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Date: Fri, 8 Feb 2002 16:05:33 -0800
From: Mike Fedyk <mfedyk@matchmail.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] New locking primitive for 2.5
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On Sat, Feb 09, 2002 at 12:09:04AM +0000, Alan Cox wrote:
> > SMP 486s would need that (if there is such a beast).  What point does x86
> > get the 64 bit instructions?  If after 586, then it would definitely need a
> > spin-lock or some-such in those functions.
> 
> There are SMP 486 class x86 machines that are MP 1.1 compliant. They are
> sufficiently rare that I think its quite acceptable to "implement" a
> cmpxchg8b macro on 486 as spin_lock_irqsave/blah/spin_unlock_irqrestore. It
> would be wrong to cripple the other 99.99% of SMP users
> 

Sorry, I only meant to say that the only question is where the split should
be between spin-lock and 64bit instruction...

This would be included in the appropriate config option.

Mike
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