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Commit edd75ffd authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
Browse files

cfq-iosched: get rid of ->cur_rr and ->cfq_list 



It's only used for preemption now that the IDLE and RT queues also
use the rbtree. If we pass an 'add_front' variable to
cfq_service_tree_add(), we can set ->rb_key to 0 to force insertion
at the front of the tree.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 67e6b49e

block/cfq-iosched.c

+32 −55
Original line number Diff line number Diff line
@@ -45,9 +45,6 @@ static int cfq_slice_idle = HZ / 125; 
 */

#define CFQ_QHASH_SHIFT		6

#define CFQ_QHASH_ENTRIES	(1 << CFQ_QHASH_SHIFT)

#define list_entry_qhash(entry)	hlist_entry((entry), struct cfq_queue, cfq_hash)



#define list_entry_cfqq(ptr)	list_entry((ptr), struct cfq_queue, cfq_list)



#define RQ_CIC(rq)		((struct cfq_io_context*)(rq)->elevator_private)

#define RQ_CFQQ(rq)		((rq)->elevator_private2)
@@ -91,7 +88,6 @@ struct cfq_data { 
	 * rr list of queues with requests and the count of them

	 */

	struct cfq_rb_root service_tree;

	struct list_head cur_rr;

	unsigned int busy_queues;



	/*
@@ -146,8 +142,6 @@ struct cfq_queue { 
	struct hlist_node cfq_hash;

	/* hash key */

	unsigned int key;

	/* member of the rr/busy/cur/idle cfqd list */

	struct list_head cfq_list;

	/* service_tree member */

	struct rb_node rb_node;

	/* service_tree key */
@@ -452,16 +446,19 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd, 
 * we will service the queues.

 */

static void cfq_service_tree_add(struct cfq_data *cfqd,

				    struct cfq_queue *cfqq)

				    struct cfq_queue *cfqq, int add_front)

{

	struct rb_node **p = &cfqd->service_tree.rb.rb_node;

	struct rb_node *parent = NULL;

	unsigned long rb_key;

	int left;



	if (!add_front) {

		rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;

		rb_key += cfqq->slice_resid;

		cfqq->slice_resid = 0;

	} else

		rb_key = 0;



	if (!RB_EMPTY_NODE(&cfqq->rb_node)) {

		/*
@@ -516,13 +513,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, 
/*

 * Update cfqq's position in the service tree.

 */

static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)

static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)

{

	/*

	 * Resorting requires the cfqq to be on the RR list already.

	 */

	if (cfq_cfqq_on_rr(cfqq))

		cfq_service_tree_add(cfqq->cfqd, cfqq);

		cfq_service_tree_add(cfqd, cfqq, 0);

}



/*
@@ -536,7 +533,7 @@ cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) 
	cfq_mark_cfqq_on_rr(cfqq);

	cfqd->busy_queues++;



	cfq_resort_rr_list(cfqq, 0);

	cfq_resort_rr_list(cfqd, cfqq);

}



/*
@@ -548,7 +545,6 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) 
{

	BUG_ON(!cfq_cfqq_on_rr(cfqq));

	cfq_clear_cfqq_on_rr(cfqq);

	list_del_init(&cfqq->cfq_list);



	if (!RB_EMPTY_NODE(&cfqq->rb_node))

		cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
@@ -771,7 +767,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, 
	if (timed_out && !cfq_cfqq_slice_new(cfqq))

		cfqq->slice_resid = cfqq->slice_end - jiffies;



	cfq_resort_rr_list(cfqq, preempted);

	cfq_resort_rr_list(cfqd, cfqq);



	if (cfqq == cfqd->active_queue)

		cfqd->active_queue = NULL;
@@ -799,17 +795,15 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted, 
 */

static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)

{

	struct cfq_queue *cfqq = NULL;

	struct cfq_queue *cfqq;

	struct rb_node *n;



	if (!list_empty(&cfqd->cur_rr)) {

		/*

		 * if current list is non-empty, grab first entry.

		 */

		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);

	if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))

		return NULL;



	n = cfq_rb_first(&cfqd->service_tree);

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



	if (cfq_class_idle(cfqq)) {

		unsigned long end;
@@ -825,7 +819,6 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) 
			cfqq = NULL;

		}

	}

	}



	return cfqq;

}
@@ -1075,18 +1068,6 @@ static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) 
	return dispatched;

}



static int cfq_forced_dispatch_cfqqs(struct list_head *list)

{

	struct cfq_queue *cfqq, *next;

	int dispatched;



	dispatched = 0;

	list_for_each_entry_safe(cfqq, next, list, cfq_list)

		dispatched += __cfq_forced_dispatch_cfqq(cfqq);



	return dispatched;

}



/*

 * Drain our current requests. Used for barriers and when switching

 * io schedulers on-the-fly.
@@ -1102,8 +1083,6 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) 
		dispatched += __cfq_forced_dispatch_cfqq(cfqq);

	}



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



	cfq_slice_expired(cfqd, 0, 0);



	BUG_ON(cfqd->busy_queues);
@@ -1433,7 +1412,6 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, 
		memset(cfqq, 0, sizeof(*cfqq));



		INIT_HLIST_NODE(&cfqq->cfq_hash);

		INIT_LIST_HEAD(&cfqq->cfq_list);

		RB_CLEAR_NODE(&cfqq->rb_node);

		INIT_LIST_HEAD(&cfqq->fifo);
@@ -1712,8 +1690,8 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) 
	 * so we know that it will be selected next.

	 */

	BUG_ON(!cfq_cfqq_on_rr(cfqq));

	list_del_init(&cfqq->cfq_list);

	list_add(&cfqq->cfq_list, &cfqd->cur_rr);



	cfq_service_tree_add(cfqd, cfqq, 1);



	cfqq->slice_end = 0;

	cfq_mark_cfqq_slice_new(cfqq);
@@ -2077,7 +2055,6 @@ static void *cfq_init_queue(request_queue_t *q) 
	memset(cfqd, 0, sizeof(*cfqd));



	cfqd->service_tree = CFQ_RB_ROOT;

	INIT_LIST_HEAD(&cfqd->cur_rr);

	INIT_LIST_HEAD(&cfqd->cic_list);



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