From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp•fujitsu.com>
To: Glauber Costa <glommer@parallels•com>
Cc: David Miller <davem@davemloft•net>,
netdev@vger•kernel.org, akpm@linux-foundation•org
Subject: Re: [BUGFIX][PATCH 3/3] memcg/tcp: ignore tcp usage before accounting started
Date: Mon, 09 Apr 2012 09:58:43 +0900 [thread overview]
Message-ID: <4F823443.9070908@jp.fujitsu.com> (raw)
In-Reply-To: <4F7B7A54.9000501@parallels.com>
(2012/04/04 7:31), Glauber Costa wrote:
> On 04/02/2012 07:41 AM, David Miller wrote:
>> From: Glauber Costa<glommer@parallels•com>
>> Date: Thu, 29 Mar 2012 11:21:07 +0200
>>
>>> On 03/29/2012 09:10 AM, KAMEZAWA Hiroyuki wrote:
>>>> tcp memcontrol starts accouting after res->limit is set. So, if a sockets
>>>> starts before setting res->limit, there are already used resource.
>>>> After setting res->limit, the resource (already used) will be uncharged and
>>>> make res_counter below 0 because they are not charged. This causes warning.
>>>>
>>>> This patch fixes that by adding res_counter_uncharge_nowarn().
>>>> (*) We cannot avoid this while we have 'account start' switch.
>>>>
>>>> Signed-off-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp•fujitsu.com>
>>>
>>> Fine by me.
>>>
>>> Acked-by: Glauber Costa<glommer@parallels•com>
>>
>> I'm not applying patches that simply ignore accounting counter
>> underflows.
>>
>> You must either:
>>
>> 1) Integrate the socket's existing usage when the limit is set.
>>
>> 2) Avoid accounting completely for a socket that started before
>> the limit was set.
>>
>> No half-way solutions, please. Otherwise it is impossible to design
>> validations of the resource usage for a particular socket or group of
>> sockets, because they can always be potentially "wrong" and over the
>> limit. That's a design for a buggy system.
>>
>>
> Kame,
>
> I agree with Dave FWIW.
>
> We should be able to do this by dropping the reference count when the
> cgroup is finally destroyed, instead of from the remove callback. At
> that point, no more pending sockets should be attached to it.
>
> Prior to increasing the static key, they are all assigned to the global
> cgroup, so we shouldn't care about them.
>
Could you do the fix ?
Thanks,
-Kame
next prev parent reply other threads:[~2012-04-09 1:00 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
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 [this message]
2012-04-09 1:44 ` Glauber Costa
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