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Date: Tue, 20 Jun 2006 17:34:30 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: Andrew Morton <akpm@osdl.org>, npiggin@suse.de, Paul.McKenney@us.ibm.com,
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Subject: Re: [patch 0/3] 2.6.17 radix-tree: updates and lockless
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On Wed, 21 Jun 2006, Benjamin Herrenschmidt wrote:

> Anyway, I can drop a spinlock in (in fact I have) the ppc64 irq code for
> now but that sucks, thus we should really seriously consider having the
> lockless tree in 2.6.18 or I might have to look into doing an alternate
> implementation specifically in arch code... or find some other way of
> doing the inverse mapping there...

How many interrupts do you have to ? I would expect a simple table 
lookup would be fine to get from the virtual to the real interrupt.