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 "blk-cgroup.h"
20 #include <linux/genhd.h>
22 #define MAX_KEY_LEN 100
24 static DEFINE_SPINLOCK(blkio_list_lock);
25 static LIST_HEAD(blkio_list);
27 struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
28 EXPORT_SYMBOL_GPL(blkio_root_cgroup);
30 static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
32 static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
33 struct task_struct *, bool);
34 static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
35 struct cgroup *, struct task_struct *, bool);
36 static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
37 static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
39 struct cgroup_subsys blkio_subsys = {
41 .create = blkiocg_create,
42 .can_attach = blkiocg_can_attach,
43 .attach = blkiocg_attach,
44 .destroy = blkiocg_destroy,
45 .populate = blkiocg_populate,
46 #ifdef CONFIG_BLK_CGROUP
47 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
48 .subsys_id = blkio_subsys_id,
51 .module = THIS_MODULE,
53 EXPORT_SYMBOL_GPL(blkio_subsys);
55 static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
56 struct blkio_policy_node *pn)
58 list_add(&pn->node, &blkcg->policy_list);
61 /* Must be called with blkcg->lock held */
62 static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
67 /* Must be called with blkcg->lock held */
68 static struct blkio_policy_node *
69 blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev)
71 struct blkio_policy_node *pn;
73 list_for_each_entry(pn, &blkcg->policy_list, node) {
81 struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
83 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
84 struct blkio_cgroup, css);
86 EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
88 void blkio_group_init(struct blkio_group *blkg)
90 spin_lock_init(&blkg->stats_lock);
92 EXPORT_SYMBOL_GPL(blkio_group_init);
95 * Add to the appropriate stat variable depending on the request type.
96 * This should be called with the blkg->stats_lock held.
98 static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
102 stat[BLKIO_STAT_WRITE] += add;
104 stat[BLKIO_STAT_READ] += add;
106 stat[BLKIO_STAT_SYNC] += add;
108 stat[BLKIO_STAT_ASYNC] += add;
112 * Decrements the appropriate stat variable if non-zero depending on the
113 * request type. Panics on value being zero.
114 * This should be called with the blkg->stats_lock held.
116 static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
119 BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
120 stat[BLKIO_STAT_WRITE]--;
122 BUG_ON(stat[BLKIO_STAT_READ] == 0);
123 stat[BLKIO_STAT_READ]--;
126 BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
127 stat[BLKIO_STAT_SYNC]--;
129 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
130 stat[BLKIO_STAT_ASYNC]--;
134 #ifdef CONFIG_DEBUG_BLK_CGROUP
135 /* This should be called with the blkg->stats_lock held. */
136 static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
137 struct blkio_group *curr_blkg)
139 if (blkio_blkg_waiting(&blkg->stats))
141 if (blkg == curr_blkg)
143 blkg->stats.start_group_wait_time = sched_clock();
144 blkio_mark_blkg_waiting(&blkg->stats);
147 /* This should be called with the blkg->stats_lock held. */
148 static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
150 unsigned long long now;
152 if (!blkio_blkg_waiting(stats))
156 if (time_after64(now, stats->start_group_wait_time))
157 stats->group_wait_time += now - stats->start_group_wait_time;
158 blkio_clear_blkg_waiting(stats);
161 /* This should be called with the blkg->stats_lock held. */
162 static void blkio_end_empty_time(struct blkio_group_stats *stats)
164 unsigned long long now;
166 if (!blkio_blkg_empty(stats))
170 if (time_after64(now, stats->start_empty_time))
171 stats->empty_time += now - stats->start_empty_time;
172 blkio_clear_blkg_empty(stats);
175 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
179 spin_lock_irqsave(&blkg->stats_lock, flags);
180 BUG_ON(blkio_blkg_idling(&blkg->stats));
181 blkg->stats.start_idle_time = sched_clock();
182 blkio_mark_blkg_idling(&blkg->stats);
183 spin_unlock_irqrestore(&blkg->stats_lock, flags);
185 EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
187 void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
190 unsigned long long now;
191 struct blkio_group_stats *stats;
193 spin_lock_irqsave(&blkg->stats_lock, flags);
194 stats = &blkg->stats;
195 if (blkio_blkg_idling(stats)) {
197 if (time_after64(now, stats->start_idle_time))
198 stats->idle_time += now - stats->start_idle_time;
199 blkio_clear_blkg_idling(stats);
201 spin_unlock_irqrestore(&blkg->stats_lock, flags);
203 EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
205 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
208 struct blkio_group_stats *stats;
210 spin_lock_irqsave(&blkg->stats_lock, flags);
