From: Glauber Costa <glommer@parallels.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
Mel Gorman <mgorman@suse.de>, Tejun Heo <tj@kernel.org>,
Michal Hocko <mhocko@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
kamezawa.hiroyu@jp.fujitsu.com, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
devel@openvz.org, linux-kernel@vger.kernel.org,
Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH v5 06/14] memcg: kmem controller infrastructure
Date: Fri, 19 Oct 2012 14:00:23 +0400 [thread overview]
Message-ID: <508124B7.2050002@parallels.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1210190229450.26815@chino.kir.corp.google.com>
On 10/19/2012 01:31 PM, David Rientjes wrote:
> On Fri, 19 Oct 2012, Glauber Costa wrote:
>
>>>>> Do we actually need to test PF_KTHREAD when current->mm == NULL?
>>>>> Perhaps because of aio threads whcih temporarily adopt a userspace mm?
>>>>
>>>> I believe so. I remember I discussed this in the past with David
>>>> Rientjes and he advised me to test for both.
>>>>
>>>
>>> PF_KTHREAD can do use_mm() to assume an ->mm but hopefully they aren't
>>> allocating slab while doing so. Have you considered actually charging
>>> current->mm->owner for that memory, though, since the kthread will have
>>> freed the memory before unuse_mm() or otherwise have charged it on behalf
>>> of a user process, i.e. only exempting PF_KTHREAD?
>>>
>> I always charge current->mm->owner.
>>
>
> Yeah, I'm asking have you considered charging current->mm->owner for the
> memory when a kthread (current) assumes the mm of a user process via
> use_mm()? It may free the memory before calling unuse_mm(), but it's also
> allocating the memory on behalf of a user so this exemption might be
> dangerous if use_mm() becomes more popular. I don't think there's
> anything that prevents that charge, I'm just wondering if you considered
> doing it even for kthreads with an mm.
>
Well, I thought about it.
And I personally don't like it. I think all kthreads should be treated
the same. We have control over it, unlike any userspace application. We
never expect its memory consumption to explode.
Specially considering that those allocations are supposed to be
short-lived, we are only paying the res_counters count for no reason.
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next prev parent reply other threads:[~2012-10-19 10:00 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-16 10:16 [PATCH v5 00/14] kmem controller for memcg Glauber Costa
2012-10-16 10:16 ` [PATCH v5 01/14] memcg: Make it possible to use the stock for more than one page Glauber Costa
2012-10-17 22:11 ` Andrew Morton
2012-10-18 16:54 ` Glauber Costa
2012-10-16 10:16 ` [PATCH v5 02/14] memcg: Reclaim when more than one page needed Glauber Costa
2012-10-17 21:46 ` David Rientjes
2012-10-16 10:16 ` [PATCH v5 03/14] memcg: change defines to an enum Glauber Costa
2012-10-17 21:50 ` David Rientjes
2012-10-16 10:16 ` [PATCH v5 04/14] kmem accounting basic infrastructure Glauber Costa
2012-10-16 12:14 ` Michal Hocko
2012-10-17 22:08 ` David Rientjes
2012-10-18 17:01 ` Glauber Costa
2012-10-18 19:47 ` Tejun Heo
2012-10-18 19:37 ` Tejun Heo
2012-10-17 22:12 ` Andrew Morton
2012-10-18 17:03 ` Glauber Costa
2012-10-16 10:16 ` [PATCH v5 05/14] Add a __GFP_KMEMCG flag Glauber Costa
2012-10-16 12:15 ` Michal Hocko
2012-10-17 22:09 ` David Rientjes
2012-10-16 10:16 ` [PATCH v5 06/14] memcg: kmem controller infrastructure Glauber Costa
2012-10-17 6:40 ` Kamezawa Hiroyuki
2012-10-17 22:12 ` Andrew Morton
2012-10-18 9:16 ` Glauber Costa
2012-10-18 22:06 ` David Rientjes
2012-10-19 9:10 ` Glauber Costa
2012-10-19 9:31 ` David Rientjes
2012-10-19 10:00 ` Glauber Costa [this message]
2012-10-17 22:37 ` David Rientjes
2012-10-18 9:23 ` Glauber Costa
2012-10-18 21:59 ` David Rientjes
2012-10-19 10:08 ` Glauber Costa
2012-10-19 20:34 ` David Rientjes
2012-10-22 12:34 ` Glauber Costa
2012-10-22 12:51 ` Michal Hocko
2012-10-22 12:52 ` Glauber Costa
2012-10-16 10:16 ` [PATCH v5 07/14] mm: Allocate kernel pages to the right memcg Glauber Costa
2012-10-16 15:31 ` Christoph Lameter
2012-10-16 18:55 ` Glauber Costa
2012-10-17 22:12 ` Andrew Morton
2012-10-18 9:24 ` Glauber Costa
2012-10-18 20:44 ` Andrew Morton
2012-10-18 11:53 ` Glauber Costa
2012-10-17 22:43 ` David Rientjes
2012-10-16 10:16 ` [PATCH v5 08/14] res_counter: return amount of charges after res_counter_uncharge Glauber Costa
2012-10-17 23:23 ` David Rientjes
2012-10-16 10:16 ` [PATCH v5 09/14] memcg: kmem accounting lifecycle management Glauber Costa
2012-10-17 23:28 ` David Rientjes
2012-10-18 6:14 ` Michal Hocko
2012-10-18 9:42 ` Glauber Costa
2012-10-16 10:16 ` [PATCH v5 10/14] memcg: use static branches when code not in use Glauber Costa
2012-10-16 10:16 ` [PATCH v5 11/14] memcg: allow a memcg with kmem charges to be destructed Glauber Costa
2012-10-17 22:12 ` Andrew Morton
2012-10-18 9:33 ` Glauber Costa
2012-10-16 10:16 ` [PATCH v5 12/14] execute the whole memcg freeing in free_worker Glauber Costa
2012-10-17 6:56 ` Kamezawa Hiroyuki
2012-10-16 10:16 ` [PATCH v5 13/14] protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs Glauber Costa
2012-10-17 22:12 ` Andrew Morton
2012-10-18 9:37 ` Glauber Costa
2012-10-16 10:16 ` [PATCH v5 14/14] Add documentation about the kmem controller Glauber Costa
2012-10-16 12:23 ` Michal Hocko
2012-10-16 18:25 ` Christoph Lameter
2012-10-16 18:55 ` Aristeu Rozanski
2012-10-16 19:02 ` Glauber Costa
2012-10-16 19:30 ` Christoph Lameter
2012-10-17 22:12 ` Andrew Morton
2012-10-18 9:38 ` Glauber Costa
2012-10-17 22:11 ` [PATCH v5 00/14] kmem controller for memcg Andrew Morton
2012-10-18 16:51 ` Glauber Costa
2012-10-18 19:21 ` Andrew Morton
2012-10-19 9:55 ` Glauber Costa
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