linux-kernel - Re: [PATCH v2 RFC 1/3] documentation: Add needed ACCESS

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Date:	Thu, 21 Nov 2013 22:55:17 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...nel.org,
	laijs@...fujitsu.com, dipankar@...ibm.com,
	akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
	josh@...htriplett.org, niv@...ibm.com, tglx@...utronix.de,
	rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
	darren@...art.com, fweisbec@...il.com, sbw@....edu
Subject: Re: [PATCH v2 RFC 1/3] documentation: Add needed ACCESS_ONCE() calls
 to memory-barriers.txt

On Thu, Nov 21, 2013 at 01:31:27PM -0800, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
> 
> The Documentation/memory-barriers.txt file was written before the need
> for ACCESS_ONCE() was fully appreciated.  It therefore contains no
> ACCESS_ONCE() calls, which can be a problem when people lift examples
> from it.  This commit therefore adds ACCESS_ONCE() calls.

So I find the repeated ACCESS_ONCE() significantly detracts from the
readability of the text.

Can't we simply state that all accesses are assumed single-copy atomic
and this can be achieved for naturally aligned words using ACCESS_ONCE()
in C/C++ ?
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