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From: Stefan Richter <stefanr@s5r6.in-berlin.de>
To: Noah Watkins <noah@noahdesu.com>
Cc: "Leonidas ." <leonidas137@gmail.com>,
	Chris Friesen <cfriesen@nortel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Difference between atomic operations and memory barriers
Date: Mon, 26 Oct 2009 20:34:17 +0100	[thread overview]
Message-ID: <4AE5F9B9.2010707@s5r6.in-berlin.de> (raw)
In-Reply-To: <E1A2BB8B-F291-4C9E-B095-39F0AE7A0587@noahdesu.com>

Noah Watkins wrote:
>> So we can safely assume that pointer assignment will be done in an
>> atomic manner?
> 
> See the the comment above rcu_assign_pointer in
> include/linux/rcupdate.h

This comment only talks about ordering, not about atomicity.

Again, AFAIR the ISO C spec should explain what is going to be
guaranteed atomic and what might not be atomic.

rcu_assign_pointer() itself does rely on atomicity of pointer
assignments though, like lots of code elsewhere in the kernel.
-- 
Stefan Richter
-=====-==--= =-=- ==-=-
http://arcgraph.de/sr/

  reply	other threads:[~2009-10-26 19:34 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-26 17:19 Leonidas .
     [not found] ` <7ADB5FD7-9C97-4987-BC20-997258B25FD2@noahdesu.com>
2009-10-26 18:22   ` Leonidas .
2009-10-26 18:54     ` Chris Friesen
2009-10-26 19:00       ` Leonidas .
2009-10-26 19:07         ` Noah Watkins
2009-10-26 19:34           ` Stefan Richter [this message]
2009-10-26 19:42             ` Noah Watkins
2009-10-27 11:51         ` Valdis.Kletnieks
2009-10-28 10:00           ` Boaz Harrosh
2009-10-28 13:26             ` Valdis.Kletnieks
2009-10-26 19:00     ` Stefan Richter
2009-10-26 19:05       ` Leonidas .
2009-10-27 10:21         ` Michael Schnell
2009-10-27 10:23           ` Leonidas .
2009-10-27 11:01             ` Michael Schnell
2009-10-27 14:57             ` Stefan Richter

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