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Subject: Re: [patch] powerpc: hash lock use lock bitops
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Nick Piggin <npiggin@suse.de>
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On Tue, 2007-11-20 at 07:26 +0100, Nick Piggin wrote:
> 
> BTW, here is another thing which you might want to think about. Again
> untested for temporary lack of hardware.
> 
> --
> 
> The radix-tree is now RCU safe, so powerpc can avoid the games it was playing
> in order to have a lockless readside. Saves an irq disable/enable, a couple of
> __get_cpu_var()s, a cacheline, and a memory barrier, in the fastpath. Should
> save a cycle or two...

Yup, I know. I need to work on that for -rt anyway due to other issues...

Thanks !

Ben.