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SubjectRe: [PATCH] IO Controller: Add per-device weight and ioprio_class handling
On Thu, May 14, 2009 at 03:26:35PM +0800, Gui Jianfeng wrote:
> Hi Vivek,
>
> This patch enables per-cgroup per-device weight and ioprio_class handling.
> A new cgroup interface "policy" is introduced. You can make use of this
> file to configure weight and ioprio_class for each device in a given cgroup.
> The original "weight" and "ioprio_class" files are still available. If you
> don't do special configuration for a particular device, "weight" and
> "ioprio_class" are used as default values in this device.
>
> You can use the following format to play with the new interface.
> #echo DEV:weight:ioprio_class > /patch/to/cgroup/policy
> weight=0 means removing the policy for DEV.
>
> Examples:
> Configure weight=300 ioprio_class=2 on /dev/hdb in this cgroup
> # echo /dev/hdb:300:2 > io.policy
> # cat io.policy
> dev weight class
> /dev/hdb 300 2
>
> Configure weight=500 ioprio_class=1 on /dev/hda in this cgroup
> # echo /dev/hda:500:1 > io.policy
> # cat io.policy
> dev weight class
> /dev/hda 500 1
> /dev/hdb 300 2
>
> Remove the policy for /dev/hda in this cgroup
> # echo /dev/hda:0:1 > io.policy
> # cat io.policy
> dev weight class
> /dev/hdb 300 2
>
> Changelog (v1 -> v2)
> - Rename some structures
> - Use spin_lock_irqsave() and spin_lock_irqrestore() version to prevent
> from enabling the interrupts unconditionally.
> - Fix policy setup bug when switching to another io scheduler.
> - If a policy is available for a specific device, don't update weight and
> io class when writing "weight" and "iprio_class".
> - Fix a bug when parsing policy string.
>
> Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
> ---

Thanks a lot Gui. This patch seems to be working fine for me now. I will
continue to do more testing and let you know if there are more issues. I
will include it in next posting (V3).

Thanks
Vivek

> block/elevator-fq.c | 258 +++++++++++++++++++++++++++++++++++++++++++++++++--
> block/elevator-fq.h | 12 +++
> 2 files changed, 261 insertions(+), 9 deletions(-)
>
> diff --git a/block/elevator-fq.c b/block/elevator-fq.c
> index 69435ab..43b30a4 100644
> --- a/block/elevator-fq.c
> +++ b/block/elevator-fq.c
> @@ -12,6 +12,9 @@
> #include "elevator-fq.h"
> #include <linux/blktrace_api.h>
> #include <linux/biotrack.h>
> +#include <linux/seq_file.h>
> +#include <linux/genhd.h>
> +
>
> /* Values taken from cfq */
> const int elv_slice_sync = HZ / 10;
> @@ -1045,12 +1048,31 @@ struct io_group *io_lookup_io_group_current(struct request_queue *q)
> }
> EXPORT_SYMBOL(io_lookup_io_group_current);
>
> -void io_group_init_entity(struct io_cgroup *iocg, struct io_group *iog)
> +static struct io_policy_node *policy_search_node(const struct io_cgroup *iocg,
> + dev_t dev);
> +
> +void io_group_init_entity(struct io_cgroup *iocg, struct io_group *iog,
> + dev_t dev)
> {
> struct io_entity *entity = &iog->entity;
> + struct io_policy_node *pn;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&iocg->lock, flags);
> + pn = policy_search_node(iocg, dev);
> + if (pn) {
> + entity->weight = pn->weight;
> + entity->new_weight = pn->weight;
> + entity->ioprio_class = pn->ioprio_class;
> + entity->new_ioprio_class = pn->ioprio_class;
> + } else {
> + entity->weight = iocg->weight;
