2 * Common Block IO controller cgroup interface
4 * Based on ideas and code from CFQ, CFS and BFQ:
5 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
7 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
8 * Paolo Valente <paolo.valente@unimore.it>
10 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
11 * Nauman Rafique <nauman@google.com>
13 #include <linux/ioprio.h>
14 #include <linux/seq_file.h>
15 #include <linux/kdev_t.h>
16 #include <linux/module.h>
17 #include <linux/err.h>
18 #include <linux/blkdev.h>
19 #include <linux/slab.h>
20 #include "blk-cgroup.h"
21 #include <linux/genhd.h>
23 #define MAX_KEY_LEN 100
25 static DEFINE_SPINLOCK(blkio_list_lock);
26 static LIST_HEAD(blkio_list);
28 struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
29 EXPORT_SYMBOL_GPL(blkio_root_cgroup);
31 static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
33 static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
34 struct cgroup_taskset *);
35 static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
36 struct cgroup_taskset *);
37 static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
38 static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
40 /* for encoding cft->private value on file */
41 #define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
42 /* What policy owns the file, proportional or throttle */
43 #define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
44 #define BLKIOFILE_ATTR(val) ((val) & 0xffff)
46 struct cgroup_subsys blkio_subsys = {
48 .create = blkiocg_create,
49 .can_attach = blkiocg_can_attach,
50 .attach = blkiocg_attach,
51 .destroy = blkiocg_destroy,
52 .populate = blkiocg_populate,
53 #ifdef CONFIG_BLK_CGROUP
54 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
55 .subsys_id = blkio_subsys_id,
58 .module = THIS_MODULE,
60 EXPORT_SYMBOL_GPL(blkio_subsys);
62 static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
63 struct blkio_policy_node *pn)
65 list_add(&pn->node, &blkcg->policy_list);
68 static inline bool cftype_blkg_same_policy(struct cftype *cft,
69 struct blkio_group *blkg)
71 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
73 if (blkg->plid == plid)
79 /* Determines if policy node matches cgroup file being accessed */
80 static inline bool pn_matches_cftype(struct cftype *cft,
81 struct blkio_policy_node *pn)
83 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
84 int fileid = BLKIOFILE_ATTR(cft->private);
86 return (plid == pn->plid && fileid == pn->fileid);
89 /* Must be called with blkcg->lock held */
90 static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
95 /* Must be called with blkcg->lock held */
96 static struct blkio_policy_node *
97 blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
98 enum blkio_policy_id plid, int fileid)
100 struct blkio_policy_node *pn;
102 list_for_each_entry(pn, &blkcg->policy_list, node) {
103 if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
110 struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
112 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
113 struct blkio_cgroup, css);
115 EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
117 struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk)
119 return container_of(task_subsys_state(tsk, blkio_subsys_id),
120 struct blkio_cgroup, css);
122 EXPORT_SYMBOL_GPL(task_blkio_cgroup);
125 blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
127 struct blkio_policy_type *blkiop;
129 list_for_each_entry(blkiop, &blkio_list, list) {
130 /* If this policy does not own the blkg, do not send updates */
131 if (blkiop->plid != blkg->plid)
133 if (blkiop->ops.blkio_update_group_weight_fn)
134 blkiop->ops.blkio_update_group_weight_fn(blkg->key,
139 static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
142 struct blkio_policy_type *blkiop;
144 list_for_each_entry(blkiop, &blkio_list, list) {
146 /* If this policy does not own the blkg, do not send updates */
147 if (blkiop->plid != blkg->plid)
150 if (fileid == BLKIO_THROTL_read_bps_device
151 && blkiop->ops.blkio_update_group_read_bps_fn)
152 blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
155 if (fileid == BLKIO_THROTL_write_bps_device
156 && blkiop->ops.blkio_update_group_write_bps_fn)
157 blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
162 static inline void blkio_update_group_iops(struct blkio_group *blkg,
163 unsigned int iops, int fileid)
165 struct blkio_policy_type *blkiop;
167 list_for_each_entry(blkiop, &blkio_list, list) {
169 /* If this policy does not own the blkg, do not send updates */
170 if (blkiop->plid != blkg->plid)
173 if (fileid == BLKIO_THROTL_read_iops_device
174 && blkiop->ops.blkio_update_group_read_iops_fn)
175 blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
178 if (fileid == BLKIO_THROTL_write_iops_device
179 && blkiop->ops.blkio_update_group_write_iops_fn)
180 blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
186 * Add to the appropriate stat variable depending on the request type.
187 * This should be called with the blkg->stats_lock held.
189 static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
193 stat[BLKIO_STAT_WRITE] += add;
195 stat[BLKIO_STAT_READ] += add;
197 stat[BLKIO_STAT_SYNC] += add;
199 stat[BLKIO_STAT_ASYNC] += add;
203 * Decrements the appropriate stat variable if non-zero depending on the
204 * request type. Panics on value being zero.
205 * This should be called with the blkg->stats_lock held.
