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Subject[PATCH 4/4] Use disk-names to set blkio.weight_device policy
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Date
This patch also cleans up a few fields and arguments that are no
longer used once request_queue is the key for both blkio_groups as
well as blkio_policy_nodes.
---
block/blk-cgroup.c | 103 ++++++++++++++-------------------------------------
block/blk-cgroup.h | 6 +--
block/cfq-iosched.c | 9 +---
3 files changed, 35 insertions(+), 83 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index bf77b99..086a00d 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -28,7 +28,7 @@ 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);
+ struct request_queue *queue);


static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
@@ -72,7 +72,7 @@ void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_stats);

void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, struct request_queue *queue, dev_t dev)
+ struct blkio_group *blkg, struct request_queue *queue)
{
unsigned long flags;

@@ -85,7 +85,6 @@ void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
/* Need to take css reference ? */
cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
#endif
- blkg->dev = dev;
}
EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);

@@ -172,7 +171,7 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
blkcg->weight = (unsigned int)val;

hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
- pn = policy_search_node(blkcg, blkg->dev);
+ pn = policy_search_node(blkcg, blkg->queue);

if (pn)
continue;
@@ -227,87 +226,39 @@ 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)
+static int policy_parse_and_set(char *buf, struct blkio_policy_node *newpn)
{
+ char disk_name[BDEVNAME_SIZE];
+ int weight;
+ int nfields;
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)
+ nfields = sscanf(buf, "%s %d", disk_name, &weight);
+ if (nfields != 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;
+ dev = blk_lookup_devt(disk_name, 0);
+ if (!dev)
+ return -ENODEV;

- ret = strict_strtoul(s[1], 10, &temp);
- if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
- temp > BLKIO_WEIGHT_MAX)
- return -EINVAL;
+ disk = get_gendisk(dev, &part);
+ if (!disk || part)
+ return -ENODEV;

- newpn->weight = temp;
+ newpn->weight = weight;
+ newpn->queue = disk->queue;

return 0;
}

unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
- dev_t dev)
+ struct request_queue *queue)
{
struct blkio_policy_node *pn;

- pn = policy_search_node(blkcg, dev);
+ pn = policy_search_node(blkcg, queue);
if (pn)
return pn->weight;
else
@@ -329,12 +280,12 @@ static inline void policy_delete_node(struct blkio_policy_node *pn)

/* Must be called with blkcg->lock held */
static struct blkio_policy_node *policy_search_node(const struct blkio_cgroup *blkcg,
- dev_t dev)
+ struct request_queue *queue)
{
struct blkio_policy_node *pn;

list_for_each_entry(pn, &blkcg->policy_list, node) {
- if (pn->dev == dev)
+ if (pn->queue == queue)
return pn;
}

@@ -372,7 +323,7 @@ static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,

spin_lock_irq(&blkcg->lock);

- pn = policy_search_node(blkcg, newpn->dev);
+ pn = policy_search_node(blkcg, newpn->queue);
if (!pn) {
if (newpn->weight != 0) {
policy_insert_node(blkcg, newpn);
@@ -398,7 +349,7 @@ update_io_group:
spin_lock_irq(&blkcg->lock);

hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
- if (newpn->dev == blkg->dev) {
+ if (newpn->queue == blkg->queue) {
list_for_each_entry(blkiop, &blkio_list, list)
blkiop->ops.blkio_update_group_weight_fn(blkg,
newpn->weight ?
@@ -423,6 +374,7 @@ static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
{
struct blkio_cgroup *blkcg;
struct blkio_policy_node *pn;
+ struct gendisk *disk;

seq_printf(m, "dev\tweight\n");

@@ -430,12 +382,15 @@ static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
if (list_empty(&blkcg->policy_list))
goto out;

+ rcu_read_lock();
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);
+ disk = rcu_dereference(pn->queue->disk);
+ if (disk != NULL)
+ seq_printf(m, "%s\t%u\n", disk->disk_name, pn->weight);
}
spin_unlock_irq(&blkcg->lock);
+ rcu_read_unlock();
out:
return 0;
}
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 92296b8..14177b5 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -53,12 +53,12 @@ struct blkio_group {

struct blkio_policy_node {
struct list_head node;
- dev_t dev;
+ struct request_queue *queue;
unsigned int weight;
};

extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
- dev_t dev);
+ struct request_queue *queue);

typedef void (blkio_unlink_group_fn) (struct blkio_group *blkg);
typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
@@ -112,7 +112,7 @@ static inline void blkiocg_update_blkio_group_dequeue_stats(
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, struct request_queue *queue, dev_t dev);
+ struct blkio_group *blkg, struct request_queue *queue);
extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
struct request_queue *queue);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d4d57a3..39d2048 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -944,7 +944,6 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
int i, j;
struct cfq_rb_root *st;
struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
- unsigned int major, minor;

cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, queue));
if (cfqg || !create)
@@ -967,10 +966,8 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
atomic_set(&cfqg->ref, 1);

/* Add group onto cgroup list */
- 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);
+ blkiocg_add_blkio_group(blkcg, &cfqg->blkg, cfqd->queue);
+ cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.queue);

/* Add group on cfqd list */
hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
@@ -3671,7 +3668,7 @@ static void *cfq_init_queue(struct request_queue *q)
* to make sure that cfq_put_cfqg() does not try to kfree root group
*/
atomic_set(&cfqg->ref, 1);
- blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, q, 0);
+ blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, q);
#endif
/*
* Not strictly needed (since RB_ROOT just clears the node and we


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