1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * cgroups support for the BFQ I/O scheduler.
5 #include <linux/module.h>
6 #include <linux/slab.h>
7 #include <linux/blkdev.h>
8 #include <linux/cgroup.h>
9 #include <linux/ktime.h>
10 #include <linux/rbtree.h>
11 #include <linux/ioprio.h>
12 #include <linux/sbitmap.h>
13 #include <linux/delay.h>
16 #include "bfq-iosched.h"
18 #ifdef CONFIG_BFQ_CGROUP_DEBUG
19 static int bfq_stat_init(struct bfq_stat *stat, gfp_t gfp)
23 ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
27 atomic64_set(&stat->aux_cnt, 0);
31 static void bfq_stat_exit(struct bfq_stat *stat)
33 percpu_counter_destroy(&stat->cpu_cnt);
37 * bfq_stat_add - add a value to a bfq_stat
38 * @stat: target bfq_stat
41 * Add @val to @stat. The caller must ensure that IRQ on the same CPU
42 * don't re-enter this function for the same counter.
44 static inline void bfq_stat_add(struct bfq_stat *stat, uint64_t val)
46 percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
50 * bfq_stat_read - read the current value of a bfq_stat
51 * @stat: bfq_stat to read
53 static inline uint64_t bfq_stat_read(struct bfq_stat *stat)
55 return percpu_counter_sum_positive(&stat->cpu_cnt);
59 * bfq_stat_reset - reset a bfq_stat
60 * @stat: bfq_stat to reset
62 static inline void bfq_stat_reset(struct bfq_stat *stat)
64 percpu_counter_set(&stat->cpu_cnt, 0);
65 atomic64_set(&stat->aux_cnt, 0);
69 * bfq_stat_add_aux - add a bfq_stat into another's aux count
70 * @to: the destination bfq_stat
73 * Add @from's count including the aux one to @to's aux count.
75 static inline void bfq_stat_add_aux(struct bfq_stat *to,
76 struct bfq_stat *from)
78 atomic64_add(bfq_stat_read(from) + atomic64_read(&from->aux_cnt),
83 * blkg_prfill_stat - prfill callback for bfq_stat
84 * @sf: seq_file to print to
85 * @pd: policy private data of interest
86 * @off: offset to the bfq_stat in @pd
88 * prfill callback for printing a bfq_stat.
90 static u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd,
93 return __blkg_prfill_u64(sf, pd, bfq_stat_read((void *)pd + off));
96 /* bfqg stats flags */
97 enum bfqg_stats_flags {
98 BFQG_stats_waiting = 0,
103 #define BFQG_FLAG_FNS(name) \
104 static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \
106 stats->flags |= (1 << BFQG_stats_##name); \
108 static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \
110 stats->flags &= ~(1 << BFQG_stats_##name); \
112 static int bfqg_stats_##name(struct bfqg_stats *stats) \
114 return (stats->flags & (1 << BFQG_stats_##name)) != 0; \
117 BFQG_FLAG_FNS(waiting)
118 BFQG_FLAG_FNS(idling)
122 /* This should be called with the scheduler lock held. */
123 static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)
127 if (!bfqg_stats_waiting(stats))
130 now = ktime_get_ns();
131 if (now > stats->start_group_wait_time)
132 bfq_stat_add(&stats->group_wait_time,
133 now - stats->start_group_wait_time);
134 bfqg_stats_clear_waiting(stats);
137 /* This should be called with the scheduler lock held. */
138 static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
139 struct bfq_group *curr_bfqg)
141 struct bfqg_stats *stats = &bfqg->stats;
143 if (bfqg_stats_waiting(stats))
145 if (bfqg == curr_bfqg)
147 stats->start_group_wait_time = ktime_get_ns();
148 bfqg_stats_mark_waiting(stats);
151 /* This should be called with the scheduler lock held. */
152 static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)
156 if (!bfqg_stats_empty(stats))
159 now = ktime_get_ns();
160 if (now > stats->start_empty_time)
161 bfq_stat_add(&stats->empty_time,
162 now - stats->start_empty_time);
163 bfqg_stats_clear_empty(stats);
166 void bfqg_stats_update_dequeue(struct bfq_group *bfqg)
168 bfq_stat_add(&bfqg->stats.dequeue, 1);
171 void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg)
173 struct bfqg_stats *stats = &bfqg->stats;
175 if (blkg_rwstat_total(&stats->queued))
179 * group is already marked empty. This can happen if bfqq got new
180 * request in parent group and moved to this group while being added
181 * to service tree. Just ignore the event and move on.
