1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Header file for the BFQ I/O scheduler: data structures and
4 * prototypes of interface functions among BFQ components.
9 #include <linux/blktrace_api.h>
10 #include <linux/hrtimer.h>
12 #include "blk-cgroup-rwstat.h"
14 #define BFQ_IOPRIO_CLASSES 3
15 #define BFQ_CL_IDLE_TIMEOUT (HZ/5)
17 #define BFQ_MIN_WEIGHT 1
18 #define BFQ_MAX_WEIGHT 1000
19 #define BFQ_WEIGHT_CONVERSION_COEFF 10
21 #define BFQ_DEFAULT_QUEUE_IOPRIO 4
23 #define BFQ_WEIGHT_LEGACY_DFL 100
24 #define BFQ_DEFAULT_GRP_IOPRIO 0
25 #define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE
27 #define MAX_BFQQ_NAME_LENGTH 16
30 * Soft real-time applications are extremely more latency sensitive
31 * than interactive ones. Over-raise the weight of the former to
32 * privilege them against the latter.
34 #define BFQ_SOFTRT_WEIGHT_FACTOR 100
39 * struct bfq_service_tree - per ioprio_class service tree.
41 * Each service tree represents a B-WF2Q+ scheduler on its own. Each
42 * ioprio_class has its own independent scheduler, and so its own
43 * bfq_service_tree. All the fields are protected by the queue lock
44 * of the containing bfqd.
46 struct bfq_service_tree
{
47 /* tree for active entities (i.e., those backlogged) */
48 struct rb_root active
;
49 /* tree for idle entities (i.e., not backlogged, with V < F_i)*/
52 /* idle entity with minimum F_i */
53 struct bfq_entity
*first_idle
;
54 /* idle entity with maximum F_i */
55 struct bfq_entity
*last_idle
;
57 /* scheduler virtual time */
59 /* scheduler weight sum; active and idle entities contribute to it */
64 * struct bfq_sched_data - multi-class scheduler.
66 * bfq_sched_data is the basic scheduler queue. It supports three
67 * ioprio_classes, and can be used either as a toplevel queue or as an
68 * intermediate queue in a hierarchical setup.
70 * The supported ioprio_classes are the same as in CFQ, in descending
71 * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
72 * Requests from higher priority queues are served before all the
73 * requests from lower priority queues; among requests of the same
74 * queue requests are served according to B-WF2Q+.
76 * The schedule is implemented by the service trees, plus the field
77 * @next_in_service, which points to the entity on the active trees
78 * that will be served next, if 1) no changes in the schedule occurs
79 * before the current in-service entity is expired, 2) the in-service
80 * queue becomes idle when it expires, and 3) if the entity pointed by
81 * in_service_entity is not a queue, then the in-service child entity
82 * of the entity pointed by in_service_entity becomes idle on
83 * expiration. This peculiar definition allows for the following
84 * optimization, not yet exploited: while a given entity is still in
85 * service, we already know which is the best candidate for next
86 * service among the other active entities in the same parent
87 * entity. We can then quickly compare the timestamps of the
88 * in-service entity with those of such best candidate.
90 * All fields are protected by the lock of the containing bfqd.
92 struct bfq_sched_data
{
93 /* entity in service */
94 struct bfq_entity
*in_service_entity
;
95 /* head-of-line entity (see comments above) */
96 struct bfq_entity
*next_in_service
;
97 /* array of service trees, one per ioprio_class */
98 struct bfq_service_tree service_tree
[BFQ_IOPRIO_CLASSES
];
99 /* last time CLASS_IDLE was served */
100 unsigned long bfq_class_idle_last_service
;
105 * struct bfq_weight_counter - counter of the number of all active queues
106 * with a given weight.
108 struct bfq_weight_counter
{
109 unsigned int weight
; /* weight of the queues this counter refers to */
110 unsigned int num_active
; /* nr of active queues with this weight */
112 * Weights tree member (see bfq_data's @queue_weights_tree)
114 struct rb_node weights_node
;
118 * struct bfq_entity - schedulable entity.
