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From: Andi Kleen <ak@suse.de>
Subject: Re: [PATCH] Document Linux's memory barriers [try #2]
Date: Wed, 8 Mar 2006 12:38:38 +0100
References: <20060308184500.GA17716@devserv.devel.redhat.com> <11922.1141842907@warthog.cambridge.redhat.com> <14067.1141844393@warthog.cambridge.redhat.com>
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To: David Howells <dhowells@redhat.com>
Cc: Alan Cox <alan@redhat.com>, torvalds@osdl.org, akpm@osdl.org, mingo@redhat.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org
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On Wednesday 08 March 2006 19:59, David Howells wrote:
> Alan Cox <alan@redhat.com> wrote:
> 
> > then on some NUMA infrastructures the order may not be as you expect.
> 
> Oh, yuck!
> 
> Okay... does NUMA guarantee the same for ordinary memory accesses inside the
> critical section?


If you use barriers the ordering should be the same on cc/NUMA vs SMP.
Otherwise it wouldn't be "cc" 

But it might be quite unfair.

-Andi