Date: Thu, 2 Feb 2006 16:49:04 -0500 (EST)
From: Alan Stern <stern@rowland.harvard.edu>
To: Roland Dreier <rdreier@cisco.com>
cc: Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Question about memory barriers
In-Reply-To: <adamzh9xx03.fsf@cisco.com>
Message-ID: <Pine.LNX.4.44L0.0602021647140.4715-100000@iolanthe.rowland.org>
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On Thu, 2 Feb 2006, Roland Dreier wrote:

> Most of this is correct, except that mb() is stronger than just rmb()
> and wmb() put together.  All memory operations before the mb() will
> complete before any operations after the mb().  A better way to
> understand this is to look at the sparc64 definition:
> 
> #define mb()    \
>         membar_safe("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad")

Thanks for the explanation.  Is there any appropriate place, say in 
Documentation/, where these things could be spelled out more completely?

Alan Stern

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