From: Glauber Costa <glommer@parallels.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com,
Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Greg Thelen <gthelen@google.com>,
Suleiman Souhlal <suleiman@google.com>,
Michal Hocko <mhocko@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
devel@openvz.org, David Rientjes <rientjes@google.com>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH v3 16/28] memcg: kmem controller charge/uncharge infrastructure
Date: Wed, 30 May 2012 17:55:38 +0400 [thread overview]
Message-ID: <4FC626DA.3030408@parallels.com> (raw)
In-Reply-To: <20120530135319.GG25094@somewhere.redhat.com>
On 05/30/2012 05:53 PM, Frederic Weisbecker wrote:
> On Wed, May 30, 2012 at 05:37:57PM +0400, Glauber Costa wrote:
>> On 05/30/2012 05:37 PM, Frederic Weisbecker wrote:
>>> Right. __mem_cgroup_get_kmem_cache() fetches the memcg of the owner
>>> and calls memcg_create_cache_enqueue() which does css_tryget(&memcg->css).
>>> After this tryget I think you're fine. And in-between you're safe against
>>> css_set removal due to rcu_read_lock().
>>>
>>> I'm less clear with __mem_cgroup_new_kmem_page() though...
>>
>> That one does not get memcg->css but it does call mem_cgroup_get(),
>> that does prevent against the memcg structure being freed, which I
>> believe to be good enough.
>
> What if the owner calls cgroup_exit() between mem_cgroup_from_task()
> and mem_cgroup_get()? The css_set which contains the memcg gets freed.
> Also the reference on the memcg doesn't even prevent the css_set to
> be removed, does it?
It doesn't, but we don't really care. The css can go away, if the memcg
structure stays. The caches will outlive the memcg anyway, since it is
possible that you delete it, with some caches still holding objects that
are not freed (they will be marked as dead).
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next prev parent reply other threads:[~2012-05-30 13:58 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-25 13:03 [PATCH v3 00/28] kmem limitation for memcg Glauber Costa
2012-05-25 13:03 ` [PATCH v3 01/28] slab: move FULL state transition to an initcall Glauber Costa
2012-05-25 13:03 ` [PATCH v3 02/28] memcg: Always free struct memcg through schedule_work() Glauber Costa
2012-05-25 13:03 ` [PATCH v3 03/28] slab: rename gfpflags to allocflags Glauber Costa
2012-05-25 13:03 ` [PATCH v3 04/28] memcg: Make it possible to use the stock for more than one page Glauber Costa
2012-05-25 13:03 ` [PATCH v3 05/28] memcg: Reclaim when more than one page needed Glauber Costa
2012-05-29 14:19 ` Christoph Lameter
2012-05-29 14:20 ` Christoph Lameter
2012-05-29 15:45 ` Glauber Costa
2012-05-25 13:03 ` [PATCH v3 06/28] slab: use obj_size field of struct kmem_cache when not debugging Glauber Costa
2012-05-25 13:03 ` [PATCH v3 07/28] memcg: change defines to an enum Glauber Costa
2012-05-25 13:03 ` [PATCH v3 08/28] res_counter: don't force return value checking in res_counter_charge_nofail Glauber Costa
2012-05-25 13:03 ` [PATCH v3 09/28] kmem slab accounting basic infrastructure Glauber Costa
2012-05-25 13:03 ` [PATCH v3 10/28] slab/slub: struct memcg_params Glauber Costa
2012-05-25 13:03 ` [PATCH v3 11/28] slub: consider a memcg parameter in kmem_create_cache Glauber Costa
2012-05-25 13:03 ` [PATCH v3 12/28] slab: pass memcg parameter to kmem_cache_create Glauber Costa
2012-05-29 14:27 ` Christoph Lameter
2012-05-29 15:50 ` Glauber Costa
2012-05-29 16:33 ` Christoph Lameter
2012-05-29 16:36 ` Glauber Costa
