blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy

[cascardo/linux.git] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0fe721e..04de884 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1522,6 +1522,9 @@ static void cfq_init_cfqg_base(struct cfq_group *cfqg)
 }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
+static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
+                           bool on_dfl, bool reset_dev, bool is_leaf_weight);
+
 static void cfqg_stats_exit(struct cfqg_stats *stats)
 {
        blkg_rwstat_exit(&stats->merged);
@@ -1578,14 +1581,14 @@ static struct blkcg_policy_data *cfq_cpd_alloc(gfp_t gfp)
 static void cfq_cpd_init(struct blkcg_policy_data *cpd)
 {
        struct cfq_group_data *cgd = cpd_to_cfqgd(cpd);
+       unsigned int weight = cgroup_on_dfl(blkcg_root.css.cgroup) ?
+                             CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
 
-       if (cpd_to_blkcg(cpd) == &blkcg_root) {
-               cgd->weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
-               cgd->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
-       } else {
-               cgd->weight = CFQ_WEIGHT_LEGACY_DFL;
-               cgd->leaf_weight = CFQ_WEIGHT_LEGACY_DFL;
-       }
+       if (cpd_to_blkcg(cpd) == &blkcg_root)
+               weight *= 2;
+
+       cgd->weight = weight;
+       cgd->leaf_weight = weight;
 }
 
 static void cfq_cpd_free(struct blkcg_policy_data *cpd)
@@ -1593,6 +1596,19 @@ static void cfq_cpd_free(struct blkcg_policy_data *cpd)
        kfree(cpd_to_cfqgd(cpd));
 }
 
+static void cfq_cpd_bind(struct blkcg_policy_data *cpd)
+{
+       struct blkcg *blkcg = cpd_to_blkcg(cpd);
+       bool on_dfl = cgroup_on_dfl(blkcg_root.css.cgroup);
+       unsigned int weight = on_dfl ? CGROUP_WEIGHT_DFL : CFQ_WEIGHT_LEGACY_DFL;
+
+       if (blkcg == &blkcg_root)
+               weight *= 2;
+
+       WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, false));
+       WARN_ON_ONCE(__cfq_set_weight(&blkcg->css, weight, on_dfl, true, true));
+}
+
 static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node)
 {
        struct cfq_group *cfqg;
@@ -1742,6 +1758,8 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
                                        char *buf, size_t nbytes, loff_t off,
                                        bool on_dfl, bool is_leaf_weight)
 {
+       unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN;
+       unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX;
        struct blkcg *blkcg = css_to_blkcg(of_css(of));
        struct blkg_conf_ctx ctx;
        struct cfq_group *cfqg;
@@ -1769,7 +1787,7 @@ static ssize_t __cfqg_set_weight_device(struct kernfs_open_file *of,
        cfqgd = blkcg_to_cfqgd(blkcg);
 
        ret = -ERANGE;
-       if (!v || (v >= CFQ_WEIGHT_LEGACY_MIN && v <= CFQ_WEIGHT_LEGACY_MAX)) {
+       if (!v || (v >= min && v <= max)) {
                if (!is_leaf_weight) {
                        cfqg->dev_weight = v;
                        cfqg->new_weight = v ?: cfqgd->weight;
@@ -1797,15 +1815,17 @@ static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of,
 }
 
 static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
-                           bool is_leaf_weight)
+                           bool on_dfl, bool reset_dev, bool is_leaf_weight)
 {
+       unsigned int min = on_dfl ? CGROUP_WEIGHT_MIN : CFQ_WEIGHT_LEGACY_MIN;
+       unsigned int max = on_dfl ? CGROUP_WEIGHT_MAX : CFQ_WEIGHT_LEGACY_MAX;
        struct blkcg *blkcg = css_to_blkcg(css);
        struct blkcg_gq *blkg;
        struct cfq_group_data *cfqgd;
        int ret = 0;
 
-       if (val < CFQ_WEIGHT_LEGACY_MIN || val > CFQ_WEIGHT_LEGACY_MAX)
-               return -EINVAL;
+       if (val < min || val > max)
+               return -ERANGE;
 
        spin_lock_irq(&blkcg->lock);
        cfqgd = blkcg_to_cfqgd(blkcg);
@@ -1826,9 +1846,13 @@ static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
                        continue;
 
                if (!is_leaf_weight) {
+                       if (reset_dev)
+                               cfqg->dev_weight = 0;
                        if (!cfqg->dev_weight)
                                cfqg->new_weight = cfqgd->weight;
                } else {
+                       if (reset_dev)
+                               cfqg->dev_leaf_weight = 0;
                        if (!cfqg->dev_leaf_weight)
                                cfqg->new_leaf_weight = cfqgd->leaf_weight;
                }
@@ -1842,13 +1866,13 @@ out:
 static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,
                          u64 val)
 {
-       return __cfq_set_weight(css, val, false);
+       return __cfq_set_weight(css, val, false, false, false);
 }
 
 static int cfq_set_leaf_weight(struct cgroup_subsys_state *css,
                               struct cftype *cft, u64 val)
 {
-       return __cfq_set_weight(css, val, true);
+       return __cfq_set_weight(css, val, false, false, true);
 }
 
 static int cfqg_print_stat(struct seq_file *sf, void *v)
@@ -2135,7 +2159,7 @@ static ssize_t cfq_set_weight_on_dfl(struct kernfs_open_file *of,
        /* "WEIGHT" or "default WEIGHT" sets the default weight */
        v = simple_strtoull(buf, &endp, 0);
        if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
-               ret = __cfq_set_weight(of_css(of), v, false);
+               ret = __cfq_set_weight(of_css(of), v, true, false, false);
                return ret ?: nbytes;
        }
 
@@ -4512,9 +4536,9 @@ static int cfq_init_queue(struct request_queue *q, struct elevator_type *e)
                goto out_free;
 
        cfq_init_cfqg_base(cfqd->root_group);
-#endif
        cfqd->root_group->weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
        cfqd->root_group->leaf_weight = 2 * CFQ_WEIGHT_LEGACY_DFL;
+#endif
 
        /*
         * Not strictly needed (since RB_ROOT just clears the node and we
@@ -4715,6 +4739,7 @@ static struct blkcg_policy blkcg_policy_cfq = {
        .cpd_alloc_fn           = cfq_cpd_alloc,
        .cpd_init_fn            = cfq_cpd_init,
        .cpd_free_fn            = cfq_cpd_free,
+       .cpd_bind_fn            = cfq_cpd_bind,
 
        .pd_alloc_fn            = cfq_pd_alloc,
        .pd_init_fn             = cfq_pd_init,