Subject: Re: CVS commit: src/sys/sys
To: None <>
From: Jason Thorpe <>
List: tech-kern
Date: 12/29/2007 07:21:09
Sorry, trying to catch up, here...

I object to this change for a couple of reasons:

1- It makes us incompatible with the Solaris atomic API, which was a  
major goal of mine.

2- On most platforms I wrote code for, the sub-word ops were, in fact,  
implemented in terms of a 32-bit CAS.

I'm pretty sure I documented the possible oddities of sub-word ops in  
the man pages I wrote on the thorpej-atomic branch.

On Nov 27, 2007, at 5:30 PM, Andrew Doran wrote:

> Module Name:	src
> Committed By:	ad
> Date:		Wed Nov 28 01:30:06 UTC 2007
> Modified Files:
> 	src/sys/sys: atomic.h
> Log Message:
> Remove the sub-word atomic ops because they can not be implemented  
> correctly
> on some architectures and so are misleading. The same effect can be  
> had by
> building on top of the 32-bit CAS. As a side effect this makes it  
> somewhat
> easier to complete and document the operations across all platforms.
> To generate a diff of this commit:
> cvs rdiff -r1.2 -r1.3 src/sys/sys/atomic.h
> Please note that diffs are not public domain; they are subject to the
> copyright notices on the relevant files.

-- thorpej