From: Glauber Costa <glommer@parallels.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
kamezawa.hiroyu@jp.fujitsu.com, devel@openvz.org,
linux-mm@kvack.org, Suleiman Souhlal <suleiman@google.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Mel Gorman <mgorman@suse.de>,
David Rientjes <rientjes@google.com>,
Michal Hocko <mhocko@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH v3 12/13] execute the whole memcg freeing in rcu callback
Date: Mon, 24 Sep 2012 12:48:01 +0400 [thread overview]
Message-ID: <50601E41.5000603@parallels.com> (raw)
In-Reply-To: <20120921172355.GD7264@google.com>
> And the above description too makes me scratch my head quite a bit. I
> can see what the patch is doing but can't understand the why.
>
> * Why was it punting the freeing to workqueue anyway? ISTR something
> about static_keys but my memory fails. What changed? Why don't we
> need it anymore?
>
> * As for locking context, the above description seems a bit misleading
> to me. Synchronization constructs involved there currently doesn't
> require softirq or irq safe context. If that needs to change,
> that's fine but that's a completely different reason than given
> above.
>
> Thanks.
>
I just suck at changelogs =(
The problem here is very much like the one we had with static branches.
In that case, we had the problem with the cgroup_lock() being held, in
which case the jump label lock could not be called.
In here, after the kmem patches are in, the destruction function could
be called directly from memcg_kmem_uncharge_page() when the last put is
done. But this can actually be called from the page allocator, with an
incompatible softirq context. So it is not that it could be called, they
are actually called in that context at this point.
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next prev parent reply other threads:[~2012-09-24 8:51 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-18 14:03 [PATCH v3 00/13] kmem controller for memcg Glauber Costa
2012-09-18 14:03 ` [PATCH v3 01/13] memcg: Make it possible to use the stock for more than one page Glauber Costa
2012-10-01 18:48 ` Johannes Weiner
2012-09-18 14:03 ` [PATCH v3 02/13] memcg: Reclaim when more than one page needed Glauber Costa
2012-10-01 19:00 ` Johannes Weiner
2012-09-18 14:04 ` [PATCH v3 03/13] memcg: change defines to an enum Glauber Costa
2012-10-01 19:06 ` Johannes Weiner
2012-10-02 9:10 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 04/13] kmem accounting basic infrastructure Glauber Costa
2012-09-21 16:34 ` Tejun Heo
2012-09-24 8:09 ` Glauber Costa
2012-09-26 14:03 ` Michal Hocko
2012-09-26 14:33 ` Glauber Costa
2012-09-26 16:01 ` Michal Hocko
2012-09-26 17:34 ` Glauber Costa
2012-09-26 16:36 ` Tejun Heo
2012-09-26 17:36 ` Glauber Costa
2012-09-26 17:44 ` Tejun Heo
2012-09-26 17:53 ` Glauber Costa
2012-09-26 18:01 ` Tejun Heo
2012-09-26 18:56 ` Glauber Costa
2012-09-26 19:34 ` Tejun Heo
2012-09-26 19:46 ` Glauber Costa
2012-09-26 19:56 ` Tejun Heo
2012-09-26 20:02 ` Glauber Costa
2012-09-26 20:16 ` Tejun Heo
2012-09-26 21:24 ` Glauber Costa
2012-09-26 22:10 ` Tejun Heo
2012-09-26 22:29 ` Glauber Costa
2012-09-26 22:42 ` Tejun Heo
2012-09-26 22:54 ` Glauber Costa
2012-09-26 23:08 ` Tejun Heo
2012-09-26 23:20 ` Glauber Costa
2012-09-26 23:33 ` Tejun Heo
2012-09-27 12:15 ` Michal Hocko
2012-09-27 12:20 ` Glauber Costa
2012-09-27 12:40 ` Michal Hocko
2012-09-27 12:40 ` Glauber Costa
2012-09-27 12:54 ` Michal Hocko
