From: Suleiman Souhlal <suleiman@google.com>
To: Glauber Costa <glommer@parallels.com>
Cc: Suleiman Souhlal <ssouhlal@freebsd.org>,
cgroups@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com,
penberg@kernel.org, yinghan@google.com, hughd@google.com,
gthelen@google.com, linux-mm@kvack.org, devel@openvz.org
Subject: Re: [PATCH 08/10] memcg: Add CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT.
Date: Wed, 29 Feb 2012 11:24:05 -0800 [thread overview]
Message-ID: <CABCjUKBFFKap9SfCWDO6ZsA5o+b0152sNhGhckpYG2-f0LaMUw@mail.gmail.com> (raw)
In-Reply-To: <4F4E5BC5.9010408@parallels.com>
On Wed, Feb 29, 2012 at 9:09 AM, Glauber Costa <glommer@parallels.com> wrote:
> On 02/28/2012 08:36 PM, Suleiman Souhlal wrote:
>>
>> On Tue, Feb 28, 2012 at 5:34 AM, Glauber Costa<glommer@parallels.com>
>> wrote:
>>>
>>> On 02/27/2012 07:58 PM, Suleiman Souhlal wrote:
>>>>
>>>>
>>>> This config option dictates whether or not kernel memory in the
>>>> root cgroup should be accounted.
>>>>
>>>> This may be useful in an environment where everything is supposed to be
>>>> in a cgroup and accounted for. Large amounts of kernel memory in the
>>>> root cgroup would indicate problems with memory isolation or accounting.
>>>
>>>
>>>
>>> I don't like accounting this stuff to the root memory cgroup. This causes
>>> overhead for everybody, including people who couldn't care less about
>>> memcg.
>>>
>>> If it were up to me, we would simply not account it, and end of story.
>>>
>>> However, if this is terribly important for you, I think you need to at
>>> least make it possible to enable it at runtime, and default it to
>>> disabled.
>>
>>
>> Yes, that is why I made it a config option. If the config option is
>> disabled, that memory does not get accounted at all.
>
>
> Doesn't work. In reality, most of the distributions enable those stuff if
> there is the possibility that someone will end up using. So everybody gets
> to pay the penalty.
>
>
>> Making it configurable at runtime is not ideal, because we would
>> prefer slab memory that was allocated before cgroups are created to
>> still be counted toward root.
>>
>
> Again: Why is that you really need it ? Accounting slab to the root cgroup
> feels quite weird to me
Because, for us, having large amounts of unaccounted memory is a
"bug", and we would like to know when it happens.
Also, we want to know how much memory is actually available in the
machine for jobs (sum of(accounted memory in containers) - unaccounted
kernel memory).
That said, I will drop this patch from the series for now.
-- Suleiman
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next prev parent reply other threads:[~2012-02-29 19:24 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-27 22:58 [PATCH 00/10] memcg: Kernel Memory Accounting Suleiman Souhlal
2012-02-27 22:58 ` [PATCH 01/10] memcg: Kernel memory accounting infrastructure Suleiman Souhlal
2012-02-28 13:10 ` Glauber Costa
2012-02-29 0:37 ` Suleiman Souhlal
2012-02-28 13:11 ` Glauber Costa
2012-02-27 22:58 ` [PATCH 02/10] memcg: Uncharge all kmem when deleting a cgroup Suleiman Souhlal
2012-02-28 19:00 ` Glauber Costa
2012-02-29 0:24 ` Suleiman Souhlal
2012-02-29 16:51 ` Glauber Costa
2012-02-29 6:22 ` KAMEZAWA Hiroyuki
2012-02-29 19:00 ` Suleiman Souhlal
2012-02-27 22:58 ` [PATCH 03/10] memcg: Reclaim when more than one page needed Suleiman Souhlal
2012-02-29 6:18 ` KAMEZAWA Hiroyuki
2012-02-27 22:58 ` [PATCH 04/10] memcg: Introduce __GFP_NOACCOUNT Suleiman Souhlal
2012-02-29 6:00 ` KAMEZAWA Hiroyuki
2012-02-29 16:53 ` Glauber Costa
2012-02-29 19:09 ` Suleiman Souhlal
2012-03-01 0:10 ` KAMEZAWA Hiroyuki
2012-03-01 0:24 ` Glauber Costa
2012-03-01 6:05 ` KAMEZAWA Hiroyuki
2012-03-03 14:22 ` Glauber Costa
2012-03-03 16:38 ` Suleiman Souhlal
2012-03-03 23:24 ` Glauber Costa
2012-03-04 0:10 ` Suleiman Souhlal
2012-03-06 10:36 ` Glauber Costa
2012-03-06 16:13 ` Suleiman Souhlal
2012-03-06 18:31 ` Glauber Costa
2012-02-27 22:58 ` [PATCH 05/10] memcg: Slab accounting Suleiman Souhlal
2012-02-28 13:24 ` Glauber Costa
2012-02-28 23:31 ` Suleiman Souhlal
2012-02-29 17:00 ` Glauber Costa
2012-02-27 22:58 ` [PATCH 06/10] memcg: Track all the memcg children of a kmem_cache Suleiman Souhlal
2012-02-27 22:58 ` [PATCH 07/10] memcg: Stop res_counter underflows Suleiman Souhlal
2012-02-28 13:31 ` Glauber Costa
2012-02-28 23:07 ` Suleiman Souhlal
2012-02-29 17:05 ` Glauber Costa
2012-02-29 19:17 ` Suleiman Souhlal
2012-02-27 22:58 ` [PATCH 08/10] memcg: Add CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT Suleiman Souhlal
2012-02-28 13:34 ` Glauber Costa
2012-02-28 23:36 ` Suleiman Souhlal
2012-02-28 23:54 ` KAMEZAWA Hiroyuki
2012-02-29 17:09 ` Glauber Costa
2012-02-29 19:24 ` Suleiman Souhlal [this message]
2012-02-27 22:58 ` [PATCH 09/10] memcg: Per-memcg memory.kmem.slabinfo file Suleiman Souhlal
2012-02-27 22:58 ` [PATCH 10/10] memcg: Document kernel memory accounting Suleiman Souhlal
2012-02-27 23:05 ` Randy Dunlap
2012-02-28 8:49 ` [PATCH 00/10] memcg: Kernel Memory Accounting Pekka Enberg
2012-02-28 22:12 ` Suleiman Souhlal
2012-02-28 13:03 ` Glauber Costa
2012-02-28 22:47 ` Suleiman Souhlal
2012-02-29 16:47 ` Glauber Costa
2012-02-29 19:28 ` Suleiman Souhlal
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