1 files changed, 126 insertions, 8 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index bc076f45ca4..175218d66d6 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -223,10 +223,21 @@ struct cfq_group {
 
 	/* group service_tree key */
 	u64 vdisktime;
+
+	/*
+	 * There are two weights - (internal) weight is the weight of this
+	 * cfqg against the sibling cfqgs.  leaf_weight is the wight of
+	 * this cfqg against the child cfqgs.  For the root cfqg, both
+	 * weights are kept in sync for backward compatibility.
+	 */
 	unsigned int weight;
 	unsigned int new_weight;
 	unsigned int dev_weight;
 
+	unsigned int leaf_weight;
+	unsigned int new_leaf_weight;
+	unsigned int dev_leaf_weight;
+
 	/* number of cfqq currently on this group */
 	int nr_cfqq;
 
@@ -1182,10 +1193,16 @@ static void
 cfq_update_group_weight(struct cfq_group *cfqg)
 {
 	BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
+
 	if (cfqg->new_weight) {
 		cfqg->weight = cfqg->new_weight;
 		cfqg->new_weight = 0;
 	}
+
+	if (cfqg->new_leaf_weight) {
+		cfqg->leaf_weight = cfqg->new_leaf_weight;
+		cfqg->new_leaf_weight = 0;
+	}
 }
 
 static void
@@ -1348,6 +1365,7 @@ static void cfq_pd_init(struct blkcg_gq *blkg)
 
 	cfq_init_cfqg_base(cfqg);
 	cfqg->weight = blkg->blkcg->cfq_weight;
+	cfqg->leaf_weight = blkg->blkcg->cfq_leaf_weight;
 }
 
 /*
@@ -1404,6 +1422,26 @@ static int cfqg_print_weight_device(struct cgroup *cgrp, struct cftype *cft,
 	return 0;
 }
 
+static u64 cfqg_prfill_leaf_weight_device(struct seq_file *sf,
+					  struct blkg_policy_data *pd, int off)
+{
+	struct cfq_group *cfqg = pd_to_cfqg(pd);
+
+	if (!cfqg->dev_leaf_weight)
+		return 0;
+	return __blkg_prfill_u64(sf, pd, cfqg->dev_leaf_weight);
+}
+
+static int cfqg_print_leaf_weight_device(struct cgroup *cgrp,
+					 struct cftype *cft,
+					 struct seq_file *sf)
+{
+	blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp),
+			  cfqg_prfill_leaf_weight_device, &blkcg_policy_cfq, 0,
+			  false);
+	return 0;
+}
+
 static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft,
 			    struct seq_file *sf)
 {
@@ -1411,8 +1449,16 @@ static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft,
 	return 0;
 }
 
-static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
-				  const char *buf)
+static int cfq_print_leaf_weight(struct cgroup *cgrp, struct cftype *cft,
+				 struct seq_file *sf)
+{
+	seq_printf(sf, "%u\n",
+		   cgroup_to_blkcg(cgrp)->cfq_leaf_weight);
+	return 0;
+}
+
+static int __cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
+				    const char *buf, bool is_leaf_weight)
 {
 	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 	struct blkg_conf_ctx ctx;
@@ -1426,8 +1472,13 @@ static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
 	ret = -EINVAL;
 	cfqg = blkg_to_cfqg(ctx.blkg);
 	if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) {
-		cfqg->dev_weight = ctx.v;
-		cfqg->new_weight = cfqg->dev_weight ?: blkcg->cfq_weight;
+		if (!is_leaf_weight) {
+			cfqg->dev_weight = ctx.v;
+			cfqg->new_weight = ctx.v ?: blkcg->cfq_weight;
+		} else {
+			cfqg->dev_leaf_weight = ctx.v;
+			cfqg->new_leaf_weight = ctx.v ?: blkcg->cfq_leaf_weight;
+		}
 		ret = 0;
 	}
 
@@ -1435,7 +1486,20 @@ static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
 	return ret;
 }
 
-static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
+static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
+				  const char *buf)
+{
+	return __cfqg_set_weight_device(cgrp, cft, buf, false);
+}
+
+static int cfqg_set_leaf_weight_device(struct cgroup *cgrp, struct cftype *cft,
+				       const char *buf)
+{
+	return __cfqg_set_weight_device(cgrp, cft, buf, true);
+}
+
+static int __cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val,
+			    bool is_leaf_weight)
 {
 	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 	struct blkcg_gq *blkg;
@@ -1445,19 +1509,41 @@ static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
 		return -EINVAL;
 
 	spin_lock_irq(&blkcg->lock);
-	blkcg->cfq_weight = (unsigned int)val;
+
+	if (!is_leaf_weight)
+		blkcg->cfq_weight = val;
+	else
+		blkcg->cfq_leaf_weight = val;
 
 	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
 		struct cfq_group *cfqg = blkg_to_cfqg(blkg);
 
-		if (cfqg && !cfqg->dev_weight)
-			cfqg->new_weight = blkcg->cfq_weight;
+		if (!cfqg)
+			continue;
+
+		if (!is_leaf_weight) {
+			if (!cfqg->dev_weight)
+				cfqg->new_weight = blkcg->cfq_weight;
+		} else {
+			if (!cfqg->dev_leaf_weight)
+				cfqg->new_leaf_weight = blkcg->cfq_leaf_weight;
+		}
 	}
 
 	spin_unlock_irq(&blkcg->lock);
 	return 0;
 }
 
+static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+	return __cfq_set_weight(cgrp, cft, val, false);
+}
+
+static int cfq_set_leaf_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+	return __cfq_set_weight(cgrp, cft, val, true);
+}
+
 static int cfqg_print_stat(struct cgroup *cgrp, struct cftype *cft,
 			   struct seq_file *sf)
 {
@@ -1518,6 +1604,37 @@ static struct cftype cfq_blkcg_files[] = {
 		.read_seq_string = cfq_print_weight,
 		.write_u64 = cfq_set_weight,
 	},
+
+	/* on root, leaf_weight is mapped to weight */
+	{
+		.name = "leaf_weight_device",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.read_seq_string = cfqg_print_weight_device,
+		.write_string = cfqg_set_weight_device,
+		.max_write_len = 256,
+	},
+	{
+		.name = "leaf_weight",
+		.flags = CFTYPE_ONLY_ON_ROOT,
+		.read_seq_string = cfq_print_weight,
+		.write_u64 = cfq_set_weight,
+	},
+
+	/* no such mapping necessary for !roots */
+	{
+		.name = "leaf_weight_device",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_seq_string = cfqg_print_leaf_weight_device,
+		.write_string = cfqg_set_leaf_weight_device,
+		.max_write_len = 256,
+	},
+	{
+		.name = "leaf_weight",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_seq_string = cfq_print_leaf_weight,
+		.write_u64 = cfq_set_leaf_weight,
+	},
+
 	{
 		.name = "time",
 		.private = offsetof(struct cfq_group, stats.time),
@@ -3992,6 +4109,7 @@ static int cfq_init_queue(struct request_queue *q)
 	cfq_init_cfqg_base(cfqd->root_group);
 #endif
 	cfqd->root_group->weight = 2 * CFQ_WEIGHT_DEFAULT;
+	cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_DEFAULT;
 
 	/*
 	 * Not strictly needed (since RB_ROOT just clears the node and we