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 <[email protected]> --- 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 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
