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authorTejun Heo <tj@kernel.org>2015-08-18 14:55:36 -0700
committerJens Axboe <axboe@fb.com>2015-08-18 15:49:36 -0700
commit69d7fde5909b614114343974cfc52cb8ff30b544 (patch)
tree231d68d331b286767109c616823781ed030ecb2b /block/cfq-iosched.c
parent3ecca62931ee6a30822a1ab7299bc8b8a21e5288 (diff)
downloadlinux-0-day-69d7fde5909b614114343974cfc52cb8ff30b544.tar.gz
blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy
cgroup is trying to make interface consistent across different controllers. For weight based resource control, the knob should have the range [1, 10000] and default to 100. This patch updates cfq-iosched so that the weight range conforms. The internal calculations have enough range and the widening of the weight range shouldn't cause any problem. * blkcg_policy->cpd_bind_fn() is added. If present, this is invoked when blkcg is attached to a hierarchy. * cfq_cpd_init() is updated to use the new default value on the unified hierarchy. * cfq_cpd_bind() callback is implemented to clear per-blkg configs and apply the default config matching the hierarchy type. * cfqd->root_group->[leaf_]weight initialization in cfq_init_queue() is moved into !CONFIG_CFQ_GROUP_IOSCHED block. cfq_cpd_bind() is now responsible for initializing the initial weights when blkcg is enabled. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Arianna Avanzini <avanzini.arianna@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c55
1 files changed, 40 insertions, 15 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 0fe721e..04de884 100644
--- 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,