[PATCH 4/6 v4] cfq-iosched: Extract some common code of service tree handling for CFQ queue and CFQ group

[Gui Jianfeng <guijianfeng@cn.fujitsu.com>]

Extract some common code of service tree handling for CFQ queue
and CFQ group. This helps when CFQ queue and CFQ group are scheduling
together.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
---
 block/cfq-iosched.c |   86 +++++++++++++++++++++-----------------------------
 1 files changed, 36 insertions(+), 50 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 41cef2e..aa3eda8 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -871,12 +871,11 @@ entity_key(struct cfq_rb_root *st, struct cfq_entity *entity)
 }
 
 static void
-__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
+__cfq_entity_service_tree_add(struct cfq_rb_root *st, struct cfq_entity *cfqe)
 {
 	struct rb_node **node = &st->rb.rb_node;
 	struct rb_node *parent = NULL;
 	struct cfq_entity *__cfqe;
-	struct cfq_entity *cfqe = &cfqg->cfqe;
 	s64 key = entity_key(st, cfqe);
 	int left = 1;
 
@@ -900,6 +899,14 @@ __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
 }
 
 static void
+cfq_entity_service_tree_add(struct cfq_rb_root *st, struct cfq_entity *cfqe)
+{
+	__cfq_entity_service_tree_add(st, cfqe);
+	st->count++;
+	st->total_weight += cfqe->weight;
+}
+
+static void
 cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
 	struct cfq_rb_root *st = &cfqd->grp_service_tree;
@@ -923,8 +930,23 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	} else
 		cfqe->vdisktime = st->min_vdisktime;
 
-	__cfq_group_service_tree_add(st, cfqg);
-	st->total_weight += cfqe->weight;
+	cfq_entity_service_tree_add(st, cfqe);
+}
+
+static void
+__cfq_entity_service_tree_del(struct cfq_rb_root *st, struct cfq_entity *cfqe)
+{
+	cfq_rb_erase(&cfqe->rb_node, st);
+}
+
+static void
+cfq_entity_service_tree_del(struct cfq_rb_root *st, struct cfq_entity *cfqe)
+{
+	if (!RB_EMPTY_NODE(&cfqe->rb_node)) {
+		__cfq_entity_service_tree_del(st, cfqe);
+		st->total_weight -= cfqe->weight;
+		cfqe->service_tree = NULL;
+	}
 }
 
 static void
@@ -941,9 +963,7 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 		return;
 
 	cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
-	st->total_weight -= cfqe->weight;
-	if (!RB_EMPTY_NODE(&cfqe->rb_node))
-		cfq_rb_erase(&cfqe->rb_node, st);
+	cfq_entity_service_tree_del(st, cfqe);
 	cfqg->saved_workload_slice = 0;
 	cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
 }
@@ -992,9 +1012,9 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
 		charge = cfqq->allocated_slice;
 
 	/* Can't update vdisktime while group is on service tree */
-	cfq_rb_erase(&cfqe->rb_node, st);
+	__cfq_entity_service_tree_del(st, cfqe);
 	cfqe->vdisktime += cfq_scale_slice(charge, cfqe);
-	__cfq_group_service_tree_add(st, cfqg);
+	__cfq_entity_service_tree_add(st, cfqe);
 
 	/* This group is being expired. Save the context */
 	if (time_after(cfqd->workload_expires, jiffies)) {
@@ -1237,13 +1257,11 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 				 bool add_front)
 {
 	struct cfq_entity *cfqe;
-	struct rb_node **p, *parent;
+	struct rb_node *parent;
 	struct cfq_entity *__cfqe;
 	struct cfq_rb_root *service_tree, *orig_st;
-	int left;
 	int new_cfqq = 1;
 	int group_changed = 0;
-	s64 key;
 
 	cfqe = &cfqq->cfqe;
 	orig_st = cfqe->service_tree;
@@ -1260,8 +1278,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 			 * Group changed, dequeue this CFQ queue from the
 			 * original service tree.
 			 */
-			cfq_rb_erase(&cfqe->rb_node, cfqe->service_tree);
-			orig_st->total_weight -= cfqe->weight;
+			cfq_entity_service_tree_del(orig_st, cfqe);
 		}
 		cfqq->orig_cfqg = cfqq->cfqg;
 		cfqq->cfqg = &cfqd->root_group;
@@ -1277,8 +1294,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 			 * Group changed, dequeue this CFQ queue from the
 			 * original service tree.
 			 */
-			cfq_rb_erase(&cfqe->rb_node, cfqe->service_tree);
-			orig_st->total_weight -= cfqe->weight;
+			cfq_entity_service_tree_del(orig_st, cfqe);
 		}
 		cfq_put_cfqg(cfqq->cfqg);
 		cfqq->cfqg = cfqq->orig_cfqg;
@@ -1320,8 +1336,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	 * Ok, we get here, this CFQ queue is on the service tree, dequeue it
 	 * firstly.
 	 */
-	cfq_rb_erase(&cfqe->rb_node, cfqe->service_tree);
-	orig_st->total_weight -= cfqe->weight;
+	cfq_entity_service_tree_del(orig_st, cfqe);
 
 	new_cfqq = 0;
 
@@ -1347,38 +1362,11 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	}
 
 insert:
-	left = 1;
-	parent = NULL;
 	cfqe->service_tree = service_tree;
-	p = &service_tree->rb.rb_node;
-	key = entity_key(service_tree, cfqe);
-	while (*p) {
-		struct rb_node **n;
-
-		parent = *p;
-		__cfqe = rb_entry(parent, struct cfq_entity, rb_node);
-
-		/*
-		 * sort by key, that represents service time.
-		 */
-		if (key < entity_key(service_tree, __cfqe))
-			n = &(*p)->rb_left;
-		else {
-			n = &(*p)->rb_right;
-			left = 0;
-		}
-
-		p = n;
-	}
 
-	if (left)
-		service_tree->left = &cfqe->rb_node;
-
-	rb_link_node(&cfqe->rb_node, parent, p);
-	rb_insert_color(&cfqe->rb_node, &service_tree->rb);
+	/* Add cfqq onto service tree. */
+	cfq_entity_service_tree_add(service_tree, cfqe);
 	update_min_vdisktime(service_tree);
-	service_tree->count++;
-	service_tree->total_weight += cfqe->weight;
 	cfqq->reposition_time = jiffies;
 	if ((add_front || !new_cfqq) && !group_changed)
 		return;
@@ -1491,9 +1479,7 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	service_tree = cfqe->service_tree;
 
 	if (!RB_EMPTY_NODE(&cfqe->rb_node)) {
-		cfq_rb_erase(&cfqe->rb_node, cfqe->service_tree);
-		service_tree->total_weight -= cfqe->weight;
-		cfqe->service_tree = NULL;
+		cfq_entity_service_tree_del(service_tree, cfqe);
 	}
 	if (cfqq->p_root) {
 		rb_erase(&cfqq->p_node, cfqq->p_root);
-- 
1.7.1