183 if (bfqg_stats_empty(stats))
186 stats->start_empty_time = ktime_get_ns();
187 bfqg_stats_mark_empty(stats);
190 void bfqg_stats_update_idle_time(struct bfq_group *bfqg)
192 struct bfqg_stats *stats = &bfqg->stats;
194 if (bfqg_stats_idling(stats)) {
195 u64 now = ktime_get_ns();
197 if (now > stats->start_idle_time)
198 bfq_stat_add(&stats->idle_time,
199 now - stats->start_idle_time);
200 bfqg_stats_clear_idling(stats);
204 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg)
206 struct bfqg_stats *stats = &bfqg->stats;
208 stats->start_idle_time = ktime_get_ns();
209 bfqg_stats_mark_idling(stats);
212 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg)
214 struct bfqg_stats *stats = &bfqg->stats;
216 bfq_stat_add(&stats->avg_queue_size_sum,
217 blkg_rwstat_total(&stats->queued));
218 bfq_stat_add(&stats->avg_queue_size_samples, 1);
219 bfqg_stats_update_group_wait_time(stats);
222 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
225 blkg_rwstat_add(&bfqg->stats.queued, opf, 1);
226 bfqg_stats_end_empty_time(&bfqg->stats);
227 if (!(bfqq == bfqg->bfqd->in_service_queue))
228 bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq));
231 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf)
233 blkg_rwstat_add(&bfqg->stats.queued, opf, -1);
236 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf)
238 blkg_rwstat_add(&bfqg->stats.merged, opf, 1);
241 void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
242 u64 io_start_time_ns, blk_opf_t opf)
244 struct bfqg_stats *stats = &bfqg->stats;
245 u64 now = ktime_get_ns();
247 if (now > io_start_time_ns)
248 blkg_rwstat_add(&stats->service_time, opf,
249 now - io_start_time_ns);
250 if (io_start_time_ns > start_time_ns)
251 blkg_rwstat_add(&stats->wait_time, opf,
252 io_start_time_ns - start_time_ns);
255 #else /* CONFIG_BFQ_CGROUP_DEBUG */
257 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf) { }
258 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf) { }
259 void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
260 u64 io_start_time_ns, blk_opf_t opf) { }
261 void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { }
262 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }
264 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
266 #ifdef CONFIG_BFQ_GROUP_IOSCHED
269 * blk-cgroup policy-related handlers
270 * The following functions help in converting between blk-cgroup
271 * internal structures and BFQ-specific structures.
274 static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd)
276 return pd ? container_of(pd, struct bfq_group, pd) : NULL;
279 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg)
281 return pd_to_blkg(&bfqg->pd);
284 static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg)
286 return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq));
291 * The following functions help in navigating the bfq_group hierarchy
292 * by allowing to find the parent of a bfq_group or the bfq_group
293 * associated to a bfq_queue.
296 static struct bfq_group *bfqg_parent(struct bfq_group *bfqg)
298 struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent;
300 return pblkg ? blkg_to_bfqg(pblkg) : NULL;
303 struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
305 struct bfq_entity *group_entity = bfqq->entity.parent;
307 return group_entity ? container_of(group_entity, struct bfq_group,
309 bfqq->bfqd->root_group;
313 * The following two functions handle get and put of a bfq_group by
314 * wrapping the related blk-cgroup hooks.
317 static void bfqg_get(struct bfq_group *bfqg)
319 refcount_inc(&bfqg->ref);
322 static void bfqg_put(struct bfq_group *bfqg)
324 if (refcount_dec_and_test(&bfqg->ref))
328 static void bfqg_and_blkg_get(struct bfq_group *bfqg)
330 /* see comments in bfq_bic_update_cgroup for why refcounting bfqg */
333 blkg_get(bfqg_to_blkg(bfqg));
336 void bfqg_and_blkg_put(struct bfq_group *bfqg)
338 blkg_put(bfqg_to_blkg(bfqg));
343 void bfqg_stats_update_legacy_io(struct request_queue *q, struct request *rq)
345 struct bfq_group *bfqg = blkg_to_bfqg(rq->bio->bi_blkg);
350 blkg_rwstat_add(&bfqg->stats.bytes, rq->cmd_flags, blk_rq_bytes(rq));
351 blkg_rwstat_add(&bfqg->stats.ios, rq->cmd_flags, 1);
355 static void bfqg_stats_reset(struct bfqg_stats *stats)
357 #ifdef CONFIG_BFQ_CGROUP_DEBUG
358 /* queued stats shouldn't be cleared */
359 blkg_rwstat_reset(&stats->merged);
360 blkg_rwstat_reset(&stats->service_time);
361 blkg_rwstat_reset(&stats->wait_time);
362 bfq_stat_reset(&stats->time);
363 bfq_stat_reset(&stats->avg_queue_size_sum);
364 bfq_stat_reset(&stats->avg_queue_size_samples);
365 bfq_stat_reset(&stats->dequeue);
366 bfq_stat_reset(&stats->group_wait_time);
367 bfq_stat_reset(&stats->idle_time);
368 bfq_stat_reset(&stats->empty_time);
373 static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
378 #ifdef CONFIG_BFQ_CGROUP_DEBUG
379 /* queued stats shouldn't be cleared */
380 blkg_rwstat_add_aux(&to->merged, &from->merged);
381 blkg_rwstat_add_aux(&to->service_time, &from->service_time);
382 blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
383 bfq_stat_add_aux(&from->time, &from->time);
384 bfq_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
385 bfq_stat_add_aux(&to->avg_queue_size_samples,
386 &from->avg_queue_size_samples);
387 bfq_stat_add_aux(&to->dequeue, &from->dequeue);
388 bfq_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
389 bfq_stat_add_aux(&to->idle_time, &from->idle_time);
390 bfq_stat_add_aux(&to->empty_time, &from->empty_time);
395 * Transfer @bfqg's stats to its parent's aux counts so that the ancestors'
396 * recursive stats can still account for the amount used by this bfqg after
399 static void bfqg_stats_xfer_dead(struct bfq_group *bfqg)
401 struct bfq_group *parent;
403 if (!bfqg) /* root_group */
406 parent = bfqg_parent(bfqg);
408 lockdep_assert_held(&bfqg_to_blkg(bfqg)->q->queue_lock);
410 if (unlikely(!parent))
413 bfqg_stats_add_aux(&parent->stats, &bfqg->stats);
414 bfqg_stats_reset(&bfqg->stats);
417 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg)
419 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
421 entity->weight = entity->new_weight;
422 entity->orig_weight = entity->new_weight;
424 bfqq->ioprio = bfqq->new_ioprio;
425 bfqq->ioprio_class = bfqq->new_ioprio_class;
427 * Make sure that bfqg and its associated blkg do not
428 * disappear before entity.
