From: Arnd Bergmann <arnd@arndb.de>
To: Mike Frysinger <vapier@gentoo.org>
Subject: Re: [PATCH/RFC] asm-generic/mutex-dec.h: add SMP support
Date: Mon, 30 May 2011 09:00:02 +0200
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On Monday 30 May 2011 05:19:28 Mike Frysinger wrote:
> To make these guys work on SMP systems, we just need to sprinkle a few
> barriers around.
> 
> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
> ---
> note: this is what the Blackfin SMP port is using, but it doesn't seem
> like other SMP ports are ... so I wonder if we're just trying too hard
> and these barriers aren't actually necessary ?

On some architectures, atomic instructions are implicit barriers. On
others, the cmpxchg() macro contains a barrier. I'm not sure if there
is other code relying on that.

	Arnd
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