From: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
To: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: Lennart Poettering
<lennart-mdGvqq1h2p+GdvJs77BJ7Q@public.gmane.org>,
Neil Horman <nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org>,
"Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Kay Sievers <kay.sievers-tD+1rO4QERM@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>,
Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>,
Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
"Aneesh Kumar K.V"
<aneesh.kumar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
Arnaldo Carvalho de Melo
<acme-f8uhVLnGfZaxAyOMLChx1axOck334EZe@public.gmane.org>,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Paul Turner <pjt-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC] cgroup TODOs
Date: Fri, 14 Sep 2012 13:22:20 +0200 [thread overview]
Message-ID: <1347621740.7172.27.camel@twins> (raw)
In-Reply-To: <5052F4FF.6070508-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
On Fri, 2012-09-14 at 17:12 +0800, Li Zefan wrote:
> > I think this is a pressing problem, yes, but not the only problem with
> > cgroup lock. Even if we restrict its usage to cgroup core, we still can
> > call cgroup functions, which will lock. And then we gain nothing.
> >
>
> Agreed. The biggest issue in cpuset is if hotplug makes a cpuset's cpulist
> empty the tasks in it will be moved to an ancestor cgroup, which requires
> holding cgroup lock. We have to either change cpuset's behavior or eliminate
> the global lock.
PJ (the original cpuset author) has always been very conservative in
changing cpuset semantics/behaviour. Its being used at the big HPC labs
and those people simply don't like change.
It also ties in with us having to preserve ABI, Linus says you can only
do so if nobody notices -- if a tree falls in a forest and there's
nobody to hear it, it really didn't fall at all.
Which I guess means we're going to have to split locks :-)
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>, Tejun Heo <tj@kernel.org>,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, Michal Hocko <mhocko@suse.cz>,
Paul Turner <pjt@google.com>,
Johannes Weiner <hannes@cmpxchg.org>, Thomas Graf <tgraf@suug.ch>,
"Serge E. Hallyn" <serue@us.ibm.com>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Neil Horman <nhorman@tuxdriver.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
"Daniel P. Berrange" <berrange@redhat.com>,
Lennart Poettering <lennart@poettering.net>,
Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: [RFC] cgroup TODOs
Date: Fri, 14 Sep 2012 13:22:20 +0200 [thread overview]
Message-ID: <1347621740.7172.27.camel@twins> (raw)
In-Reply-To: <5052F4FF.6070508@huawei.com>
On Fri, 2012-09-14 at 17:12 +0800, Li Zefan wrote:
> > I think this is a pressing problem, yes, but not the only problem with
> > cgroup lock. Even if we restrict its usage to cgroup core, we still can
> > call cgroup functions, which will lock. And then we gain nothing.
> >
>
> Agreed. The biggest issue in cpuset is if hotplug makes a cpuset's cpulist
> empty the tasks in it will be moved to an ancestor cgroup, which requires
> holding cgroup lock. We have to either change cpuset's behavior or eliminate
> the global lock.
PJ (the original cpuset author) has always been very conservative in
changing cpuset semantics/behaviour. Its being used at the big HPC labs
and those people simply don't like change.
It also ties in with us having to preserve ABI, Linus says you can only
do so if nobody notices -- if a tree falls in a forest and there's
nobody to hear it, it really didn't fall at all.