430 bfqg_and_blkg_get(bfqg);
432 entity->parent = bfqg->my_entity; /* NULL for root group */
433 entity->sched_data = &bfqg->sched_data;
436 static void bfqg_stats_exit(struct bfqg_stats *stats)
438 blkg_rwstat_exit(&stats->bytes);
439 blkg_rwstat_exit(&stats->ios);
440 #ifdef CONFIG_BFQ_CGROUP_DEBUG
441 blkg_rwstat_exit(&stats->merged);
442 blkg_rwstat_exit(&stats->service_time);
443 blkg_rwstat_exit(&stats->wait_time);
444 blkg_rwstat_exit(&stats->queued);
445 bfq_stat_exit(&stats->time);
446 bfq_stat_exit(&stats->avg_queue_size_sum);
447 bfq_stat_exit(&stats->avg_queue_size_samples);
448 bfq_stat_exit(&stats->dequeue);
449 bfq_stat_exit(&stats->group_wait_time);
450 bfq_stat_exit(&stats->idle_time);
451 bfq_stat_exit(&stats->empty_time);
455 static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
457 if (blkg_rwstat_init(&stats->bytes, gfp) ||
458 blkg_rwstat_init(&stats->ios, gfp))
461 #ifdef CONFIG_BFQ_CGROUP_DEBUG
462 if (blkg_rwstat_init(&stats->merged, gfp) ||
463 blkg_rwstat_init(&stats->service_time, gfp) ||
464 blkg_rwstat_init(&stats->wait_time, gfp) ||
465 blkg_rwstat_init(&stats->queued, gfp) ||
466 bfq_stat_init(&stats->time, gfp) ||
467 bfq_stat_init(&stats->avg_queue_size_sum, gfp) ||
468 bfq_stat_init(&stats->avg_queue_size_samples, gfp) ||
469 bfq_stat_init(&stats->dequeue, gfp) ||
470 bfq_stat_init(&stats->group_wait_time, gfp) ||
471 bfq_stat_init(&stats->idle_time, gfp) ||
472 bfq_stat_init(&stats->empty_time, gfp))
479 bfqg_stats_exit(stats);
483 static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd)
485 return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL;
488 static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg)
490 return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq));
493 static struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp)
495 struct bfq_group_data *bgd;
497 bgd = kzalloc(sizeof(*bgd), gfp);
503 static void bfq_cpd_init(struct blkcg_policy_data *cpd)
505 struct bfq_group_data *d = cpd_to_bfqgd(cpd);
507 d->weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
508 CGROUP_WEIGHT_DFL : BFQ_WEIGHT_LEGACY_DFL;
511 static void bfq_cpd_free(struct blkcg_policy_data *cpd)
513 kfree(cpd_to_bfqgd(cpd));
516 static struct blkg_policy_data *bfq_pd_alloc(gfp_t gfp, struct request_queue *q,
519 struct bfq_group *bfqg;
521 bfqg = kzalloc_node(sizeof(*bfqg), gfp, q->node);
525 if (bfqg_stats_init(&bfqg->stats, gfp)) {
530 /* see comments in bfq_bic_update_cgroup for why refcounting */
531 refcount_set(&bfqg->ref, 1);
535 static void bfq_pd_init(struct blkg_policy_data *pd)
537 struct blkcg_gq *blkg = pd_to_blkg(pd);
538 struct bfq_group *bfqg = blkg_to_bfqg(blkg);
539 struct bfq_data *bfqd = blkg->q->elevator->elevator_data;
540 struct bfq_entity *entity = &bfqg->entity;
541 struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg);
543 entity->orig_weight = entity->weight = entity->new_weight = d->weight;
544 entity->my_sched_data = &bfqg->sched_data;
545 entity->last_bfqq_created = NULL;
547 bfqg->my_entity = entity; /*
548 * the root_group's will be set to NULL
549 * in bfq_init_queue()
552 bfqg->active_entities = 0;
553 bfqg->num_queues_with_pending_reqs = 0;
555 bfqg->rq_pos_tree = RB_ROOT;
558 static void bfq_pd_free(struct blkg_policy_data *pd)
560 struct bfq_group *bfqg = pd_to_bfqg(pd);
562 bfqg_stats_exit(&bfqg->stats);
566 static void bfq_pd_reset_stats(struct blkg_policy_data *pd)
568 struct bfq_group *bfqg = pd_to_bfqg(pd);
570 bfqg_stats_reset(&bfqg->stats);
573 static void bfq_group_set_parent(struct bfq_group *bfqg,
574 struct bfq_group *parent)
576 struct bfq_entity *entity;
578 entity = &bfqg->entity;
579 entity->parent = parent->my_entity;
580 entity->sched_data = &parent->sched_data;
583 static void bfq_link_bfqg(struct bfq_data *bfqd, struct bfq_group *bfqg)
585 struct bfq_group *parent;
586 struct bfq_entity *entity;
589 * Update chain of bfq_groups as we might be handling a leaf group
590 * which, along with some of its relatives, has not been hooked yet
591 * to the private hierarchy of BFQ.
