From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: torvalds@linux-foundation.org, mingo@elte.hu, tglx@linutronix.de,
marcin.slusarz@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] printk vs rq->lock and xtime lock
Date: Mon, 24 Mar 2008 11:57:38 -0700 [thread overview]
Message-ID: <20080324115738.85c72bb5.akpm@linux-foundation.org> (raw)
In-Reply-To: <1206382547.6437.131.camel@lappy>
On Mon, 24 Mar 2008 19:15:47 +0100
Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> How about I use the lockdep infrastructure to check if printk() is
> invoked whole holding either xtime or rq lock, and then avoid calling
> wake_up_klogd(). That way, we at least get sane debug output when the
> lock debugging infrastructure is enabled?
The core problem seems to be that printk shouldn't be calling wake_up().
Can we fix that?
I expect it would be acceptable to do it from the timer interrupt instead.
For NOHZ kernels a poll when we enter the idle loop would also be needed.
But does that cover everything? Is it possible for a CPU to run 100% busy
while not receiving timer interrupts? I guess so. To receive no
interrupts at all? Also possible.
next prev parent reply other threads:[~2008-03-24 18:58 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-24 12:24 [PATCH 0/2] printk vs rq->lock and xtime lock Peter Zijlstra
2008-03-24 12:24 ` [PATCH 1/2] printk_nowakeup() Peter Zijlstra
2008-03-24 12:24 ` [PATCH 2/2] time: xtime lock vs printk Peter Zijlstra
2008-03-24 14:21 ` Daniel Walker
2008-03-24 14:31 ` [PATCH 0/2] printk vs rq->lock and xtime lock Marcin Slusarz
2008-03-24 17:58 ` Linus Torvalds
2008-03-24 18:15 ` Peter Zijlstra
2008-03-24 18:57 ` Andrew Morton [this message]
2008-08-08 13:30 ` Peter Zijlstra
2008-08-08 13:46 ` Peter Zijlstra
2008-08-08 16:41 ` Linus Torvalds
2008-08-08 17:10 ` Peter Zijlstra
2008-08-08 17:25 ` Linus Torvalds
2008-08-08 17:40 ` Peter Zijlstra
2008-08-08 17:48 ` Linus Torvalds
2008-08-08 18:14 ` [PATCH] printk: robustify printk Peter Zijlstra
2008-08-08 18:30 ` Linus Torvalds
2008-08-08 18:33 ` Peter Zijlstra
2008-08-08 19:14 ` Andrew Morton
2008-08-08 19:21 ` Peter Zijlstra
2008-08-08 19:37 ` Andrew Morton
2008-08-08 19:49 ` Peter Zijlstra
2008-08-08 20:32 ` Paul E. McKenney
2008-08-08 20:37 ` Peter Zijlstra
2008-08-08 20:46 ` Andrew Morton
2008-08-08 20:57 ` Linus Torvalds
2008-08-08 21:13 ` Andrew Morton
2008-08-08 20:50 ` Steven Rostedt
2008-08-08 19:47 ` Peter Zijlstra
2008-08-11 10:45 ` Ingo Molnar
2008-08-11 11:03 ` Andi Kleen
2008-08-11 11:22 ` Peter Zijlstra
2008-08-11 11:42 ` Andi Kleen
2008-08-11 14:15 ` Valdis.Kletnieks
2008-08-11 14:29 ` Andi Kleen
2008-08-11 14:55 ` Steven Rostedt
2008-08-11 12:02 ` Ingo Molnar
2008-08-11 12:14 ` Andi Kleen
2008-08-11 11:04 ` Peter Zijlstra
2008-08-11 11:51 ` Ingo Molnar
2008-08-11 12:36 ` Ingo Molnar
2008-08-20 12:40 ` Jiri Kosina
2008-08-20 12:43 ` Peter Zijlstra
2008-08-20 13:40 ` Ingo Molnar
2008-08-11 16:09 ` Paul E. McKenney
2008-08-11 13:22 ` Paul E. McKenney
2008-08-08 20:30 ` Paul E. McKenney
2008-08-08 20:20 ` Paul E. McKenney
2008-08-08 21:35 ` Andi Kleen
2008-08-08 23:02 ` David Miller
2008-08-09 0:18 ` Paul E. McKenney
2008-08-08 17:52 ` [PATCH 0/2] printk vs rq->lock and xtime lock Steven Rostedt
2008-03-24 18:16 ` Linus Torvalds
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