| /* |
| * Common Block IO controller cgroup interface |
| * |
| * Based on ideas and code from CFQ, CFS and BFQ: |
| * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> |
| * |
| * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> |
| * Paolo Valente <paolo.valente@unimore.it> |
| * |
| * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> |
| * Nauman Rafique <nauman@google.com> |
| */ |
| #include <linux/ioprio.h> |
| #include <linux/seq_file.h> |
| #include <linux/kdev_t.h> |
| #include <linux/module.h> |
| #include <linux/err.h> |
| #include <linux/blkdev.h> |
| #include "blk-cgroup.h" |
| |
| #define MAX_KEY_LEN 100 |
| |
| static DEFINE_SPINLOCK(blkio_list_lock); |
| static LIST_HEAD(blkio_list); |
| |
| struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; |
| EXPORT_SYMBOL_GPL(blkio_root_cgroup); |
| |
| static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, |
| struct cgroup *); |
| static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, |
| struct task_struct *, bool); |
| static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *, |
| struct cgroup *, struct task_struct *, bool); |
| static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); |
| static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); |
| |
| struct cgroup_subsys blkio_subsys = { |
| .name = "blkio", |
| .create = blkiocg_create, |
| .can_attach = blkiocg_can_attach, |
| .attach = blkiocg_attach, |
| .destroy = blkiocg_destroy, |
| .populate = blkiocg_populate, |
| #ifdef CONFIG_BLK_CGROUP |
| /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ |
| .subsys_id = blkio_subsys_id, |
| #endif |
| .use_id = 1, |
| .module = THIS_MODULE, |
| }; |
| EXPORT_SYMBOL_GPL(blkio_subsys); |
| |
| struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) |
| { |
| return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), |
| struct blkio_cgroup, css); |
| } |
| EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); |
| |
| void blkio_group_init(struct blkio_group *blkg) |
| { |
| spin_lock_init(&blkg->stats_lock); |
| } |
| EXPORT_SYMBOL_GPL(blkio_group_init); |
| |
| /* |
| * Add to the appropriate stat variable depending on the request type. |
| * This should be called with the blkg->stats_lock held. |
| */ |
| static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction, |
| bool sync) |
| { |
| if (direction) |
| stat[BLKIO_STAT_WRITE] += add; |
| else |
| stat[BLKIO_STAT_READ] += add; |
| if (sync) |
| stat[BLKIO_STAT_SYNC] += add; |
| else |
| stat[BLKIO_STAT_ASYNC] += add; |
| } |
| |
| void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&blkg->stats_lock, flags); |
| blkg->stats.time += time; |
| spin_unlock_irqrestore(&blkg->stats_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); |
| |
| void blkiocg_update_dispatch_stats(struct blkio_group *blkg, |
| uint64_t bytes, bool direction, bool sync) |
| { |
| struct blkio_group_stats *stats; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&blkg->stats_lock, flags); |
| stats = &blkg->stats; |
| stats->sectors += bytes >> 9; |
| blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction, |
| sync); |
| blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes, |
| direction, sync); |
| spin_unlock_irqrestore(&blkg->stats_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats); |
| |
| void blkiocg_update_completion_stats(struct blkio_group *blkg, |
| uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) |
| { |
| struct blkio_group_stats *stats; |
| unsigned long flags; |
| unsigned long long now = sched_clock(); |
| |
| spin_lock_irqsave(&blkg->stats_lock, flags); |
| stats = &blkg->stats; |
| if (time_after64(now, io_start_time)) |
| blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME], |
| now - io_start_time, direction, sync); |
| if (time_after64(io_start_time, start_time)) |
| blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME], |
| io_start_time - start_time, direction, sync); |
| spin_unlock_irqrestore(&blkg->stats_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); |
| |
| void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, |