593 entity = &bfqg->entity;
594 for_each_entity(entity) {
595 struct bfq_group *curr_bfqg = container_of(entity,
596 struct bfq_group, entity);
597 if (curr_bfqg != bfqd->root_group) {
598 parent = bfqg_parent(curr_bfqg);
600 parent = bfqd->root_group;
601 bfq_group_set_parent(curr_bfqg, parent);
606 struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
608 struct blkcg_gq *blkg = bio->bi_blkg;
609 struct bfq_group *bfqg;
616 bfqg = blkg_to_bfqg(blkg);
618 bio_associate_blkg_from_css(bio, &blkg->blkcg->css);
623 bio_associate_blkg_from_css(bio,
624 &bfqg_to_blkg(bfqd->root_group)->blkcg->css);
625 return bfqd->root_group;
629 * bfq_bfqq_move - migrate @bfqq to @bfqg.
630 * @bfqd: queue descriptor.
631 * @bfqq: the queue to move.
632 * @bfqg: the group to move to.
634 * Move @bfqq to @bfqg, deactivating it from its old group and reactivating
635 * it on the new one. Avoid putting the entity on the old group idle tree.
637 * Must be called under the scheduler lock, to make sure that the blkg
638 * owning @bfqg does not disappear (see comments in
639 * bfq_bic_update_cgroup on guaranteeing the consistency of blkg
642 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
643 struct bfq_group *bfqg)
645 struct bfq_entity *entity = &bfqq->entity;
646 struct bfq_group *old_parent = bfqq_group(bfqq);
647 bool has_pending_reqs = false;
650 * No point to move bfqq to the same group, which can happen when
651 * root group is offlined
653 if (old_parent == bfqg)
657 * oom_bfqq is not allowed to move, oom_bfqq will hold ref to root_group
658 * until elevator exit.
660 if (bfqq == &bfqd->oom_bfqq)
663 * Get extra reference to prevent bfqq from being freed in
664 * next possible expire or deactivate.
668 if (entity->in_groups_with_pending_reqs) {
669 has_pending_reqs = true;
670 bfq_del_bfqq_in_groups_with_pending_reqs(bfqq);
673 /* If bfqq is empty, then bfq_bfqq_expire also invokes
674 * bfq_del_bfqq_busy, thereby removing bfqq and its entity
675 * from data structures related to current group. Otherwise we
676 * need to remove bfqq explicitly with bfq_deactivate_bfqq, as
679 if (bfqq == bfqd->in_service_queue)
680 bfq_bfqq_expire(bfqd, bfqd->in_service_queue,
681 false, BFQQE_PREEMPTED);
683 if (bfq_bfqq_busy(bfqq))
684 bfq_deactivate_bfqq(bfqd, bfqq, false, false);
685 else if (entity->on_st_or_in_serv)
686 bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
687 bfqg_and_blkg_put(old_parent);
689 if (entity->parent &&
690 entity->parent->last_bfqq_created == bfqq)
691 entity->parent->last_bfqq_created = NULL;
692 else if (bfqd->last_bfqq_created == bfqq)
693 bfqd->last_bfqq_created = NULL;
695 entity->parent = bfqg->my_entity;
696 entity->sched_data = &bfqg->sched_data;
697 /* pin down bfqg and its associated blkg */
698 bfqg_and_blkg_get(bfqg);
700 if (has_pending_reqs)
701 bfq_add_bfqq_in_groups_with_pending_reqs(bfqq);
703 if (bfq_bfqq_busy(bfqq)) {
704 if (unlikely(!bfqd->nonrot_with_queueing))
705 bfq_pos_tree_add_move(bfqd, bfqq);
706 bfq_activate_bfqq(bfqd, bfqq);
709 if (!bfqd->in_service_queue && !bfqd->rq_in_driver)
710 bfq_schedule_dispatch(bfqd);
711 /* release extra ref taken above, bfqq may happen to be freed now */
716 * __bfq_bic_change_cgroup - move @bic to @bfqg.
717 * @bfqd: the queue descriptor.
718 * @bic: the bic to move.
719 * @bfqg: the group to move to.
721 * Move bic to blkcg, assuming that bfqd->lock is held; which makes
722 * sure that the reference to cgroup is valid across the call (see
723 * comments in bfq_bic_update_cgroup on this issue)
725 static void __bfq_bic_change_cgroup(struct bfq_data *bfqd,
726 struct bfq_io_cq *bic,
727 struct bfq_group *bfqg)
729 struct bfq_queue *async_bfqq = bic_to_bfqq(bic, false);
730 struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, true);
731 struct bfq_entity *entity;
734 entity = &async_bfqq->entity;
736 if (entity->sched_data != &bfqg->sched_data) {
737 bic_set_bfqq(bic, NULL, false);
738 bfq_release_process_ref(bfqd, async_bfqq);
743 if (!sync_bfqq->new_bfqq && !bfq_bfqq_coop(sync_bfqq)) {
744 /* We are the only user of this bfqq, just move it */
745 if (sync_bfqq->entity.sched_data != &bfqg->sched_data)
746 bfq_bfqq_move(bfqd, sync_bfqq, bfqg);
748 struct bfq_queue *bfqq;
751 * The queue was merged to a different queue. Check
752 * that the merge chain still belongs to the same
755 for (bfqq = sync_bfqq; bfqq; bfqq = bfqq->new_bfqq)
756 if (bfqq->entity.sched_data !=
761 * Some queue changed cgroup so the merge is
762 * not valid anymore. We cannot easily just
763 * cancel the merge (by clearing new_bfqq) as
764 * there may be other processes using this
765 * queue and holding refs to all queues below
766 * sync_bfqq->new_bfqq. Similarly if the merge
767 * already happened, we need to detach from
768 * bfqq now so that we cannot merge bio to a
769 * request from the old cgroup.