120 * A bfq_entity is used to represent either a bfq_queue (leaf node in the
121 * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each
122 * entity belongs to the sched_data of the parent group in the cgroup
123 * hierarchy. Non-leaf entities have also their own sched_data, stored
126 * Each entity stores independently its priority values; this would
127 * allow different weights on different devices, but this
128 * functionality is not exported to userspace by now. Priorities and
129 * weights are updated lazily, first storing the new values into the
130 * new_* fields, then setting the @prio_changed flag. As soon as
131 * there is a transition in the entity state that allows the priority
132 * update to take place the effective and the requested priority
133 * values are synchronized.
135 * Unless cgroups are used, the weight value is calculated from the
136 * ioprio to export the same interface as CFQ. When dealing with
137 * "well-behaved" queues (i.e., queues that do not spend too much
138 * time to consume their budget and have true sequential behavior, and
139 * when there are no external factors breaking anticipation) the
140 * relative weights at each level of the cgroups hierarchy should be
141 * guaranteed. All the fields are protected by the queue lock of the
145 /* service_tree member */
146 struct rb_node rb_node
;
149 * Flag, true if the entity is on a tree (either the active or
150 * the idle one of its service_tree) or is in service.
152 bool on_st_or_in_serv
;
154 /* B-WF2Q+ start and finish timestamps [sectors/weight] */
157 /* tree the entity is enqueued into; %NULL if not on a tree */
158 struct rb_root
*tree
;
161 * minimum start time of the (active) subtree rooted at this
162 * entity; used for O(log N) lookups into active trees
166 /* amount of service received during the last service slot */
169 /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */
172 /* Number of requests allocated in the subtree of this entity */
175 /* device weight, if non-zero, it overrides the default weight of
178 /* weight of the queue */
180 /* next weight if a change is in progress */
183 /* original weight, used to implement weight boosting */
186 /* parent entity, for hierarchical scheduling */
187 struct bfq_entity
*parent
;
190 * For non-leaf nodes in the hierarchy, the associated
191 * scheduler queue, %NULL on leaf nodes.
193 struct bfq_sched_data
*my_sched_data
;
194 /* the scheduler queue this entity belongs to */
195 struct bfq_sched_data
*sched_data
;
197 /* flag, set to request a weight, ioprio or ioprio_class change */
200 /* flag, set if the entity is counted in groups_with_pending_reqs */
201 bool in_groups_with_pending_reqs
;
203 /* last child queue of entity created (for non-leaf entities) */
204 struct bfq_queue
*last_bfqq_created
;
210 * struct bfq_ttime - per process thinktime stats.
213 /* completion time of the last request */
214 u64 last_end_request
;
216 /* total process thinktime */
218 /* number of thinktime samples */
219 unsigned long ttime_samples
;
220 /* average process thinktime */
225 * struct bfq_queue - leaf schedulable entity.
227 * A bfq_queue is a leaf request queue; it can be associated with an
228 * io_context or more, if it is async or shared between cooperating
229 * processes. @cgroup holds a reference to the cgroup, to be sure that it
230 * does not disappear while a bfqq still references it (mostly to avoid
231 * races between request issuing and task migration followed by cgroup
233 * All the fields are protected by the queue lock of the containing bfqd.
