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Date: Fri, 07 Jul 2006 02:40:35 +1000
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
CC: Arjan van de Ven <arjan@infradead.org>, Ingo Molnar <mingo@elte.hu>,
       Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
       linux-kernel@vger.kernel.org
Subject: Re: [patch] spinlocks: remove 'volatile'
References: <20060705114630.GA3134@elte.hu> <20060705101059.66a762bf.akpm@osdl.org> <20060705193551.GA13070@elte.hu> <20060705131824.52fa20ec.akpm@osdl.org> <Pine.LNX.4.64.0607051332430.12404@g5.osdl.org> <20060705204727.GA16615@elte.hu> <Pine.LNX.4.64.0607051411460.12404@g5.osdl.org> <20060705214502.GA27597@elte.hu> <Pine.LNX.4.64.0607051458200.12404@g5.osdl.org> <Pine.LNX.4.64.0607051555140.12404@g5.osdl.org> <20060706081639.GA24179@elte.hu> <Pine.LNX.4.61.0607060756050.8312@chaos.analogic.com> <1152187268.3084.29.camel@laptopd505.fenrus.org> <Pine.LNX.4.61.0607060816110.8320@chaos.analogic.com>
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linux-os (Dick Johnson) wrote:

>  	http://en.wikipedia.org/wiki/Memory_barrier
> 
> This is used to prevent out-of-order execution, not at all what is
> necessary.

I don't think memory barriers prevent out of order execution,
just out of order loads and stores (which could happen on CPUs
that do in-order execution).

-- 
SUSE Labs, Novell Inc.
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