Function tdq_runq_add

freebsd/kern/sched_ule.c:459–503

* Add a thread to the actual run-queue. Keeps transferable counts up to * date with what is actually on the run-queue. Selects the correct * queue position for timeshare threads. */

 * queue position for timeshare threads.
 */
static __inline void
tdq_runq_add(struct tdq *tdq, struct thread *td, int flags)
{
	struct td_sched *ts;
	u_char pri;

	TDQ_LOCK_ASSERT(tdq, MA_OWNED);
	THREAD_LOCK_BLOCKED_ASSERT(td, MA_OWNED);

	pri = td->td_priority;
	ts = td_get_sched(td);
	TD_SET_RUNQ(td);
	if (THREAD_CAN_MIGRATE(td)) {
		tdq->tdq_transferable++;
		ts->ts_flags |= TSF_XFERABLE;
	}
	if (pri < PRI_MIN_BATCH) {
		ts->ts_runq = &tdq->tdq_realtime;
	} else if (pri <= PRI_MAX_BATCH) {
		ts->ts_runq = &tdq->tdq_timeshare;
		KASSERT(pri <= PRI_MAX_BATCH && pri >= PRI_MIN_BATCH,
			("Invalid priority %d on timeshare runq", pri));
		/*
		 * This queue contains only priorities between MIN and MAX
		 * realtime.  Use the whole queue to represent these values.
		 */
		if ((flags & (SRQ_BORROWING|SRQ_PREEMPTED)) == 0) {
			pri = RQ_NQS * (pri - PRI_MIN_BATCH) / PRI_BATCH_RANGE;
			pri = (pri + tdq->tdq_idx) % RQ_NQS;
			/*
			 * This effectively shortens the queue by one so we
			 * can have a one slot difference between idx and
			 * ridx while we wait for threads to drain.
			 */
			if (tdq->tdq_ridx != tdq->tdq_idx &&
			    pri == tdq->tdq_ridx)
				pri = (unsigned char)(pri - 1) % RQ_NQS;
		} else
			pri = tdq->tdq_ridx;
		runq_add_pri(ts->ts_runq, td, pri, flags);
		return;
	} else
		ts->ts_runq = &tdq->tdq_idle;
	runq_add(ts->ts_runq, td, flags);
}

/* 
 * Remove a thread from a run-queue.  This typically happens when a thread