C++ row_log函数代码示例

static bool row_urgent_pending(struct request_queue *q)
{
	struct row_data *rd = q->elevator->elevator_data;

	if (rd->urgent_in_flight) {
		row_log(rd->dispatch_queue, "%d urgent requests in flight",
			rd->urgent_in_flight);
		return false;
	}

	if (rd->pending_urgent_rq) {
		row_log(rd->dispatch_queue, "Urgent request pending");
		return true;
	}

	row_log(rd->dispatch_queue, "no urgent request pending/in flight");
	return false;
}

static void row_restart_cycle(struct row_data *rd,
				int start_idx, int end_idx)
{
	int i;

	row_dump_queues_stat(rd);
	for (i = start_idx; i < end_idx; i++) {
		if (rd->row_queues[i].nr_dispatched <
		    rd->row_queues[i].disp_quantum)
			row_mark_rowq_unserved(rd, i);
		rd->row_queues[i].nr_dispatched = 0;
	}
	row_log(rd->dispatch_queue, "Restarting cycle for class @ %d-%d",
		start_idx, end_idx);
}

/*
 * row_dispatch_requests() - selects the next request to dispatch
 * @q:		requests queue
 * @force:		flag indicating if forced dispatch
 *
 * Return 0 if no requests were moved to the dispatch queue.
 *	  1 otherwise
 *
 */
static int row_dispatch_requests(struct request_queue *q, int force)
{
	struct row_data *rd = (struct row_data *)q->elevator->elevator_data;
	int ret = 0, currq, ioprio_class_to_serve, start_idx, end_idx;

	if (force && hrtimer_active(&rd->rd_idle_data.hr_timer)) {
		(void)hrtimer_cancel(&rd->rd_idle_data.hr_timer);
		row_log_rowq(rd, rd->rd_idle_data.idling_queue_idx,
			"Canceled delayed work on %d - forced dispatch",
			rd->rd_idle_data.idling_queue_idx);
		rd->rd_idle_data.idling_queue_idx = ROWQ_MAX_PRIO;
	}

	ioprio_class_to_serve = row_get_ioprio_class_to_serve(rd, force);
	row_log(rd->dispatch_queue, "Dispatching from %d priority class",
		ioprio_class_to_serve);

	switch (ioprio_class_to_serve) {
	case IOPRIO_CLASS_NONE:
		goto done;
	case IOPRIO_CLASS_RT:
		start_idx = ROWQ_HIGH_PRIO_IDX;
		end_idx = ROWQ_REG_PRIO_IDX;
		break;
	case IOPRIO_CLASS_BE:
		start_idx = ROWQ_REG_PRIO_IDX;
		end_idx = ROWQ_LOW_PRIO_IDX;
		break;
	case IOPRIO_CLASS_IDLE:
		start_idx = ROWQ_LOW_PRIO_IDX;
		end_idx = ROWQ_MAX_PRIO;
		break;
	default:
		pr_err("%s(): Invalid I/O priority class", __func__);
		goto done;
	}

	currq = row_get_next_queue(q, rd, start_idx, end_idx);

	/* Dispatch */
	if (currq >= 0) {
		row_dispatch_insert(rd, currq);
		ret = 1;
	}
done:
	return ret;
}

static void row_completed_req(struct request_queue *q, struct request *rq)
{
	struct row_data *rd = q->elevator->elevator_data;

	 if (rq->cmd_flags & REQ_URGENT) {
		if (!rd->urgent_in_flight) {
			WARN_ON(1);
			pr_err("%s(): URGENT req but urgent_in_flight = F",
				__func__);
		}
		rd->urgent_in_flight = false;
		rq->cmd_flags &= ~REQ_URGENT;
	}
	row_log(q, "completed %s %s req.",
		(rq->cmd_flags & REQ_URGENT ? "URGENT" : "regular"),
		(rq_data_dir(rq) == READ ? "READ" : "WRITE"));
}

static enum hrtimer_restart row_idle_hrtimer_fn(struct hrtimer *hr_timer)
{
	struct idling_data *read_data =
		container_of(hr_timer, struct idling_data, hr_timer);
	struct row_data *rd =
		container_of(read_data, struct row_data, rd_idle_data);

	row_log_rowq(rd, rd->rd_idle_data.idling_queue_idx,
			 "Performing delayed work");
	/* Mark idling process as done */
	rd->row_queues[rd->rd_idle_data.idling_queue_idx].
			idle_data.begin_idling = false;
	rd->rd_idle_data.idling_queue_idx = ROWQ_MAX_PRIO;

	if (!rd->nr_reqs[READ] && !rd->nr_reqs[WRITE])
		row_log(rd->dispatch_queue, "No requests in scheduler");
	else
		kblockd_schedule_work(&read_data->idle_work);
	return HRTIMER_NORESTART;
}

