linux-kernel - Re: [rfc: cpuops adv V1 3/8] x86: this_cpu_cmpxchg and this_cpu_cmpxchg

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Message-ID: <4CFD1A05.3020900@redhat.com>
Date:	Mon, 06 Dec 2010 19:14:45 +0200
From:	Avi Kivity <avi@...hat.com>
To:	Christoph Lameter <cl@...ux.com>
CC:	akpm@...ux-foundation.org, Pekka Enberg <penberg@...helsinki.fi>,
	linux-kernel@...r.kernel.org,
	Eric Dumazet <eric.dumazet@...il.com>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Tejun Heo <tj@...nel.org>
Subject: Re: [rfc: cpuops adv V1 3/8] x86: this_cpu_cmpxchg and this_cpu_cmpxchg_double
 operations

On 12/02/2010 11:53 PM, Christoph Lameter wrote:
> Provide support as far as the hardware capabilities of the x86 cpus
> allow.
>
>
>
> +/*
> + * Beware: xchg on x86 has an implied lock prefix. There will be the cost of
> + * full lock semantics even though they are not needed.
> + */

Perhaps we can use cmpxchg instead of xchg to avoid this? costs one more 
instruction but may be worth it.

-- 
error compiling committee.c: too many arguments to function

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