- why doesn't sched_changepri() change l_priority if it was < PUSER? 

- which of the following is the preferred way to change the priority?

	- uvm_scheduler does:
		l = curlwp;
		lwp_lock(l);
		lwp_changepri(l, PVM);
		lwp_unlock(l);

	- workqueue_worker does:
		l = curlwp;
		lwp_lock(l);
		l->l_priority = wq->wq_prio;
		l->l_usrpri = wq->wq_prio;
		lwp_unlock(l);

YAMAMOTO Takashi