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Subject: Re: [PATCH] sched: Support current clocksource handling in
 fallback sched_clock().
From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Walker <dwalker@fifo99.com>
Cc: Paul Mundt <lethal@linux-sh.org>, Thomas Gleixner <tglx@linutronix.de>,
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Date: Thu, 28 May 2009 18:32:09 +0200
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On Thu, 2009-05-28 at 09:13 -0700, Daniel Walker wrote:
> On Thu, 2009-05-28 at 14:59 +0200, Peter Zijlstra wrote:
> 
> > 
> > 
> > CPU0                           CPU1
> > 
> > clock = ACCESS_ONCE(sched_clocksource);
> > 
> >                                unload module
> >                                  clocksource_unregister()
> >                                    sched_clocksource = jiffies
> >                                  unmap data/text
> > 
> > cyc2ns(clock, clocksource_read(clock)) <--- fireworks
> > 
> > 
> 
> Do any module based clocksources even exist right now?
> clocksource_unregister only seems to be used 3 times..

Good point, it appears its not even exported.

Thomas mentioned modules, I assumed.