/* * 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 <linux/slab.h> #include "blk-cgroup.h" #include <linux/genhd.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_task(struct cgroup *, struct task_struct *); static void blkiocg_attach_task(struct cgroup *, struct task_struct *); static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); /* for encoding cft->private value on file */ #define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val)) /* What policy owns the file, proportional or throttle */ #define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff) #define BLKIOFILE_ATTR(val) ((val) & 0xffff) struct cgroup_subsys blkio_subsys = { .name = "blkio", .create = blkiocg_create, .can_attach_task = blkiocg_can_attach_task, .attach_task = blkiocg_attach_task, .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); static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg, struct blkio_policy_node *pn) { list_add(&pn->node, &blkcg->policy_list); } static inline bool cftype_blkg_same_policy(struct cftype *cft, struct blkio_group *blkg) { enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); if (blkg->plid == plid) return 1; return 0; } /* Determines if policy node matches cgroup file being accessed */ static inline bool pn_matches_cftype(struct cftype *cft, struct blkio_policy_node *pn) { enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); int fileid = BLKIOFILE_ATTR(cft->private); return (plid == pn->plid && fileid == pn->fileid); } /* 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, enum blkio_policy_id plid, int fileid) { struct blkio_policy_node *pn; list_for_each_entry(pn, &blkcg->policy_list, node) { if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid) return pn; } return NULL; } 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); struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk) { return container_of(task_subsys_state(tsk, blkio_subsys_id), struct blkio_cgroup, css); } EXPORT_SYMBOL_GPL(task_blkio_cgroup); static inline void blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight) { struct blkio_policy_type *blkiop; list_for_each_entry(blkiop, &blkio_list, list) { /* If this policy does not own the blkg, do not send updates */ if (blkiop->plid != blkg->plid) continue; if (blkiop->ops.blkio_update_group_weight_fn) blkiop->ops.blkio_update_group_weight_fn(blkg->key, blkg, weight); } } static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps, int fileid) { struct blkio_policy_type *blkiop; list_for_each_entry(blkiop, &blkio_list, list) { /* If this policy does not own the blkg, do not send updates */ if (blkiop->plid != blkg->plid) continue; if (fileid == BLKIO_THROTL_read_bps_device && blkiop->ops.blkio_update_group_read_bps_fn) blkiop->ops.blkio_update_group_read_bps_fn(blkg->key, blkg, bps); if (fileid == BLKIO_THROTL_write_bps_device && blkiop->ops.blkio_update_group_write_bps_fn) blkiop->ops.blkio_update_group_write_bps_fn(blkg->key, blkg, bps); } } static inline void blkio_update_group_iops(struct blkio_group *blkg, unsigned int iops, int fileid) { struct blkio_policy_type *blkiop; list_for_each_entry(blkiop, &blkio_list, list) { /* If this policy does not own the blkg, do not send updates */ if (blkiop->plid != blkg->plid) continue; if (fileid == BLKIO_THROTL_read_iops_device && blkiop->ops.blkio_update_group_read_iops_fn) blkiop->ops.blkio_update_group_read_iops_fn(blkg->key, blkg, iops); if (fileid == BLKIO_THROTL_write_iops_device && blkiop->ops.blkio_update_group_write_iops_fn) blkiop->ops.blkio_update_group_write_iops_fn(blkg->key, blkg,iops); } } /* * 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; } /* * Decrements the appropriate stat variable if non-zero depending on the * request type. Panics on value being zero. * This should be called with the blkg->stats_lock held. */ static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync) { if (direction) { BUG_ON(stat[BLKIO_STAT_WRITE] == 0); stat[BLKIO_STAT_WRITE]--; } else { BUG_ON(stat[BLKIO_STAT_READ] == 0); stat[BLKIO_STAT_READ]--; } if (sync) { BUG_ON(stat[BLKIO_STAT_SYNC] == 0); stat[BLKIO_STAT_SYNC]--; } else { BUG_ON(stat[BLKIO_STAT_ASYNC] == 0); stat[BLKIO_STAT_ASYNC]--; } } #ifdef CONFIG_DEBUG_BLK_CGROUP /* This should be called with the blkg->stats_lock held. */ static void blkio_set_start_group_wait_time(struct blkio_group *blkg, struct blkio_group *curr_blkg) { if (blkio_blkg_waiting(&blkg->stats)) return; if (blkg == curr_blkg) return; blkg->stats.start_group_wait_time = sched_clock(); blkio_mark_blkg_waiting(&blkg->stats); } /* This should be called with the blkg->stats_lock held. */ static void blkio_update_group_wait_time(struct blkio_group_stats *stats) { unsigned long long now; if (!blkio_blkg_waiting(stats)) return; now = sched_clock(); if (time_after64(now, stats->start_group_wait_time)) stats->group_wait_time += now - stats->start_group_wait_time; blkio_clear_blkg_waiting(stats); } /* This should be called with the blkg->stats_lock held. */ static void blkio_end_empty_time(struct blkio_group_stats *stats) { unsigned long long now; if (!blkio_blkg_empty(stats)) return; now = sched_clock(); if (time_after64(now, stats->start_empty_time)) stats->empty_time += now - stats->start_empty_time; blkio_clear_blkg_empty(stats); } void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) { unsigned long flags; spin_lock_irqsave(&blkg->stats_lock, flags); BUG_ON(blkio_blkg_idling(&blkg->stats)); blkg->stats.start_idle_time = sched_clock(); blkio_mark_blkg_idling(&blkg->stats); spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats); void blkiocg_update_idle_time_stats(struct blkio_group *blkg) { unsigned long flags; unsigned long long now; struct blkio_group_stats *stats; spin_lock_irqsave(&blkg->stats_lock, flags); stats = &blkg->stats; if (blkio_blkg_idling(stats)) { now = sched_clock(); if (time_after64(now, stats->start_idle_time)) stats->idle_time += now - stats->start_idle_time; blkio_clear_blkg_idling(stats); } spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats); void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg) { unsigned long flags; struct blkio_group_stats *stats; spin_lock_irqsave(&blkg->stats_lock, flags); stats = &blkg->stats; stats->avg_queue_size_sum += stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] + stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]; stats->avg_queue_size_samples++; blkio_update_group_wait_time(stats); spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats); void blkiocg_set_start_empty_time(struct blkio_group *blkg) { unsigned long flags; struct blkio_group_stats *stats; spin_lock_irqsave(&blkg->stats_lock, flags); stats = &blkg->stats; if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] || stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) { spin_unlock_irqrestore(&blkg->stats_lock, flags); return; } /* * group is already marked empty. This can happen if cfqq got new * request in parent group and moved to this group while being added * to service tree. Just ignore the event and move on. */ if(blkio_blkg_empty(stats)) { spin_unlock_irqrestore(&blkg->stats_lock, flags); return; } stats->start_empty_time = sched_clock(); blkio_mark_blkg_empty(stats); spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time); void blkiocg_update_dequeue_stats(struct blkio_group *blkg, unsigned long dequeue) { blkg->stats.dequeue += dequeue; } EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); #else static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg, struct blkio_group *curr_blkg) {} static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {} #endif void blkiocg_update_io_add_stats(struct blkio_group *blkg, struct blkio_group *curr_blkg, bool direction, bool sync) { unsigned long flags; spin_lock_irqsave(&blkg->stats_lock, flags); blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction, sync); blkio_end_empty_time(&blkg->stats); blkio_set_start_group_wait_time(blkg, curr_blkg); spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats); void blkiocg_update_io_remove_stats(struct blkio_group *blkg, bool direction, bool sync) { unsigned long flags; spin_lock_irqsave(&blkg->stats_lock, flags); blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], direction, sync); spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats); void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time, unsigned long unaccounted_time) { unsigned long flags; spin_lock_irqsave(&blkg->stats_lock, flags); blkg->stats.time += time; #ifdef CONFIG_DEBUG_BLK_CGROUP blkg->stats.unaccounted_time += unaccounted_time; #endif spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); /* * should be called under rcu read lock or queue lock to make sure