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Subject[PATCH 3/4] io-controller: Add a new interface "weight_device" for IO-Controller
From
Date
This is Gui Jianfeng's original patch.
---
block/blk-cgroup.c | 240 +++++++++++++++++++++++++++++++++++++++++++++++++++
block/blk-cgroup.h | 10 ++
block/cfq-iosched.c | 2
3 files changed, 251 insertions(+), 1 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 809451f..bf77b99 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -24,6 +24,13 @@ static LIST_HEAD(blkio_list);
struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
EXPORT_SYMBOL_GPL(blkio_root_cgroup);

+static inline void policy_insert_node(struct blkio_cgroup *blkcg,
+ struct blkio_policy_node *pn);
+static inline void policy_delete_node(struct blkio_policy_node *pn);
+static struct blkio_policy_node *policy_search_node(const struct blkio_cgroup *blkcg,
+ dev_t dev);
+
+
static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
struct cgroup *);
static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
@@ -154,6 +161,7 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
struct blkio_group *blkg;
struct hlist_node *n;
struct blkio_policy_type *blkiop;
+ struct blkio_policy_node *pn;

if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
return -EINVAL;
@@ -162,7 +170,13 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
spin_lock(&blkio_list_lock);
spin_lock_irq(&blkcg->lock);
blkcg->weight = (unsigned int)val;
+
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+ pn = policy_search_node(blkcg, blkg->dev);
+
+ if (pn)
+ continue;
+
list_for_each_entry(blkiop, &blkio_list, list)
blkiop->ops.blkio_update_group_weight_fn(blkg,
blkcg->weight);
@@ -213,8 +227,227 @@ void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_dequeue_stats);
#endif

+static int check_dev_num(dev_t dev)
+{
+ int part = 0;
+ struct gendisk *disk;
+
+ disk = get_gendisk(dev, &part);
+ if (!disk || part)
+ return -ENODEV;
+
+ return 0;
+}
+
+static int policy_parse_and_set(char *buf, struct blkio_policy_node *newpn)
+{
+ char *s[4], *p, *major_s = NULL, *minor_s = NULL;
+ int ret;
+ unsigned long major, minor, temp;
+ int i = 0;
+ dev_t dev;
+
+ memset(s, 0, sizeof(s));
+
+ while ((p = strsep(&buf, " ")) != NULL) {
+ if (!*p)
+ continue;
+
+ s[i++] = p;
+
+ /* Prevent from inputing too many things */
+ if (i == 3)
+ break;
+ }
+
+ if (i != 2)
+ return -EINVAL;
+
+ p = strsep(&s[0], ":");
+ if (p != NULL)
+ major_s = p;
+ else
+ return -EINVAL;
+
+ minor_s = s[0];
+ if (!minor_s)
+ return -EINVAL;
+
+ ret = strict_strtoul(major_s, 10, &major);
+ if (ret)
+ return -EINVAL;
+
+ ret = strict_strtoul(minor_s, 10, &minor);
+ if (ret)
+ return -EINVAL;
+
+ dev = MKDEV(major, minor);
+
+ ret = check_dev_num(dev);
+ if (ret)
+ return ret;
+
+ newpn->dev = dev;
+
+ if (s[1] == NULL)
+ return -EINVAL;
+
+ ret = strict_strtoul(s[1], 10, &temp);
+ if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
+ temp > BLKIO_WEIGHT_MAX)
+ return -EINVAL;
+
+ newpn->weight = temp;
+
+ return 0;
+}
+
+unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
+ dev_t dev)
+{
+ struct blkio_policy_node *pn;
+
+ pn = policy_search_node(blkcg, dev);
+ if (pn)
+ return pn->weight;
+ else
+ return blkcg->weight;
+}
+EXPORT_SYMBOL_GPL(blkcg_get_weight);
+
+static inline void policy_insert_node(struct blkio_cgroup *blkcg,
+ struct blkio_policy_node *pn)
+{
+ list_add(&pn->node, &blkcg->policy_list);
+}
+
+/* Must be called with blkcg->lock held */
+static inline void policy_delete_node(struct blkio_policy_node *pn)
+{
+ list_del(&pn->node);
+}
+
+/* Must be called with blkcg->lock held */
+static struct blkio_policy_node *policy_search_node(const struct blkio_cgroup *blkcg,
+ dev_t dev)
+{
+ struct blkio_policy_node *pn;
+
+ list_for_each_entry(pn, &blkcg->policy_list, node) {
+ if (pn->dev == dev)
+ return pn;
+ }
+
+ return NULL;
+}
+
+
+static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
+ const char *buffer)
+{
+ int ret = 0;
+ char *buf;
+ struct blkio_policy_node *newpn, *pn;
+ struct blkio_cgroup *blkcg;
+ struct blkio_group *blkg;
+ int keep_newpn = 0;
+ struct hlist_node *n;
+ struct blkio_policy_type *blkiop;
+
+ buf = kstrdup(buffer, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
+ if (!newpn) {
+ ret = -ENOMEM;
+ goto free_buf;
+ }
+
+ ret = policy_parse_and_set(buf, newpn);
+ if (ret)
+ goto free_newpn;
+
+ blkcg = cgroup_to_blkio_cgroup(cgrp);
+
+ spin_lock_irq(&blkcg->lock);
+
+ pn = policy_search_node(blkcg, newpn->dev);
+ if (!pn) {
+ if (newpn->weight != 0) {
+ policy_insert_node(blkcg, newpn);
+ keep_newpn = 1;
+ }
+ spin_unlock_irq(&blkcg->lock);
+ goto update_io_group;
+ }
+
+ if (newpn->weight == 0) {
+ /* weight == 0 means deleteing a specific weight */
+ policy_delete_node(pn);
+ spin_unlock_irq(&blkcg->lock);
+ goto update_io_group;
+ }
+ spin_unlock_irq(&blkcg->lock);
+
+ pn->weight = newpn->weight;
+
+update_io_group:
+ /* update weight for each cfqg */
+ spin_lock(&blkio_list_lock);
+ spin_lock_irq(&blkcg->lock);
+
+ hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+ if (newpn->dev == blkg->dev) {
+ list_for_each_entry(blkiop, &blkio_list, list)
+ blkiop->ops.blkio_update_group_weight_fn(blkg,
+ newpn->weight ?
+ newpn->weight :
+ blkcg->weight);
+ }
+ }
+
+ spin_unlock_irq(&blkcg->lock);
+ spin_unlock(&blkio_list_lock);
+
+free_newpn:
+ if (!keep_newpn)
+ kfree(newpn);
+free_buf:
+ kfree(buf);
+ return ret;
+}
+
+static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
+ struct seq_file *m)
+{
+ struct blkio_cgroup *blkcg;
+ struct blkio_policy_node *pn;
+
+ seq_printf(m, "dev\tweight\n");
+
+ blkcg = cgroup_to_blkio_cgroup(cgrp);
+ if (list_empty(&blkcg->policy_list))
+ goto out;
+
+ spin_lock_irq(&blkcg->lock);
+ list_for_each_entry(pn, &blkcg->policy_list, node) {
+ seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
+ MINOR(pn->dev), pn->weight);
+ }
+ spin_unlock_irq(&blkcg->lock);
+out:
+ return 0;
+}
+
struct cftype blkio_files[] = {
{
+ .name = "weight_device",
+ .read_seq_string = blkiocg_weight_device_read,
+ .write_string = blkiocg_weight_device_write,
+ .max_write_len = 256,
+ },
+ {
.name = "weight",
.read_u64 = blkiocg_weight_read,
.write_u64 = blkiocg_weight_write,
@@ -247,6 +480,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
unsigned long flags;
struct blkio_group *blkg;
struct blkio_policy_type *blkiop;
+ struct blkio_policy_node *pn, *pntmp;

