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From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tejun Heo <htejun@gmail.com>, LKML <linux-kernel@vger.kernel.org>,
	Li Zefan <lizf@cn.fujitsu.com>, Paul Menage <paul@paulmenage.org>,
	David Rientjes <rientjes@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [patch] cpusets, cgroups: disallow attaching kthreadd
Date: Tue, 11 Oct 2011 18:57:16 +0200	[thread overview]
Message-ID: <1318352236.6194.22.camel@marge.simson.net> (raw)
In-Reply-To: <1318342087.14615.5.camel@twins>

On Tue, 2011-10-11 at 16:08 +0200, Peter Zijlstra wrote:
> On Mon, 2011-10-10 at 09:43 -0700, Tejun Heo wrote:
> 
> > Yes, I think we need something like this.  wq workers were using
> > PF_THREAD_BOUND to prevent diddling from userland which made some
> > unhappy. 
> 
> But that can be properly fixed.
> 
> >  Maybe we need a flag to properly indicate "don't diddle with
> > this thread from userland"?  But, then, mainline kernel wouldn't need
> > the current PF_THREAD_BOUND at all.  Peter, Steven, what do you think?
> 
> Strict per-cpu affinity that is needed for correctness and disallows
> sched_setaffinity() is something entirely different from not being
> allowed to put something in a cgroup.

Agreed.  The proposed patchlet is purely a practical matter.

> As to not allowing to put in a cgroup thing, is there anything other
> than kthreadd for which we need to enforce that? So far I've mostly
> treated it like: root can do stupid things, this is one of them, don't
> do that then.

Yeah, that's the other side of the coin.  The only thing I can think of
justifying a response other than "well, gee, don't do that" is that Joe
User shouldn't need to know or care about kernel workqueue details.

I don't know of anything other than kthreadd where moving it here, or
over yonder matters one bit.

	-Mike


  reply	other threads:[~2011-10-11 16:57 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-23  6:21 [patch] cpusets: allow PF_THREAD_BOUND kworkers to escape from a cpuset Mike Galbraith
2011-09-23  7:00 ` Li Zefan
2011-09-23  7:19   ` Mike Galbraith
2011-09-23  9:12     ` David Rientjes
2011-09-23  9:42       ` Mike Galbraith
2011-09-23 10:53         ` Mike Galbraith
2011-09-23 13:27           ` David Rientjes
2011-09-23 14:33             ` Mike Galbraith
2011-09-23 18:16               ` Mike Galbraith
2011-09-23 20:20               ` David Rientjes
2011-09-24  3:21                 ` Tejun Heo
2011-10-10  5:34               ` Mike Galbraith
2011-10-10  8:03                 ` [patch] cpusets, cgroups: disallow attaching kthreadd Mike Galbraith
2011-10-10 16:43                   ` Tejun Heo
2011-10-11  2:31                     ` Mike Galbraith
2011-10-11 14:08                     ` Peter Zijlstra
2011-10-11 16:57                       ` Mike Galbraith [this message]
2011-10-12  1:22                         ` David Rientjes
2011-10-12  1:45                           ` Mike Galbraith
2011-10-12  1:20                       ` David Rientjes
2011-10-18  8:10                   ` patch] " Mike Galbraith
2011-10-18  8:16                     ` David Rientjes
2011-10-18  8:42                     ` Peter Zijlstra
2011-10-18  8:47                       ` Mike Galbraith
2011-10-18  9:06                         ` Peter Zijlstra
2011-10-18  9:23                           ` Mike Galbraith
2011-10-18 10:11                             ` Mike Galbraith
2011-10-18 20:38                               ` David Rientjes
2011-10-19  4:00                                 ` Mike Galbraith
2011-10-19  4:53                                   ` Paul Menage
2011-10-19  4:56                                     ` Paul Menage
2011-10-19  5:28                                       ` Mike Galbraith
2011-10-19  7:50                                 ` Peter Zijlstra
2011-10-19 19:47                                   ` David Rientjes
2011-10-20 10:32                                     ` Peter Zijlstra
2011-10-20 21:24                                       ` David Rientjes
2011-10-19  4:57                     ` Paul Menage
2011-10-19  5:24                       ` [patch-final] " Mike Galbraith
2011-10-19  7:54                         ` Peter Zijlstra
2011-10-19  8:00                           ` Paul Menage
2011-10-19  8:21                           ` Mike Galbraith
2011-10-26 20:27                         ` David Rientjes
2011-11-10 20:51                           ` David Rientjes
2011-12-06 20:13                             ` David Rientjes
2011-12-06 22:47                               ` Andrew Morton
2011-12-06 23:53                                 ` David Rientjes
2011-12-07  0:05                                   ` Andrew Morton
2011-12-07  3:18                                   ` [resubmit] " Mike Galbraith
2011-12-07  4:36                                     ` Mike Galbraith
2011-12-07 22:03                                       ` David Rientjes
2011-12-14 20:16                                         ` Andrew Morton
2011-12-15  2:50                                           ` David Rientjes
2012-01-06 22:06                                       ` Andrew Morton
2012-01-07  6:34                                         ` Mike Galbraith
2012-01-07  7:59                                           ` Andrew Morton
2011-12-07 22:01                                     ` David Rientjes

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