Subject: Re: [PATCH 6/24] make atomic_read() behave consistently on frv

From: Chris Snook <[email-masked]>
Date: Fri, 10 Aug 2007 15:54:19 -0400

David Howells wrote:
> Chris Snook <[email-masked]> wrote:
> 
>> To head off the criticism, I admit this is an oversimplification, and true
>> busy-waiters should be using cpu_relax(), which contains a barrier.
> 
> Why would you want to use cpu_relax()?  That's there to waste time efficiently,
> isn't it?  Shouldn't you be using smp_rmb() or something like that?
> 
> David

cpu_relax() contains a barrier, so it should do the right thing.  For 
non-smp architectures, I'm concerned about interacting with interrupt 
handlers.  Some drivers do use atomic_* operations.

	-- Chris