blkg pointer * is valid. */ void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes, bool direction, bool sync) { struct blkio_group_stats_cpu *stats_cpu; unsigned long flags; /* * Disabling interrupts to provide mutual exclusion between two * writes on same cpu. It probably is not needed for 64bit. Not * optimizing that case yet. */ local_irq_save(flags); stats_cpu = this_cpu_ptr(blkg->stats_cpu); u64_stats_update_begin(&stats_cpu->syncp); stats_cpu->sectors += bytes >> 9; blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED], 1, direction, sync); blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES], bytes, direction, sync); u64_stats_update_end(&stats_cpu->syncp); local_irq_restore(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); /* Merged stats are per cpu. */ void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, bool sync) { struct blkio_group_stats_cpu *stats_cpu; unsigned long flags; /* * Disabling interrupts to provide mutual exclusion between two * writes on same cpu. It probably is not needed for 64bit. Not * optimizing that case yet. */ local_irq_save(flags); stats_cpu = this_cpu_ptr(blkg->stats_cpu); u64_stats_update_begin(&stats_cpu->syncp); blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1, direction, sync); u64_stats_update_end(&stats_cpu->syncp); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); /* * This function allocates the per cpu stats for blkio_group. Should be called * from sleepable context as alloc_per_cpu() requires that. */ int blkio_alloc_blkg_stats(struct blkio_group *blkg) { /* Allocate memory for per cpu stats */ blkg->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu); if (!blkg->stats_cpu) return -ENOMEM; return 0; } EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats); void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, struct blkio_group *blkg, void *key, dev_t dev, enum blkio_policy_id plid) { unsigned long flags; spin_lock_irqsave(&blkcg->lock, flags); spin_lock_init(&blkg->stats_lock); rcu_assign_pointer(blkg->key, key); blkg->blkcg_id = css_id(&blkcg->css); hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); blkg->plid = plid; spin_unlock_irqrestore(&blkcg->lock, flags); /* Need to take css reference ? */ cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); 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) { 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); } 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); static void blkio_reset_stats_cpu(struct blkio_group *blkg) { struct blkio_group_stats_cpu *stats_cpu; int i, j, k; /* * Note: On 64 bit arch this should not be an issue. This has the * possibility of returning some inconsistent value on 32bit arch * as 64bit update on 32bit is non atomic. Taking care of this * corner case makes code very complicated, like sending IPIs to * cpus, taking care of stats of offline cpus etc. * * reset stats is anyway more of a debug feature and this sounds a * corner case. So I am not complicating the code yet until and * unless this becomes a real issue. */ for_each_possible_cpu(i) { stats_cpu = per_cpu_ptr(blkg->stats_cpu, i); stats_cpu->sectors = 0; for(j = 0; j < BLKIO_STAT_CPU_NR; j++) for (k = 0; k < BLKIO_STAT_TOTAL; k++) stats_cpu->stat_arr_cpu[j][k] = 0; } } static int blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) { struct blkio_cgroup *blkcg; struct blkio_group *blkg; struct blkio_group_stats *stats; struct hlist_node *n; uint64_t queued[BLKIO_STAT_TOTAL]; int i; #ifdef CONFIG_DEBUG_BLK_CGROUP bool idling, waiting, empty; unsigned long long now = sched_clock(); #endif 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; #ifdef CONFIG_DEBUG_BLK_CGROUP idling = blkio_blkg_idling(stats); waiting = blkio_blkg_waiting(stats); empty = blkio_blkg_empty(stats); #endif for (i = 0; i < BLKIO_STAT_TOTAL; i++) queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i]; memset(stats, 0, sizeof(struct blkio_group_stats)); for (i = 0; i < BLKIO_STAT_TOTAL; i++) stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i]; #ifdef CONFIG_DEBUG_BLK_CGROUP if (idling) { blkio_mark_blkg_idling(stats); stats->start_idle_time = now; } if (waiting) { blkio_mark_blkg_waiting(stats); stats->start_group_wait_time = now; } if (empty) { blkio_mark_blkg_empty(stats); stats->start_empty_time = now; } #endif spin_unlock(&blkg->stats_lock); /* Reset