On Fri, Mar 02, 2007 at 09:52:17AM -0800, Jason Thorpe wrote:
> 
> On Mar 2, 2007, at 9:10 AM, Andrew Doran wrote:
> 
> >Log Message:
> >pmap_reference, pmap_destroy: update the pmap reference count using
> >_lock_cas. This is ugly and needs to be redone when atomic ops are
> >available, but for now it knocks about 5% contention off the kernel
> >lock in one test that I have done.
> 
> I am working on an atomic ops API.  I'll propose it on tech-kern within a few 
> days.

Doesn't gcc provide what we need?

http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Atomic-Builtins.html