From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Subject: Re: [RFC PATCH 3/3] KVM: MMU: Optimize guest page table walk
Date: Fri, 29 Apr 2011 14:38:08 +0900
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Cc: Avi Kivity <avi@redhat.com>, mtosatti@redhat.com,
	kvm@vger.kernel.org, yoshikawa.takuya@oss.ntt.co.jp
To: Andi Kleen <andi@firstfloor.org>
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On Thu, 28 Apr 2011 19:46:00 -0700
Andi Kleen <andi@firstfloor.org> wrote:

> Avi Kivity <avi@redhat.com> writes:
> >
> > Good optimization.  copy_from_user() really isn't optimized for short
> > buffers, I expect much of the improvement comes from that.
> 
> Actually it is equivalent to get_user for the lenghts supported by
> get_user, assuming you pass in a constant length. You probably do not.
> 
> -Andi


Weird, I actually measured some changes even after dropping other parts
than get_user() usage.

Only I can guess for that reason is the reduction of some function calls
by inlining some functions.

Takuya