From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch 1/4] Ignore stolen time in the softlockup watchdog
Date: Tue, 24 Apr 2007 14:14:18 -0700
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To: Ingo Molnar <mingo@elte.hu>
Cc: Prarit Bhargava <prarit@redhat.com>, Daniel Walker <dwalker@mvista.com>, Rick Lindsley <ricklind@us.ibm.com>, john stultz <johnstul@us.ibm.com>, Linux Kernel <linux-kernel@vger.kernel.org>, Eric Dumazet <dada1@cosmosbay.com>, virtualization@lists.osdl.org, Chris Lalancette <clalance@redhat.com>, Mackerras <paulus@samba.org>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Paul@smtp2.linux-foundation.org, Thomas Gleixner <tglx@linutronix.de>
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On Tue, 24 Apr 2007 22:59:18 +0200 Ingo Molnar <mingo@elte.hu> wrote:

> 
> * Daniel Walker <dwalker@mvista.com> wrote:
> 
> > On Tue, 2007-04-24 at 13:24 -0700, Jeremy Fitzhardinge wrote:
> > 
> > > And sched_clock's use of local_irq_save/restore appears to be absolutely
> > > correct, so I think it must be triggering a bug in either the self-tests
> > > or lockdep itself.
> > 
> > Why does sched_clock need to disable interrupts?
> 
> i concur. To me it appears not "absolutely correct" that someone 
> apparently added local_irq_save/restore to sched_clock(), but "absolute 
> madness". sched_clock() is _very_ performance-sensitive for the 
> scheduler, do not mess with it.

Why does a local_irq_save/restore make the selftests fail??