From: Glauber Costa <glommer@parallels.com>
To: Tejun Heo <htejun@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
akpm@linux-foundation.org, mhocko@suse.cz,
kamezawa.hiroyu@jp.fujitsu.com, liwanp@linux.vnet.ibm.com,
lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] cgroup: Don't drop the cgroup_mutex in cgroup_rmdir
Date: Fri, 20 Jul 2012 19:07:08 -0300 [thread overview]
Message-ID: <5009D68C.4020104@parallels.com> (raw)
In-Reply-To: <20120720200542.GD21218@google.com>
On 07/20/2012 05:05 PM, Tejun Heo wrote:
> Hey, Peter.
>
> On Fri, Jul 20, 2012 at 05:45:40PM +0200, Peter Zijlstra wrote:
>>> So, Peter, why does cpuset mangle with cgroup_mutex? What guarantees
>>> does it need? Why can't it work on "changed" notification while
>>> caching the current css like blkcg does?
>>
>> I've no clue sorry.. /me goes stare at this stuff.. Looks like something
>> Paul Menage did when he created cgroups. I'll have to have a hard look
>> at all that to untangle this. Not something obvious to me.
>
> Yeah, it would be great if this can be untangled. I really don't see
> any other reasonable way out of this circular locking mess. If cpuset
> needs stable css association across certain period, the RTTD is
> caching the css by holding its ref and synchronize modifications to
> that cache, rather than synchronizing cgroup operations themselves.
>
> Thanks.
>
IIRC, cpuset can insert a task into an existing cgroup itself. Besides
that, it needs go have a stable vision of the cpumask used by all tasks
in the cgroup.
But this is what I remember from the top of my head, and I am still
officially on vacations....
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next prev parent reply other threads:[~2012-07-20 22:09 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120718212637.133475C0050@hpza9.eem.corp.google.com>
2012-07-19 11:39 ` + hugetlb-cgroup-simplify-pre_destroy-callback.patch added to -mm tree Michal Hocko
2012-07-19 12:21 ` Aneesh Kumar K.V
2012-07-19 12:38 ` Michal Hocko
2012-07-19 13:48 ` Aneesh Kumar K.V
2012-07-19 14:09 ` [PATCH] cgroup: Don't drop the cgroup_mutex in cgroup_rmdir Aneesh Kumar K.V
2012-07-19 16:50 ` Tejun Heo
2012-07-20 15:45 ` Peter Zijlstra
2012-07-20 20:05 ` Tejun Heo
2012-07-20 22:07 ` Glauber Costa [this message]
2012-07-27 6:15 ` Li Zefan
2012-07-30 18:25 ` Tejun Heo
2012-07-20 7:51 ` Michal Hocko
2012-07-20 19:49 ` Tejun Heo
2012-07-20 1:05 ` + hugetlb-cgroup-simplify-pre_destroy-callback.patch added to -mm tree Kamezawa Hiroyuki
2012-07-20 1:20 ` Kamezawa Hiroyuki
2012-07-20 8:01 ` Michal Hocko
2012-07-20 8:08 ` Kamezawa Hiroyuki
2012-07-20 8:06 ` Michal Hocko
2012-07-20 19:18 ` Aneesh Kumar K.V
2012-07-20 19:56 ` Tejun Heo
2012-07-21 2:14 ` Kamezawa Hiroyuki
2012-07-21 2:46 ` Tejun Heo
2012-07-21 4:05 ` Kamezawa Hiroyuki
2012-07-22 17:34 ` Tejun Heo
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