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From: Andi Kleen <ak@suse.de>
Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg)
To: Fernando Luis =?iso-8859-15?q?V=E1zquez_Cao?= 
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Subject: Re: [PATCH] mm: PageLRU can be non-atomic bit operation
Date: Wed, 25 Apr 2007 10:59:24 +0200
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> This seems to imply that we need the lock prefix even when updating
> different bits within the same long (not just the same byte). Is this
> interpretation correct?

Yes, that is what I said. The consistency applies to loads/stores
(so e.g. for 128bit SSE2 load/stores too), not bytes.

The current IA32 manuals have a more detailed description of the rules 
in volume 3

-Andi