From: Tejun Heo <tj@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: paul@paulmenage.org, rjw@sisk.pl, lizf@cn.fujitsu.com,
linux-pm@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org, fweisbec@gmail.com,
matthltc@us.ibm.com, akpm@linux-foundation.org, oleg@redhat.com,
kamezawa.hiroyu@jp.fujitsu.com
Subject: Re: [PATCH UPDATED 03/10] threadgroup: extend threadgroup_lock() to cover exit and exec
Date: Thu, 1 Dec 2011 11:29:35 -0800 [thread overview]
Message-ID: <20111201192935.GE13173@google.com> (raw)
In-Reply-To: <20111127212558.GE4266@google.com>
Hello again, Linus.
On Sun, Nov 27, 2011 at 01:25:58PM -0800, Tejun Heo wrote:
> The problem is that cred_guard_mutex uses _interruptible/_killable
> operations and rwsem doesn't have them, so cred_guard_mutex can't be
> easily replaced with write-locking group_rwsem.
>
> If the two locks can't be merged, under the proposed scheme, while not
> exactly pretty, both fork/exit and exec paths go through single
> locking and only the ones which want stable threadgroup need to grab
> both locks, so IMHO it is at least reasonable.
>
> Any better ideas?
I agree that the proposed solution is rather ugly but stable
thread-group is a valid mechanism to have and cgroup can benefit a lot
from it. I'd be happy to revamp the implementation if anyone can come
up with a better way and can add big fat comment stating that. Until
something better comes up, would it be okay to stick with this
implementation?
Thanks.
--
tejun
next prev parent reply other threads:[~2011-12-01 19:29 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-01 23:46 [PATCHSET] cgroup: stable threadgroup during attach & subsys methods consolidation Tejun Heo
2011-11-01 23:46 ` [PATCH 01/10] cgroup: add cgroup_root_mutex Tejun Heo
2011-11-04 8:38 ` KAMEZAWA Hiroyuki
2011-11-01 23:46 ` [PATCH 02/10] threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem Tejun Heo
2011-11-04 8:40 ` KAMEZAWA Hiroyuki
2011-11-04 15:16 ` Tejun Heo
2011-11-01 23:46 ` [PATCH 03/10] threadgroup: extend threadgroup_lock() to cover exit and exec Tejun Heo
2011-11-04 8:45 ` KAMEZAWA Hiroyuki
2011-11-13 16:44 ` Frederic Weisbecker
2011-11-14 13:54 ` Frederic Weisbecker
2011-11-21 22:03 ` Tejun Heo
2011-11-23 14:34 ` Frederic Weisbecker
2011-11-21 21:58 ` Tejun Heo
2011-11-23 14:02 ` Frederic Weisbecker
2011-11-24 21:22 ` Tejun Heo
2011-11-13 18:20 ` Frederic Weisbecker
2011-11-24 22:50 ` [PATCH UPDATED " Tejun Heo
2011-11-25 4:02 ` Linus Torvalds
2011-11-27 19:21 ` Tejun Heo
2011-11-27 21:25 ` Tejun Heo
2011-12-01 19:29 ` Tejun Heo [this message]
2011-11-25 14:01 ` Frederic Weisbecker
2011-11-27 19:30 ` Tejun Heo
2011-12-02 16:28 ` Frederic Weisbecker
2011-12-05 18:43 ` Tejun Heo
2011-12-07 15:30 ` Frederic Weisbecker
2011-12-07 18:22 ` Tejun Heo
2011-12-08 20:50 ` [PATCH UPDATED AGAIN " Tejun Heo
2011-12-09 23:42 ` Frederic Weisbecker
2011-12-13 1:33 ` Tejun Heo
2011-12-13 2:17 ` Tejun Heo
2011-11-01 23:46 ` [PATCH 04/10] cgroup: always lock threadgroup during migration Tejun Heo
2011-11-04 8:54 ` KAMEZAWA Hiroyuki
2011-11-04 15:21 ` Tejun Heo
2011-11-14 18:46 ` Frederic Weisbecker
2011-11-14 18:52 ` Frederic Weisbecker
2011-11-21 22:05 ` Tejun Heo
2011-11-01 23:46 ` [PATCH 05/10] cgroup: subsys->attach_task() should be called after migration Tejun Heo
2011-11-14 20:06 ` Frederic Weisbecker
2011-11-21 22:04 ` Tejun Heo
2011-11-01 23:46 ` [PATCH 06/10] cgroup: improve old cgroup handling in cgroup_attach_proc() Tejun Heo
2011-11-14 20:37 ` Frederic Weisbecker
2011-11-01 23:46 ` [PATCH 07/10] cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach() Tejun Heo
2011-11-14 21:16 ` Frederic Weisbecker
2011-11-01 23:46 ` [PATCH 08/10] cgroup: don't use subsys->can_attach_task() or ->attach_task() Tejun Heo
2011-11-04 9:08 ` KAMEZAWA Hiroyuki
2011-11-14 23:54 ` Frederic Weisbecker
2011-11-01 23:46 ` [PATCH 09/10] cgroup, cpuset: don't use ss->pre_attach() Tejun Heo
2011-11-15 0:51 ` Frederic Weisbecker
2011-11-01 23:46 ` [PATCH 10/10] cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task() Tejun Heo
2011-11-04 9:10 ` KAMEZAWA Hiroyuki
2011-11-15 0:54 ` Frederic Weisbecker
2011-11-21 22:07 ` [PATCHSET] cgroup: stable threadgroup during attach & subsys methods consolidation Tejun Heo
2011-11-22 2:27 ` Li Zefan
2011-11-22 16:20 ` Tejun Heo
2011-11-24 22:51 ` Tejun Heo
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