> + entity->new_weight = iocg->weight;
> + entity->ioprio_class = iocg->ioprio_class;
> + entity->new_ioprio_class = iocg->ioprio_class;
> + }
> + spin_unlock_irqrestore(&iocg->lock, flags);
>
> - entity->weight = entity->new_weight = iocg->weight;
> - entity->ioprio_class = entity->new_ioprio_class = iocg->ioprio_class;
> entity->ioprio_changed = 1;
> entity->my_sched_data = &iog->sched_data;
> }
> @@ -1114,6 +1136,7 @@ static int io_cgroup_##__VAR##_write(struct cgroup *cgroup, \
> struct io_cgroup *iocg; \
> struct io_group *iog; \
> struct hlist_node *n; \
> + struct io_policy_node *pn; \
> \
> if (val < (__MIN) || val > (__MAX)) \
> return -EINVAL; \
> @@ -1126,6 +1149,9 @@ static int io_cgroup_##__VAR##_write(struct cgroup *cgroup, \
> spin_lock_irq(&iocg->lock); \
> iocg->__VAR = (unsigned long)val; \
> hlist_for_each_entry(iog, n, &iocg->group_data, group_node) { \
> + pn = policy_search_node(iocg, iog->dev); \
> + if (pn) \
> + continue; \
> iog->entity.new_##__VAR = (unsigned long)val; \
> smp_wmb(); \
> iog->entity.ioprio_changed = 1; \
> @@ -1237,7 +1263,7 @@ static u64 io_cgroup_disk_sectors_read(struct cgroup *cgroup,
> * to the root has already an allocated group on @bfqd.
> */
> struct io_group *io_group_chain_alloc(struct request_queue *q, void *key,
> - struct cgroup *cgroup)
> + struct cgroup *cgroup, struct bio *bio)
> {
> struct io_cgroup *iocg;
> struct io_group *iog, *leaf = NULL, *prev = NULL;
> @@ -1263,12 +1289,17 @@ struct io_group *io_group_chain_alloc(struct request_queue *q, void *key,
> atomic_set(&iog->ref, 0);
> iog->deleting = 0;
>
> - io_group_init_entity(iocg, iog);
> - iog->my_entity = &iog->entity;
> #ifdef CONFIG_DEBUG_GROUP_IOSCHED
> iog->iocg_id = css_id(&iocg->css);
> + if (bio) {
> + struct gendisk *disk = bio->bi_bdev->bd_disk;
> + iog->dev = MKDEV(disk->major, disk->first_minor);
> + }
> #endif
>
> + io_group_init_entity(iocg, iog, iog->dev);
> + iog->my_entity = &iog->entity;
> +
> blk_init_request_list(&iog->rl);
>
> if (leaf == NULL) {
> @@ -1379,7 +1410,7 @@ void io_group_chain_link(struct request_queue *q, void *key,
> */
> struct io_group *io_find_alloc_group(struct request_queue *q,
> struct cgroup *cgroup, struct elv_fq_data *efqd,
> - int create)
> + int create, struct bio *bio)
> {
> struct io_cgroup *iocg = cgroup_to_io_cgroup(cgroup);
> struct io_group *iog = NULL;
> @@ -1390,7 +1421,7 @@ struct io_group *io_find_alloc_group(struct request_queue *q,
> if (iog != NULL || !create)
> return iog;
>
> - iog = io_group_chain_alloc(q, key, cgroup);
> + iog = io_group_chain_alloc(q, key, cgroup, bio);
> if (iog != NULL)
> io_group_chain_link(q, key, cgroup, iog, efqd);
>
> @@ -1489,7 +1520,7 @@ struct io_group *io_get_io_group_bio(struct request_queue *q, struct bio *bio,
> goto out;
> }
>
> - iog = io_find_alloc_group(q, cgroup, efqd, create);
> + iog = io_find_alloc_group(q, cgroup, efqd, create, bio);
> if (!iog) {
> if (create)
> iog = efqd->root_group;
> @@ -1549,8 +1580,209 @@ struct io_group *io_alloc_root_group(struct request_queue *q,
> return iog;
> }
>
> +static int io_cgroup_policy_read(struct cgroup *cgrp, struct cftype *cft,
> + struct seq_file *m)
> +{
> + struct io_cgroup *iocg;
> + struct io_policy_node *pn;
> +
> + iocg = cgroup_to_io_cgroup(cgrp);
> +
> + if (list_empty(&iocg->policy_list))
> + goto out;
> +
> + seq_printf(m, "dev weight class\n");
