Function taskq_create

freebsd/contrib/openzfs/lib/libzpool/taskq.c:251–299

ARGSUSED*/

/*ARGSUSED*/
taskq_t *
taskq_create(const char *name, int nthreads, pri_t pri,
    int minalloc, int maxalloc, uint_t flags)
{
	taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
	int t;

	if (flags & TASKQ_THREADS_CPU_PCT) {
		int pct;
		ASSERT3S(nthreads, >=, 0);
		ASSERT3S(nthreads, <=, 100);
		pct = MIN(nthreads, 100);
		pct = MAX(pct, 0);

		nthreads = (sysconf(_SC_NPROCESSORS_ONLN) * pct) / 100;
		nthreads = MAX(nthreads, 1);	/* need at least 1 thread */
	} else {
		ASSERT3S(nthreads, >=, 1);
	}

	rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
	mutex_init(&tq->tq_lock, NULL, MUTEX_DEFAULT, NULL);
	cv_init(&tq->tq_dispatch_cv, NULL, CV_DEFAULT, NULL);
	cv_init(&tq->tq_wait_cv, NULL, CV_DEFAULT, NULL);
	cv_init(&tq->tq_maxalloc_cv, NULL, CV_DEFAULT, NULL);
	(void) strncpy(tq->tq_name, name, TASKQ_NAMELEN);
	tq->tq_flags = flags | TASKQ_ACTIVE;
	tq->tq_active = nthreads;
	tq->tq_nthreads = nthreads;
	tq->tq_minalloc = minalloc;
	tq->tq_maxalloc = maxalloc;
	tq->tq_task.tqent_next = &tq->tq_task;
	tq->tq_task.tqent_prev = &tq->tq_task;
	tq->tq_threadlist = kmem_alloc(nthreads * sizeof (kthread_t *),
	    KM_SLEEP);

	if (flags & TASKQ_PREPOPULATE) {
		mutex_enter(&tq->tq_lock);
		while (minalloc-- > 0)
			task_free(tq, task_alloc(tq, KM_SLEEP));
		mutex_exit(&tq->tq_lock);
	}

	for (t = 0; t < nthreads; t++)
		VERIFY((tq->tq_threadlist[t] = thread_create(NULL, 0,
		    taskq_thread, tq, 0, &p0, TS_RUN, pri)) != NULL);

	return (tq);
}

void
taskq_destroy(taskq_t *tq)