/*
 * row_get_ioprio_class_to_serve() - Return the next I/O priority
 *				      class to dispatch requests from
 * @rd:	pointer to struct row_data
 * @force:	flag indicating if forced dispatch
 *
 * This function returns the next I/O priority class to serve
 * {IOPRIO_CLASS_NONE, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE}.
 * If there are no more requests in scheduler or if we're idling on some queue
 * IOPRIO_CLASS_NONE will be returned.
 * If idling is scheduled on a lower priority queue than the one that needs
 * to be served, it will be canceled.
 *
 */
static int row_get_ioprio_class_to_serve(struct row_data *rd, int force)
{
	int i;
	int ret = IOPRIO_CLASS_NONE;

	if (!rd->nr_reqs[READ] && !rd->nr_reqs[WRITE]) {
		row_log(rd->dispatch_queue, "No more requests in scheduler");
		goto check_idling;
	}

	/* First, go over the high priority queues */
	for (i = 0; i < ROWQ_REG_PRIO_IDX; i++) {
		if (!list_empty(&rd->row_queues[i].fifo)) {
			if (hrtimer_active(&rd->rd_idle_data.hr_timer)) {
				if (hrtimer_try_to_cancel(
					&rd->rd_idle_data.hr_timer) >= 0) {
					row_log(rd->dispatch_queue,
					"Canceling delayed work on %d. RT pending",
					     rd->rd_idle_data.idling_queue_idx);
					rd->rd_idle_data.idling_queue_idx =
						ROWQ_MAX_PRIO;
				}
			}

			if (row_regular_req_pending(rd) &&
			    (rd->reg_prio_starvation.starvation_counter >=
			     rd->reg_prio_starvation.starvation_limit))
				ret = IOPRIO_CLASS_BE;
			else if (row_low_req_pending(rd) &&
			    (rd->low_prio_starvation.starvation_counter >=
			     rd->low_prio_starvation.starvation_limit))
				ret = IOPRIO_CLASS_IDLE;
			else
				ret = IOPRIO_CLASS_RT;

			goto done;
		}
	}

	/*
	 * At the moment idling is implemented only for READ queues.
	 * If enabled on WRITE, this needs updating
	 */
	if (hrtimer_active(&rd->rd_idle_data.hr_timer)) {
		row_log(rd->dispatch_queue, "Delayed work pending. Exiting");
		goto done;
	}
check_idling:
	/* Check for (high priority) idling and enable if needed */
	for (i = 0; i < ROWQ_REG_PRIO_IDX && !force; i++) {
		if (rd->row_queues[i].idle_data.begin_idling &&
		    row_queues_def[i].idling_enabled)
			goto initiate_idling;
	}

	/* Regular priority queues */
	for (i = ROWQ_REG_PRIO_IDX; i < ROWQ_LOW_PRIO_IDX; i++) {
		if (list_empty(&rd->row_queues[i].fifo)) {
			/* We can idle only if this is not a forced dispatch */
			if (rd->row_queues[i].idle_data.begin_idling &&
			    !force && row_queues_def[i].idling_enabled)
				goto initiate_idling;
		} else {
			if (row_low_req_pending(rd) &&
			    (rd->low_prio_starvation.starvation_counter >=
			     rd->low_prio_starvation.starvation_limit))
				ret = IOPRIO_CLASS_IDLE;
			else
				ret = IOPRIO_CLASS_BE;
			goto done;
		}
	}

	if (rd->nr_reqs[READ] || rd->nr_reqs[WRITE])
		ret = IOPRIO_CLASS_IDLE;
	goto done;

initiate_idling:
	hrtimer_start(&rd->rd_idle_data.hr_timer,
		ktime_set(0, rd->rd_idle_data.idle_time_ms * NSEC_PER_MSEC),
		HRTIMER_MODE_REL);

	rd->rd_idle_data.idling_queue_idx = i;
	row_log_rowq(rd, i, "Scheduled delayed work on %d. exiting", i);

done:
//.........这里部分代码省略.........

/*
 * row_dispatch_requests() - selects the next request to dispatch
 * @q:		requests queue
 * @force:		flag indicating if forced dispatch
 *
 * Return 0 if no requests were moved to the dispatch queue.
 *	  1 otherwise
 *
 */
static int row_dispatch_requests(struct request_queue *q, int force)
{
	struct row_data *rd = (struct row_data *)q->elevator->elevator_data;
	int ret = 0, currq, ioprio_class_to_serve, start_idx, end_idx;
	int expire_index = -1;

	if (force && hrtimer_active(&rd->rd_idle_data.hr_timer)) {
		if (hrtimer_try_to_cancel(&rd->rd_idle_data.hr_timer) >= 0) {
			row_log(rd->dispatch_queue,
				"Canceled delayed work on %d - forced dispatch",
				rd->rd_idle_data.idling_queue_idx);
			rd->rd_idle_data.idling_queue_idx = ROWQ_MAX_PRIO;
		}
	}

	if (rd->pending_urgent_rq) {
		row_log(rd->dispatch_queue, "dispatching urgent request");
		row_dispatch_insert(rd, rd->pending_urgent_rq);
		ret = 1;
		goto done;
	}