207 static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
210 BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
211 stat[BLKIO_STAT_WRITE]--;
213 BUG_ON(stat[BLKIO_STAT_READ] == 0);
214 stat[BLKIO_STAT_READ]--;
217 BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
218 stat[BLKIO_STAT_SYNC]--;
220 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
221 stat[BLKIO_STAT_ASYNC]--;
225 #ifdef CONFIG_DEBUG_BLK_CGROUP
226 /* This should be called with the blkg->stats_lock held. */
227 static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
228 struct blkio_group *curr_blkg)
230 if (blkio_blkg_waiting(&blkg->stats))
232 if (blkg == curr_blkg)
234 blkg->stats.start_group_wait_time = sched_clock();
235 blkio_mark_blkg_waiting(&blkg->stats);
238 /* This should be called with the blkg->stats_lock held. */
239 static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
241 unsigned long long now;
243 if (!blkio_blkg_waiting(stats))
247 if (time_after64(now, stats->start_group_wait_time))
248 stats->group_wait_time += now - stats->start_group_wait_time;
249 blkio_clear_blkg_waiting(stats);
252 /* This should be called with the blkg->stats_lock held. */
253 static void blkio_end_empty_time(struct blkio_group_stats *stats)
255 unsigned long long now;
257 if (!blkio_blkg_empty(stats))
261 if (time_after64(now, stats->start_empty_time))
262 stats->empty_time += now - stats->start_empty_time;
263 blkio_clear_blkg_empty(stats);
266 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
270 spin_lock_irqsave(&blkg->stats_lock, flags);
271 BUG_ON(blkio_blkg_idling(&blkg->stats));
272 blkg->stats.start_idle_time = sched_clock();
273 blkio_mark_blkg_idling(&blkg->stats);
274 spin_unlock_irqrestore(&blkg->stats_lock, flags);
276 EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
278 void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
281 unsigned long long now;
282 struct blkio_group_stats *stats;
284 spin_lock_irqsave(&blkg->stats_lock, flags);
285 stats = &blkg->stats;
286 if (blkio_blkg_idling(stats)) {
288 if (time_after64(now, stats->start_idle_time))
289 stats->idle_time += now - stats->start_idle_time;
290 blkio_clear_blkg_idling(stats);
292 spin_unlock_irqrestore(&blkg->stats_lock, flags);
294 EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
296 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
299 struct blkio_group_stats *stats;
301 spin_lock_irqsave(&blkg->stats_lock, flags);
302 stats = &blkg->stats;
303 stats->avg_queue_size_sum +=
304 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
305 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
306 stats->avg_queue_size_samples++;
307 blkio_update_group_wait_time(stats);
308 spin_unlock_irqrestore(&blkg->stats_lock, flags);
310 EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
312 void blkiocg_set_start_empty_time(struct blkio_group *blkg)
315 struct blkio_group_stats *stats;
317 spin_lock_irqsave(&blkg->stats_lock, flags);
318 stats = &blkg->stats;
320 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
321 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
322 spin_unlock_irqrestore(&blkg->stats_lock, flags);
327 * group is already marked empty. This can happen if cfqq got new
328 * request in parent group and moved to this group while being added
329 * to service tree. Just ignore the event and move on.
331 if(blkio_blkg_empty(stats)) {
332 spin_unlock_irqrestore(&blkg->stats_lock, flags);
336 stats->start_empty_time = sched_clock();
337 blkio_mark_blkg_empty(stats);
338 spin_unlock_irqrestore(&blkg->stats_lock, flags);
340 EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
342 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
343 unsigned long dequeue)
345 blkg->stats.dequeue += dequeue;
347 EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
349 static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
350 struct blkio_group *curr_blkg) {}
351 static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
354 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
355 struct blkio_group *curr_blkg, bool direction,
360 spin_lock_irqsave(&blkg->stats_lock, flags);
361 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
363 blkio_end_empty_time(&blkg->stats);
364 blkio_set_start_group_wait_time(blkg, curr_blkg);
365 spin_unlock_irqrestore(&blkg->stats_lock, flags);
367 EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
369 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
370 bool direction, bool sync)
374 spin_lock_irqsave(&blkg->stats_lock, flags);
375 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
377 spin_unlock_irqrestore(&blkg->stats_lock, flags);
379 EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
381 void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time,
382 unsigned long unaccounted_time)
386 spin_lock_irqsave(&blkg->stats_lock, flags);
387 blkg->stats.time += time;
388 #ifdef CONFIG_DEBUG_BLK_CGROUP
389 blkg->stats.unaccounted_time += unaccounted_time;
391 spin_unlock_irqrestore(&blkg->stats_lock, flags);
393 EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
396 * should be called under rcu read lock or queue lock to make sure blkg pointer
399 void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
400 uint64_t bytes, bool direction, bool sync)
402 struct blkio_group_stats_cpu *stats_cpu;
406 * Disabling interrupts to provide mutual exclusion between two
407 * writes on same cpu. It probably is not needed for 64bit. Not
408 * optimizing that case yet.
