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Date: Thu, 18 Feb 2010 07:20:38 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Peter Zijlstra <peterz@infradead.org>
CC: Luca Barbieri <luca@luca-barbieri.com>, mingo@elte.hu,
       akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/10] x86-32: support atomic64_t on 386/486 UP/SMP
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On 02/18/2010 02:25 AM, Peter Zijlstra wrote:
> On Wed, 2010-02-17 at 12:42 +0100, Luca Barbieri wrote:
>> This patch makes atomic64 use either the generic implementation or
>> the rewritten cmpxchg8b one just introduced by inserting a "call" to
>> either, using the alternatives system to dynamically switch the calls.
>>
>> This allows to use atomic64_t on 386/486 which lack cmpxchg8b
> 
> IIRC we dropped <i586 SMP support, and since we don't have a PMU on
> those chips atomic64_t doesn't need to be NMI safe, so a simple
> UP-IRQ-disable implementation should suffice.

... which is what we have now, with the cmpxchg8b alternates emulation.

	-hpa

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

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