236 /* reference counter */
238 /* counter of references from other queues for delayed stable merge */
240 /* parent bfq_data */
241 struct bfq_data
*bfqd
;
243 /* current ioprio and ioprio class */
244 unsigned short ioprio
, ioprio_class
;
245 /* next ioprio and ioprio class if a change is in progress */
246 unsigned short new_ioprio
, new_ioprio_class
;
248 /* last total-service-time sample, see bfq_update_inject_limit() */
249 u64 last_serv_time_ns
;
250 /* limit for request injection */
251 unsigned int inject_limit
;
252 /* last time the inject limit has been decreased, in jiffies */
253 unsigned long decrease_time_jif
;
256 * Shared bfq_queue if queue is cooperating with one or more
259 struct bfq_queue
*new_bfqq
;
260 /* request-position tree member (see bfq_group's @rq_pos_tree) */
261 struct rb_node pos_node
;
262 /* request-position tree root (see bfq_group's @rq_pos_tree) */
263 struct rb_root
*pos_root
;
265 /* sorted list of pending requests */
266 struct rb_root sort_list
;
267 /* if fifo isn't expired, next request to serve */
268 struct request
*next_rq
;
269 /* number of sync and async requests queued */
271 /* number of pending metadata requests */
273 /* fifo list of requests in sort_list */
274 struct list_head fifo
;
276 /* entity representing this queue in the scheduler */
277 struct bfq_entity entity
;
279 /* pointer to the weight counter associated with this entity */
280 struct bfq_weight_counter
*weight_counter
;
282 /* maximum budget allowed from the feedback mechanism */
284 /* budget expiration (in jiffies) */
285 unsigned long budget_timeout
;
287 /* number of requests on the dispatch list or inside driver */
293 /* node for active/idle bfqq list inside parent bfqd */
294 struct list_head bfqq_list
;
296 /* associated @bfq_ttime struct */
297 struct bfq_ttime ttime
;
299 /* when bfqq started to do I/O within the last observation window */
301 /* how long bfqq has remained empty during the last observ. window */
304 /* bit vector: a 1 for each seeky requests in history */
307 /* node for the device's burst list */
308 struct hlist_node burst_list_node
;
310 /* position of the last request enqueued */
311 sector_t last_request_pos
;
313 /* Number of consecutive pairs of request completion and
314 * arrival, such that the queue becomes idle after the
315 * completion, but the next request arrives within an idle
316 * time slice; used only if the queue's IO_bound flag has been
319 unsigned int requests_within_timer
;
321 /* pid of the process owning the queue, used for logging purposes */
325 * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL
326 * if the queue is shared.
328 struct bfq_io_cq
*bic
;
330 /* current maximum weight-raising time for this queue */
331 unsigned long wr_cur_max_time
;
333 * Minimum time instant such that, only if a new request is
334 * enqueued after this time instant in an idle @bfq_queue with
335 * no outstanding requests, then the task associated with the
336 * queue it is deemed as soft real-time (see the comments on
337 * the function bfq_bfqq_softrt_next_start())
339 unsigned long soft_rt_next_start
;
341 * Start time of the current weight-raising period if
342 * the @bfq-queue is being weight-raised, otherwise
343 * finish time of the last weight-raising period.
345 unsigned long last_wr_start_finish
;
346 /* factor by which the weight of this queue is multiplied */
347 unsigned int wr_coeff
;
349 * Time of the last transition of the @bfq_queue from idle to
352 unsigned long last_idle_bklogged
;
354 * Cumulative service received from the @bfq_queue since the
355 * last transition from idle to backlogged.
357 unsigned long service_from_backlogged
;
359 * Cumulative service received from the @bfq_queue since its
360 * last transition to weight-raised state.
362 unsigned long service_from_wr
;
365 * Value of wr start time when switching to soft rt
367 unsigned long wr_start_at_switch_to_srt
;
369 unsigned long split_time
; /* time of last split */
371 unsigned long first_IO_time
; /* time of first I/O for this queue */
372 unsigned long creation_time
; /* when this queue is created */
375 * Pointer to the waker queue for this queue, i.e., to the
376 * queue Q such that this queue happens to get new I/O right
377 * after some I/O request of Q is completed. For details, see
378 * the comments on the choice of the queue for injection in
379 * bfq_select_queue().
381 struct bfq_queue
*waker_bfqq
;
382 /* pointer to the curr. tentative waker queue, see bfq_check_waker() */
383 struct bfq_queue
*tentative_waker_bfqq
;
384 /* number of times the same tentative waker has been detected */
385 unsigned int num_waker_detections
;
386 /* time when we started considering this waker */
387 u64 waker_detection_started
;
389 /* node for woken_list, see below */
390 struct hlist_node woken_list_node
;
392 * Head of the list of the woken queues for this queue, i.e.,
393 * of the list of the queues for which this queue is a waker
394 * queue. This list is used to reset the waker_bfqq pointer in
395 * the woken queues when this queue exits.