| bool sync) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&blkg->stats_lock, flags); |
| blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction, |
| sync); |
| spin_unlock_irqrestore(&blkg->stats_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); |
| |
| void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, |
| struct blkio_group *blkg, void *key, dev_t dev) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&blkcg->lock, flags); |
| rcu_assign_pointer(blkg->key, key); |
| blkg->blkcg_id = css_id(&blkcg->css); |
| hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); |
| spin_unlock_irqrestore(&blkcg->lock, flags); |
| #ifdef CONFIG_DEBUG_BLK_CGROUP |
| /* 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); |
| |
| static void __blkiocg_del_blkio_group(struct blkio_group *blkg) |
| { |
| hlist_del_init_rcu(&blkg->blkcg_node); |
| blkg->blkcg_id = 0; |
| } |
| |
| /* |
| * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 |
| * indicating that blk_group was unhashed by the time we got to it. |
| */ |
| int blkiocg_del_blkio_group(struct blkio_group *blkg) |
| { |
| struct blkio_cgroup *blkcg; |
| unsigned long flags; |
| struct cgroup_subsys_state *css; |
| int ret = 1; |
| |
| rcu_read_lock(); |
| css = css_lookup(&blkio_subsys, blkg->blkcg_id); |
| if (!css) |
| goto out; |
| |
| blkcg = container_of(css, struct blkio_cgroup, css); |
| spin_lock_irqsave(&blkcg->lock, flags); |
| if (!hlist_unhashed(&blkg->blkcg_node)) { |
| __blkiocg_del_blkio_group(blkg); |
| ret = 0; |
| } |
| spin_unlock_irqrestore(&blkcg->lock, flags); |
| out: |
| rcu_read_unlock(); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); |
| |
| /* called under rcu_read_lock(). */ |
| struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) |
| { |
| struct blkio_group *blkg; |
| struct hlist_node *n; |
| void *__key; |
| |
| hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { |
| __key = blkg->key; |
| if (__key == key) |
| return blkg; |
| } |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_lookup_group); |
| |
| #define SHOW_FUNCTION(__VAR) \ |
| static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ |
| struct cftype *cftype) \ |
| { \ |
| struct blkio_cgroup *blkcg; \ |
| \ |
| blkcg = cgroup_to_blkio_cgroup(cgroup); \ |
| return (u64)blkcg->__VAR; \ |
| } |
| |
| SHOW_FUNCTION(weight); |
| #undef SHOW_FUNCTION |
| |
| static int |
| blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) |
| { |
| struct blkio_cgroup *blkcg; |
| struct blkio_group *blkg; |
| struct hlist_node *n; |
| struct blkio_policy_type *blkiop; |
| |
| if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) |
| return -EINVAL; |
| |
| blkcg = cgroup_to_blkio_cgroup(cgroup); |
| 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) { |
| list_for_each_entry(blkiop, &blkio_list, list) |
| blkiop->ops.blkio_update_group_weight_fn(blkg, |
| blkcg->weight); |
| } |
| spin_unlock_irq(&blkcg->lock); |
| spin_unlock(&blkio_list_lock); |
| return 0; |
| } |
| |
| static int |
| blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) |
| { |
| struct blkio_cgroup *blkcg; |
| struct blkio_group *blkg; |
| struct hlist_node *n; |
| struct blkio_group_stats *stats; |
| |
| blkcg = cgroup_to_blkio_cgroup(cgroup); |
| spin_lock_irq(&blkcg->lock); |
| hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
| spin_lock(&blkg->stats_lock); |
| stats = &blkg->stats; |
| memset(stats, 0, sizeof(struct blkio_group_stats)); |
| spin_unlock(&blkg->stats_lock); |
| } |
| spin_unlock_irq(&blkcg->lock); |
| return 0; |
| } |
| |
| static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, |
| int chars_left, bool diskname_only) |
| { |
| snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); |
| chars_left -= strlen(str); |
| if (chars_left <= 0) { |
| printk(KERN_WARNING |
| "Possibly incorrect cgroup stat display format"); |
| return; |
| } |
| if (diskname_only) |
| return; |
| switch (type) { |
| case BLKIO_STAT_READ: |
| strlcat(str, " Read", chars_left); |
| break; |
| case BLKIO_STAT_WRITE: |
| strlcat(str, " Write", chars_left); |
| break; |
| case BLKIO_STAT_SYNC: |
| strlcat(str, " Sync", chars_left); |