771 bfq_put_cooperator(sync_bfqq);
772 bic_set_bfqq(bic, NULL, true);
773 bfq_release_process_ref(bfqd, sync_bfqq);
779 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio)
781 struct bfq_data *bfqd = bic_to_bfqd(bic);
782 struct bfq_group *bfqg = bfq_bio_bfqg(bfqd, bio);
785 serial_nr = bfqg_to_blkg(bfqg)->blkcg->css.serial_nr;
788 * Check whether blkcg has changed. The condition may trigger
789 * spuriously on a newly created cic but there's no harm.
791 if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr))
795 * New cgroup for this process. Make sure it is linked to bfq internal
798 bfq_link_bfqg(bfqd, bfqg);
799 __bfq_bic_change_cgroup(bfqd, bic, bfqg);
801 * Update blkg_path for bfq_log_* functions. We cache this
802 * path, and update it here, for the following
803 * reasons. Operations on blkg objects in blk-cgroup are
804 * protected with the request_queue lock, and not with the
805 * lock that protects the instances of this scheduler
806 * (bfqd->lock). This exposes BFQ to the following sort of
809 * The blkg_lookup performed in bfq_get_queue, protected
810 * through rcu, may happen to return the address of a copy of
811 * the original blkg. If this is the case, then the
812 * bfqg_and_blkg_get performed in bfq_get_queue, to pin down
813 * the blkg, is useless: it does not prevent blk-cgroup code
814 * from destroying both the original blkg and all objects
815 * directly or indirectly referred by the copy of the
818 * On the bright side, destroy operations on a blkg invoke, as
819 * a first step, hooks of the scheduler associated with the
820 * blkg. And these hooks are executed with bfqd->lock held for
821 * BFQ. As a consequence, for any blkg associated with the
822 * request queue this instance of the scheduler is attached
823 * to, we are guaranteed that such a blkg is not destroyed, and
824 * that all the pointers it contains are consistent, while we
825 * are holding bfqd->lock. A blkg_lookup performed with
826 * bfqd->lock held then returns a fully consistent blkg, which
827 * remains consistent until this lock is held.
829 * Thanks to the last fact, and to the fact that: (1) bfqg has
830 * been obtained through a blkg_lookup in the above
831 * assignment, and (2) bfqd->lock is being held, here we can
832 * safely use the policy data for the involved blkg (i.e., the
833 * field bfqg->pd) to get to the blkg associated with bfqg,
834 * and then we can safely use any field of blkg. After we
835 * release bfqd->lock, even just getting blkg through this
836 * bfqg may cause dangling references to be traversed, as
837 * bfqg->pd may not exist any more.
839 * In view of the above facts, here we cache, in the bfqg, any
840 * blkg data we may need for this bic, and for its associated
841 * bfq_queue. As of now, we need to cache only the path of the
842 * blkg, which is used in the bfq_log_* functions.
844 * Finally, note that bfqg itself needs to be protected from
845 * destruction on the blkg_free of the original blkg (which
846 * invokes bfq_pd_free). We use an additional private
847 * refcounter for bfqg, to let it disappear only after no
848 * bfq_queue refers to it any longer.
850 blkg_path(bfqg_to_blkg(bfqg), bfqg->blkg_path, sizeof(bfqg->blkg_path));
851 bic->blkcg_serial_nr = serial_nr;
855 * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st.
856 * @st: the service tree being flushed.
858 static void bfq_flush_idle_tree(struct bfq_service_tree *st)
860 struct bfq_entity *entity = st->first_idle;
862 for (; entity ; entity = st->first_idle)
863 __bfq_deactivate_entity(entity, false);
867 * bfq_reparent_leaf_entity - move leaf entity to the root_group.
868 * @bfqd: the device data structure with the root group.
869 * @entity: the entity to move, if entity is a leaf; or the parent entity
870 * of an active leaf entity to move, if entity is not a leaf.
871 * @ioprio_class: I/O priority class to reparent.
873 static void bfq_reparent_leaf_entity(struct bfq_data *bfqd,
874 struct bfq_entity *entity,
877 struct bfq_queue *bfqq;
878 struct bfq_entity *child_entity = entity;
880 while (child_entity->my_sched_data) { /* leaf not reached yet */
881 struct bfq_sched_data *child_sd = child_entity->my_sched_data;
882 struct bfq_service_tree *child_st = child_sd->service_tree +
884 struct rb_root *child_active = &child_st->active;
886 child_entity = bfq_entity_of(rb_first(child_active));
889 child_entity = child_sd->in_service_entity;
892 bfqq = bfq_entity_to_bfqq(child_entity);
893 bfq_bfqq_move(bfqd, bfqq, bfqd->root_group);
897 * bfq_reparent_active_queues - move to the root group all active queues.
898 * @bfqd: the device data structure with the root group.
899 * @bfqg: the group to move from.
900 * @st: the service tree to start the search from.
901 * @ioprio_class: I/O priority class to reparent.
903 static void bfq_reparent_active_queues(struct bfq_data *bfqd,
904 struct bfq_group *bfqg,
905 struct bfq_service_tree *st,
908 struct rb_root *active = &st->active;
909 struct bfq_entity *entity;
911 while ((entity = bfq_entity_of(rb_first(active))))
912 bfq_reparent_leaf_entity(bfqd, entity, ioprio_class);
914 if (bfqg->sched_data.in_service_entity)
915 bfq_reparent_leaf_entity(bfqd,
916 bfqg->sched_data.in_service_entity,
921 * bfq_pd_offline - deactivate the entity associated with @pd,
922 * and reparent its children entities.