> +
> + spin_lock_irq(&iocg->lock);
> + list_for_each_entry(pn, &iocg->policy_list, node) {
> + seq_printf(m, "%s %lu %lu\n", pn->dev_name,
> + pn->weight, pn->ioprio_class);
> + }
> + spin_unlock_irq(&iocg->lock);
> +out:
> + return 0;
> +}
> +
> +static inline void policy_insert_node(struct io_cgroup *iocg,
> + struct io_policy_node *pn)
> +{
> + list_add(&pn->node, &iocg->policy_list);
> +}
> +
> +/* Must be called with iocg->lock held */
> +static inline void policy_delete_node(struct io_policy_node *pn)
> +{
> + list_del(&pn->node);
> +}
> +
> +/* Must be called with iocg->lock held */
> +static struct io_policy_node *policy_search_node(const struct io_cgroup *iocg,
> + dev_t dev)
> +{
> + struct io_policy_node *pn;
> +
> + if (list_empty(&iocg->policy_list))
> + return NULL;
> +
> + list_for_each_entry(pn, &iocg->policy_list, node) {
> + if (pn->dev == dev)
> + return pn;
> + }
> +
> + return NULL;
> +}
> +
> +static int devname_to_devnum(const char *buf, dev_t *dev)
> +{
> + struct block_device *bdev;
> + struct gendisk *disk;
> + int part;
> +
> + bdev = lookup_bdev(buf);
> + if (IS_ERR(bdev))
> + return -ENODEV;
> +
> + disk = get_gendisk(bdev->bd_dev, &part);
> + *dev = MKDEV(disk->major, disk->first_minor);
> + bdput(bdev);
> +
> + return 0;
> +}
> +
> +static int policy_parse_and_set(char *buf, struct io_policy_node *newpn)
> +{
> + char *s[3], *p;
> + int ret;
> + int i = 0;
> +
> + memset(s, 0, sizeof(s));
> + while ((p = strsep(&buf, ":")) != NULL) {
> + if (!*p)
> + continue;
> + s[i++] = p;
> + }
> +
> + ret = devname_to_devnum(s[0], &newpn->dev);
> + if (ret)
> + return ret;
> +
> + strcpy(newpn->dev_name, s[0]);
> +
> + if (s[1] == NULL)
> + return -EINVAL;
> +
> + ret = strict_strtoul(s[1], 10, &newpn->weight);
> + if (ret || newpn->weight > WEIGHT_MAX)
> + return -EINVAL;
> +
> + if (s[2] == NULL)
> + return -EINVAL;
> +
> + ret = strict_strtoul(s[2], 10, &newpn->ioprio_class);
> + if (ret || newpn->ioprio_class < IOPRIO_CLASS_RT ||
> + newpn->ioprio_class > IOPRIO_CLASS_IDLE)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int io_cgroup_policy_write(struct cgroup *cgrp, struct cftype *cft,
> + const char *buffer)
> +{
> + struct io_cgroup *iocg;
> + struct io_policy_node *newpn, *pn;
> + char *buf;
> + int ret = 0;
> + int keep_newpn = 0;
> + struct hlist_node *n;
> + struct io_group *iog;
> +
> + 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;
> +
> + if (!cgroup_lock_live_group(cgrp)) {
> + ret = -ENODEV;
> + goto free_newpn;
> + }
> +
> + iocg = cgroup_to_io_cgroup(cgrp);
> + spin_lock_irq(&iocg->lock);
> +
> + pn = policy_search_node(iocg, newpn->dev);
> + if (!pn) {
> + if (newpn->weight != 0) {
> + policy_insert_node(iocg, newpn);
> + keep_newpn = 1;
> + }
> + goto update_io_group;
> + }
> +
> + if (newpn->weight == 0) {
> + /* weight == 0 means deleteing a policy */
> + policy_delete_node(pn);
> + goto update_io_group;
> + }
> +
> + pn->weight = newpn->weight;
> + pn->ioprio_class = newpn->ioprio_class;
> +
> +update_io_group:
> + hlist_for_each_entry(iog, n, &iocg->group_data, group_node) {
> + if (iog->dev == newpn->dev) {
> + if (newpn->weight) {
> + iog->entity.new_weight = newpn->weight;
> + iog->entity.new_ioprio_class =
> + newpn->ioprio_class;
> + /*
> + * iog weight and ioprio_class updating
> + * actually happens if ioprio_changed is set.
