On Wed, 04 May 2011 15:04:39 CDT, Christoph Lameter said:
> On Wed, 4 May 2011, Linus Torvalds wrote:

> > But cmpxchg DOES NOT MAKE SENSE without atomicity guarantees.
> 
> This is not a real cmpxchg after all. Its not atomic in the sense of
> other functions. Its only "percpu atomic" if you want it that way. This is
> *not* a full cmpxchg_double().

Calling it a cmpxchg when it doesn't have the primary distinguishing property
of a hardware cmpxchg is just loading a bullet in the chamber and inviting
kernel hackers to point it at their feet...