Per cpu stats which don't take blkg->stats_lock */ blkio_reset_stats_cpu(blkg); } 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; } static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg, enum stat_type_cpu type, enum stat_sub_type sub_type) { int cpu; struct blkio_group_stats_cpu *stats_cpu; u64 val = 0, tval; for_each_possible_cpu(cpu) { unsigned int start; stats_cpu = per_cpu_ptr(blkg->stats_cpu, cpu); do { start = u64_stats_fetch_begin(&stats_cpu->syncp); if (type == BLKIO_STAT_CPU_SECTORS) tval = stats_cpu->sectors; else tval = stats_cpu->stat_arr_cpu[type][sub_type]; } while(u64_stats_fetch_retry(&stats_cpu->syncp, start)); val += tval; } return val; } static uint64_t blkio_get_stat_cpu(struct blkio_group *blkg, struct cgroup_map_cb *cb, dev_t dev, enum stat_type_cpu type) { uint64_t disk_total, val; char key_str[MAX_KEY_LEN]; enum stat_sub_type sub_type; if (type == BLKIO_STAT_CPU_SECTORS) { val = blkio_read_stat_cpu(blkg, type, 0); return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb, dev); } 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); val = blkio_read_stat_cpu(blkg, type, sub_type); cb->fill(cb, key_str, val); } disk_total = blkio_read_stat_cpu(blkg, type, BLKIO_STAT_READ) + blkio_read_stat_cpu(blkg, 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; } /* 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); #ifdef CONFIG_DEBUG_BLK_CGROUP if (type == BLKIO_STAT_UNACCOUNTED_TIME) return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, blkg->stats.unaccounted_time, cb, dev); if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { uint64_t sum = blkg->stats.avg_queue_size_sum; uint64_t samples = blkg->stats.avg_queue_size_samples; if (samples) do_div(sum, samples); else sum = 0; return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev); } if (type == BLKIO_STAT_GROUP_WAIT_TIME) return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, blkg->stats.group_wait_time, cb, dev); if (type == BLKIO_STAT_IDLE_TIME) return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, blkg->stats.idle_time, cb, dev); if (type == BLKIO_STAT_EMPTY_TIME) return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, blkg->stats.empty_time, cb, dev); 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; } 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, enum blkio_policy_id plid, int fileid) { char *s[4], *p, *major_s = NULL, *minor_s = NULL; int ret; unsigned long major, minor; int i = 0; dev_t dev; u64 temp; 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 = strict_strtoull(s[1], 10, &temp); if (ret) return -EINVAL; /* For rule removal, do not check for device presence. */ if (temp) { ret = blkio_check_dev_num(dev); if (ret) return ret; } newpn->dev = dev; switch (plid) { case BLKIO_POLICY_PROP: if ((temp < BLKIO_WEIGHT_MIN && temp > 0) || temp > BLKIO_WEIGHT_MAX) return -EINVAL; newpn->plid = plid; newpn->fileid = fileid; newpn->val.weight = temp; break; case BLKIO_POLICY_THROTL: switch(fileid) { case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: newpn->plid = plid; newpn->fileid = fileid; newpn->val.bps = temp; break; case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: if (temp > THROTL_IOPS_MAX) return -EINVAL; newpn->plid = plid; newpn->fileid = fileid; newpn->val.iops = (unsigned int)temp; break; } break; default: BUG(); } 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, BLKIO_POLICY_PROP, BLKIO_PROP_weight_device); if (pn) return pn->val.weight; else return blkcg->weight; } EXPORT_SYMBOL_GPL(blkcg_get_weight); uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_read_bps_device); if (pn) return pn->val.bps; else return -1; } uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_write_bps_device); if (pn) return pn->val.bps; else return -1; } unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_read_iops_device); if (pn) return pn->val.iops; else return -1; } unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_write_iops_device); if (pn) return pn->val.iops; else return -1; } /* Checks whether user asked for deleting a policy rule */ static bool blkio_delete_rule_command(struct blkio_policy_node *pn) { switch(pn->plid) { case BLKIO_POLICY_PROP: if (pn->val.weight == 0) return 1; break; case BLKIO_POLICY_THROTL: switch(pn->fileid) { case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: if (pn->val.bps == 0) return 1; break; case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: if (pn->val.iops == 0) return 1; } break; default: BUG(); } return 0; } static void blkio_update_policy_rule(struct blkio_policy_node *oldpn, struct blkio_policy_node *newpn) { switch(oldpn->plid) { case BLKIO_POLICY_PROP: oldpn->val.weight = newpn->val.weight; break; case BLKIO_POLICY_THROTL: switch(newpn->fileid) { case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: oldpn->val.bps = newpn->val.bps; break; case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: oldpn->val.iops = newpn->val.iops; } break; default: BUG(); } } /* * Some rules/values in blkg have changed. Propagate those to respective * policies. */ static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg, struct blkio_group *blkg, struct blkio_policy_node *pn) { unsigned int weight, iops; u64 bps; switch(pn->plid) { case BLKIO_POLICY_PROP: weight = pn->val.weight ? pn->val.weight : blkcg->weight; blkio_update_group_weight(blkg, weight); break; case BLKIO_POLICY_THROTL: switch(pn->fileid) { case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: bps = pn->val.bps ? pn->val.bps : (-1); blkio_update_group_bps(blkg, bps, pn->fileid); break; case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: iops = pn->val.iops ? pn->val.iops : (-1); blkio_update_group_iops(blkg, iops, pn->fileid); break; } break; default: BUG(); } } /* * A policy node rule has been updated. Propagate this update to all the * block groups which might be affected by this update. */ static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg, struct blkio_policy_node *pn) { struct blkio_group *blkg; struct hlist_node *n; spin_lock(&blkio_list_lock); spin_lock_irq(&blkcg->lock); hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { if (pn->dev != blkg->dev || pn->plid != blkg->plid) continue; blkio_update_blkg_policy(blkcg, blkg, pn); } spin_unlock_irq(&blkcg->lock); spin_unlock(&blkio_list_lock); } static int blkiocg_file_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; int keep_newpn = 0; enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); int fileid = BLKIOFILE_ATTR(cft->private); 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, plid, fileid); if (ret) goto free_newpn; blkcg = cgroup_to_blkio_cgroup(cgrp); spin_lock_irq(&blkcg->lock); pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid); if (!pn) { if (!blkio_delete_rule_command(newpn)) { blkio_policy_insert_node(blkcg, newpn); keep_newpn = 1; } spin_unlock_irq(&blkcg->lock); goto update_io_group; } if (blkio_delete_rule_command(newpn)) { blkio_policy_delete_node(pn); spin_unlock_irq(&blkcg->lock); goto update_io_group; } spin_unlock_irq(&blkcg->lock); blkio_update_policy_rule(pn, newpn); update_io_group: blkio_update_policy_node_blkg(blkcg, newpn); free_newpn: if (!keep_newpn) kfree(newpn); free_buf: kfree(buf); return ret; } static void blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn) { switch(pn->plid) { case BLKIO_POLICY_PROP: if (pn->fileid == BLKIO_PROP_weight_device) seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), MINOR(pn->dev), pn->val.weight); break; case BLKIO_POLICY_THROTL: switch(pn->fileid) { case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev), MINOR(pn->dev), pn->val.bps); break; case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), MINOR(pn->dev), pn->val.iops); break; } break; default: BUG(); } } /* cgroup files which read their data from policy nodes end up here */ static void blkio_read_policy_node_files(struct cftype *cft, struct blkio_cgroup *blkcg, struct seq_file *m) { struct blkio_policy_node *pn; if (!list_empty(&blkcg->policy_list)) { spin_lock_irq(&blkcg->lock); list_for_each_entry(pn, &blkcg->policy_list, node) { if (!pn_matches_cftype(cft, pn)) continue; blkio_print_policy_node(m, pn); } spin_unlock_irq(&blkcg->lock); } } static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft, struct seq_file *m) { struct blkio_cgroup *blkcg; enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); int name = BLKIOFILE_ATTR(cft->private); blkcg = cgroup_to_blkio_cgroup(cgrp); switch(plid) { case BLKIO_POLICY_PROP: switch(name) { case BLKIO_PROP_weight_device: blkio_read_policy_node_files(cft, blkcg, m); return 0; default: BUG(); } break; case BLKIO_POLICY_THROTL: switch(name){ case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: blkio_read_policy_node_files(cft, blkcg, m); return 0; default: BUG(); } break; default: BUG(); } return 0; } static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg, struct cftype *cft, struct cgroup_map_cb *cb, enum stat_type type, bool show_total, bool pcpu) { struct blkio_group *blkg; struct hlist_node *n; uint64_t cgroup_total = 0; rcu_read_lock(); hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { if (blkg->dev) { if (!cftype_blkg_same_policy(cft, blkg)) continue; if (pcpu) cgroup_total += blkio_get_stat_cpu(blkg, cb, blkg->dev, type); else { 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(); return 0; } /* All map kind of cgroup file get serviced by this function */ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft, struct cgroup_map_cb *cb) { struct blkio_cgroup *blkcg; enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); int name = BLKIOFILE_ATTR(cft->private); blkcg = cgroup_to_blkio_cgroup(cgrp); switch(plid) { case BLKIO_POLICY_PROP: switch(name) { case BLKIO_PROP_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_TIME, 0, 0); case BLKIO_PROP_sectors: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_CPU_SECTORS, 0, 1); case BLKIO_PROP_io_service_bytes: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1); case BLKIO_PROP_io_serviced: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_CPU_SERVICED, 1, 1); case BLKIO_PROP_io_service_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_SERVICE_TIME, 1, 0); case BLKIO_PROP_io_wait_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_WAIT_TIME, 1, 0); case BLKIO_PROP_io_merged: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_CPU_MERGED, 1, 1); case BLKIO_PROP_io_queued: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_QUEUED, 1, 0); #ifdef CONFIG_DEBUG_BLK_CGROUP case BLKIO_PROP_unaccounted_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_UNACCOUNTED_TIME, 0, 0); case BLKIO_PROP_dequeue: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_DEQUEUE, 0, 0); case BLKIO_PROP_avg_queue_size: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_AVG_QUEUE_SIZE, 0, 0); case BLKIO_PROP_group_wait_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_GROUP_WAIT_TIME, 0, 0); case BLKIO_PROP_idle_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_IDLE_TIME, 0, 0); case BLKIO_PROP_empty_time: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_EMPTY_TIME, 0, 0); #endif default: BUG(); } break; case BLKIO_POLICY_THROTL: switch(name){ case BLKIO_THROTL_io_service_bytes: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1); case BLKIO_THROTL_io_serviced: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_CPU_SERVICED, 1, 1); default: BUG(); } break; default: BUG(); } return 0; } static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val) { struct blkio_group *blkg; struct hlist_node *n; struct blkio_policy_node *pn; if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) return -EINVAL; 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, BLKIO_POLICY_PROP, BLKIO_PROP_weight_device); if (pn) continue; blkio_update_group_weight(blkg, blkcg->weight); } spin_unlock_irq(&blkcg->lock); spin_unlock(&blkio_list_lock); return 0; } static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) { struct blkio_cgroup *blkcg; enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); int name = BLKIOFILE_ATTR(cft->private); blkcg = cgroup_to_blkio_cgroup(cgrp); switch(plid) { case BLKIO_POLICY_PROP: switch(name) { case BLKIO_PROP_weight: return (u64)blkcg->weight; } break; default: BUG(); } return 0; } static int blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val) { struct blkio_cgroup *blkcg; enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private); int name = BLKIOFILE_ATTR(cft->private); blkcg = cgroup_to_blkio_cgroup(cgrp); switch(plid) { case BLKIO_POLICY_PROP: switch(name) { case BLKIO_PROP_weight: return blkio_weight_write(blkcg, val); } break; default: BUG(); } return 0; } struct cftype blkio_files[] = { { .name = "weight_device", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_weight_device), .read_seq_string = blkiocg_file_read, .write_string = blkiocg_file_write, .max_write_len = 256, }, { .name = "weight", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_weight), .read_u64 = blkiocg_file_read_u64, .write_u64 = blkiocg_file_write_u64, }, { .name = "time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_time), .read_map = blkiocg_file_read_map, }, { .name = "sectors", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_sectors), .read_map = blkiocg_file_read_map, }, { .name = "io_service_bytes", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_io_service_bytes), .read_map = blkiocg_file_read_map, }, { .name = "io_serviced", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_io_serviced), .read_map = blkiocg_file_read_map, }, { .name = "io_service_time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_io_service_time), .read_map = blkiocg_file_read_map, }, { .name = "io_wait_time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_io_wait_time), .read_map = blkiocg_file_read_map, }, { .name = "io_merged", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_io_merged), .read_map = blkiocg_file_read_map, }, { .name = "io_queued", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_io_queued), .read_map = blkiocg_file_read_map, }, { .name = "reset_stats", .write_u64 = blkiocg_reset_stats, }, #ifdef CONFIG_BLK_DEV_THROTTLING { .name = "throttle.read_bps_device", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, BLKIO_THROTL_read_bps_device), .read_seq_string = blkiocg_file_read, .write_string = blkiocg_file_write, .max_write_len = 256, }, { .name = "throttle.write_bps_device", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, BLKIO_THROTL_write_bps_device), .read_seq_string = blkiocg_file_read, .write_string = blkiocg_file_write, .max_write_len = 256, }, { .name = "throttle.read_iops_device", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, BLKIO_THROTL_read_iops_device), .read_seq_string = blkiocg_file_read, .write_string = blkiocg_file_write, .max_write_len = 256, }, { .name = "throttle.write_iops_device", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, BLKIO_THROTL_write_iops_device), .read_seq_string = blkiocg_file_read, .write_string = blkiocg_file_write, .max_write_len = 256, }, { .name = "throttle.io_service_bytes", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, BLKIO_THROTL_io_service_bytes), .read_map = blkiocg_file_read_map, }, { .name = "throttle.io_serviced", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL, BLKIO_THROTL_io_serviced), .read_map = blkiocg_file_read_map, }, #endif /* CONFIG_BLK_DEV_THROTTLING */ #ifdef CONFIG_DEBUG_BLK_CGROUP { .name = "avg_queue_size", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_avg_queue_size), .read_map = blkiocg_file_read_map, }, { .name = "group_wait_time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_group_wait_time), .read_map = blkiocg_file_read_map, }, { .name = "idle_time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_idle_time), .read_map = blkiocg_file_read_map, }, { .name = "empty_time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_empty_time), .read_map = blkiocg_file_read_map, }, { .name = "dequeue", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_dequeue), .read_map = blkiocg_file_read_map, }, { .name = "unaccounted_time", .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, BLKIO_PROP_unaccounted_time), .read_map = blkiocg_file_read_map, }, #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; struct blkio_policy_node *pn, *pntmp; rcu_read_lock(); do { spin_lock_irqsave(&blkcg->lock, flags); if (hlist_empty(&blkcg->blkg_list)) { spin_unlock_irqrestore(&blkcg->lock, flags); break; } 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. */ spin_lock(&blkio_list_lock); list_for_each_entry(blkiop, &blkio_list, list) { if (blkiop->plid != blkg->plid) continue; blkiop->ops.blkio_unlink_group_fn(key, blkg); } spin_unlock(&blkio_list_lock); } while (1); 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) kfree(blkcg); } static struct cgroup_subsys_state * blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) { struct blkio_cgroup *blkcg; struct cgroup *parent = cgroup->parent; if (!parent) { blkcg = &blkio_root_cgroup; goto done; } 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); INIT_LIST_HEAD(&blkcg->policy_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_task(struct cgroup *cgrp, struct task_struct *tsk) { 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_task(struct cgroup *cgrp, struct task_struct *tsk) { 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");