2012-05-29 16:52 ` Christoph Lameter
2012-05-29 16:59 ` Glauber Costa
2012-05-30 11:01 ` Frederic Weisbecker
2012-05-25 13:03 ` [PATCH v3 13/28] slub: create duplicate cache Glauber Costa
2012-05-29 14:36 ` Christoph Lameter
2012-05-29 15:56 ` Glauber Costa
2012-05-29 16:05 ` Christoph Lameter
2012-05-29 17:05 ` Glauber Costa
2012-05-29 17:25 ` Christoph Lameter
2012-05-29 17:27 ` Glauber Costa
2012-05-29 19:26 ` Christoph Lameter
2012-05-29 19:40 ` Glauber Costa
2012-05-29 19:55 ` Christoph Lameter
2012-05-29 20:08 ` Glauber Costa
2012-05-29 20:21 ` Christoph Lameter
2012-05-29 20:25 ` Glauber Costa
2012-05-30 1:29 ` Tejun Heo
2012-05-30 7:28 ` [Devel] " James Bottomley
2012-05-30 7:54 ` Glauber Costa
2012-05-30 8:02 ` Tejun Heo
2012-05-30 15:37 ` Christoph Lameter
2012-05-29 20:57 ` Suleiman Souhlal
2012-05-25 13:03 ` [PATCH v3 14/28] slab: " Glauber Costa
2012-05-25 13:03 ` [PATCH v3 15/28] slub: always get the cache from its page in kfree Glauber Costa
2012-05-29 14:42 ` Christoph Lameter
2012-05-29 15:59 ` Glauber Costa
2012-05-25 13:03 ` [PATCH v3 16/28] memcg: kmem controller charge/uncharge infrastructure Glauber Costa
2012-05-29 14:47 ` Christoph Lameter
2012-05-29 16:00 ` Glauber Costa
2012-05-30 12:17 ` Frederic Weisbecker
2012-05-30 12:26 ` Glauber Costa
2012-05-30 12:34 ` Frederic Weisbecker
2012-05-30 12:38 ` Glauber Costa
2012-05-30 13:11 ` Frederic Weisbecker
2012-05-30 13:09 ` Glauber Costa
2012-05-30 13:04 ` Frederic Weisbecker
2012-05-30 13:06 ` Glauber Costa
2012-05-30 13:37 ` Frederic Weisbecker
2012-05-30 13:37 ` Glauber Costa
2012-05-30 13:53 ` Frederic Weisbecker
2012-05-30 13:55 ` Glauber Costa [this message]
2012-05-30 15:33 ` Frederic Weisbecker
2012-05-30 16:16 ` Glauber Costa
2012-05-25 13:03 ` [PATCH v3 17/28] skip memcg kmem allocations in specified code regions Glauber Costa
2012-05-25 13:03 ` [PATCH v3 18/28] slub: charge allocation to a memcg Glauber Costa
2012-05-29 14:51 ` Christoph Lameter
2012-05-29 16:06 ` Glauber Costa
2012-05-25 13:03 ` [PATCH v3 19/28] slab: per-memcg accounting of slab caches Glauber Costa
2012-05-29 14:52 ` Christoph Lameter
2012-05-29 16:07 ` Glauber Costa
2012-05-29 16:13 ` Glauber Costa
2012-05-25 13:03 ` [PATCH v3 20/28] memcg: disable kmem code when not in use Glauber Costa
2012-05-25 13:03 ` [PATCH v3 21/28] memcg: destroy memcg caches Glauber Costa
2012-05-25 13:03 ` [PATCH v3 22/28] memcg/slub: shrink dead caches Glauber Costa
2012-05-25 13:03 ` [PATCH v3 23/28] slab: Track all the memcg children of a kmem_cache Glauber Costa
2012-05-25 13:03 ` [PATCH v3 24/28] memcg: Per-memcg memory.kmem.slabinfo file Glauber Costa
2012-05-25 13:03 ` [PATCH v3 25/28] slub: create slabinfo file for memcg Glauber Costa
2012-05-25 13:03 ` [PATCH v3 26/28] slub: track all children of a kmem cache Glauber Costa
2012-05-25 13:03 ` [PATCH v3 27/28] memcg: propagate kmem limiting information to children Glauber Costa
2012-05-25 13:03 ` [PATCH v3 28/28] Documentation: add documentation for slab tracker for memcg Glauber Costa
2012-05-25 13:34 ` [PATCH v3 00/28] kmem limitation " Michal Hocko
2012-05-25 14:34 ` Christoph Lameter
2012-05-28 8:32 ` Glauber Costa
2012-05-29 15:07 ` Christoph Lameter
2012-05-29 15:44 ` Glauber Costa
2012-05-29 16:01 ` Christoph Lameter
2012-06-07 10:26 ` Frederic Weisbecker
2012-06-07 10:53 ` Glauber Costa
2012-06-07 14:00 ` Frederic Weisbecker
2012-06-14 2:24 ` Kamezawa Hiroyuki
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