211 stats = &blkg->stats;
212 stats->avg_queue_size_sum +=
213 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
214 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
215 stats->avg_queue_size_samples++;
216 blkio_update_group_wait_time(stats);
217 spin_unlock_irqrestore(&blkg->stats_lock, flags);
219 EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
221 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
222 unsigned long dequeue)
224 blkg->stats.dequeue += dequeue;
226 EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
228 static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
229 struct blkio_group *curr_blkg) {}
230 static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
233 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
234 struct blkio_group *curr_blkg, bool direction,
239 spin_lock_irqsave(&blkg->stats_lock, flags);
240 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
242 blkio_end_empty_time(&blkg->stats);
243 blkio_set_start_group_wait_time(blkg, curr_blkg);
244 spin_unlock_irqrestore(&blkg->stats_lock, flags);
246 EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
248 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
249 bool direction, bool sync)
253 spin_lock_irqsave(&blkg->stats_lock, flags);
254 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
256 spin_unlock_irqrestore(&blkg->stats_lock, flags);
258 EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
260 void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
264 spin_lock_irqsave(&blkg->stats_lock, flags);
265 blkg->stats.time += time;
266 spin_unlock_irqrestore(&blkg->stats_lock, flags);
268 EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
270 void blkiocg_set_start_empty_time(struct blkio_group *blkg, bool ignore)
273 struct blkio_group_stats *stats;
275 spin_lock_irqsave(&blkg->stats_lock, flags);
276 stats = &blkg->stats;
278 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
279 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
280 spin_unlock_irqrestore(&blkg->stats_lock, flags);
285 * If ignore is set, we do not panic on the empty flag being set
286 * already. This is to avoid cases where there are superfluous timeslice
287 * complete events (for eg., forced_dispatch in CFQ) when no IOs are
288 * served which could result in triggering the empty check incorrectly.
290 BUG_ON(!ignore && blkio_blkg_empty(stats));
291 stats->start_empty_time = sched_clock();
292 blkio_mark_blkg_empty(stats);
293 spin_unlock_irqrestore(&blkg->stats_lock, flags);
295 EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
297 void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
298 uint64_t bytes, bool direction, bool sync)
300 struct blkio_group_stats *stats;
303 spin_lock_irqsave(&blkg->stats_lock, flags);
304 stats = &blkg->stats;
305 stats->sectors += bytes >> 9;
306 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
308 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
310 spin_unlock_irqrestore(&blkg->stats_lock, flags);
312 EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
314 void blkiocg_update_completion_stats(struct blkio_group *blkg,
315 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
317 struct blkio_group_stats *stats;
319 unsigned long long now = sched_clock();
321 spin_lock_irqsave(&blkg->stats_lock, flags);
322 stats = &blkg->stats;
323 if (time_after64(now, io_start_time))
324 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
325 now - io_start_time, direction, sync);
326 if (time_after64(io_start_time, start_time))
327 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
328 io_start_time - start_time, direction, sync);
329 spin_unlock_irqrestore(&blkg->stats_lock, flags);
331 EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
333 void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
338 spin_lock_irqsave(&blkg->stats_lock, flags);
339 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,
341 spin_unlock_irqrestore(&blkg->stats_lock, flags);
343 EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
345 void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
346 struct blkio_group *blkg, void *key, dev_t dev)
350 spin_lock_irqsave(&blkcg->lock, flags);
351 rcu_assign_pointer(blkg->key, key);
352 blkg->blkcg_id = css_id(&blkcg->css);
353 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
354 spin_unlock_irqrestore(&blkcg->lock, flags);
355 #ifdef CONFIG_DEBUG_BLK_CGROUP
356 /* Need to take css reference ? */
357 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
361 EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
363 static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
365 hlist_del_init_rcu(&blkg->blkcg_node);
370 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
371 * indicating that blk_group was unhashed by the time we got to it.
