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Commit 72ca8dab authored by Tatyana Brokhman's avatar Tatyana Brokhman Committed by Stephen Boyd
Browse files

block: row: Don't notify URGENT if there are un-completed urgent req 



When ROW scheduler reports to the block layer that there is an urgent
request pending, the device driver may decide to stop the transmission
of the current request in order to handle the urgent one. If the current
transmitted request is an urgent request - we don't want it to be
stopped.
Due to the above ROW scheduler won't notify of an urgent request if
there are urgent requests in flight.

Change-Id: I2fa186d911b908ec7611682b378b9cdc48637ac7
Signed-off-by: default avatarTatyana Brokhman <tlinder@codeaurora.org>
parent 279fe73d

block/row-iosched.c

+37 −1
Original line number Diff line number Diff line
@@ -165,6 +165,8 @@ struct idling_data { 
 * @nr_reqs: nr_reqs[0] holds the number of all READ requests in

 *			scheduler, nr_reqs[1] holds the number of all WRITE

 *			requests in scheduler

 * @nr_urgent_in_flight: number of uncompleted urgent requests

 *			(both reads and writes)

 * @cycle_flags:	used for marking unserved queueus

 *

 */
@@ -175,6 +177,7 @@ struct row_data { 


	struct idling_data		rd_idle_data;

	unsigned int			nr_reqs[2];

	unsigned int			nr_urgent_in_flight;



	unsigned int			cycle_flags;

};
@@ -303,6 +306,7 @@ static void row_add_request(struct request_queue *q, 
		row_log_rowq(rd, rqueue->prio,

			"added urgent request (total on queue=%d)",

			rqueue->nr_req);

		rq->cmd_flags |= REQ_URGENT;

	} else

		row_log_rowq(rd, rqueue->prio,

			"added request (total on queue=%d)", rqueue->nr_req);
@@ -341,6 +345,20 @@ static int row_reinsert_req(struct request_queue *q, 
	return 0;

}



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->nr_urgent_in_flight) {

			pr_err("ROW BUG: %s() nr_urgent_in_flight = 0",

				__func__);

			return;

		}

		rd->nr_urgent_in_flight--;

	}

}



/**

 * row_urgent_pending() - Return TRUE if there is an urgent

 *			  request on scheduler
@@ -351,7 +369,20 @@ static bool row_urgent_pending(struct request_queue *q) 
	struct row_data *rd = q->elevator->elevator_data;

	int i;



	for (i = 0; i < ROWQ_MAX_PRIO; i++)

	if (rd->nr_urgent_in_flight) {

		row_log(rd->dispatch_queue, "%d urgent requests in flight",

			rd->nr_urgent_in_flight);

		return false;

	}



	for (i = ROWQ_HIGH_PRIO_IDX; i < ROWQ_REG_PRIO_IDX; i++)

		if (!list_empty(&rd->row_queues[i].fifo)) {

			row_log_rowq(rd, i,

				"Urgent (high prio) request pending");

			return true;

		}



	for (i = ROWQ_REG_PRIO_IDX; i < ROWQ_MAX_PRIO; i++)

		if (row_queues_def[i].is_urgent && row_rowq_unserved(rd, i) &&

		    !list_empty(&rd->row_queues[i].fifo)) {

			row_log_rowq(rd, i, "Urgent request pending");
@@ -398,6 +429,8 @@ static void row_dispatch_insert(struct row_data *rd, int queue_idx) 
	row_clear_rowq_unserved(rd, queue_idx);

	row_log_rowq(rd, queue_idx, " Dispatched request nr_disp = %d",

		     rd->row_queues[queue_idx].nr_dispatched);

	if (rq->cmd_flags & REQ_URGENT)

		rd->nr_urgent_in_flight++;

}



/*
@@ -643,6 +676,7 @@ static int row_init_queue(struct request_queue *q) 
	rdata->dispatch_queue = q;

	q->elevator->elevator_data = rdata;



	rdata->nr_urgent_in_flight = 0;

	rdata->nr_reqs[READ] = rdata->nr_reqs[WRITE] = 0;



	return 0;
@@ -709,6 +743,7 @@ static enum row_queue_prio row_get_queue_prio(struct request *rq) 
				rq->rq_disk->disk_name, __func__);

			q_type = ROWQ_PRIO_REG_WRITE;

		}

		rq->cmd_flags |= REQ_URGENT;

		break;

	case IOPRIO_CLASS_IDLE:

		if (data_dir == READ)
@@ -866,6 +901,7 @@ static struct elevator_type iosched_row = { 
		.elevator_add_req_fn		= row_add_request,

		.elevator_reinsert_req_fn	= row_reinsert_req,

		.elevator_is_urgent_fn		= row_urgent_pending,

		.elevator_completed_req_fn	= row_completed_req,

		.elevator_former_req_fn		= elv_rb_former_request,

		.elevator_latter_req_fn		= elv_rb_latter_request,

		.elevator_set_req_fn		= row_set_request,