	ioprio_class_to_serve = row_get_ioprio_class_to_serve(rd, force);
	row_log(rd->dispatch_queue, "Dispatching from %d priority class",
		ioprio_class_to_serve);

	if (ioprio_class_to_serve == IOPRIO_CLASS_RT) {
		expire_index = row_be_expire_adjust(rd);
		if (expire_index >= ROWQ_REG_PRIO_IDX)
			ioprio_class_to_serve = IOPRIO_CLASS_BE;
	}

	switch (ioprio_class_to_serve) {
	case IOPRIO_CLASS_NONE:
		rd->last_served_ioprio_class = IOPRIO_CLASS_NONE;
		goto done;
	case IOPRIO_CLASS_RT:
		if (expire_index >= 0) {
			start_idx = expire_index;
			end_idx = expire_index + 1;
			expire_index = -1;
		} else {
			start_idx = ROWQ_HIGH_PRIO_IDX;
			end_idx = ROWQ_REG_PRIO_IDX;
		}
		break;
	case IOPRIO_CLASS_BE:
		if (expire_index > 0) {
			start_idx = expire_index;
			end_idx = expire_index + 1;
			expire_index = -1;
		} else {
			start_idx = ROWQ_REG_PRIO_IDX;
			end_idx = ROWQ_LOW_PRIO_IDX;
		}
		break;
	case IOPRIO_CLASS_IDLE:
		start_idx = ROWQ_LOW_PRIO_IDX;
		end_idx = ROWQ_MAX_PRIO;
		break;
	default:
		pr_err("%s(): Invalid I/O priority class", __func__);
		goto done;
	}

	currq = row_get_next_queue(q, rd, start_idx, end_idx);

	/* Dispatch */
	if (currq >= 0) {
		row_dispatch_insert(rd,
			rq_entry_fifo(rd->row_queues[currq].fifo.next));
		ret = 1;
	}
done:
	return ret;
}

static int row_get_ioprio_class_to_serve(struct row_data *rd, int force)
{
	int i;
	int ret = IOPRIO_CLASS_NONE;

	if (!rd->nr_reqs[READ] && !rd->nr_reqs[WRITE]) {
		row_log(rd->dispatch_queue, "No more requests in scheduler");
		goto check_idling;
	}

	
	for (i = 0; i < ROWQ_REG_PRIO_IDX; i++) {
		if (!list_empty(&rd->row_queues[i].fifo)) {
			if (hrtimer_active(&rd->rd_idle_data.hr_timer)) {
				if (hrtimer_try_to_cancel(
					&rd->rd_idle_data.hr_timer) >= 0) {
					row_log(rd->dispatch_queue,
					"Canceling delayed work on %d. RT pending",
					     rd->rd_idle_data.idling_queue_idx);
					rd->rd_idle_data.idling_queue_idx =
						ROWQ_MAX_PRIO;
				}
			}

			if (row_regular_req_pending(rd) &&
			    (rd->reg_prio_starvation.starvation_counter >=
			     rd->reg_prio_starvation.starvation_limit))
				ret = IOPRIO_CLASS_BE;
			else if (row_low_req_pending(rd) &&
			    (rd->low_prio_starvation.starvation_counter >=
			     rd->low_prio_starvation.starvation_limit))
				ret = IOPRIO_CLASS_IDLE;
			else
				ret = IOPRIO_CLASS_RT;

			goto done;
		}
	}

	if (hrtimer_active(&rd->rd_idle_data.hr_timer)) {
		row_log(rd->dispatch_queue, "Delayed work pending. Exiting");
		goto done;
	}
check_idling:
	
	for (i = 0; i < ROWQ_REG_PRIO_IDX && !force; i++) {
		if (rd->row_queues[i].idle_data.begin_idling &&
		    row_queues_def[i].idling_enabled)
			goto initiate_idling;
	}

	
	for (i = ROWQ_REG_PRIO_IDX; i < ROWQ_LOW_PRIO_IDX; i++) {
		if (list_empty(&rd->row_queues[i].fifo)) {
			
			if (rd->row_queues[i].idle_data.begin_idling &&
			    !force && row_queues_def[i].idling_enabled)
				goto initiate_idling;
		} else {
			if (row_low_req_pending(rd) &&
			    (rd->low_prio_starvation.starvation_counter >=
			     rd->low_prio_starvation.starvation_limit))
				ret = IOPRIO_CLASS_IDLE;
			else
				ret = IOPRIO_CLASS_BE;
			goto done;
		}
	}

	if (rd->nr_reqs[READ] || rd->nr_reqs[WRITE])
		ret = IOPRIO_CLASS_IDLE;
	goto done;

initiate_idling:
	hrtimer_start(&rd->rd_idle_data.hr_timer,
		ktime_set(0, rd->rd_idle_data.idle_time_ms * NSEC_PER_MSEC),
		HRTIMER_MODE_REL);

	rd->rd_idle_data.idling_queue_idx = i;
	row_log_rowq(rd, i, "Scheduled delayed work on %d. exiting", i);

done:
	return ret;
}