| break; |
| case BLKIO_STAT_ASYNC: |
| strlcat(str, " Async", chars_left); |
| break; |
| case BLKIO_STAT_TOTAL: |
| strlcat(str, " Total", chars_left); |
| break; |
| default: |
| strlcat(str, " Invalid", chars_left); |
| } |
| } |
| |
| static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, |
| struct cgroup_map_cb *cb, dev_t dev) |
| { |
| blkio_get_key_name(0, dev, str, chars_left, true); |
| cb->fill(cb, str, val); |
| return val; |
| } |
| |
| /* This should be called with blkg->stats_lock held */ |
| static uint64_t blkio_get_stat(struct blkio_group *blkg, |
| struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) |
| { |
| uint64_t disk_total; |
| char key_str[MAX_KEY_LEN]; |
| enum stat_sub_type sub_type; |
| |
| if (type == BLKIO_STAT_TIME) |
| return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, |
| blkg->stats.time, cb, dev); |
| if (type == BLKIO_STAT_SECTORS) |
| return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, |
| blkg->stats.sectors, cb, dev); |
| #ifdef CONFIG_DEBUG_BLK_CGROUP |
| if (type == BLKIO_STAT_DEQUEUE) |
| return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, |
| blkg->stats.dequeue, cb, dev); |
| #endif |
| |
| for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; |
| sub_type++) { |
| blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); |
| cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); |
| } |
| disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + |
| blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; |
| blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); |
| cb->fill(cb, key_str, disk_total); |
| return disk_total; |
| } |
| |
| #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \ |
| static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ |
| struct cftype *cftype, struct cgroup_map_cb *cb) \ |
| { \ |
| struct blkio_cgroup *blkcg; \ |
| struct blkio_group *blkg; \ |
| struct hlist_node *n; \ |
| uint64_t cgroup_total = 0; \ |
| \ |
| if (!cgroup_lock_live_group(cgroup)) \ |
| return -ENODEV; \ |
| \ |
| blkcg = cgroup_to_blkio_cgroup(cgroup); \ |
| rcu_read_lock(); \ |
| hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ |
| if (blkg->dev) { \ |
| spin_lock_irq(&blkg->stats_lock); \ |
| cgroup_total += blkio_get_stat(blkg, cb, \ |
| blkg->dev, type); \ |
| spin_unlock_irq(&blkg->stats_lock); \ |
| } \ |
| } \ |
| if (show_total) \ |
| cb->fill(cb, "Total", cgroup_total); \ |
| rcu_read_unlock(); \ |
| cgroup_unlock(); \ |
| return 0; \ |
| } |
| |
| SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0); |
| SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0); |
| SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1); |
| SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1); |
| SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1); |
| SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1); |
| SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1); |
| #ifdef CONFIG_DEBUG_BLK_CGROUP |
| SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0); |
| #endif |
| #undef SHOW_FUNCTION_PER_GROUP |
| |
| #ifdef CONFIG_DEBUG_BLK_CGROUP |
| void blkiocg_update_dequeue_stats(struct blkio_group *blkg, |
| unsigned long dequeue) |
| { |
| blkg->stats.dequeue += dequeue; |
| } |
| EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); |
| #endif |
| |
| struct cftype blkio_files[] = { |
| { |
| .name = "weight", |
| .read_u64 = blkiocg_weight_read, |
| .write_u64 = blkiocg_weight_write, |
| }, |
| { |
| .name = "time", |
| .read_map = blkiocg_time_read, |
| }, |
| { |
| .name = "sectors", |
| .read_map = blkiocg_sectors_read, |
| }, |
| { |
| .name = "io_service_bytes", |
| .read_map = blkiocg_io_service_bytes_read, |
| }, |
| { |
| .name = "io_serviced", |
| .read_map = blkiocg_io_serviced_read, |
| }, |
| { |
| .name = "io_service_time", |
| .read_map = blkiocg_io_service_time_read, |
| }, |
| { |
| .name = "io_wait_time", |
| .read_map = blkiocg_io_wait_time_read, |
| }, |
| { |
| .name = "io_merged", |
| .read_map = blkiocg_io_merged_read, |
| }, |
| { |
| .name = "reset_stats", |
| .write_u64 = blkiocg_reset_stats, |
| }, |
| #ifdef CONFIG_DEBUG_BLK_CGROUP |