373 int blkiocg_del_blkio_group(struct blkio_group *blkg)
375 struct blkio_cgroup *blkcg;
377 struct cgroup_subsys_state *css;
381 css = css_lookup(&blkio_subsys, blkg->blkcg_id);
385 blkcg = container_of(css, struct blkio_cgroup, css);
386 spin_lock_irqsave(&blkcg->lock, flags);
387 if (!hlist_unhashed(&blkg->blkcg_node)) {
388 __blkiocg_del_blkio_group(blkg);
391 spin_unlock_irqrestore(&blkcg->lock, flags);
396 EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
398 /* called under rcu_read_lock(). */
399 struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
401 struct blkio_group *blkg;
402 struct hlist_node *n;
405 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
413 EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
415 #define SHOW_FUNCTION(__VAR) \
416 static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \
417 struct cftype *cftype) \
419 struct blkio_cgroup *blkcg; \
421 blkcg = cgroup_to_blkio_cgroup(cgroup); \
422 return (u64)blkcg->__VAR; \
425 SHOW_FUNCTION(weight);
429 blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
431 struct blkio_cgroup *blkcg;
432 struct blkio_group *blkg;
433 struct hlist_node *n;
434 struct blkio_policy_type *blkiop;
435 struct blkio_policy_node *pn;
437 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
440 blkcg = cgroup_to_blkio_cgroup(cgroup);
441 spin_lock(&blkio_list_lock);
442 spin_lock_irq(&blkcg->lock);
443 blkcg->weight = (unsigned int)val;
445 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
446 pn = blkio_policy_search_node(blkcg, blkg->dev);
451 list_for_each_entry(blkiop, &blkio_list, list)
452 blkiop->ops.blkio_update_group_weight_fn(blkg,
455 spin_unlock_irq(&blkcg->lock);
456 spin_unlock(&blkio_list_lock);
461 blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
463 struct blkio_cgroup *blkcg;
464 struct blkio_group *blkg;
465 struct blkio_group_stats *stats;
466 struct hlist_node *n;
467 uint64_t queued[BLKIO_STAT_TOTAL];
469 #ifdef CONFIG_DEBUG_BLK_CGROUP
470 bool idling, waiting, empty;
471 unsigned long long now = sched_clock();
474 blkcg = cgroup_to_blkio_cgroup(cgroup);
475 spin_lock_irq(&blkcg->lock);
476 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
477 spin_lock(&blkg->stats_lock);
478 stats = &blkg->stats;
479 #ifdef CONFIG_DEBUG_BLK_CGROUP
480 idling = blkio_blkg_idling(stats);
481 waiting = blkio_blkg_waiting(stats);
482 empty = blkio_blkg_empty(stats);
484 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
485 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
486 memset(stats, 0, sizeof(struct blkio_group_stats));
487 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
488 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
489 #ifdef CONFIG_DEBUG_BLK_CGROUP
491 blkio_mark_blkg_idling(stats);
492 stats->start_idle_time = now;
495 blkio_mark_blkg_waiting(stats);
496 stats->start_group_wait_time = now;
499 blkio_mark_blkg_empty(stats);
500 stats->start_empty_time = now;
503 spin_unlock(&blkg->stats_lock);
505 spin_unlock_irq(&blkcg->lock);
509 static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
510 int chars_left, bool diskname_only)
512 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
513 chars_left -= strlen(str);
514 if (chars_left <= 0) {
516 "Possibly incorrect cgroup stat display format");
522 case BLKIO_STAT_READ:
523 strlcat(str, " Read", chars_left);
525 case BLKIO_STAT_WRITE:
526 strlcat(str, " Write", chars_left);
528 case BLKIO_STAT_SYNC:
529 strlcat(str, " Sync", chars_left);
531 case BLKIO_STAT_ASYNC:
532 strlcat(str, " Async", chars_left);
534 case BLKIO_STAT_TOTAL:
535 strlcat(str, " Total", chars_left);
538 strlcat(str, " Invalid", chars_left);
542 static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
543 struct cgroup_map_cb *cb, dev_t dev)
545 blkio_get_key_name(0, dev, str, chars_left, true);
546 cb->fill(cb, str, val);
550 /* This should be called with blkg->stats_lock held */