923 * @pd: descriptor of the policy going offline.
925 * blkio already grabs the queue_lock for us, so no need to use
928 static void bfq_pd_offline(struct blkg_policy_data *pd)
930 struct bfq_service_tree *st;
931 struct bfq_group *bfqg = pd_to_bfqg(pd);
932 struct bfq_data *bfqd = bfqg->bfqd;
933 struct bfq_entity *entity = bfqg->my_entity;
937 spin_lock_irqsave(&bfqd->lock, flags);
939 if (!entity) /* root group */
940 goto put_async_queues;
943 * Empty all service_trees belonging to this group before
944 * deactivating the group itself.
946 for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) {
947 st = bfqg->sched_data.service_tree + i;
950 * It may happen that some queues are still active
951 * (busy) upon group destruction (if the corresponding
952 * processes have been forced to terminate). We move
953 * all the leaf entities corresponding to these queues
955 * Also, it may happen that the group has an entity
956 * in service, which is disconnected from the active
957 * tree: it must be moved, too.
958 * There is no need to put the sync queues, as the
959 * scheduler has taken no reference.
961 bfq_reparent_active_queues(bfqd, bfqg, st, i);
964 * The idle tree may still contain bfq_queues
965 * belonging to exited task because they never
966 * migrated to a different cgroup from the one being
967 * destroyed now. In addition, even
968 * bfq_reparent_active_queues() may happen to add some
969 * entities to the idle tree. It happens if, in some
970 * of the calls to bfq_bfqq_move() performed by
971 * bfq_reparent_active_queues(), the queue to move is
972 * empty and gets expired.
974 bfq_flush_idle_tree(st);
977 __bfq_deactivate_entity(entity, false);
980 bfq_put_async_queues(bfqd, bfqg);
981 bfqg->online = false;
983 spin_unlock_irqrestore(&bfqd->lock, flags);
985 * @blkg is going offline and will be ignored by
986 * blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
987 * that they don't get lost. If IOs complete after this point, the
988 * stats for them will be lost. Oh well...
990 bfqg_stats_xfer_dead(bfqg);
993 void bfq_end_wr_async(struct bfq_data *bfqd)
995 struct blkcg_gq *blkg;
997 list_for_each_entry(blkg, &bfqd->queue->blkg_list, q_node) {
998 struct bfq_group *bfqg = blkg_to_bfqg(blkg);
1000 bfq_end_wr_async_queues(bfqd, bfqg);
1002 bfq_end_wr_async_queues(bfqd, bfqd->root_group);
1005 static int bfq_io_show_weight_legacy(struct seq_file *sf, void *v)
1007 struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
1008 struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
1009 unsigned int val = 0;
1012 val = bfqgd->weight;
1014 seq_printf(sf, "%u\n", val);
1019 static u64 bfqg_prfill_weight_device(struct seq_file *sf,
1020 struct blkg_policy_data *pd, int off)
1022 struct bfq_group *bfqg = pd_to_bfqg(pd);
1024 if (!bfqg->entity.dev_weight)
1026 return __blkg_prfill_u64(sf, pd, bfqg->entity.dev_weight);
1029 static int bfq_io_show_weight(struct seq_file *sf, void *v)
1031 struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
1032 struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
1034 seq_printf(sf, "default %u\n", bfqgd->weight);
1035 blkcg_print_blkgs(sf, blkcg, bfqg_prfill_weight_device,
1036 &blkcg_policy_bfq, 0, false);
1040 static void bfq_group_set_weight(struct bfq_group *bfqg, u64 weight, u64 dev_weight)
1042 weight = dev_weight ?: weight;
1044 bfqg->entity.dev_weight = dev_weight;
1046 * Setting the prio_changed flag of the entity
1047 * to 1 with new_weight == weight would re-set
1048 * the value of the weight to its ioprio mapping.
1049 * Set the flag only if necessary.
1051 if ((unsigned short)weight != bfqg->entity.new_weight) {
1052 bfqg->entity.new_weight = (unsigned short)weight;
1054 * Make sure that the above new value has been
1055 * stored in bfqg->entity.new_weight before
1056 * setting the prio_changed flag. In fact,
1057 * this flag may be read asynchronously (in
1058 * critical sections protected by a different
1059 * lock than that held here), and finding this
1060 * flag set may cause the execution of the code
1061 * for updating parameters whose value may
1062 * depend also on bfqg->entity.new_weight (in
1063 * __bfq_entity_update_weight_prio).
1064 * This barrier makes sure that the new value
1065 * of bfqg->entity.new_weight is correctly
1066 * seen in that code.