> + * So ensure ioprio_changed is not set until
> + * new weight and new ioprio_class are updated.
> + */
> + smp_wmb();
> + iog->entity.ioprio_changed = 1;
> + } else {
> + iog->entity.new_weight = iocg->weight;
> + iog->entity.new_ioprio_class =
> + iocg->ioprio_class;
> +
> + /* The same as above */
> + smp_wmb();
> + iog->entity.ioprio_changed = 1;
> + }
> + }
> + }
> + spin_unlock_irq(&iocg->lock);
> +
> + cgroup_unlock();
> +
> +free_newpn:
> + if (!keep_newpn)
> + kfree(newpn);
> +free_buf:
> + kfree(buf);
> + return ret;
> +}
> +
> struct cftype bfqio_files[] = {
> {
> + .name = "policy",
> + .read_seq_string = io_cgroup_policy_read,
> + .write_string = io_cgroup_policy_write,
> + .max_write_len = 256,
> + },
> + {
> .name = "weight",
> .read_u64 = io_cgroup_weight_read,
> .write_u64 = io_cgroup_weight_write,
> @@ -1592,6 +1824,7 @@ struct cgroup_subsys_state *iocg_create(struct cgroup_subsys *subsys,
> INIT_HLIST_HEAD(&iocg->group_data);
> iocg->weight = IO_DEFAULT_GRP_WEIGHT;
> iocg->ioprio_class = IO_DEFAULT_GRP_CLASS;
> + INIT_LIST_HEAD(&iocg->policy_list);
>
> return &iocg->css;
> }
> @@ -1750,6 +1983,7 @@ void iocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
> unsigned long flags, flags1;
> int queue_lock_held = 0;
> struct elv_fq_data *efqd;
> + struct io_policy_node *pn, *pntmp;
>
> /*
> * io groups are linked in two lists. One list is maintained
> @@ -1823,6 +2057,12 @@ locked:
> BUG_ON(!hlist_empty(&iocg->group_data));
>
> free_css_id(&io_subsys, &iocg->css);
> +
> + list_for_each_entry_safe(pn, pntmp, &iocg->policy_list, node) {
> + policy_delete_node(pn);
> + kfree(pn);
> + }
> +
> kfree(iocg);
> }
>
> diff --git a/block/elevator-fq.h b/block/elevator-fq.h
> index db3a347..b1d97e6 100644
> --- a/block/elevator-fq.h
> +++ b/block/elevator-fq.h
> @@ -250,9 +250,18 @@ struct io_group {
>
> #ifdef CONFIG_DEBUG_GROUP_IOSCHED
> unsigned short iocg_id;
> + dev_t dev;
> #endif
> };
>
> +struct io_policy_node {
> + struct list_head node;
> + char dev_name[32];
> + dev_t dev;
> + unsigned long weight;
> + unsigned long ioprio_class;
> +};
> +
> /**
> * struct bfqio_cgroup - bfq cgroup data structure.
> * @css: subsystem state for bfq in the containing cgroup.
> @@ -269,6 +278,9 @@ struct io_cgroup {
>
> unsigned long weight, ioprio_class;
>
> + /* list of io_policy_node */
> + struct list_head policy_list;
> +
> spinlock_t lock;
> struct hlist_head group_data;
> };
> --
> 1.5.4.rc3
>
>


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