changelog since v2
>>  - removed unnecessary lines.
>>  - Fixed 'From' , this patch comes from his series. Please signed-off-by if good.
>>
>> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
> 
> Frederic's Signed-off-by: is unavaliable?
> 

I didn't add his Signed-off because I modified his orignal patch a little...
I dropped res_counter_charge_until() because it's not used in this series,
I have no justification for adding it.
The idea of res_counter_uncharge_until() is from his patch.

Thanks,
-Kame