---

yaml
---
r: 242295
b: refs/heads/master
c: 8184f93
h: refs/heads/master
i:
  242293: ed44cba
  242291: 73d329e
  242287: 7f6b536
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 95f28604a65b1c40b6c6cd95e58439cd7ded3add
+refs/heads/master: 8184f93eced1e304721c2a55c00d87d5a14f8907

trunk/block/cfq-iosched.c

@@ -178,6 +178,8 @@ struct cfq_group {
 	/* group service_tree key */
 	u64 vdisktime;
 	unsigned int weight;
+	unsigned int new_weight;
+	bool needs_update;
 
 	/* number of cfqq currently on this group */
 	int nr_cfqq;
@@ -853,7 +855,27 @@ __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
 }
 
 static void
-cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
+cfq_update_group_weight(struct cfq_group *cfqg)
+{
+	BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
+	if (cfqg->needs_update) {
+		cfqg->weight = cfqg->new_weight;
+		cfqg->needs_update = false;
+	}
+}
+
+static void
+cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
+{
+	BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
+
+	cfq_update_group_weight(cfqg);
+	__cfq_group_service_tree_add(st, cfqg);
+	st->total_weight += cfqg->weight;
+}
+
+static void
+cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
 	struct cfq_rb_root *st = &cfqd->grp_service_tree;
 	struct cfq_group *__cfqg;
@@ -874,13 +896,19 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 		cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY;
 	} else
 		cfqg->vdisktime = st->min_vdisktime;
+	cfq_group_service_tree_add(st, cfqg);
+}
 
-	__cfq_group_service_tree_add(st, cfqg);
-	st->total_weight += cfqg->weight;
+static void
+cfq_group_service_tree_del(struct cfq_rb_root *st, struct cfq_group *cfqg)
+{
+	st->total_weight -= cfqg->weight;
+	if (!RB_EMPTY_NODE(&cfqg->rb_node))
+		cfq_rb_erase(&cfqg->rb_node, st);
 }
 
 static void
-cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
+cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
 	struct cfq_rb_root *st = &cfqd->grp_service_tree;
 
@@ -892,9 +920,7 @@ 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 -= cfqg->weight;
-	if (!RB_EMPTY_NODE(&cfqg->rb_node))
-		cfq_rb_erase(&cfqg->rb_node, st);
+	cfq_group_service_tree_del(st, cfqg);
 	cfqg->saved_workload_slice = 0;
 	cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
 }
@@ -948,9 +974,10 @@ 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(&cfqg->rb_node, st);
+	cfq_group_service_tree_del(st, cfqg);
 	cfqg->vdisktime += cfq_scale_slice(charge, cfqg);
-	__cfq_group_service_tree_add(st, cfqg);
+	/* If a new weight was requested, update now, off tree */
+	cfq_group_service_tree_add(st, cfqg);
 
 	/* This group is being expired. Save the context */
 	if (time_after(cfqd->workload_expires, jiffies)) {
@@ -982,7 +1009,9 @@ static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg)
 void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg,
 					unsigned int weight)
 {
-	cfqg_of_blkg(blkg)->weight = weight;
+	struct cfq_group *cfqg = cfqg_of_blkg(blkg);
+	cfqg->new_weight = weight;
+	cfqg->needs_update = true;
 }
 
 static struct cfq_group *
@@ -1255,7 +1284,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	service_tree->count++;
 	if ((add_front || !new_cfqq) && !group_changed)
 		return;
-	cfq_group_service_tree_add(cfqd, cfqq->cfqg);
+	cfq_group_notify_queue_add(cfqd, cfqq->cfqg);
 }
 
 static struct cfq_queue *
@@ -1368,7 +1397,7 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 		cfqq->p_root = NULL;
 	}
 
-	cfq_group_service_tree_del(cfqd, cfqq->cfqg);
+	cfq_group_notify_queue_del(cfqd, cfqq->cfqg);
 	BUG_ON(!cfqd->busy_queues);
 	cfqd->busy_queues--;
 	if (cfq_cfqq_sync(cfqq))