2012-09-27 14:28 ` Mel Gorman
2012-09-27 14:49 ` Tejun Heo
2012-09-27 14:57 ` Glauber Costa
2012-09-27 17:46 ` Tejun Heo
2012-09-27 17:56 ` Michal Hocko
2012-09-27 18:45 ` Glauber Costa
2012-09-30 7:57 ` Tejun Heo
2012-09-30 8:02 ` Tejun Heo
2012-09-30 8:56 ` James Bottomley
2012-09-30 10:37 ` Tejun Heo
2012-09-30 11:25 ` James Bottomley
2012-10-01 0:57 ` Tejun Heo
2012-10-01 8:43 ` Glauber Costa
2012-10-01 8:46 ` Glauber Costa
2012-10-03 22:59 ` Tejun Heo
2012-10-01 8:36 ` Glauber Costa
2012-09-27 12:08 ` Michal Hocko
2012-09-27 12:11 ` Glauber Costa
2012-09-27 14:33 ` Tejun Heo
2012-09-27 14:43 ` Mel Gorman
2012-09-27 14:58 ` Tejun Heo
2012-09-27 18:30 ` Glauber Costa
2012-09-30 8:23 ` Tejun Heo
2012-10-01 8:45 ` Glauber Costa
2012-10-03 22:54 ` Tejun Heo
2012-10-04 11:55 ` Glauber Costa
2012-10-06 2:19 ` Tejun Heo
2012-09-27 15:09 ` Michal Hocko
2012-09-30 8:47 ` Tejun Heo
2012-10-01 9:27 ` Michal Hocko
2012-10-03 22:43 ` Tejun Heo
2012-10-05 13:47 ` Michal Hocko
2012-09-26 22:11 ` Johannes Weiner
2012-09-26 22:45 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 05/13] Add a __GFP_KMEMCG flag Glauber Costa
2012-09-18 14:15 ` Rik van Riel
2012-09-18 15:06 ` Christoph Lameter
2012-09-19 7:39 ` Glauber Costa
2012-09-19 14:07 ` Christoph Lameter
2012-09-27 13:34 ` Mel Gorman
2012-09-27 13:41 ` Glauber Costa
2012-10-01 19:09 ` Johannes Weiner
2012-09-18 14:04 ` [PATCH v3 06/13] memcg: kmem controller infrastructure Glauber Costa
2012-09-20 16:05 ` JoonSoo Kim
2012-09-21 8:41 ` Glauber Costa
2012-09-21 9:14 ` JoonSoo Kim
2012-09-26 15:51 ` Michal Hocko
2012-09-27 11:31 ` Glauber Costa
2012-09-27 13:44 ` Michal Hocko
2012-09-28 11:34 ` Glauber Costa
2012-09-30 8:25 ` Tejun Heo
2012-10-01 8:28 ` Glauber Costa
2012-10-03 22:11 ` Tejun Heo
2012-10-01 9:44 ` Michal Hocko
2012-10-01 9:48 ` Michal Hocko
2012-10-01 10:09 ` Glauber Costa
2012-10-01 11:51 ` Michal Hocko
2012-10-01 11:51 ` Glauber Costa
2012-10-01 11:58 ` Michal Hocko
2012-10-01 12:04 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 07/13] mm: Allocate kernel pages to the right memcg Glauber Costa
2012-09-27 13:50 ` Mel Gorman
2012-09-28 9:43 ` Glauber Costa
2012-09-28 13:28 ` Mel Gorman
2012-09-27 13:52 ` Michal Hocko
2012-09-18 14:04 ` [PATCH v3 08/13] res_counter: return amount of charges after res_counter_uncharge Glauber Costa
2012-10-01 10:00 ` Michal Hocko
2012-10-01 10:01 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 09/13] memcg: kmem accounting lifecycle management Glauber Costa
2012-10-01 12:15 ` Michal Hocko
2012-10-01 12:29 ` Glauber Costa
2012-10-01 12:36 ` Michal Hocko
2012-10-01 12:43 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 10/13] memcg: use static branches when code not in use Glauber Costa
2012-10-01 12:25 ` Michal Hocko
2012-10-01 12:27 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 11/13] memcg: allow a memcg with kmem charges to be destructed Glauber Costa
2012-10-01 12:30 ` Michal Hocko
2012-09-18 14:04 ` [PATCH v3 12/13] execute the whole memcg freeing in rcu callback Glauber Costa
2012-09-21 17:23 ` Tejun Heo
2012-09-24 8:48 ` Glauber Costa [this message]
2012-10-01 13:27 ` Michal Hocko
2012-10-04 10:53 ` Glauber Costa
2012-10-04 14:20 ` Glauber Costa
2012-10-05 15:31 ` Johannes Weiner
2012-10-08 9:45 ` Glauber Costa
2012-09-18 14:04 ` [PATCH v3 13/13] protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs Glauber Costa
2012-10-01 13:17 ` Michal Hocko
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