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From: Glauber Costa <glommer@parallels.com>
To: Suleiman Souhlal <suleiman@google.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 02/10] memcg: Uncharge all kmem when deleting a cgroup.
Date: Wed, 29 Feb 2012 13:51:25 -0300	[thread overview]
Message-ID: <4F4E578D.7080202@parallels.com> (raw)
In-Reply-To: <CABCjUKDYUwR9FsjFW_Ea30zbvFx80-ObuN92_cNcUfGjPqWJiQ@mail.gmail.com>

On 02/28/2012 09:24 PM, Suleiman Souhlal wrote:
> On Tue, Feb 28, 2012 at 11:00 AM, Glauber Costa<glommer@parallels.com>  wrote:
>> On 02/27/2012 07:58 PM, Suleiman Souhlal wrote:
>>>
>>> A later patch will also use this to move the accounting to the root
>>> cgroup.
>>>
>>
>> Suleiman,
>>
>> Did you do any measurements to figure out how long does it take, average,
>> for dangling caches to go away ? Under memory pressure, let's say
>
> Unfortunately, I don't have any such measurements, other than a very artificial:
>
> # mkdir /dev/cgroup/memory/c
> # echo 1073741824>  /dev/cgroup/memory/c/memory.limit_in_bytes
> # sync&&  echo 3>  /proc/sys/vm/drop_caches
> # echo $$>  /dev/cgroup/memory/c/tasks
> # find />  /dev/null
> # grep '(c)' /proc/slabinfo | wc -l
> 42
> # echo $$>  /dev/cgroup/memory/tasks
> # rmdir /dev/cgroup/memory/c
> # grep '(c)dead' /proc/slabinfo | wc -l
> 42
> # sleep 60&&  sync&&  for i in `seq 1 1000`; do echo 3>
> /proc/sys/vm/drop_caches ; done
> # grep '(c)dead' /proc/slabinfo | wc -l
> 6
> # sleep 60&&  grep '(c)dead' /proc/slabinfo | wc -l
> 5
> # sleep 60&&  grep '(c)dead' /proc/slabinfo | wc -l
> 5
>
> (Note that this is without any per-memcg shrinking patch applied. With
> shrinking, things will be a bit better, because deleting the cgroup
> will force the dentries to get shrunk.)
>
> Some of these dead caches may take a long time to go away, but we
> haven't found them to be a problem for us, so far.
>

Ok. When we start doing shrinking, however, I'd like to see a shrink 
step being done before we destroy the memcg. This way we can at least 
reduce the number of pages lying around.

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  reply	other threads:[~2012-02-29 16:52 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 [this message]
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
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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