From: Robert Love <rml@tech9.net>

Basically, the problem is that setscheduler() does not set need_resched
when needed.  There are two basic cases where this is needed:

	- the task is running, but now it is no longer the highest
	  priority task on the rq
	- the task is not running, but now it is the highest
	  priority task on the rq

In either case, we need to set need_resched to invoke the scheduler.