551 static uint64_t blkio_get_stat(struct blkio_group *blkg,
552 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
555 char key_str[MAX_KEY_LEN];
556 enum stat_sub_type sub_type;
558 if (type == BLKIO_STAT_TIME)
559 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
560 blkg->stats.time, cb, dev);
561 if (type == BLKIO_STAT_SECTORS)
562 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
563 blkg->stats.sectors, cb, dev);
564 #ifdef CONFIG_DEBUG_BLK_CGROUP
565 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
566 uint64_t sum = blkg->stats.avg_queue_size_sum;
567 uint64_t samples = blkg->stats.avg_queue_size_samples;
569 do_div(sum, samples);
572 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
574 if (type == BLKIO_STAT_GROUP_WAIT_TIME)
575 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
576 blkg->stats.group_wait_time, cb, dev);
577 if (type == BLKIO_STAT_IDLE_TIME)
578 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
579 blkg->stats.idle_time, cb, dev);
580 if (type == BLKIO_STAT_EMPTY_TIME)
581 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
582 blkg->stats.empty_time, cb, dev);
583 if (type == BLKIO_STAT_DEQUEUE)
584 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
585 blkg->stats.dequeue, cb, dev);
588 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
590 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
591 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
593 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
594 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
595 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
596 cb->fill(cb, key_str, disk_total);
600 #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \
601 static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \
602 struct cftype *cftype, struct cgroup_map_cb *cb) \
604 struct blkio_cgroup *blkcg; \
605 struct blkio_group *blkg; \
606 struct hlist_node *n; \
607 uint64_t cgroup_total = 0; \
609 if (!cgroup_lock_live_group(cgroup)) \
612 blkcg = cgroup_to_blkio_cgroup(cgroup); \
614 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\
616 spin_lock_irq(&blkg->stats_lock); \
617 cgroup_total += blkio_get_stat(blkg, cb, \
619 spin_unlock_irq(&blkg->stats_lock); \
623 cb->fill(cb, "Total", cgroup_total); \
629 SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0);
630 SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0);
631 SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1);
632 SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1);
633 SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1);
634 SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1);
635 SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1);
636 SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1);
637 #ifdef CONFIG_DEBUG_BLK_CGROUP
638 SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0);
639 SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0);
640 SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0);
641 SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0);
642 SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0);
644 #undef SHOW_FUNCTION_PER_GROUP
646 static int blkio_check_dev_num(dev_t dev)
649 struct gendisk *disk;
651 disk = get_gendisk(dev, &part);
658 static int blkio_policy_parse_and_set(char *buf,
659 struct blkio_policy_node *newpn)
661 char *s[4], *p, *major_s = NULL, *minor_s = NULL;
663 unsigned long major, minor, temp;
667 memset(s, 0, sizeof(s));
669 while ((p = strsep(&buf, " ")) != NULL) {
675 /* Prevent from inputing too many things */
683 p = strsep(&s[0], ":");
693 ret = strict_strtoul(major_s, 10, &major);
697 ret = strict_strtoul(minor_s, 10, &minor);
701 dev = MKDEV(major, minor);
703 ret = blkio_check_dev_num(dev);
712 ret = strict_strtoul(s[1], 10, &temp);
713 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
714 temp > BLKIO_WEIGHT_MAX)
