Re: fix BUG: using smp_processor_id() in touch_nmi_watchdog andtouch_softlockup_watchdog

[Don Zickus]

On Mon, Aug 16, 2010 at 03:46:58PM +0200, Peter Zijlstra wrote:
> > I don't see a problem with the patch, but my low level understanding of
> > the __get_cpu_var vs. per_cpu isn't very strong.
> 
> __get_cpu_var() gets you the value on the current cpu, per_cpu() takes a
> cpu argument.

Well I know that much. :-)  It seems that __get_cpu_var depends on
preemption being disabled whereas per_cpu does not?  Though for some
reason I thought __get_cpu_var would be more atomic when it grabbed the
current cpu such that you wouldn't need to disable preemption.  Guess not.

Cheers,
Don

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