397 struct hlist_head woken_list
;
401 * struct bfq_io_cq - per (request_queue, io_context) structure.
404 /* associated io_cq structure */
405 struct io_cq icq
; /* must be the first member */
406 /* array of two process queues, the sync and the async */
407 struct bfq_queue
*bfqq
[2];
408 /* per (request_queue, blkcg) ioprio */
410 #ifdef CONFIG_BFQ_GROUP_IOSCHED
411 uint64_t blkcg_serial_nr
; /* the current blkcg serial */
414 * Snapshot of the has_short_time flag before merging; taken
415 * to remember its value while the queue is merged, so as to
416 * be able to restore it in case of split.
418 bool saved_has_short_ttime
;
420 * Same purpose as the previous two fields for the I/O bound
421 * classification of a queue.
425 u64 saved_io_start_time
;
426 u64 saved_tot_idle_time
;
429 * Same purpose as the previous fields for the value of the
430 * field keeping the queue's belonging to a large burst
432 bool saved_in_large_burst
;
434 * True if the queue belonged to a burst list before its merge
435 * with another cooperating queue.
437 bool was_in_burst_list
;
440 * Save the weight when a merge occurs, to be able
441 * to restore it in case of split. If the weight is not
442 * correctly resumed when the queue is recycled,
443 * then the weight of the recycled queue could differ
444 * from the weight of the original queue.
446 unsigned int saved_weight
;
449 * Similar to previous fields: save wr information.
451 unsigned long saved_wr_coeff
;
452 unsigned long saved_last_wr_start_finish
;
453 unsigned long saved_service_from_wr
;
454 unsigned long saved_wr_start_at_switch_to_srt
;
455 unsigned int saved_wr_cur_max_time
;
456 struct bfq_ttime saved_ttime
;
458 /* Save also injection state */
459 u64 saved_last_serv_time_ns
;
460 unsigned int saved_inject_limit
;
461 unsigned long saved_decrease_time_jif
;
463 /* candidate queue for a stable merge (due to close creation time) */
464 struct bfq_queue
*stable_merge_bfqq
;
466 bool stably_merged
; /* non splittable if true */
467 unsigned int requests
; /* Number of requests this process has in flight */
471 * struct bfq_data - per-device data structure.
473 * All the fields are protected by @lock.
476 /* device request queue */
477 struct request_queue
*queue
;
479 struct list_head dispatch
;
481 /* root bfq_group for the device */
482 struct bfq_group
*root_group
;
485 * rbtree of weight counters of @bfq_queues, sorted by
486 * weight. Used to keep track of whether all @bfq_queues have
487 * the same weight. The tree contains one counter for each
488 * distinct weight associated to some active and not
489 * weight-raised @bfq_queue (see the comments to the functions
490 * bfq_weights_tree_[add|remove] for further details).
492 struct rb_root_cached queue_weights_tree
;
495 * Number of groups with at least one process that
496 * has at least one request waiting for completion. Note that
497 * this accounts for also requests already dispatched, but not
498 * yet completed. Therefore this number of groups may differ
499 * (be larger) than the number of active groups, as a group is
500 * considered active only if its corresponding entity has
501 * queues with at least one request queued. This
502 * number is used to decide whether a scenario is symmetric.
503 * For a detailed explanation see comments on the computation
504 * of the variable asymmetric_scenario in the function
505 * bfq_better_to_idle().
