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From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@osdl.org>
Cc: vatsa@in.ibm.com, Bjorn Helgaas <bjorn.helgaas@hp.com>,
	linux-kernel@vger.kernel.org, Myron Stowe <myron.stowe@hp.com>,
	Jens Axboe <axboe@kernel.dk>, Dipankar <dipankar@in.ibm.com>,
	Gautham shenoy <ego@in.ibm.com>
Subject: Re: workqueue deadlock
Date: Sat, 9 Dec 2006 11:26:52 +0100	[thread overview]
Message-ID: <20061209102652.GA16607@elte.hu> (raw)
In-Reply-To: <20061207205407.b4e356aa.akpm@osdl.org>


* Andrew Morton <akpm@osdl.org> wrote:

> > > +		if (cpu != -1)
> > > +			mutex_lock(&workqueue_mutex);
> > 
> > events/4 thread itself wanting the same mutex above?
> 
> Could do, not sure.  I'm planning on converting all the locking around 
> here to preempt_disable() though.

please at least use an owner-recursive per-CPU lock, not a naked 
preempt_disable()! The concurrency rules for data structures changed via 
preempt_disable() are quite hard to sort out after the fact. 
(preempt_disable() is too opaque, it doesnt attach data structure to 
critical section, like normal locks do.)

	Ingo

  parent reply	other threads:[~2006-12-09 10:28 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-07  0:26 workqueue deadlock Bjorn Helgaas
2006-12-07  6:17 ` Srivatsa Vaddagiri
2006-12-07  6:45   ` Srivatsa Vaddagiri
2006-12-07 18:51 ` Andrew Morton
2006-12-07 19:37   ` Andrew Morton
2006-12-08  2:53     ` Srivatsa Vaddagiri
2006-12-08  4:54       ` Andrew Morton
2006-12-08  7:58         ` Srivatsa Vaddagiri
2006-12-09 10:26         ` Ingo Molnar [this message]
2006-12-09 19:47           ` Andrew Morton
2006-12-10  8:26             ` Ingo Molnar
2006-12-10  8:43               ` Andrew Morton
2006-12-10 11:49                 ` Ingo Molnar
2006-12-10 12:16                   ` Andrew Morton
2006-12-10 12:19                     ` Ingo Molnar
2006-12-10 12:34                       ` Andrew Morton
2006-12-11  6:09                         ` Ingo Molnar
2006-12-10 14:18                     ` Rafael J. Wysocki
2006-12-11  6:52                       ` Dipankar Sarma
2006-12-11 16:34                         ` Rafael J. Wysocki
2006-12-11  5:45                     ` Srivatsa Vaddagiri
2006-12-11  6:03                       ` Andrew Morton
2006-12-11  4:58               ` Srivatsa Vaddagiri

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