717 newpn->weight = temp;
722 unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
725 struct blkio_policy_node *pn;
727 pn = blkio_policy_search_node(blkcg, dev);
731 return blkcg->weight;
733 EXPORT_SYMBOL_GPL(blkcg_get_weight);
736 static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
741 struct blkio_policy_node *newpn, *pn;
742 struct blkio_cgroup *blkcg;
743 struct blkio_group *blkg;
745 struct hlist_node *n;
746 struct blkio_policy_type *blkiop;
748 buf = kstrdup(buffer, GFP_KERNEL);
752 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
758 ret = blkio_policy_parse_and_set(buf, newpn);
762 blkcg = cgroup_to_blkio_cgroup(cgrp);
764 spin_lock_irq(&blkcg->lock);
766 pn = blkio_policy_search_node(blkcg, newpn->dev);
768 if (newpn->weight != 0) {
769 blkio_policy_insert_node(blkcg, newpn);
772 spin_unlock_irq(&blkcg->lock);
773 goto update_io_group;
776 if (newpn->weight == 0) {
777 /* weight == 0 means deleteing a specific weight */
778 blkio_policy_delete_node(pn);
779 spin_unlock_irq(&blkcg->lock);
780 goto update_io_group;
782 spin_unlock_irq(&blkcg->lock);
784 pn->weight = newpn->weight;
787 /* update weight for each cfqg */
788 spin_lock(&blkio_list_lock);
789 spin_lock_irq(&blkcg->lock);
791 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
792 if (newpn->dev == blkg->dev) {
793 list_for_each_entry(blkiop, &blkio_list, list)
794 blkiop->ops.blkio_update_group_weight_fn(blkg,
801 spin_unlock_irq(&blkcg->lock);
802 spin_unlock(&blkio_list_lock);
812 static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
815 struct blkio_cgroup *blkcg;
816 struct blkio_policy_node *pn;
818 seq_printf(m, "dev\tweight\n");
820 blkcg = cgroup_to_blkio_cgroup(cgrp);
821 if (list_empty(&blkcg->policy_list))
824 spin_lock_irq(&blkcg->lock);
825 list_for_each_entry(pn, &blkcg->policy_list, node) {
826 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
827 MINOR(pn->dev), pn->weight);
829 spin_unlock_irq(&blkcg->lock);
835 struct cftype blkio_files[] = {
837 .name = "weight_device",
838 .read_seq_string = blkiocg_weight_device_read,
839 .write_string = blkiocg_weight_device_write,
840 .max_write_len = 256,
844 .read_u64 = blkiocg_weight_read,
845 .write_u64 = blkiocg_weight_write,
849 .read_map = blkiocg_time_read,
853 .read_map = blkiocg_sectors_read,
856 .name = "io_service_bytes",
857 .read_map = blkiocg_io_service_bytes_read,
860 .name = "io_serviced",
861 .read_map = blkiocg_io_serviced_read,
864 .name = "io_service_time",
865 .read_map = blkiocg_io_service_time_read,
868 .name = "io_wait_time",
869 .read_map = blkiocg_io_wait_time_read,
873 .read_map = blkiocg_io_merged_read,
877 .read_map = blkiocg_io_queued_read,
880 .name = "reset_stats",
881 .write_u64 = blkiocg_reset_stats,
883 #ifdef CONFIG_DEBUG_BLK_CGROUP
885 .name = "avg_queue_size",
886 .read_map = blkiocg_avg_queue_size_read,
889 .name = "group_wait_time",
890 .read_map = blkiocg_group_wait_time_read,
894 .read_map = blkiocg_idle_time_read,
897 .name = "empty_time",
898 .read_map = blkiocg_empty_time_read,
902 .read_map = blkiocg_dequeue_read,
907 static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
909 return cgroup_add_files(cgroup, subsys, blkio_files,
910 ARRAY_SIZE(blkio_files));
913 static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
915 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
917 struct blkio_group *blkg;
919 struct blkio_policy_type *blkiop;
920 struct blkio_policy_node *pn, *pntmp;
924 spin_lock_irqsave(&blkcg->lock, flags);
926 if (hlist_empty(&blkcg->blkg_list)) {
927 spin_unlock_irqrestore(&blkcg->lock, flags);
931 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
933 key = rcu_dereference(blkg->key);
934 __blkiocg_del_blkio_group(blkg);
936 spin_unlock_irqrestore(&blkcg->lock, flags);
939 * This blkio_group is being unlinked as associated cgroup is going
940 * away. Let all the IO controlling policies know about this event.
