Re: [PATCH] [4/7] oprofile - NMI hook

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On Wed, Oct 16, 2002 at 12:56:28AM +0200, Andi Kleen wrote:

> > This patch provides a simple api to let oprofile hook into
> > the NMI interrupt for the perfctr profiler.
>
> I would suggest using a notifier list instead (include/linux/notifier.h)
> This would handle multiple users cleanly.

How ? The only safe way I can see would be to spin lock around the NMI
(and try lock when an NMI arrives). This would either make every NMI
contend on a single spinlock, or require a NR_CPUS-sized array of
spinlocks, which is just ugly. And that wouldn't solve the
power-management problem - any NMI users need to collaborate to disable
NMI generation on a suspend.

regards
john

-- 
"CUT IT OUT FACEHEAD"
	- jeffk
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