Commit 67060e37 authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
Browse files

cfq-iosched: sort IDLE queues into the rbtree 



Same treatment as the RT conversion, just put the sorted idle
branch at the end of the tree.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 0c534e0a

block/cfq-iosched.c

+31 −36
Original line number Diff line number Diff line
@@ -92,7 +92,6 @@ struct cfq_data { 
	 */

	struct cfq_rb_root service_tree;

	struct list_head cur_rr;

	struct list_head idle_rr;

	unsigned int busy_queues;



	/*
@@ -467,25 +466,33 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, 


	while (*p) {

		struct cfq_queue *__cfqq;

		struct rb_node **n;



		parent = *p;

		__cfqq = rb_entry(parent, struct cfq_queue, rb_node);



		/*

		 * sort RT queues first, we always want to give

		 * preference to them. after that, sort on the next

		 * service time.

		 * preference to them. IDLE queues goes to the back.

		 * after that, sort on the next service time.

		 */

		if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))

			p = &(*p)->rb_left;

			n = &(*p)->rb_left;

		else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))

			p = &(*p)->rb_right;

			n = &(*p)->rb_right;

		else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))

			n = &(*p)->rb_left;

		else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))

			n = &(*p)->rb_right;

		else if (rb_key < __cfqq->rb_key)

			p = &(*p)->rb_left;

		else {

			p = &(*p)->rb_right;

			n = &(*p)->rb_left;

		else

			n = &(*p)->rb_right;



		if (n == &(*p)->rb_right)

			left = 0;

		}



		p = n;

	}



	if (left)
@@ -506,20 +513,8 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) 
	if (!cfq_cfqq_on_rr(cfqq))

		return;



	list_del_init(&cfqq->cfq_list);



	if (cfq_class_idle(cfqq)) {

		/*

		 * IDLE goes to the tail of the idle list

		 */

		list_add_tail(&cfqq->cfq_list, &cfqd->idle_rr);

	} else {

		/*

		 * RT and BE queues, sort into the rbtree

		 */

	cfq_service_tree_add(cfqd, cfqq);

}

}



/*

 * add to busy list of queues for service, trying to be fair in ordering
@@ -797,20 +792,22 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) 
		cfqq = list_entry_cfqq(cfqd->cur_rr.next);

	} else if (!RB_EMPTY_ROOT(&cfqd->service_tree.rb)) {

		struct rb_node *n = cfq_rb_first(&cfqd->service_tree);

		unsigned long end;



		cfqq = rb_entry(n, struct cfq_queue, rb_node);

	} else if (!list_empty(&cfqd->idle_rr)) {

		if (cfq_class_idle(cfqq)) {

			/*

		 * if we have idle queues and no rt or be queues had pending

		 * requests, either allow immediate service if the grace period

		 * has passed or arm the idle grace timer

			 * if we have idle queues and no rt or be queues had

			 * pending requests, either allow immediate service if

			 * the grace period has passed or arm the idle grace

			 * timer

			 */

		unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;



		if (time_after_eq(jiffies, end))

			cfqq = list_entry_cfqq(cfqd->idle_rr.next);

		else

			end = cfqd->last_end_request + CFQ_IDLE_GRACE;

			if (time_before(jiffies, end)) {

				mod_timer(&cfqd->idle_class_timer, end);

				cfqq = NULL;

			}

		}

	}



	return cfqq;
@@ -1074,7 +1071,6 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) 
	}



	dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);

	dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);



	cfq_slice_expired(cfqd, 0, 0);
@@ -2047,7 +2043,6 @@ static void *cfq_init_queue(request_queue_t *q) 


	cfqd->service_tree = CFQ_RB_ROOT;

	INIT_LIST_HEAD(&cfqd->cur_rr);

	INIT_LIST_HEAD(&cfqd->idle_rr);

	INIT_LIST_HEAD(&cfqd->cic_list);



	cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);