io-controller: Add a new interface "weight_device" for IO-Controller
Currently, IO Controller makes use of blkio.weight to assign weight for
all devices. Here a new user interface "blkio.weight_device" is introduced to
assign different weights for different devices. blkio.weight becomes the
default value for devices which are not configured by "blkio.weight_device"
You can use the following format to assigned specific weight for a given
device:
#echo "major:minor weight" > blkio.weight_device
major:minor represents device number.
And you can remove weight for a given device as following:
#echo "major:minor 0" > blkio.weight_device
V1->V2 changes:
- use user interface "weight_device" instead of "policy" suggested by Vivek
- rename some struct suggested by Vivek
- rebase to 2.6-block "for-linus" branch
- remove an useless list_empty check pointed out by Li Zefan
- some trivial typo fix
V2->V3 changes:
- Move policy_*_node() functions up to get rid of forward declarations
- rename related functions by adding prefix "blkio_"
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1ecff7a..649b05d 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -17,6 +17,7 @@
#include <linux/err.h>
#include <linux/blkdev.h>
#include "blk-cgroup.h"
+#include <linux/genhd.h>
#define MAX_KEY_LEN 100
@@ -51,6 +52,32 @@
};
EXPORT_SYMBOL_GPL(blkio_subsys);
+static inline void blkio_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 blkio_policy_delete_node(struct blkio_policy_node *pn)
+{
+ list_del(&pn->node);
+}
+
+/* Must be called with blkcg->lock held */
+static struct blkio_policy_node *
+blkio_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;
+}
+
struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
{
return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
@@ -398,6 +425,7 @@
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;
@@ -406,7 +434,13 @@
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 = blkio_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);
@@ -611,8 +645,203 @@
EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
#endif
+static int blkio_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 blkio_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 = blkio_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 = blkio_policy_search_node(blkcg, dev);
+ if (pn)
+ return pn->weight;
+ else
+ return blkcg->weight;
+}
+EXPORT_SYMBOL_GPL(blkcg_get_weight);
+
+
+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 = blkio_policy_parse_and_set(buf, newpn);
+ if (ret)
+ goto free_newpn;
+
+ blkcg = cgroup_to_blkio_cgroup(cgrp);
+
+ spin_lock_irq(&blkcg->lock);
+
+ pn = blkio_policy_search_node(blkcg, newpn->dev);
+ if (!pn) {
+ if (newpn->weight != 0) {
+ blkio_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 */
+ blkio_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,
@@ -690,6 +919,7 @@
struct blkio_group *blkg;
void *key;
struct blkio_policy_type *blkiop;
+ struct blkio_policy_node *pn, *pntmp;
rcu_read_lock();
remove_entry:
@@ -720,7 +950,12 @@
blkiop->ops.blkio_unlink_group_fn(key, blkg);
spin_unlock(&blkio_list_lock);
goto remove_entry;
+
done:
+ list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
+ blkio_policy_delete_node(pn);
+ kfree(pn);
+ }
free_css_id(&blkio_subsys, &blkcg->css);
rcu_read_unlock();
if (blkcg != &blkio_root_cgroup)
@@ -751,6 +986,7 @@
spin_lock_init(&blkcg->lock);
INIT_HLIST_HEAD(&blkcg->blkg_list);
+ INIT_LIST_HEAD(&blkcg->policy_list);
return &blkcg->css;
}