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SubjectRe: [PATCH 1/2 V3] io-controller: Add a new interface "weight_device" for IO-Controller
On Fri, Mar 05, 2010 at 10:25:58AM +0800, Gui Jianfeng wrote:
> 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:
>
> major:minor represents device number.
>
> And you can remove a specific weight as following:
>
> 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_"
>

Thanks for the changes Gui. Looks good to me.

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Vivek

> Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
> ---
> block/blk-cgroup.c | 236 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> block/blk-cgroup.h | 10 ++
> block/cfq-iosched.c | 2 +-
> 3 files changed, 246 insertions(+), 2 deletions(-)
>
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index c85d74c..8825e49 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -16,6 +16,7 @@
> #include <linux/module.h>
> #include <linux/err.h>
> #include "blk-cgroup.h"
> +#include <linux/genhd.h>
>
> static DEFINE_SPINLOCK(blkio_list_lock);
> static LIST_HEAD(blkio_list);
> @@ -23,6 +24,32 @@ 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 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),
> @@ -128,6 +155,7 @@ 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;
> @@ -136,7 +164,13 @@ 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 = 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);
> @@ -178,15 +212,208 @@ SHOW_FUNCTION_PER_GROUP(dequeue);
>
> #ifdef CONFIG_DEBUG_BLK_CGROUP
> void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
> - unsigned long dequeue)
> + unsigned long dequeue)
> {
> blkg->dequeue += dequeue;
> }
> EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_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,
> @@ -220,6 +447,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
> struct blkio_group *blkg;
> void *key;
> struct blkio_policy_type *blkiop;
> + struct blkio_policy_node *pn, *pntmp;
>
> rcu_read_lock();
> remove_entry:
> @@ -250,7 +478,12 @@ remove_entry:
> 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();
> kfree(blkcg);
> @@ -280,6 +513,7 @@ 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 84bf745..c8144a2 100644
> --- a/block/blk-cgroup.h
> +++ b/block/blk-cgroup.h
> @@ -22,6 +22,7 @@ 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 {
> @@ -43,6 +44,15 @@ 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) (void *key, 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 dee9d93..6945e9b 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, (void *)cfqd,
> 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);
> --
> 1.5.4.rc3
>
>
>
>


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