This patch makes all the changes suggested by Christopher, with the 
exception of the suggestion to use the sched_flags field versus a new 
member to the spu_context struct to signal the need to "notify already 
active".  I don't have the sched_flags change in my 2.6.20-rc1 tree.  I 
can send another patch later if/when the sched_flags changes appears in 
the kernel version we end up picking for final oprofile-spu development.

Comments welcome.  Thanks.

-Maynard