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From: Robert Noland <rnoland@FreeBSD.org>
To: Ryan Stone <rysto32@gmail.com>
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Date: Fri, 25 Sep 2009 09:40:20 -0500
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Cc: attilio@freebsd.org, hackers@freebsd.org,
	Fabio Checconi <fabio@freebsd.org>
Subject: Re: sx locks and memory barriers
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On Fri, 2009-09-25 at 09:30 -0400, Ryan Stone wrote:
> The code that Fabio proposes looks like this:
> 
> sx_slock(&data->lock);
> if (data->buffer)
>     a = *data->buffer;
> sx_sunlock(&data->lock);
> 
> 
> This point is that without a memory barrier on the unlock, the CPU is
> free to reorder the instructions into the order is his message.

Ok, then I will sit back and wait for someone with more clue to
respond...

robert.

-- 
Robert Noland <rnoland@FreeBSD.org>
FreeBSD