410 local_irq_save(flags);
412 stats_cpu = this_cpu_ptr(blkg->stats_cpu);
414 u64_stats_update_begin(&stats_cpu->syncp);
415 stats_cpu->sectors += bytes >> 9;
416 blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED],
418 blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES],
419 bytes, direction, sync);
420 u64_stats_update_end(&stats_cpu->syncp);
421 local_irq_restore(flags);
423 EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
425 void blkiocg_update_completion_stats(struct blkio_group *blkg,
426 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
428 struct blkio_group_stats *stats;
430 unsigned long long now = sched_clock();
432 spin_lock_irqsave(&blkg->stats_lock, flags);
433 stats = &blkg->stats;
434 if (time_after64(now, io_start_time))
435 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
436 now - io_start_time, direction, sync);
437 if (time_after64(io_start_time, start_time))
438 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
439 io_start_time - start_time, direction, sync);
440 spin_unlock_irqrestore(&blkg->stats_lock, flags);
442 EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
444 /* Merged stats are per cpu. */
445 void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
448 struct blkio_group_stats_cpu *stats_cpu;
452 * Disabling interrupts to provide mutual exclusion between two
453 * writes on same cpu. It probably is not needed for 64bit. Not
454 * optimizing that case yet.
456 local_irq_save(flags);
458 stats_cpu = this_cpu_ptr(blkg->stats_cpu);
460 u64_stats_update_begin(&stats_cpu->syncp);
461 blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1,
463 u64_stats_update_end(&stats_cpu->syncp);
464 local_irq_restore(flags);
466 EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
469 * This function allocates the per cpu stats for blkio_group. Should be called
470 * from sleepable context as alloc_per_cpu() requires that.
472 int blkio_alloc_blkg_stats(struct blkio_group *blkg)
474 /* Allocate memory for per cpu stats */
475 blkg->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu);
476 if (!blkg->stats_cpu)
480 EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats);
482 void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
483 struct blkio_group *blkg, void *key, dev_t dev,
484 enum blkio_policy_id plid)
488 spin_lock_irqsave(&blkcg->lock, flags);
489 spin_lock_init(&blkg->stats_lock);
490 rcu_assign_pointer(blkg->key, key);
491 blkg->blkcg_id = css_id(&blkcg->css);
492 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
494 spin_unlock_irqrestore(&blkcg->lock, flags);
495 /* Need to take css reference ? */
496 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
499 EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
501 static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
503 hlist_del_init_rcu(&blkg->blkcg_node);
508 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
509 * indicating that blk_group was unhashed by the time we got to it.
511 int blkiocg_del_blkio_group(struct blkio_group *blkg)
513 struct blkio_cgroup *blkcg;
515 struct cgroup_subsys_state *css;
519 css = css_lookup(&blkio_subsys, blkg->blkcg_id);
521 blkcg = container_of(css, struct blkio_cgroup, css);
522 spin_lock_irqsave(&blkcg->lock, flags);
523 if (!hlist_unhashed(&blkg->blkcg_node)) {
524 __blkiocg_del_blkio_group(blkg);
527 spin_unlock_irqrestore(&blkcg->lock, flags);
533 EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
535 /* called under rcu_read_lock(). */
536 struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
538 struct blkio_group *blkg;
539 struct hlist_node *n;
542 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
550 EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
552 static void blkio_reset_stats_cpu(struct blkio_group *blkg)
554 struct blkio_group_stats_cpu *stats_cpu;
557 * Note: On 64 bit arch this should not be an issue. This has the
558 * possibility of returning some inconsistent value on 32bit arch
559 * as 64bit update on 32bit is non atomic. Taking care of this
560 * corner case makes code very complicated, like sending IPIs to
561 * cpus, taking care of stats of offline cpus etc.
563 * reset stats is anyway more of a debug feature and this sounds a
564 * corner case. So I am not complicating the code yet until and
565 * unless this becomes a real issue.
567 for_each_possible_cpu(i) {
568 stats_cpu = per_cpu_ptr(blkg->stats_cpu, i);
569 stats_cpu->sectors = 0;
570 for(j = 0; j < BLKIO_STAT_CPU_NR; j++)
571 for (k = 0; k < BLKIO_STAT_TOTAL; k++)
572 stats_cpu->stat_arr_cpu[j][k] = 0;
577 blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
579 struct blkio_cgroup *blkcg;
580 struct blkio_group *blkg;
581 struct blkio_group_stats *stats;
582 struct hlist_node *n;
583 uint64_t queued[BLKIO_STAT_TOTAL];