507 * However, it is hard to compute this number exactly, for
508 * groups with multiple processes. Consider a group
509 * that is inactive, i.e., that has no process with
510 * pending I/O inside BFQ queues. Then suppose that
511 * num_groups_with_pending_reqs is still accounting for this
512 * group, because the group has processes with some
513 * I/O request still in flight. num_groups_with_pending_reqs
514 * should be decremented when the in-flight request of the
515 * last process is finally completed (assuming that
516 * nothing else has changed for the group in the meantime, in
517 * terms of composition of the group and active/inactive state of child
518 * groups and processes). To accomplish this, an additional
519 * pending-request counter must be added to entities, and must
520 * be updated correctly. To avoid this additional field and operations,
521 * we resort to the following tradeoff between simplicity and
522 * accuracy: for an inactive group that is still counted in
523 * num_groups_with_pending_reqs, we decrement
524 * num_groups_with_pending_reqs when the first
525 * process of the group remains with no request waiting for
528 * Even this simpler decrement strategy requires a little
529 * carefulness: to avoid multiple decrements, we flag a group,
530 * more precisely an entity representing a group, as still
531 * counted in num_groups_with_pending_reqs when it becomes
532 * inactive. Then, when the first queue of the
533 * entity remains with no request waiting for completion,
534 * num_groups_with_pending_reqs is decremented, and this flag
535 * is reset. After this flag is reset for the entity,
536 * num_groups_with_pending_reqs won't be decremented any
537 * longer in case a new queue of the entity remains
538 * with no request waiting for completion.
540 unsigned int num_groups_with_pending_reqs
;
543 * Per-class (RT, BE, IDLE) number of bfq_queues containing
544 * requests (including the queue in service, even if it is
547 unsigned int busy_queues
[3];
548 /* number of weight-raised busy @bfq_queues */
550 /* number of queued requests */
552 /* number of requests dispatched and waiting for completion */
555 /* true if the device is non rotational and performs queueing */
556 bool nonrot_with_queueing
;
559 * Maximum number of requests in driver in the last
560 * @hw_tag_samples completed requests.
562 int max_rq_in_driver
;
563 /* number of samples used to calculate hw_tag */
565 /* flag set to one if the driver is showing a queueing behavior */
568 /* number of budgets assigned */
569 int budgets_assigned
;
572 * Timer set when idling (waiting) for the next request from
573 * the queue in service.
575 struct hrtimer idle_slice_timer
;
577 /* bfq_queue in service */
578 struct bfq_queue
*in_service_queue
;
580 /* on-disk position of the last served request */
581 sector_t last_position
;
583 /* position of the last served request for the in-service queue */
584 sector_t in_serv_last_pos
;
586 /* time of last request completion (ns) */
589 /* bfqq owning the last completed rq */
590 struct bfq_queue
*last_completed_rq_bfqq
;
592 /* last bfqq created, among those in the root group */
593 struct bfq_queue
*last_bfqq_created
;
595 /* time of last transition from empty to non-empty (ns) */
596 u64 last_empty_occupied_ns
;
599 * Flag set to activate the sampling of the total service time
600 * of a just-arrived first I/O request (see
601 * bfq_update_inject_limit()). This will cause the setting of
602 * waited_rq when the request is finally dispatched.
606 * If set, then bfq_update_inject_limit() is invoked when
607 * waited_rq is eventually completed.
609 struct request
*waited_rq
;
611 * True if some request has been injected during the last service hole.
615 /* time of first rq dispatch in current observation interval (ns) */
617 /* time of last rq dispatch in current observation interval (ns) */
620 /* beginning of the last budget */
621 ktime_t last_budget_start
;
622 /* beginning of the last idle slice */
623 ktime_t last_idling_start
;
624 unsigned long last_idling_start_jiffies
;
626 /* number of samples in current observation interval */
627 int peak_rate_samples
;
628 /* num of samples of seq dispatches in current observation interval */
629 u32 sequential_samples
;
630 /* total num of sectors transferred in current observation interval */
631 u64 tot_sectors_dispatched
;
632 /* max rq size seen during current observation interval (sectors) */
633 u32 last_rq_max_size
;
634 /* time elapsed from first dispatch in current observ. interval (us) */
635 u64 delta_from_first
;
637 * Current estimate of the device peak rate, measured in
638 * [(sectors/usec) / 2^BFQ_RATE_SHIFT]. The left-shift by
639 * BFQ_RATE_SHIFT is performed to increase precision in
640 * fixed-point calculations.
644 /* maximum budget allotted to a bfq_queue before rescheduling */
647 /* list of all the bfq_queues active on the device */
648 struct list_head active_list
;
649 /* list of all the bfq_queues idle on the device */
650 struct list_head idle_list
;
653 * Timeout for async/sync requests; when it fires, requests
654 * are served in fifo order.
