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Date: Wed, 7 Jan 2009 18:49:45 -0500 (EST)
From: Steven Rostedt <rostedt@goodmis.org>
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To: Linus Torvalds <torvalds@linux-foundation.org>
cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>,
       Peter Zijlstra <peterz@infradead.org>, paulmck@linux.vnet.ibm.com,
       Gregory Haskins <ghaskins@novell.com>, Ingo Molnar <mingo@elte.hu>,
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       Sven Dietrich <SDietrich@novell.com>
Subject: Re: [PATCH -v5][RFC]: mutex: implement adaptive spinning
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On Wed, 7 Jan 2009, Linus Torvalds wrote:
> On Wed, 7 Jan 2009, Dave Kleikamp wrote:
> > 
> > Do you need to even do that if CONFIG_DEBUG_PAGEALLOC is unset?
> 
> No.
> 
> > Something like:
> > 
> > #ifdef CONFIG_DEBUG_PAGEALLOC
> >                 /*
> >                  * Need to access the cpu field knowing that
> >                  * DEBUG_PAGEALLOC could have unmapped it if
> >                  * the mutex owner just released it and exited.
> >                  */
> >                 if (probe_kernel_address(&thread->cpu, cpu))
> >                         break;
> > #else
> > 		cpu = thread->cpu;
> > #endif
> 
> yes. That would work fine.

What about memory hotplug as Ingo mentioned?

Should that be:

#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_MEMORY_HOTPLUG)

??

-- Steve

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