585 #ifdef CONFIG_DEBUG_BLK_CGROUP
586 bool idling, waiting, empty;
587 unsigned long long now = sched_clock();
590 blkcg = cgroup_to_blkio_cgroup(cgroup);
591 spin_lock_irq(&blkcg->lock);
592 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
593 spin_lock(&blkg->stats_lock);
594 stats = &blkg->stats;
595 #ifdef CONFIG_DEBUG_BLK_CGROUP
596 idling = blkio_blkg_idling(stats);
597 waiting = blkio_blkg_waiting(stats);
598 empty = blkio_blkg_empty(stats);
600 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
601 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
602 memset(stats, 0, sizeof(struct blkio_group_stats));
603 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
604 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
605 #ifdef CONFIG_DEBUG_BLK_CGROUP
607 blkio_mark_blkg_idling(stats);
608 stats->start_idle_time = now;
611 blkio_mark_blkg_waiting(stats);
612 stats->start_group_wait_time = now;
615 blkio_mark_blkg_empty(stats);
616 stats->start_empty_time = now;
619 spin_unlock(&blkg->stats_lock);
621 /* Reset Per cpu stats which don't take blkg->stats_lock */
622 blkio_reset_stats_cpu(blkg);
625 spin_unlock_irq(&blkcg->lock);
629 static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
630 int chars_left, bool diskname_only)
632 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
633 chars_left -= strlen(str);
634 if (chars_left <= 0) {
636 "Possibly incorrect cgroup stat display format");
642 case BLKIO_STAT_READ:
643 strlcat(str, " Read", chars_left);
645 case BLKIO_STAT_WRITE:
646 strlcat(str, " Write", chars_left);
648 case BLKIO_STAT_SYNC:
649 strlcat(str, " Sync", chars_left);
651 case BLKIO_STAT_ASYNC:
652 strlcat(str, " Async", chars_left);
654 case BLKIO_STAT_TOTAL:
655 strlcat(str, " Total", chars_left);
658 strlcat(str, " Invalid", chars_left);
662 static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
663 struct cgroup_map_cb *cb, dev_t dev)
665 blkio_get_key_name(0, dev, str, chars_left, true);
666 cb->fill(cb, str, val);
671 static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg,
672 enum stat_type_cpu type, enum stat_sub_type sub_type)
675 struct blkio_group_stats_cpu *stats_cpu;
678 for_each_possible_cpu(cpu) {
680 stats_cpu = per_cpu_ptr(blkg->stats_cpu, cpu);
683 start = u64_stats_fetch_begin(&stats_cpu->syncp);
684 if (type == BLKIO_STAT_CPU_SECTORS)
685 tval = stats_cpu->sectors;
687 tval = stats_cpu->stat_arr_cpu[type][sub_type];
688 } while(u64_stats_fetch_retry(&stats_cpu->syncp, start));
696 static uint64_t blkio_get_stat_cpu(struct blkio_group *blkg,
697 struct cgroup_map_cb *cb, dev_t dev, enum stat_type_cpu type)
699 uint64_t disk_total, val;
700 char key_str[MAX_KEY_LEN];
701 enum stat_sub_type sub_type;
703 if (type == BLKIO_STAT_CPU_SECTORS) {
704 val = blkio_read_stat_cpu(blkg, type, 0);
705 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb, dev);
708 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
710 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
711 val = blkio_read_stat_cpu(blkg, type, sub_type);
712 cb->fill(cb, key_str, val);
715 disk_total = blkio_read_stat_cpu(blkg, type, BLKIO_STAT_READ) +
716 blkio_read_stat_cpu(blkg, type, BLKIO_STAT_WRITE);
718 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
719 cb->fill(cb, key_str, disk_total);
723 /* This should be called with blkg->stats_lock held */
724 static uint64_t blkio_get_stat(struct blkio_group *blkg,
725 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
728 char key_str[MAX_KEY_LEN];
729 enum stat_sub_type sub_type;
731 if (type == BLKIO_STAT_TIME)
732 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
733 blkg->stats.time, cb, dev);
734 #ifdef CONFIG_DEBUG_BLK_CGROUP
735 if (type == BLKIO_STAT_UNACCOUNTED_TIME)
736 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
737 blkg->stats.unaccounted_time, cb, dev);
738 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
739 uint64_t sum = blkg->stats.avg_queue_size_sum;
740 uint64_t samples = blkg->stats.avg_queue_size_samples;
742 do_div(sum, samples);
745 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
747 if (type == BLKIO_STAT_GROUP_WAIT_TIME)
748 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
749 blkg->stats.group_wait_time, cb, dev);
750 if (type == BLKIO_STAT_IDLE_TIME)
751 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
752 blkg->stats.idle_time, cb, dev);
753 if (type == BLKIO_STAT_EMPTY_TIME)
754 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
755 blkg->stats.empty_time, cb, dev);
756 if (type == BLKIO_STAT_DEQUEUE)
757 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
758 blkg->stats.dequeue, cb, dev);
761 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
763 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
764 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
