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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp•fujitsu.com>
To: Glauber Costa <glommer@parallels•com>
Cc: netdev@vger•kernel.org, David Miller <davem@davemloft•net>,
	Andrew Morton <akpm@linux-foundation•org>
Subject: Re: [PATCH 1/3] [BUGFIX] memcg/tcp : fix to see use_hierarchy in tcp memcontrol cgroup
Date: Thu, 29 Mar 2012 18:16:39 +0900	[thread overview]
Message-ID: <4F742877.10402@jp.fujitsu.com> (raw)
In-Reply-To: <4F7427E4.2020307@parallels.com>

(2012/03/29 18:14), Glauber Costa wrote:

> On 03/29/2012 09:03 AM, KAMEZAWA Hiroyuki wrote:
>>
>> Now, tcp memory control cgroup ignores memcg's use_hierarchy value
>> and act as use_hierarchy=1 always. After this patch, tcp memcontrol will
>> work as memcg is designed.
>>
>> Note:
>>     I know there is a discussion to remove use_hierarchy but this is BUG, now.
>>
> 
> Kame,
> 
> Are you sure about that?
> 
> I just tried it myself, and it seems to work:
> 
> root@inf5072-11:~/glommer-temporary/a/b# cat memory.kmem.tcp.usage_in_bytes
> 724992
> root@inf5072-11:~/glommer-temporary/a/b# cat
> ../memory.kmem.tcp.usage_in_bytes
> 0
> 
> 
> Did you got this conclusion through testing or code inspection?
> 
> As a matter of fact, that's why I believe the current behavior is indeed
> correct:
> 
> the res_counter is initialized as:
> 
>         parent_cg = tcp_prot.proto_cgroup(parent);
>         if (parent_cg)
>                 res_parent = parent_cg->memory_allocated;
> 
>         res_counter_init(&tcp->tcp_memory_allocated, res_parent);
> 
> now, parent is drawn from parent_mem_cgroup(), that reads as follows:
> 
> struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
> {
>         if (!memcg->res.parent)
>                 return NULL;
>         return mem_cgroup_from_res_counter(memcg->res.parent, res);
> }
> 
> 
> so if we have use_hierarchy = 0, res.parent should be NULL (because that
> is the way we initialize it)
> 


Ah, sorry. you're right. please forget this patch.

To be honest, I wrote this after seeing WARN_ON in patch 2 and 3 and
misunderstood the code at writing patch 2 and 3.

Thanks,
-Kame

next prev parent reply	other threads:[~2012-03-29  9:18 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-29  7:01 [BUGFIX][PATCH 0/3] memcg: tcp memcontrol fixes KAMEZAWA Hiroyuki
2012-03-29  7:03 ` [PATCH 1/3] [BUGFIX] memcg/tcp : fix to see use_hierarchy in tcp memcontrol cgroup KAMEZAWA Hiroyuki
2012-03-29  9:14   ` Glauber Costa
2012-03-29  9:16     ` KAMEZAWA Hiroyuki [this message]
2012-03-29  7:07 ` [BUGFIX][PATCH 2/3] memcg/tcp: remove static_branch_slow_dec() at changing limit KAMEZAWA Hiroyuki
2012-03-29 10:58   ` Glauber Costa
2012-03-29 23:51     ` KAMEZAWA Hiroyuki
2012-03-30  6:18       ` Glauber Costa
2012-03-29  7:10 ` [BUGFIX][PATCH 3/3] memcg/tcp: ignore tcp usage before accounting started KAMEZAWA Hiroyuki
2012-03-29  9:21   ` Glauber Costa
2012-03-30  1:44     ` [PATCH] memcg/tcp: fix warning caused b res->usage go to negative KAMEZAWA Hiroyuki
2012-04-06 15:49       ` Glauber Costa
2012-04-10  2:37         ` KAMEZAWA Hiroyuki
2012-04-10  2:51           ` Glauber Costa
2012-04-10  3:01             ` Glauber Costa
2012-04-10  4:15               ` KAMEZAWA Hiroyuki
2012-04-11  2:22                 ` Glauber Costa
2012-04-10  3:21             ` KAMEZAWA Hiroyuki
2012-04-13 17:33           ` Glauber Costa
2012-04-18  8:02             ` KAMEZAWA Hiroyuki
2012-04-18 16:32               ` Glauber Costa
2012-04-02  3:41     ` [BUGFIX][PATCH 3/3] memcg/tcp: ignore tcp usage before accounting started David Miller
2012-04-03 22:31       ` Glauber Costa
2012-04-09  0:58         ` KAMEZAWA Hiroyuki
2012-04-09  1:44           ` Glauber Costa

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