942 * Currently this is static call to one io controlling policy. Once
943 * we have more policies in place, we need some dynamic registration
944 * of callback function.
946 spin_lock(&blkio_list_lock);
947 list_for_each_entry(blkiop, &blkio_list, list)
948 blkiop->ops.blkio_unlink_group_fn(key, blkg);
949 spin_unlock(&blkio_list_lock);
953 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
954 blkio_policy_delete_node(pn);
957 free_css_id(&blkio_subsys, &blkcg->css);
959 if (blkcg != &blkio_root_cgroup)
963 static struct cgroup_subsys_state *
964 blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
966 struct blkio_cgroup *blkcg, *parent_blkcg;
968 if (!cgroup->parent) {
969 blkcg = &blkio_root_cgroup;
973 /* Currently we do not support hierarchy deeper than two level (0,1) */
974 parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent);
975 if (css_depth(&parent_blkcg->css) > 0)
976 return ERR_PTR(-EINVAL);
978 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
980 return ERR_PTR(-ENOMEM);
982 blkcg->weight = BLKIO_WEIGHT_DEFAULT;
984 spin_lock_init(&blkcg->lock);
985 INIT_HLIST_HEAD(&blkcg->blkg_list);
987 INIT_LIST_HEAD(&blkcg->policy_list);
992 * We cannot support shared io contexts, as we have no mean to support
993 * two tasks with the same ioc in two different groups without major rework
994 * of the main cic data structures. For now we allow a task to change
995 * its cgroup only if it's the only owner of its ioc.
997 static int blkiocg_can_attach(struct cgroup_subsys *subsys,
998 struct cgroup *cgroup, struct task_struct *tsk,
1001 struct io_context *ioc;
1004 /* task_lock() is needed to avoid races with exit_io_context() */
1006 ioc = tsk->io_context;
1007 if (ioc && atomic_read(&ioc->nr_tasks) > 1)
1014 static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup,
1015 struct cgroup *prev, struct task_struct *tsk,
1018 struct io_context *ioc;
1021 ioc = tsk->io_context;
1023 ioc->cgroup_changed = 1;
1027 void blkio_policy_register(struct blkio_policy_type *blkiop)
1029 spin_lock(&blkio_list_lock);
1030 list_add_tail(&blkiop->list, &blkio_list);
1031 spin_unlock(&blkio_list_lock);
1033 EXPORT_SYMBOL_GPL(blkio_policy_register);
1035 void blkio_policy_unregister(struct blkio_policy_type *blkiop)
1037 spin_lock(&blkio_list_lock);
1038 list_del_init(&blkiop->list);
1039 spin_unlock(&blkio_list_lock);
1041 EXPORT_SYMBOL_GPL(blkio_policy_unregister);
1043 static int __init init_cgroup_blkio(void)
1045 return cgroup_load_subsys(&blkio_subsys);
1048 static void __exit exit_cgroup_blkio(void)
1050 cgroup_unload_subsys(&blkio_subsys);
1053 module_init(init_cgroup_blkio);
1054 module_exit(exit_cgroup_blkio);
1055 MODULE_LICENSE("GPL");