766 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
767 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
768 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
769 cb->fill(cb, key_str, disk_total);
773 static int blkio_policy_parse_and_set(char *buf,
774 struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
776 struct gendisk *disk = NULL;
777 char *s[4], *p, *major_s = NULL, *minor_s = NULL;
778 unsigned long major, minor;
779 int i = 0, ret = -EINVAL;
784 memset(s, 0, sizeof(s));
786 while ((p = strsep(&buf, " ")) != NULL) {
792 /* Prevent from inputing too many things */
800 p = strsep(&s[0], ":");
810 if (strict_strtoul(major_s, 10, &major))
813 if (strict_strtoul(minor_s, 10, &minor))
816 dev = MKDEV(major, minor);
818 if (strict_strtoull(s[1], 10, &temp))
821 /* For rule removal, do not check for device presence. */
823 disk = get_gendisk(dev, &part);
833 case BLKIO_POLICY_PROP:
834 if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
835 temp > BLKIO_WEIGHT_MAX)
839 newpn->fileid = fileid;
840 newpn->val.weight = temp;
842 case BLKIO_POLICY_THROTL:
844 case BLKIO_THROTL_read_bps_device:
845 case BLKIO_THROTL_write_bps_device:
847 newpn->fileid = fileid;
848 newpn->val.bps = temp;
850 case BLKIO_THROTL_read_iops_device:
851 case BLKIO_THROTL_write_iops_device:
852 if (temp > THROTL_IOPS_MAX)
856 newpn->fileid = fileid;
857 newpn->val.iops = (unsigned int)temp;
870 unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
873 struct blkio_policy_node *pn;
877 spin_lock_irqsave(&blkcg->lock, flags);
879 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
880 BLKIO_PROP_weight_device);
882 weight = pn->val.weight;
884 weight = blkcg->weight;
886 spin_unlock_irqrestore(&blkcg->lock, flags);
890 EXPORT_SYMBOL_GPL(blkcg_get_weight);
892 uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
894 struct blkio_policy_node *pn;
898 spin_lock_irqsave(&blkcg->lock, flags);
899 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
900 BLKIO_THROTL_read_bps_device);
903 spin_unlock_irqrestore(&blkcg->lock, flags);
908 uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
910 struct blkio_policy_node *pn;
914 spin_lock_irqsave(&blkcg->lock, flags);
915 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
916 BLKIO_THROTL_write_bps_device);
919 spin_unlock_irqrestore(&blkcg->lock, flags);
924 unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
926 struct blkio_policy_node *pn;
928 unsigned int iops = -1;
930 spin_lock_irqsave(&blkcg->lock, flags);
931 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
932 BLKIO_THROTL_read_iops_device);
935 spin_unlock_irqrestore(&blkcg->lock, flags);
940 unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
942 struct blkio_policy_node *pn;
944 unsigned int iops = -1;
946 spin_lock_irqsave(&blkcg->lock, flags);
947 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
948 BLKIO_THROTL_write_iops_device);
951 spin_unlock_irqrestore(&blkcg->lock, flags);
956 /* Checks whether user asked for deleting a policy rule */
957 static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
960 case BLKIO_POLICY_PROP:
961 if (pn->val.weight == 0)
964 case BLKIO_POLICY_THROTL:
966 case BLKIO_THROTL_read_bps_device:
967 case BLKIO_THROTL_write_bps_device:
968 if (pn->val.bps == 0)
971 case BLKIO_THROTL_read_iops_device:
972 case BLKIO_THROTL_write_iops_device:
973 if (pn->val.iops == 0)
984 static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
985 struct blkio_policy_node *newpn)
987 switch(oldpn->plid) {
988 case BLKIO_POLICY_PROP:
989 oldpn->val.weight = newpn->val.weight;
991 case BLKIO_POLICY_THROTL:
992 switch(newpn->fileid) {
993 case BLKIO_THROTL_read_bps_device:
994 case BLKIO_THROTL_write_bps_device:
995 oldpn->val.bps = newpn->val.bps;
997 case BLKIO_THROTL_read_iops_device:
998 case BLKIO_THROTL_write_iops_device:
999 oldpn->val.iops = newpn->val.iops;
1008 * Some rules/values in blkg have changed. Propagate those to respective
1011 static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
1012 struct blkio_group *blkg, struct blkio_policy_node *pn)
1014 unsigned int weight, iops;
1018 case BLKIO_POLICY_PROP:
1019 weight = pn->val.weight ? pn->val.weight :
1021 blkio_update_group_weight(blkg, weight);
1023 case BLKIO_POLICY_THROTL:
1024 switch(pn->fileid) {
1025 case BLKIO_THROTL_read_bps_device:
1026 case BLKIO_THROTL_write_bps_device:
1027 bps = pn->val.bps ? pn->val.bps : (-1);
1028 blkio_update_group_bps(blkg, bps, pn->fileid);
1030 case BLKIO_THROTL_read_iops_device:
1031 case BLKIO_THROTL_write_iops_device:
1032 iops = pn->val.iops ? pn->val.iops : (-1);
1033 blkio_update_group_iops(blkg, iops, pn->fileid);
1043 * A policy node rule has been updated. Propagate this update to all the
1044 * block groups which might be affected by this update.