1069 bfqg->entity.prio_changed = 1;
1073 static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css,
1074 struct cftype *cftype,
1077 struct blkcg *blkcg = css_to_blkcg(css);
1078 struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
1079 struct blkcg_gq *blkg;
1082 if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT)
1086 spin_lock_irq(&blkcg->lock);
1087 bfqgd->weight = (unsigned short)val;
1088 hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
1089 struct bfq_group *bfqg = blkg_to_bfqg(blkg);
1092 bfq_group_set_weight(bfqg, val, 0);
1094 spin_unlock_irq(&blkcg->lock);
1099 static ssize_t bfq_io_set_device_weight(struct kernfs_open_file *of,
1100 char *buf, size_t nbytes,
1104 struct blkg_conf_ctx ctx;
1105 struct blkcg *blkcg = css_to_blkcg(of_css(of));
1106 struct bfq_group *bfqg;
1109 ret = blkg_conf_prep(blkcg, &blkcg_policy_bfq, buf, &ctx);
1113 if (sscanf(ctx.body, "%llu", &v) == 1) {
1114 /* require "default" on dfl */
1118 } else if (!strcmp(strim(ctx.body), "default")) {
1125 bfqg = blkg_to_bfqg(ctx.blkg);
1128 if (!v || (v >= BFQ_MIN_WEIGHT && v <= BFQ_MAX_WEIGHT)) {
1129 bfq_group_set_weight(bfqg, bfqg->entity.weight, v);
1133 blkg_conf_finish(&ctx);
1134 return ret ?: nbytes;
1137 static ssize_t bfq_io_set_weight(struct kernfs_open_file *of,
1138 char *buf, size_t nbytes,
1147 /* "WEIGHT" or "default WEIGHT" sets the default weight */
1148 v = simple_strtoull(buf, &endp, 0);
1149 if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
1150 ret = bfq_io_set_weight_legacy(of_css(of), NULL, v);
1151 return ret ?: nbytes;
1154 return bfq_io_set_device_weight(of, buf, nbytes, off);
1157 static int bfqg_print_rwstat(struct seq_file *sf, void *v)
1159 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
1160 &blkcg_policy_bfq, seq_cft(sf)->private, true);
1164 static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf,
1165 struct blkg_policy_data *pd, int off)
1167 struct blkg_rwstat_sample sum;
1169 blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, off, &sum);
1170 return __blkg_prfill_rwstat(sf, pd, &sum);
1173 static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v)
1175 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
1176 bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq,
1177 seq_cft(sf)->private, true);
1181 #ifdef CONFIG_BFQ_CGROUP_DEBUG
1182 static int bfqg_print_stat(struct seq_file *sf, void *v)
1184 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
1185 &blkcg_policy_bfq, seq_cft(sf)->private, false);
1189 static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
1190 struct blkg_policy_data *pd, int off)
1192 struct blkcg_gq *blkg = pd_to_blkg(pd);
1193 struct blkcg_gq *pos_blkg;
1194 struct cgroup_subsys_state *pos_css;
1197 lockdep_assert_held(&blkg->q->queue_lock);
1200 blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
1201 struct bfq_stat *stat;
1203 if (!pos_blkg->online)
1206 stat = (void *)blkg_to_pd(pos_blkg, &blkcg_policy_bfq) + off;
1207 sum += bfq_stat_read(stat) + atomic64_read(&stat->aux_cnt);
1211 return __blkg_prfill_u64(sf, pd, sum);
1214 static int bfqg_print_stat_recursive(struct seq_file *sf, void *v)
1216 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
1217 bfqg_prfill_stat_recursive, &blkcg_policy_bfq,
1218 seq_cft(sf)->private, false);
1222 static u64 bfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
1225 struct bfq_group *bfqg = blkg_to_bfqg(pd->blkg);
1226 u64 sum = blkg_rwstat_total(&bfqg->stats.bytes);
1228 return __blkg_prfill_u64(sf, pd, sum >> 9);
1231 static int bfqg_print_stat_sectors(struct seq_file *sf, void *v)
1233 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
1234 bfqg_prfill_sectors, &blkcg_policy_bfq, 0, false);
1238 static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf,
1239 struct blkg_policy_data *pd, int off)
1241 struct blkg_rwstat_sample tmp;
1243 blkg_rwstat_recursive_sum(pd->blkg, &blkcg_policy_bfq,
1244 offsetof(struct bfq_group, stats.bytes), &tmp);
1246 return __blkg_prfill_u64(sf, pd,
1247 (tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]) >> 9);
1250 static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
1252 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
1253 bfqg_prfill_sectors_recursive, &blkcg_policy_bfq, 0,
1258 static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf,
1259 struct blkg_policy_data *pd, int off)
1261 struct bfq_group *bfqg = pd_to_bfqg(pd);
1262 u64 samples = bfq_stat_read(&bfqg->stats.avg_queue_size_samples);
1266 v = bfq_stat_read(&bfqg->stats.avg_queue_size_sum);
1267 v = div64_u64(v, samples);
1269 __blkg_prfill_u64(sf, pd, v);
1273 /* print avg_queue_size */
1274 static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v)
1276 blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
1277 bfqg_prfill_avg_queue_size, &blkcg_policy_bfq,
1281 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
1283 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
1287 ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq);
1291 return blkg_to_bfqg(bfqd->queue->root_blkg);
1294 struct blkcg_policy blkcg_policy_bfq = {
