Attached is an updated patch that addresses Michael Ellerman's comments.

One comment made by Michael has not yet been addressed:
The comment was in regard to the for-loop in 
spufs/sched.c:notify_spus_active().  He wondered if the scheduler can 
swap a context from one node to another.  If so, there's a small window 
in this loop (where we switch the lock from one node's active list to 
the next) where it may be possible we might miss waking up a context and 
send a spurious wakeup to another.
	Arnd . . . can you comment on this question?

Thanks.
-Maynard