rcu_read_lock();
remove_entry:
@@ -276,7 +510,12 @@ remove_entry:
blkiop->ops.blkio_unlink_group_fn(blkg);
spin_unlock(&blkio_list_lock);
goto remove_entry;
+
done:
+ list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
+ policy_delete_node(pn);
+ kfree(pn);
+ }
free_css_id(&blkio_subsys, &blkcg->css);
rcu_read_unlock();
if (blkcg != &blkio_root_cgroup)
@@ -307,6 +546,7 @@ done:
spin_lock_init(&blkcg->lock);
INIT_HLIST_HEAD(&blkcg->blkg_list);

+ INIT_LIST_HEAD(&blkcg->policy_list);
return &blkcg->css;
}

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 9e70c03..92296b8 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -29,6 +29,7 @@ struct blkio_cgroup {
unsigned int weight;
spinlock_t lock;
struct hlist_head blkg_list;
+ struct list_head policy_list; /* list of blkio_policy_node */
};

struct blkio_group {
@@ -50,6 +51,15 @@ struct blkio_group {
unsigned long sectors;
};

+struct blkio_policy_node {
+ struct list_head node;
+ dev_t dev;
+ unsigned int weight;
+};
+
+extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
+ dev_t dev);
+
typedef void (blkio_unlink_group_fn) (struct blkio_group *blkg);
typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
unsigned int weight);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 864b39a..d4d57a3 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -954,7 +954,6 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
if (!cfqg)
goto done;

- cfqg->weight = blkcg->weight;
for_each_cfqg_st(cfqg, i, j, st)
*st = CFQ_RB_ROOT;
RB_CLEAR_NODE(&cfqg->rb_node);
@@ -971,6 +970,7 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
blkiocg_add_blkio_group(blkcg, &cfqg->blkg, cfqd->queue,
MKDEV(major, minor));
+ cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);

/* Add group on cfqd list */
hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);


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