1295 .dfl_cftypes = bfq_blkg_files,
1296 .legacy_cftypes = bfq_blkcg_legacy_files,
1298 .cpd_alloc_fn = bfq_cpd_alloc,
1299 .cpd_init_fn = bfq_cpd_init,
1300 .cpd_bind_fn = bfq_cpd_init,
1301 .cpd_free_fn = bfq_cpd_free,
1303 .pd_alloc_fn = bfq_pd_alloc,
1304 .pd_init_fn = bfq_pd_init,
1305 .pd_offline_fn = bfq_pd_offline,
1306 .pd_free_fn = bfq_pd_free,
1307 .pd_reset_stats_fn = bfq_pd_reset_stats,
1310 struct cftype bfq_blkcg_legacy_files[] = {
1312 .name = "bfq.weight",
1313 .flags = CFTYPE_NOT_ON_ROOT,
1314 .seq_show = bfq_io_show_weight_legacy,
1315 .write_u64 = bfq_io_set_weight_legacy,
1318 .name = "bfq.weight_device",
1319 .flags = CFTYPE_NOT_ON_ROOT,
1320 .seq_show = bfq_io_show_weight,
1321 .write = bfq_io_set_weight,
1324 /* statistics, covers only the tasks in the bfqg */
1326 .name = "bfq.io_service_bytes",
1327 .private = offsetof(struct bfq_group, stats.bytes),
1328 .seq_show = bfqg_print_rwstat,
1331 .name = "bfq.io_serviced",
1332 .private = offsetof(struct bfq_group, stats.ios),
1333 .seq_show = bfqg_print_rwstat,
1335 #ifdef CONFIG_BFQ_CGROUP_DEBUG
1338 .private = offsetof(struct bfq_group, stats.time),
1339 .seq_show = bfqg_print_stat,
1342 .name = "bfq.sectors",
1343 .seq_show = bfqg_print_stat_sectors,
1346 .name = "bfq.io_service_time",
1347 .private = offsetof(struct bfq_group, stats.service_time),
1348 .seq_show = bfqg_print_rwstat,
1351 .name = "bfq.io_wait_time",
1352 .private = offsetof(struct bfq_group, stats.wait_time),
1353 .seq_show = bfqg_print_rwstat,
1356 .name = "bfq.io_merged",
1357 .private = offsetof(struct bfq_group, stats.merged),
1358 .seq_show = bfqg_print_rwstat,
1361 .name = "bfq.io_queued",
1362 .private = offsetof(struct bfq_group, stats.queued),
1363 .seq_show = bfqg_print_rwstat,
1365 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
1367 /* the same statistics which cover the bfqg and its descendants */
1369 .name = "bfq.io_service_bytes_recursive",
1370 .private = offsetof(struct bfq_group, stats.bytes),
1371 .seq_show = bfqg_print_rwstat_recursive,
1374 .name = "bfq.io_serviced_recursive",
1375 .private = offsetof(struct bfq_group, stats.ios),
1376 .seq_show = bfqg_print_rwstat_recursive,
1378 #ifdef CONFIG_BFQ_CGROUP_DEBUG
1380 .name = "bfq.time_recursive",
1381 .private = offsetof(struct bfq_group, stats.time),
1382 .seq_show = bfqg_print_stat_recursive,
1385 .name = "bfq.sectors_recursive",
1386 .seq_show = bfqg_print_stat_sectors_recursive,
1389 .name = "bfq.io_service_time_recursive",
1390 .private = offsetof(struct bfq_group, stats.service_time),
1391 .seq_show = bfqg_print_rwstat_recursive,
1394 .name = "bfq.io_wait_time_recursive",
1395 .private = offsetof(struct bfq_group, stats.wait_time),
1396 .seq_show = bfqg_print_rwstat_recursive,
1399 .name = "bfq.io_merged_recursive",
1400 .private = offsetof(struct bfq_group, stats.merged),
1401 .seq_show = bfqg_print_rwstat_recursive,
1404 .name = "bfq.io_queued_recursive",
1405 .private = offsetof(struct bfq_group, stats.queued),
1406 .seq_show = bfqg_print_rwstat_recursive,
1409 .name = "bfq.avg_queue_size",
1410 .seq_show = bfqg_print_avg_queue_size,
1413 .name = "bfq.group_wait_time",
1414 .private = offsetof(struct bfq_group, stats.group_wait_time),
1415 .seq_show = bfqg_print_stat,
1418 .name = "bfq.idle_time",
1419 .private = offsetof(struct bfq_group, stats.idle_time),
1420 .seq_show = bfqg_print_stat,
1423 .name = "bfq.empty_time",
1424 .private = offsetof(struct bfq_group, stats.empty_time),
1425 .seq_show = bfqg_print_stat,
1428 .name = "bfq.dequeue",
1429 .private = offsetof(struct bfq_group, stats.dequeue),
1430 .seq_show = bfqg_print_stat,
1432 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
1436 struct cftype bfq_blkg_files[] = {
1438 .name = "bfq.weight",
1439 .flags = CFTYPE_NOT_ON_ROOT,
1440 .seq_show = bfq_io_show_weight,
1441 .write = bfq_io_set_weight,
1446 #else /* CONFIG_BFQ_GROUP_IOSCHED */
1448 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1449 struct bfq_group *bfqg) {}
1451 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg)
1453 struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
1455 entity->weight = entity->new_weight;
1456 entity->orig_weight = entity->new_weight;
1458 bfqq->ioprio = bfqq->new_ioprio;
1459 bfqq->ioprio_class = bfqq->new_ioprio_class;
1461 entity->sched_data = &bfqg->sched_data;
1464 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) {}
1466 void bfq_end_wr_async(struct bfq_data *bfqd)
1468 bfq_end_wr_async_queues(bfqd, bfqd->root_group);
1471 struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
1473 return bfqd->root_group;
1476 struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
1478 return bfqq->bfqd->root_group;
1481 void bfqg_and_blkg_put(struct bfq_group *bfqg) {}
1483 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
1485 struct bfq_group *bfqg;
1488 bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node);
1492 for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
1493 bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
1497 #endif /* CONFIG_BFQ_GROUP_IOSCHED */