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Date: Sat, 28 Apr 2007 14:49:55 +1000
From: Paul Mackerras <paulus@samba.org>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
       Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [patch 20/38] Minor fault path optimization.
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Martin Schwidefsky writes:

> The minor fault path has grown a lot in terms of cycles. In particular
> the kprobes hook is very costly. Optimize the path to save a couple of
> cycles. If kprobes is enabled more than 300 cycles can be avoided if 
> kprobes_running() is false.

There's no good reason to use a notifier for page faults, since
there's only one external piece of code that wants to know about
them...

Regards,
Paul.