656 u64 bfq_fifo_expire
[2];
657 /* weight of backward seeks wrt forward ones */
658 unsigned int bfq_back_penalty
;
659 /* maximum allowed backward seek */
660 unsigned int bfq_back_max
;
661 /* maximum idling time */
664 /* user-configured max budget value (0 for auto-tuning) */
665 int bfq_user_max_budget
;
667 * Timeout for bfq_queues to consume their budget; used to
668 * prevent seeky queues from imposing long latencies to
669 * sequential or quasi-sequential ones (this also implies that
670 * seeky queues cannot receive guarantees in the service
671 * domain; after a timeout they are charged for the time they
672 * have been in service, to preserve fairness among them, but
673 * without service-domain guarantees).
675 unsigned int bfq_timeout
;
678 * Force device idling whenever needed to provide accurate
679 * service guarantees, without caring about throughput
680 * issues. CAVEAT: this may even increase latencies, in case
681 * of useless idling for processes that did stop doing I/O.
683 bool strict_guarantees
;
686 * Last time at which a queue entered the current burst of
687 * queues being activated shortly after each other; for more
688 * details about this and the following parameters related to
689 * a burst of activations, see the comments on the function
692 unsigned long last_ins_in_burst
;
694 * Reference time interval used to decide whether a queue has
695 * been activated shortly after @last_ins_in_burst.
697 unsigned long bfq_burst_interval
;
698 /* number of queues in the current burst of queue activations */
701 /* common parent entity for the queues in the burst */
702 struct bfq_entity
*burst_parent_entity
;
703 /* Maximum burst size above which the current queue-activation
704 * burst is deemed as 'large'.
706 unsigned long bfq_large_burst_thresh
;
707 /* true if a large queue-activation burst is in progress */
710 * Head of the burst list (as for the above fields, more
711 * details in the comments on the function bfq_handle_burst).
713 struct hlist_head burst_list
;
715 /* if set to true, low-latency heuristics are enabled */
718 * Maximum factor by which the weight of a weight-raised queue
721 unsigned int bfq_wr_coeff
;
722 /* maximum duration of a weight-raising period (jiffies) */
723 unsigned int bfq_wr_max_time
;
725 /* Maximum weight-raising duration for soft real-time processes */
726 unsigned int bfq_wr_rt_max_time
;
728 * Minimum idle period after which weight-raising may be
729 * reactivated for a queue (in jiffies).
731 unsigned int bfq_wr_min_idle_time
;
733 * Minimum period between request arrivals after which
734 * weight-raising may be reactivated for an already busy async
735 * queue (in jiffies).
737 unsigned long bfq_wr_min_inter_arr_async
;
739 /* Max service-rate for a soft real-time queue, in sectors/sec */
740 unsigned int bfq_wr_max_softrt_rate
;
742 * Cached value of the product ref_rate*ref_wr_duration, used
743 * for computing the maximum duration of weight raising
748 /* fallback dummy bfqq for extreme OOM conditions */
749 struct bfq_queue oom_bfqq
;
754 * bic associated with the task issuing current bio for
755 * merging. This and the next field are used as a support to
756 * be able to perform the bic lookup, needed by bio-merge
757 * functions, before the scheduler lock is taken, and thus
758 * avoid taking the request-queue lock while the scheduler
759 * lock is being held.
761 struct bfq_io_cq
*bio_bic
;
762 /* bfqq associated with the task issuing current bio for merging */
763 struct bfq_queue
*bio_bfqq
;
766 * Depth limits used in bfq_limit_depth (see comments on the
769 unsigned int word_depths
[2][2];
770 unsigned int full_depth_shift
;
773 enum bfqq_state_flags
{
774 BFQQF_just_created
= 0, /* queue just allocated */
775 BFQQF_busy
, /* has requests or is in service */
776 BFQQF_wait_request
, /* waiting for a request */
777 BFQQF_non_blocking_wait_rq
, /*
778 * waiting for a request
779 * without idling the device
781 BFQQF_fifo_expire
, /* FIFO checked in this slice */
782 BFQQF_has_short_ttime
, /* queue has a short think time */
783 BFQQF_sync
, /* synchronous queue */
785 * bfqq has timed-out at least once
786 * having consumed at most 2/10 of
789 BFQQF_in_large_burst
, /*
790 * bfqq activated in a large burst,
791 * see comments to bfq_handle_burst.