1046 static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
1047 struct blkio_policy_node *pn)
1049 struct blkio_group *blkg;
1050 struct hlist_node *n;
1052 spin_lock(&blkio_list_lock);
1053 spin_lock_irq(&blkcg->lock);
1055 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
1056 if (pn->dev != blkg->dev || pn->plid != blkg->plid)
1058 blkio_update_blkg_policy(blkcg, blkg, pn);
1061 spin_unlock_irq(&blkcg->lock);
1062 spin_unlock(&blkio_list_lock);
1065 static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
1070 struct blkio_policy_node *newpn, *pn;
1071 struct blkio_cgroup *blkcg;
1073 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1074 int fileid = BLKIOFILE_ATTR(cft->private);
1076 buf = kstrdup(buffer, GFP_KERNEL);
1080 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
1086 ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
1090 blkcg = cgroup_to_blkio_cgroup(cgrp);
1092 spin_lock_irq(&blkcg->lock);
1094 pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
1096 if (!blkio_delete_rule_command(newpn)) {
1097 blkio_policy_insert_node(blkcg, newpn);
1100 spin_unlock_irq(&blkcg->lock);
1101 goto update_io_group;
1104 if (blkio_delete_rule_command(newpn)) {
1105 blkio_policy_delete_node(pn);
1107 spin_unlock_irq(&blkcg->lock);
1108 goto update_io_group;
1110 spin_unlock_irq(&blkcg->lock);
1112 blkio_update_policy_rule(pn, newpn);
1115 blkio_update_policy_node_blkg(blkcg, newpn);
1126 blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
1129 case BLKIO_POLICY_PROP:
1130 if (pn->fileid == BLKIO_PROP_weight_device)
1131 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
1132 MINOR(pn->dev), pn->val.weight);
1134 case BLKIO_POLICY_THROTL:
1135 switch(pn->fileid) {
1136 case BLKIO_THROTL_read_bps_device:
1137 case BLKIO_THROTL_write_bps_device:
1138 seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
1139 MINOR(pn->dev), pn->val.bps);
1141 case BLKIO_THROTL_read_iops_device:
1142 case BLKIO_THROTL_write_iops_device:
1143 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
1144 MINOR(pn->dev), pn->val.iops);
1153 /* cgroup files which read their data from policy nodes end up here */
1154 static void blkio_read_policy_node_files(struct cftype *cft,
1155 struct blkio_cgroup *blkcg, struct seq_file *m)
1157 struct blkio_policy_node *pn;
1159 if (!list_empty(&blkcg->policy_list)) {
1160 spin_lock_irq(&blkcg->lock);
1161 list_for_each_entry(pn, &blkcg->policy_list, node) {
1162 if (!pn_matches_cftype(cft, pn))
1164 blkio_print_policy_node(m, pn);
1166 spin_unlock_irq(&blkcg->lock);
1170 static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
1173 struct blkio_cgroup *blkcg;
1174 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1175 int name = BLKIOFILE_ATTR(cft->private);
1177 blkcg = cgroup_to_blkio_cgroup(cgrp);
1180 case BLKIO_POLICY_PROP:
1182 case BLKIO_PROP_weight_device:
1183 blkio_read_policy_node_files(cft, blkcg, m);
1189 case BLKIO_POLICY_THROTL:
1191 case BLKIO_THROTL_read_bps_device:
1192 case BLKIO_THROTL_write_bps_device:
1193 case BLKIO_THROTL_read_iops_device:
1194 case BLKIO_THROTL_write_iops_device:
1195 blkio_read_policy_node_files(cft, blkcg, m);
1208 static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
1209 struct cftype *cft, struct cgroup_map_cb *cb,
1210 enum stat_type type, bool show_total, bool pcpu)
1212 struct blkio_group *blkg;
1213 struct hlist_node *n;
1214 uint64_t cgroup_total = 0;
1217 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
1219 if (!cftype_blkg_same_policy(cft, blkg))
1222 cgroup_total += blkio_get_stat_cpu(blkg, cb,
1225 spin_lock_irq(&blkg->stats_lock);
1226 cgroup_total += blkio_get_stat(blkg, cb,
1228 spin_unlock_irq(&blkg->stats_lock);
1233 cb->fill(cb, "Total", cgroup_total);
1238 /* All map kind of cgroup file get serviced by this function */
1239 static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
1240 struct cgroup_map_cb *cb)
1242 struct blkio_cgroup *blkcg;
1243 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1244 int name = BLKIOFILE_ATTR(cft->private);
1246 blkcg = cgroup_to_blkio_cgroup(cgrp);
1249 case BLKIO_POLICY_PROP:
1251 case BLKIO_PROP_time:
1252 return blkio_read_blkg_stats(blkcg, cft, cb,
1253 BLKIO_STAT_TIME, 0, 0);
1254 case BLKIO_PROP_sectors:
1255 return blkio_read_blkg_stats(blkcg, cft, cb,
1256 BLKIO_STAT_CPU_SECTORS, 0, 1);
1257 case BLKIO_PROP_io_service_bytes:
1258 return blkio_read_blkg_stats(blkcg, cft, cb,
1259 BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
1260 case BLKIO_PROP_io_serviced:
1261 return blkio_read_blkg_stats(blkcg, cft, cb,
1262 BLKIO_STAT_CPU_SERVICED, 1, 1);
1263 case BLKIO_PROP_io_service_time:
1264 return blkio_read_blkg_stats(blkcg, cft, cb,
1265 BLKIO_STAT_SERVICE_TIME, 1, 0);
1266 case BLKIO_PROP_io_wait_time:
1267 return blkio_read_blkg_stats(blkcg, cft, cb,
1268 BLKIO_STAT_WAIT_TIME, 1, 0);
1269 case BLKIO_PROP_io_merged:
1270 return blkio_read_blkg_stats(blkcg, cft, cb,
1271 BLKIO_STAT_CPU_MERGED, 1, 1);
1272 case BLKIO_PROP_io_queued:
1273 return blkio_read_blkg_stats(blkcg, cft, cb,
1274 BLKIO_STAT_QUEUED, 1, 0);
1275 #ifdef CONFIG_DEBUG_BLK_CGROUP
1276 case BLKIO_PROP_unaccounted_time:
1277 return blkio_read_blkg_stats(blkcg, cft, cb,
1278 BLKIO_STAT_UNACCOUNTED_TIME, 0, 0);
1279 case BLKIO_PROP_dequeue:
1280 return blkio_read_blkg_stats(blkcg, cft, cb,
1281 BLKIO_STAT_DEQUEUE, 0, 0);
1282 case BLKIO_PROP_avg_queue_size:
1283 return blkio_read_blkg_stats(blkcg, cft, cb,
1284 BLKIO_STAT_AVG_QUEUE_SIZE, 0, 0);
1285 case BLKIO_PROP_group_wait_time:
1286 return blkio_read_blkg_stats(blkcg, cft, cb,
1287 BLKIO_STAT_GROUP_WAIT_TIME, 0, 0);
1288 case BLKIO_PROP_idle_time:
1289 return blkio_read_blkg_stats(blkcg, cft, cb,
1290 BLKIO_STAT_IDLE_TIME, 0, 0);
1291 case BLKIO_PROP_empty_time:
1292 return blkio_read_blkg_stats(blkcg, cft, cb,
1293 BLKIO_STAT_EMPTY_TIME, 0, 0);
1299 case BLKIO_POLICY_THROTL:
1301 case BLKIO_THROTL_io_service_bytes:
1302 return blkio_read_blkg_stats(blkcg, cft, cb,
1303 BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
1304 case BLKIO_THROTL_io_serviced:
1305 return blkio_read_blkg_stats(blkcg, cft, cb,
1306 BLKIO_STAT_CPU_SERVICED, 1, 1);
1318 static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
1320 struct blkio_group *blkg;
1321 struct hlist_node *n;
1322 struct blkio_policy_node *pn;
1324 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
1327 spin_lock(&blkio_list_lock);
1328 spin_lock_irq(&blkcg->lock);
1329 blkcg->weight = (unsigned int)val;
1331 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
1332 pn = blkio_policy_search_node(blkcg, blkg->dev,
1333 BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
1337 blkio_update_group_weight(blkg, blkcg->weight);
1339 spin_unlock_irq(&blkcg->lock);
1340 spin_unlock(&blkio_list_lock);
1344 static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
1345 struct blkio_cgroup *blkcg;
1346 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1347 int name = BLKIOFILE_ATTR(cft->private);
1349 blkcg = cgroup_to_blkio_cgroup(cgrp);
1352 case BLKIO_POLICY_PROP:
1354 case BLKIO_PROP_weight:
1355 return (u64)blkcg->weight;
1365 blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
1367 struct blkio_cgroup *blkcg;
1368 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1369 int name = BLKIOFILE_ATTR(cft->private);
1371 blkcg = cgroup_to_blkio_cgroup(cgrp);
1374 case BLKIO_POLICY_PROP:
1376 case BLKIO_PROP_weight:
1377 return blkio_weight_write(blkcg, val);
1387 struct cftype blkio_files[] = {
1389 .name = "weight_device",
1390 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1391 BLKIO_PROP_weight_device),
1392 .read_seq_string = blkiocg_file_read,
1393 .write_string = blkiocg_file_write,
1394 .max_write_len = 256,
1398 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1400 .read_u64 = blkiocg_file_read_u64,
1401 .write_u64 = blkiocg_file_write_u64,
1405 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1407 .read_map = blkiocg_file_read_map,
1411 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1412 BLKIO_PROP_sectors),
1413 .read_map = blkiocg_file_read_map,
1416 .name = "io_service_bytes",
1417 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1418 BLKIO_PROP_io_service_bytes),
1419 .read_map = blkiocg_file_read_map,
1422 .name = "io_serviced",
1423 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1424 BLKIO_PROP_io_serviced),
1425 .read_map = blkiocg_file_read_map,
1428 .name = "io_service_time",
1429 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1430 BLKIO_PROP_io_service_time),
1431 .read_map = blkiocg_file_read_map,
1434 .name = "io_wait_time",
1435 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1436 BLKIO_PROP_io_wait_time),
1437 .read_map = blkiocg_file_read_map,
1440 .name = "io_merged",
1441 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1442 BLKIO_PROP_io_merged),
1443 .read_map = blkiocg_file_read_map,
1446 .name = "io_queued",
1447 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1448 BLKIO_PROP_io_queued),
1449 .read_map = blkiocg_file_read_map,
1452 .name = "reset_stats",
1453 .write_u64 = blkiocg_reset_stats,
1455 #ifdef CONFIG_BLK_DEV_THROTTLING
1457 .name = "throttle.read_bps_device",
1458 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1459 BLKIO_THROTL_read_bps_device),
1460 .read_seq_string = blkiocg_file_read,
1461 .write_string = blkiocg_file_write,
1462 .max_write_len = 256,
1466 .name = "throttle.write_bps_device",
1467 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1468 BLKIO_THROTL_write_bps_device),
1469 .read_seq_string = blkiocg_file_read,
1470 .write_string = blkiocg_file_write,
1471 .max_write_len = 256,
1475 .name = "throttle.read_iops_device",
1476 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1477 BLKIO_THROTL_read_iops_device),
1478 .read_seq_string = blkiocg_file_read,
1479 .write_string = blkiocg_file_write,
1480 .max_write_len = 256,
1484 .name = "throttle.write_iops_device",
1485 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1486 BLKIO_THROTL_write_iops_device),
