/*
* row_get_next_queue() - selects the next queue to dispatch from
* @q: requests queue
* @rd: pointer to struct row_data
* @start_idx/end_idx: indexes in the row_queues array to select a queue
* from.
*
* Return index of the queues to dispatch from. Error code if fails.
*
*/
static int row_get_next_queue(struct request_queue *q, struct row_data *rd,
int start_idx, int end_idx)
{
int i = start_idx;
bool restart = true;
int ret = -EIO;
do {
if (list_empty(&rd->row_queues[i].fifo) ||
rd->row_queues[i].nr_dispatched >=
rd->row_queues[i].disp_quantum) {
i++;
if (i == end_idx && restart) {
/* Restart cycle for this priority class */
row_restart_cycle(rd, start_idx, end_idx);
i = start_idx;
restart = false;
}
} else {
ret = i;
break;
}
} while (i < end_idx);
return ret;
}
static int row_get_next_queue(struct request_queue *q, struct row_data *rd,
int start_idx, int end_idx)
{
int i = start_idx;
bool restart = true;
int ret = -EIO;
bool print_debug_log = false;
do {
if (list_empty(&rd->row_queues[i].fifo) ||
rd->row_queues[i].nr_dispatched >=
rd->row_queues[i].disp_quantum) {
if ((i == ROWQ_PRIO_HIGH_READ || i == ROWQ_PRIO_REG_READ)
&& rd->row_queues[i].nr_dispatched >=
rd->row_queues[i].disp_quantum)
print_debug_log = true;
i++;
if (i == end_idx && restart) {
row_restart_cycle(rd, start_idx, end_idx);
i = start_idx;
restart = false;
}
} else {
ret = i;
break;
}
} while (i < end_idx);
if (print_debug_log)
row_dump_reg_and_low_stat(rd);
#define EXPIRE_REQUEST_THRESHOLD 20
if (ret == ROWQ_PRIO_REG_READ) {
struct request *check_req;
bool reset_quantum = false;
for (i = ret + 1; i < end_idx; i++) {
if (!row_queues_def[i].expire)
continue;
if (list_empty(&rd->row_queues[i].fifo)) {
reset_quantum = true;
continue;
}
check_req = list_entry_rq(rd->row_queues[i].fifo.next);
if (time_after(jiffies,
((unsigned long) (check_req)->csd.list.next)
+ row_queues_def[i].expire) &&
rd->row_queues[i].nr_req > EXPIRE_REQUEST_THRESHOLD) {
rd->row_queues[ret].disp_quantum =
row_queues_def[ret].quantum / 2;
reset_quantum = false;
break;
} else
reset_quantum = true;
}
if (reset_quantum)
rd->row_queues[ret].disp_quantum =
row_queues_def[ret].quantum;
}
return ret;
}