From: Michal Hocko <mhocko@suse.cz>
To: Glauber Costa <glommer@parallels.com>
Cc: Tejun Heo <tj@kernel.org>,
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>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH v3 04/13] kmem accounting basic infrastructure
Date: Thu, 27 Sep 2012 14:08:06 +0200 [thread overview]
Message-ID: <20120927120806.GA29104@dhcp22.suse.cz> (raw)
In-Reply-To: <50637298.2090904@parallels.com>
On Thu 27-09-12 01:24:40, Glauber Costa wrote:
[...]
> About use cases, I've already responded: my containers use case is kmem
> limited. There are people like Michal that specifically asked for
> user-only semantics to be preserved.
Yes, because we have many users (basically almost all) who care only
about the user memory because that's what occupies the vast majority of
the memory. They usually want to isolate workload which would disrupt
the global memory otherwise (e.g. backup process vs. database). You
really do not want to pay an additional overhead for kmem accounting
here.
> So your question for global vs local switch (that again, doesn't
> exist; only a local *limit* exists) should really be posed in the
> following way: "Can two different use cases with different needs be
> hosted in the same box?"
I think this is a good and a relevant question. I think this boils down
to whether you want to have trusted and untrusted workloads at the same
machine.
Trusted loads usually only need user memory accounting because kmem
consumption should be really negligible (unless kernel is doing
something really stupid and no kmem limit will help here).
On the other hand, untrusted workloads can do nasty things that
administrator has hard time to mitigate and setting a kmem limit can
help significantly.
IMHO such a different loads exist on a single machine quite often (Web
server and a back up process as the most simplistic one). The per
hierarchy accounting, therefore, sounds like a good idea without too
much added complexity (actually the only added complexity is in the
proper kmem.limit_in_bytes handling which is a single place).
So I would rather go with per-hierarchy thing.
> > Michal, Johannes, Kamezawa, what are your thoughts?
> >
> waiting! =)
Well, you guys generated a lot of discussion that one has to read
through, didn't you :P
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2012-09-27 12:08 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 [this message]
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
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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