| { |
| .name = "dequeue", |
| .read_map = blkiocg_dequeue_read, |
| }, |
| #endif |
| }; |
| |
| static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) |
| { |
| return cgroup_add_files(cgroup, subsys, blkio_files, |
| ARRAY_SIZE(blkio_files)); |
| } |
| |
| static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) |
| { |
| struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); |
| unsigned long flags; |
| struct blkio_group *blkg; |
| void *key; |
| struct blkio_policy_type *blkiop; |
| |
| rcu_read_lock(); |
| remove_entry: |
| spin_lock_irqsave(&blkcg->lock, flags); |
| |
| if (hlist_empty(&blkcg->blkg_list)) { |
| spin_unlock_irqrestore(&blkcg->lock, flags); |
| goto done; |
| } |
| |
| blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, |
| blkcg_node); |
| key = rcu_dereference(blkg->key); |
| __blkiocg_del_blkio_group(blkg); |
| |
| spin_unlock_irqrestore(&blkcg->lock, flags); |
| |
| /* |
| * This blkio_group is being unlinked as associated cgroup is going |
| * away. Let all the IO controlling policies know about this event. |
| * |
| * Currently this is static call to one io controlling policy. Once |
| * we have more policies in place, we need some dynamic registration |
| * of callback function. |
| */ |
| spin_lock(&blkio_list_lock); |
| list_for_each_entry(blkiop, &blkio_list, list) |
| blkiop->ops.blkio_unlink_group_fn(key, blkg); |
| spin_unlock(&blkio_list_lock); |
| goto remove_entry; |
| done: |
| free_css_id(&blkio_subsys, &blkcg->css); |
| rcu_read_unlock(); |
| if (blkcg != &blkio_root_cgroup) |
| kfree(blkcg); |
| } |
| |
| static struct cgroup_subsys_state * |
| blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) |
| { |
| struct blkio_cgroup *blkcg, *parent_blkcg; |
| |
| if (!cgroup->parent) { |
| blkcg = &blkio_root_cgroup; |
| goto done; |
| } |
| |
| /* Currently we do not support hierarchy deeper than two level (0,1) */ |
| parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); |
| if (css_depth(&parent_blkcg->css) > 0) |
| return ERR_PTR(-EINVAL); |
| |
| blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); |
| if (!blkcg) |
| return ERR_PTR(-ENOMEM); |
| |
| blkcg->weight = BLKIO_WEIGHT_DEFAULT; |
| done: |
| spin_lock_init(&blkcg->lock); |
| INIT_HLIST_HEAD(&blkcg->blkg_list); |
| |
| return &blkcg->css; |
| } |
| |
| /* |
| * We cannot support shared io contexts, as we have no mean to support |
| * two tasks with the same ioc in two different groups without major rework |
| * of the main cic data structures. For now we allow a task to change |
| * its cgroup only if it's the only owner of its ioc. |
| */ |
| static int blkiocg_can_attach(struct cgroup_subsys *subsys, |
| struct cgroup *cgroup, struct task_struct *tsk, |
| bool threadgroup) |
| { |
| struct io_context *ioc; |
| int ret = 0; |
| |
| /* task_lock() is needed to avoid races with exit_io_context() */ |
| task_lock(tsk); |
| ioc = tsk->io_context; |
| if (ioc && atomic_read(&ioc->nr_tasks) > 1) |
| ret = -EINVAL; |
| task_unlock(tsk); |
| |
| return ret; |
| } |
| |
| static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, |
| struct cgroup *prev, struct task_struct *tsk, |
| bool threadgroup) |
| { |
| struct io_context *ioc; |
| |
| task_lock(tsk); |
| ioc = tsk->io_context; |
| if (ioc) |
| ioc->cgroup_changed = 1; |
| task_unlock(tsk); |
| } |
| |
| void blkio_policy_register(struct blkio_policy_type *blkiop) |
| { |
| spin_lock(&blkio_list_lock); |
| list_add_tail(&blkiop->list, &blkio_list); |
| spin_unlock(&blkio_list_lock); |
| } |
| EXPORT_SYMBOL_GPL(blkio_policy_register); |
| |
| void blkio_policy_unregister(struct blkio_policy_type *blkiop) |
| { |
| spin_lock(&blkio_list_lock); |
| list_del_init(&blkiop->list); |
| spin_unlock(&blkio_list_lock); |
| } |
| EXPORT_SYMBOL_GPL(blkio_policy_unregister); |
| |
| static int __init init_cgroup_blkio(void) |
| { |
| return cgroup_load_subsys(&blkio_subsys); |
| } |
| |
| static void __exit exit_cgroup_blkio(void) |
| { |
| cgroup_unload_subsys(&blkio_subsys); |
| } |
| |
| module_init(init_cgroup_blkio); |
| module_exit(exit_cgroup_blkio); |
| MODULE_LICENSE("GPL"); |