Function sleepq_remove_thread

freebsd/kern/subr_sleepqueue.c:800–855

}

static void
sleepq_remove_thread(struct sleepqueue *sq, struct thread *td)
{
	struct sleepqueue_chain *sc __unused;

	MPASS(td != NULL);
	MPASS(sq->sq_wchan != NULL);
	MPASS(td->td_wchan == sq->sq_wchan);
	MPASS(td->td_sqqueue < NR_SLEEPQS && td->td_sqqueue >= 0);
	THREAD_LOCK_ASSERT(td, MA_OWNED);
	sc = SC_LOOKUP(sq->sq_wchan);
	mtx_assert(&sc->sc_lock, MA_OWNED);

	SDT_PROBE2(sched, , , wakeup, td, td->td_proc);

	/* Remove the thread from the queue. */
	sq->sq_blockedcnt[td->td_sqqueue]--;
	TAILQ_REMOVE(&sq->sq_blocked[td->td_sqqueue], td, td_slpq);

	/*
	 * Get a sleep queue for this thread.  If this is the last waiter,
	 * use the queue itself and take it out of the chain, otherwise,
	 * remove a queue from the free list.
	 */
	if (LIST_EMPTY(&sq->sq_free)) {
		td->td_sleepqueue = sq;
#ifdef INVARIANTS
		sq->sq_wchan = NULL;
#endif
#ifdef SLEEPQUEUE_PROFILING
		sc->sc_depth--;
#endif
	} else
		td->td_sleepqueue = LIST_FIRST(&sq->sq_free);
	LIST_REMOVE(td->td_sleepqueue, sq_hash);

	if ((td->td_flags & TDF_TIMEOUT) == 0 && td->td_sleeptimo != 0)
		/*
		 * We ignore the situation where timeout subsystem was
		 * unable to stop our callout.  The struct thread is
		 * type-stable, the callout will use the correct
		 * memory when running.  The checks of the
		 * td_sleeptimo value in this function and in
		 * sleepq_timeout() ensure that the thread does not
		 * get spurious wakeups, even if the callout was reset
		 * or thread reused.
		 */
		callout_stop(&td->td_slpcallout);

	td->td_wmesg = NULL;
	td->td_wchan = NULL;
	td->td_flags &= ~(TDF_SINTR | TDF_TIMEOUT);

	CTR3(KTR_PROC, "sleepq_wakeup: thread %p (pid %ld, %s)",
	    (void *)td, (long)td->td_proc->p_pid, td->td_name);
}

#ifdef INVARIANTS