Which I guess means we're going to have to split locks :-)
next prev parent reply other threads:[~2012-09-14 11:22 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-13 20:58 [RFC] cgroup TODOs Tejun Heo
2012-09-13 20:58 ` Tejun Heo
2012-09-14 11:15 ` Peter Zijlstra
2012-09-14 12:54 ` Daniel P. Berrange
2012-09-14 12:54 ` Daniel P. Berrange
[not found] ` <20120914125427.GW6819-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 8:55 ` Glauber Costa
2012-09-14 17:53 ` Tejun Heo
2012-09-14 17:53 ` Tejun Heo
2012-09-14 17:53 ` Tejun Heo
[not found] ` <20120913205827.GO7677-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-14 8:16 ` Glauber Costa
[not found] ` <5052E7DF.7040000-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-09-14 9:12 ` Li Zefan
2012-09-14 9:12 ` Li Zefan
[not found] ` <5052F4FF.6070508-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-09-14 11:22 ` Peter Zijlstra [this message]
2012-09-14 11:22 ` Peter Zijlstra
2012-09-14 17:59 ` Tejun Heo
2012-09-14 17:59 ` Tejun Heo
[not found] ` <20120914175944.GF17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-14 18:23 ` Peter Zijlstra
2012-09-14 18:23 ` Peter Zijlstra
2012-09-14 18:33 ` Tejun Heo
2012-09-14 18:33 ` Tejun Heo
2012-09-14 17:43 ` Tejun Heo
2012-09-14 17:43 ` Tejun Heo
[not found] ` <20120914174329.GD17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-17 8:50 ` Glauber Costa
2012-09-17 8:50 ` Glauber Costa
[not found] ` <5056E467.2090108-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-09-17 17:21 ` Tejun Heo
2012-09-17 17:21 ` Tejun Heo
[not found] ` <20120917172123.GB18677-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-18 8:16 ` Glauber Costa
2012-09-17 8:50 ` Glauber Costa
2012-09-14 9:04 ` Mike Galbraith
2012-09-14 9:04 ` Mike Galbraith
[not found] ` <1347613484.4340.132.camel-YqMYhexLQo31wTEvPJ5Q0F6hYfS7NtTn@public.gmane.org>
2012-09-14 17:17 ` Tejun Heo
2012-09-14 17:17 ` Tejun Heo
2012-09-14 9:04 ` Mike Galbraith
2012-09-14 9:10 ` Daniel P. Berrange
2012-09-14 9:10 ` Daniel P. Berrange
[not found] ` <20120914091032.GA6819-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 9:08 ` Glauber Costa
2012-09-14 13:58 ` Vivek Goyal
2012-09-14 13:58 ` Vivek Goyal
[not found] ` <20120914135830.GB6221-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 19:29 ` Tejun Heo
2012-09-14 19:29 ` Tejun Heo
[not found] ` <20120914192935.GO17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-14 21:51 ` Kay Sievers
2012-09-14 21:51 ` Kay Sievers
2012-09-14 11:15 ` Peter Zijlstra
2012-09-14 14:25 ` Vivek Goyal
2012-09-14 14:25 ` Vivek Goyal
[not found] ` <20120914142539.GC6221-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 14:53 ` Peter Zijlstra
2012-09-14 14:53 ` Peter Zijlstra
2012-09-14 15:14 ` Vivek Goyal
2012-09-14 15:14 ` Vivek Goyal
[not found] ` <20120914151447.GD6221-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 21:57 ` Tejun Heo
2012-09-14 21:57 ` Tejun Heo
[not found] ` <20120914215701.GW17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-17 15:27 ` Vivek Goyal
2012-09-17 15:27 ` Vivek Goyal
2012-09-18 18:08 ` Vivek Goyal
2012-09-18 18:08 ` Vivek Goyal
2012-09-17 8:55 ` Glauber Costa
