linux-kernel - Re: [PATCH] x86: Clean up mwait_play

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Message-ID: <4DA5D4D8.7000902@zytor.com>
Date:	Wed, 13 Apr 2011 09:52:40 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Frank Arnold <farnold@...64.org>
CC:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: Clean up mwait_play_dead

On 04/13/2011 09:11 AM, Frank Arnold wrote:
> From: Frank Arnold <frank.arnold@....com>
> 
> Commit 93789b32dbf355e70f18b17a82e8661677a7f7fb introduced
> cpuinfo_x86 *c for brevity. It is used to check for the
> mwait feature flag. The same can be done with a subsequent
> check for clflsh and save us a second per-cpu pointer
> dereference.
> 
> Signed-off-by: Frank Arnold <frank.arnold@....com>
> Acked-by: Borislav Petkov <borislav.petkov@....com>
> ---
>  arch/x86/kernel/smpboot.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 

This should be using this_cpu_has()... if that's not in the tree yet we
should add it.

Creating an absolute pointer for a percpu references is a big lose.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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