1487 .read_seq_string = blkiocg_file_read,
1488 .write_string = blkiocg_file_write,
1489 .max_write_len = 256,
1492 .name = "throttle.io_service_bytes",
1493 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1494 BLKIO_THROTL_io_service_bytes),
1495 .read_map = blkiocg_file_read_map,
1498 .name = "throttle.io_serviced",
1499 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1500 BLKIO_THROTL_io_serviced),
1501 .read_map = blkiocg_file_read_map,
1503 #endif /* CONFIG_BLK_DEV_THROTTLING */
1505 #ifdef CONFIG_DEBUG_BLK_CGROUP
1507 .name = "avg_queue_size",
1508 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1509 BLKIO_PROP_avg_queue_size),
1510 .read_map = blkiocg_file_read_map,
1513 .name = "group_wait_time",
1514 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1515 BLKIO_PROP_group_wait_time),
1516 .read_map = blkiocg_file_read_map,
1519 .name = "idle_time",
1520 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1521 BLKIO_PROP_idle_time),
1522 .read_map = blkiocg_file_read_map,
1525 .name = "empty_time",
1526 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1527 BLKIO_PROP_empty_time),
1528 .read_map = blkiocg_file_read_map,
1532 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1533 BLKIO_PROP_dequeue),
1534 .read_map = blkiocg_file_read_map,
1537 .name = "unaccounted_time",
1538 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1539 BLKIO_PROP_unaccounted_time),
1540 .read_map = blkiocg_file_read_map,
1545 static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1547 return cgroup_add_files(cgroup, subsys, blkio_files,
1548 ARRAY_SIZE(blkio_files));
1551 static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1553 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
1554 unsigned long flags;
1555 struct blkio_group *blkg;
1557 struct blkio_policy_type *blkiop;
1558 struct blkio_policy_node *pn, *pntmp;
1562 spin_lock_irqsave(&blkcg->lock, flags);
1564 if (hlist_empty(&blkcg->blkg_list)) {
1565 spin_unlock_irqrestore(&blkcg->lock, flags);
1569 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
1571 key = rcu_dereference(blkg->key);
1572 __blkiocg_del_blkio_group(blkg);
1574 spin_unlock_irqrestore(&blkcg->lock, flags);
1577 * This blkio_group is being unlinked as associated cgroup is
1578 * going away. Let all the IO controlling policies know about
1581 spin_lock(&blkio_list_lock);
1582 list_for_each_entry(blkiop, &blkio_list, list) {
1583 if (blkiop->plid != blkg->plid)
1585 blkiop->ops.blkio_unlink_group_fn(key, blkg);
1587 spin_unlock(&blkio_list_lock);
1590 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
1591 blkio_policy_delete_node(pn);
1595 free_css_id(&blkio_subsys, &blkcg->css);
1597 if (blkcg != &blkio_root_cgroup)
1601 static struct cgroup_subsys_state *
1602 blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1604 struct blkio_cgroup *blkcg;
1605 struct cgroup *parent = cgroup->parent;
1608 blkcg = &blkio_root_cgroup;
1612 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
1614 return ERR_PTR(-ENOMEM);
1616 blkcg->weight = BLKIO_WEIGHT_DEFAULT;
1618 spin_lock_init(&blkcg->lock);
1619 INIT_HLIST_HEAD(&blkcg->blkg_list);
1621 INIT_LIST_HEAD(&blkcg->policy_list);
1626 * We cannot support shared io contexts, as we have no mean to support
1627 * two tasks with the same ioc in two different groups without major rework
1628 * of the main cic data structures. For now we allow a task to change
1629 * its cgroup only if it's the only owner of its ioc.
1631 static int blkiocg_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
1632 struct cgroup_taskset *tset)
1634 struct task_struct *task;
1635 struct io_context *ioc;
1638 /* task_lock() is needed to avoid races with exit_io_context() */
1639 cgroup_taskset_for_each(task, cgrp, tset) {
1641 ioc = task->io_context;
1642 if (ioc && atomic_read(&ioc->nr_tasks) > 1)
1651 static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
1652 struct cgroup_taskset *tset)
1654 struct task_struct *task;
1655 struct io_context *ioc;
1657 cgroup_taskset_for_each(task, cgrp, tset) {
1658 /* we don't lose anything even if ioc allocation fails */
1659 ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
1661 ioc_cgroup_changed(ioc);
1662 put_io_context(ioc, NULL);
1667 void blkio_policy_register(struct blkio_policy_type *blkiop)
1669 spin_lock(&blkio_list_lock);
1670 list_add_tail(&blkiop->list, &blkio_list);
1671 spin_unlock(&blkio_list_lock);
1673 EXPORT_SYMBOL_GPL(blkio_policy_register);
1675 void blkio_policy_unregister(struct blkio_policy_type *blkiop)
1677 spin_lock(&blkio_list_lock);
1678 list_del_init(&blkiop->list);
1679 spin_unlock(&blkio_list_lock);
1681 EXPORT_SYMBOL_GPL(blkio_policy_unregister);
1683 static int __init init_cgroup_blkio(void)
1685 return cgroup_load_subsys(&blkio_subsys);
1688 static void __exit exit_cgroup_blkio(void)
1690 cgroup_unload_subsys(&blkio_subsys);
1693 module_init(init_cgroup_blkio);
1694 module_exit(exit_cgroup_blkio);
1695 MODULE_LICENSE("GPL");