2012-09-14 21:39 ` Tejun Heo
2012-09-14 21:39 ` Tejun Heo
[not found] ` <20120914213938.GV17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-17 15:05 ` Vivek Goyal
2012-09-17 15:05 ` Vivek Goyal
[not found] ` <20120917150518.GB5094-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-17 16:40 ` Tejun Heo
2012-09-17 16:40 ` Tejun Heo
2012-09-14 15:03 ` Michal Hocko
2012-09-14 15:03 ` Michal Hocko
[not found] ` <20120914150306.GQ28039-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-09-19 14:02 ` Michal Hocko
2012-09-19 14:02 ` Michal Hocko
2012-09-19 14:02 ` Michal Hocko
[not found] ` <20120919140203.GA5398-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-09-19 14:03 ` [PATCH 2.6.32] memcg: warn on deeper hierarchies with use_hierarchy==0 Michal Hocko
2012-09-19 14:03 ` Michal Hocko
[not found] ` <20120919140308.GB5398-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-09-19 19:38 ` David Rientjes
2012-09-19 19:38 ` David Rientjes
[not found] ` <alpine.DEB.2.00.1209191237020.749-X6Q0R45D7oAcqpCFd4KODRPsWskHk0ljAL8bYrjMMd8@public.gmane.org>
2012-09-20 13:24 ` Michal Hocko
2012-09-20 13:24 ` Michal Hocko
[not found] ` <20120920132400.GC23872-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-09-20 22:33 ` David Rientjes
2012-09-20 22:33 ` David Rientjes
[not found] ` <alpine.DEB.2.00.1209201531250.17455-X6Q0R45D7oAcqpCFd4KODRPsWskHk0ljAL8bYrjMMd8@public.gmane.org>
2012-09-21 7:16 ` Michal Hocko
2012-09-21 7:16 ` Michal Hocko
2012-09-21 7:16 ` Michal Hocko
2012-09-20 13:24 ` Michal Hocko
2012-09-19 14:03 ` [PATCH 3.0] " Michal Hocko
2012-09-19 14:03 ` Michal Hocko
2012-09-19 14:05 ` [PATCH 3.2+] " Michal Hocko
2012-09-19 14:05 ` Michal Hocko
2012-09-19 14:05 ` Michal Hocko
2012-09-14 15:03 ` [RFC] cgroup TODOs Michal Hocko
2012-09-14 18:07 ` Vivek Goyal
2012-09-14 18:07 ` Vivek Goyal
[not found] ` <20120914180754.GF6221-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 18:53 ` Tejun Heo
2012-09-14 18:53 ` Tejun Heo
[not found] ` <20120914185324.GI17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-14 19:28 ` Vivek Goyal
2012-09-14 19:28 ` Vivek Goyal
[not found] ` <20120914192840.GG6221-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-09-14 19:44 ` Tejun Heo
2012-09-14 19:44 ` Tejun Heo
[not found] ` <20120914194439.GP17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-14 19:49 ` Tejun Heo
2012-09-14 19:49 ` Tejun Heo
[not found] ` <20120914194950.GQ17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-14 20:39 ` Tejun Heo
2012-09-14 20:39 ` Tejun Heo
2012-09-14 20:39 ` Tejun Heo
[not found] ` <20120914203925.GR17747-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-17 8:40 ` Glauber Costa
2012-09-17 8:40 ` Glauber Costa
[not found] ` <5056E1FC.1090508-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-09-17 17:30 ` Tejun Heo
2012-09-17 17:30 ` Tejun Heo
2012-09-17 14:37 ` Vivek Goyal
2012-09-17 14:37 ` Vivek Goyal
2012-09-14 19:44 ` Tejun Heo
2012-09-14 18:36 ` Aristeu Rozanski
2012-09-14 18:36 ` Aristeu Rozanski
2012-09-14 18:36 ` Aristeu Rozanski
[not found] ` <20120914183641.GA2191-YqEmrenMroyQb786VAuzj9i2O/JbrIOy@public.gmane.org>
2012-09-14 18:54 ` Tejun Heo
2012-09-14 18:54 ` Tejun Heo
