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From: Oleg Nesterov <oleg@redhat.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Paul Menage <menage@google.com>, Li Zefan <lizf@cn.fujitsu.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Aditya Kali <adityakali@google.com>
Subject: Re: [PATCH 7/8] cgroups: Add a task counter subsystem
Date: Tue, 9 Aug 2011 20:19:47 +0200	[thread overview]
Message-ID: <20110809181947.GB28442@redhat.com> (raw)
In-Reply-To: <20110809180942.GC31645@somewhere.redhat.com>

On 08/09, Frederic Weisbecker wrote:
>
> On Tue, Aug 09, 2011 at 07:57:08PM +0200, Oleg Nesterov wrote:
> > > > cgroup_attach_proc() is different, it calls cgroup_task_migrate()
> > > > after ->attach_task(). Cough.
> > >
> > > That's bad. I need to fix that.
> > >
> > > So if it returns -ESRCH, I shall not call attach_task() on it
> > > but cancel_attach_task().
> >
> > Afaics this can't help, or I misunderstood. probably attach_task()
> > can check PF_EXITING...
>
> But cgroup_task_migrate() checks that already before migrating
> cgroups (checks PF_EXITING under task_lock() so that it's
> synchronized against cgroup_exit())

Yes, but how this can help?

->attach_task() is called before cgroup_task_migrate(). Suppose
that it exits before ->attach_task(). In this case we shouldn't
uncharge the old cgroup, it was already uncharged by cgroup_exit.

Oleg.


  reply	other threads:[~2011-08-09 18:23 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-29 16:13 [PATCH 0/8 v3] cgroups: Task counter subsystem (was: New max number of tasks subsystem) Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 1/8] cgroups: Add res_counter_write_u64() API Frederic Weisbecker
2011-08-09 15:17   ` Oleg Nesterov
2011-08-09 17:31     ` Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 2/8] cgroups: New resource counter inheritance API Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 3/8] cgroups: Add previous cgroup in can_attach_task/attach_task callbacks Frederic Weisbecker
2011-08-17  2:40   ` Li Zefan
2011-08-27 13:58     ` Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 4/8] cgroups: New cancel_attach_task subsystem callback Frederic Weisbecker
2011-08-17  2:40   ` Li Zefan
2011-08-27 13:58     ` Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 5/8] cgroups: Ability to stop res charge propagation on bounded ancestor Frederic Weisbecker
2011-08-17  2:41   ` Li Zefan
2011-08-27 13:59     ` Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 6/8] cgroups: Add res counter common ancestor searching Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 7/8] cgroups: Add a task counter subsystem Frederic Weisbecker
2011-08-01 23:13   ` Andrew Morton
2011-08-04 14:05     ` Frederic Weisbecker
2011-08-09 15:11   ` Oleg Nesterov
2011-08-09 17:27     ` Frederic Weisbecker
2011-08-09 17:57       ` Oleg Nesterov
2011-08-09 18:09         ` Frederic Weisbecker
2011-08-09 18:19           ` Oleg Nesterov [this message]
2011-08-09 18:34             ` Frederic Weisbecker
2011-08-09 18:39               ` Oleg Nesterov
2011-08-17  3:18   ` Li Zefan
2011-08-27 14:16     ` Frederic Weisbecker
2011-07-29 16:13 ` [PATCH 8/8] res_counter: Allow charge failure pointer to be null Frederic Weisbecker
2011-08-17  2:44   ` Li Zefan
2011-08-27 14:05     ` Frederic Weisbecker
2011-08-01 23:19 ` [PATCH 0/8 v3] cgroups: Task counter subsystem (was: New max number of tasks subsystem) Andrew Morton
2011-08-03 14:29   ` Frederic Weisbecker
2011-08-12 21:11   ` Tim Hockin
2011-08-16 16:01     ` Kay Sievers
2011-08-18 14:33       ` [RFD] Task counter: cgroup core feature or cgroup subsystem? (was Re: [PATCH 0/8 v3] cgroups: Task counter subsystem) Frederic Weisbecker
2011-08-23 16:07         ` Paul Menage
2011-08-24 17:54           ` Frederic Weisbecker
2011-08-26  7:28             ` Li Zefan
2011-08-26 14:58               ` Paul Menage
2011-09-06  9:06                 ` Li Zefan
2011-08-26 15:16             ` Paul Menage
2011-08-27 13:40               ` Frederic Weisbecker
2011-08-31 22:36                 ` Paul Menage
2011-08-31 21:54               ` Frederic Weisbecker

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