Date: Fri, 8 Sep 2006 18:25:24 -0400 (EDT)
From: Alan Stern <stern@rowland.harvard.edu>
To: Oliver Neukum <oliver@neukum.org>
cc: paulmck@us.ibm.com, David Howells <dhowells@redhat.com>,
       Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Uses for memory barriers
In-Reply-To: <200609082346.20740.oliver@neukum.org>
Message-ID: <Pine.LNX.4.44L0.0609081824190.8280-100000@iolanthe.rowland.org>
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On Fri, 8 Sep 2006, Oliver Neukum wrote:

> > Again you have misunderstood.  The original code was _not_ incorrect.  I 
> > was asking: Given the code as stated, would the assertion ever fail?
> 
> I claim the right to call code that fails its own assertions incorrect. :-)

Touche!

> > The code _was_ correct for my purposes, namely, to illustrate a technical 
> > point about the behavior of memory barriers.
> 
> I would say that the code may fail the assertion purely based
> on the formal definition of a memory barrier. And do so in a subtle
> and inobvious way.

But what _is_ the formal definition of a memory barrier?  I've never seen 
one that was complete and correct.

Alan Stern

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