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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: 2.6.25-rc: complete lockup on boot/start of X (bisected)
Date: Sun, 23 Mar 2008 20:06:08 +0100	[thread overview]
Message-ID: <1206299168.6437.119.camel@lappy> (raw)
In-Reply-To: <20080323184427.GA6691@joi>

On Sun, 2008-03-23 at 19:46 +0100, Marcin Slusarz wrote:

> 4 different lockups:
> http://alan.umcs.lublin.pl/~mslusarz/kernel/2008.03.23-lockup/ 

Brilliant, these are extremely helpful.

What seems to happen is a classic xtime deadlock, doing a xtime
seq_readlock while holding a seq_writelock.

Only need to figure out _why_ that is happening....

> Are there any downsides of using nmi_watchdog=2 all the time?

Some machines are said to not boot due to NMIs, hence the default is
off, but afaik, _if_ it works there are no downsides aside from the
slight NMI handling overhead.

> ps: Documentation/nmi_watchdog.txt says: "Currently, local APIC mode
> (nmi_watchdog=2) does not work on x86-64.". It's not true, so maybe someone
> should update this file?

Care to send a patch to the x86 maintainers? :-)


  reply	other threads:[~2008-03-23 19:06 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-02 19:00 Marcin Slusarz
2008-03-02 19:11 ` Peter Zijlstra
2008-03-02 19:47   ` Marcin Slusarz
2008-03-02 19:58     ` Peter Zijlstra
2008-03-23 15:44       ` Marcin Slusarz
2008-03-23 15:54         ` Peter Zijlstra
2008-03-23 18:46           ` Marcin Slusarz
2008-03-23 19:06             ` Peter Zijlstra [this message]
2008-03-23 19:09               ` Peter Zijlstra
2008-03-23 19:57                 ` Marcin Slusarz
2008-03-23 20:06               ` [PATCH] documentation: nmi_watchdog=2 works on x86_64 (was: 2.6.25-rc: complete lockup on boot/start of X (bisected)) Marcin Slusarz
2008-03-23 20:15                 ` Yinghai Lu
2008-03-27  9:51                 ` Ingo Molnar
2008-03-02 20:00 ` 2.6.25-rc: complete lockup on boot/start of X (bisected) Arjan van de Ven
2008-03-02 20:08   ` Marcin Slusarz

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