2012-09-15 2:20 ` Serge E. Hallyn
2012-09-15 2:20 ` Serge E. Hallyn
[not found] ` <20120915022037.GA6438-7LNsyQBKDXoIagZqoN9o3w@public.gmane.org>
2012-09-15 9:27 ` Controlling devices and device namespaces Eric W. Biederman
2012-09-15 9:27 ` Eric W. Biederman
[not found] ` <87wqzv7i08.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-09-15 22:05 ` Serge E. Hallyn
2012-09-15 22:05 ` Serge E. Hallyn
[not found] ` <20120915220520.GA11364-7LNsyQBKDXoIagZqoN9o3w@public.gmane.org>
2012-09-16 0:24 ` Eric W. Biederman
2012-09-16 0:24 ` Eric W. Biederman
[not found] ` <87y5kazuez.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-09-16 3:31 ` Serge E. Hallyn
2012-09-16 3:31 ` Serge E. Hallyn
2012-09-16 11:21 ` Alan Cox
2012-09-16 11:21 ` Alan Cox
[not found] ` <20120916122112.3f16178d-38n7/U1jhRXW96NNrWNlrekiAK3p4hvP@public.gmane.org>
2012-09-16 11:56 ` Eric W. Biederman
2012-09-16 11:56 ` Eric W. Biederman
[not found] ` <87sjaiuqp5.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-09-16 12:17 ` Eric W. Biederman
2012-09-16 12:17 ` Eric W. Biederman
[not found] ` <87d31mupp3.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-09-16 13:32 ` Serge Hallyn
2012-09-16 13:32 ` Serge Hallyn
[not found] ` <5055D4D1.3070407-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>
2012-09-16 14:23 ` Eric W. Biederman
2012-09-16 14:23 ` Eric W. Biederman
[not found] ` <87k3vuqc5l.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-09-16 16:13 ` Alan Cox
2012-09-16 16:13 ` Alan Cox
[not found] ` <20120916171316.517ad0fd-38n7/U1jhRXW96NNrWNlrekiAK3p4hvP@public.gmane.org>
2012-09-16 17:49 ` Eric W. Biederman
2012-09-16 17:49 ` Eric W. Biederman
2012-09-16 16:15 ` Serge Hallyn
2012-09-16 16:15 ` Serge Hallyn
[not found] ` <5055FB2A.1020103-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>
2012-09-16 16:53 ` Eric W. Biederman
2012-09-16 16:53 ` Eric W. Biederman
2012-09-16 8:19 ` [RFC] cgroup TODOs James Bottomley
2012-09-16 8:19 ` James Bottomley
2012-09-16 8:19 ` James Bottomley
[not found] ` <1347783557.2463.1.camel-sFMDBYUN5F8GjUHQrlYNx2Wm91YjaHnnhRte9Li2A+AAvxtiuMwx3w@public.gmane.org>
2012-09-16 14:41 ` Eric W. Biederman
2012-09-16 14:41 ` Eric W. Biederman
2012-09-16 14:41 ` Eric W. Biederman
2012-09-17 13:21 ` Aristeu Rozanski
2012-09-17 13:21 ` Aristeu Rozanski
2012-09-14 22:03 ` Dhaval Giani
2012-09-14 22:03 ` Dhaval Giani
2012-09-14 22:03 ` Dhaval Giani
[not found] ` <CAPhKKr8wDLrcWHLTRq1M7gU_6CGNxzzF83zJo2WZ5vrY7h8Qyw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-09-14 22:06 ` Tejun Heo
2012-09-14 22:06 ` Tejun Heo
2012-09-20 1:33 ` Andy Lutomirski
2012-09-20 1:33 ` Andy Lutomirski
[not found] ` <505A725B.2080901-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
2012-09-20 18:26 ` Tejun Heo
2012-09-20 18:26 ` Tejun Heo
2012-09-20 18:26 ` Tejun Heo
[not found] ` <20120920182651.GH28934-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 18:39 ` Andy Lutomirski
2012-09-20 18:39 ` Andy Lutomirski
2012-09-20 18:39 ` Andy Lutomirski
2012-09-20 1:33 ` Andy Lutomirski
2012-09-21 21:40 ` Tejun Heo
2012-09-21 21:40 ` Tejun Heo
2012-09-21 21:40 ` Tejun Heo
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