793 BFQQF_softrt_update
, /*
794 * may need softrt-next-start
797 BFQQF_coop
, /* bfqq is shared */
798 BFQQF_split_coop
, /* shared bfqq will be split */
801 #define BFQ_BFQQ_FNS(name) \
802 void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \
803 void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \
804 int bfq_bfqq_##name(const struct bfq_queue *bfqq);
806 BFQ_BFQQ_FNS(just_created
);
808 BFQ_BFQQ_FNS(wait_request
);
809 BFQ_BFQQ_FNS(non_blocking_wait_rq
);
810 BFQ_BFQQ_FNS(fifo_expire
);
811 BFQ_BFQQ_FNS(has_short_ttime
);
813 BFQ_BFQQ_FNS(IO_bound
);
814 BFQ_BFQQ_FNS(in_large_burst
);
816 BFQ_BFQQ_FNS(split_coop
);
817 BFQ_BFQQ_FNS(softrt_update
);
820 /* Expiration reasons. */
821 enum bfqq_expiration
{
822 BFQQE_TOO_IDLE
= 0, /*
823 * queue has been idling for
826 BFQQE_BUDGET_TIMEOUT
, /* budget took too long to be used */
827 BFQQE_BUDGET_EXHAUSTED
, /* budget consumed */
828 BFQQE_NO_MORE_REQUESTS
, /* the queue has no more requests */
829 BFQQE_PREEMPTED
/* preemption in progress */
833 struct percpu_counter cpu_cnt
;
839 struct blkg_rwstat bytes
;
840 struct blkg_rwstat ios
;
841 #ifdef CONFIG_BFQ_CGROUP_DEBUG
842 /* number of ios merged */
843 struct blkg_rwstat merged
;
844 /* total time spent on device in ns, may not be accurate w/ queueing */
845 struct blkg_rwstat service_time
;
846 /* total time spent waiting in scheduler queue in ns */
847 struct blkg_rwstat wait_time
;
848 /* number of IOs queued up */
849 struct blkg_rwstat queued
;
850 /* total disk time and nr sectors dispatched by this group */
851 struct bfq_stat time
;
852 /* sum of number of ios queued across all samples */
853 struct bfq_stat avg_queue_size_sum
;
854 /* count of samples taken for average */
855 struct bfq_stat avg_queue_size_samples
;
856 /* how many times this group has been removed from service tree */
857 struct bfq_stat dequeue
;
858 /* total time spent waiting for it to be assigned a timeslice. */
859 struct bfq_stat group_wait_time
;
860 /* time spent idling for this blkcg_gq */
861 struct bfq_stat idle_time
;
862 /* total time with empty current active q with other requests queued */
863 struct bfq_stat empty_time
;
864 /* fields after this shouldn't be cleared on stat reset */
865 u64 start_group_wait_time
;
867 u64 start_empty_time
;
869 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
872 #ifdef CONFIG_BFQ_GROUP_IOSCHED
875 * struct bfq_group_data - per-blkcg storage for the blkio subsystem.
877 * @ps: @blkcg_policy_storage that this structure inherits
878 * @weight: weight of the bfq_group
880 struct bfq_group_data
{
881 /* must be the first member */
882 struct blkcg_policy_data pd
;
888 * struct bfq_group - per (device, cgroup) data structure.
889 * @entity: schedulable entity to insert into the parent group sched_data.
890 * @sched_data: own sched_data, to contain child entities (they may be
891 * both bfq_queues and bfq_groups).
892 * @bfqd: the bfq_data for the device this group acts upon.
893 * @async_bfqq: array of async queues for all the tasks belonging to
894 * the group, one queue per ioprio value per ioprio_class,
895 * except for the idle class that has only one queue.
896 * @async_idle_bfqq: async queue for the idle class (ioprio is ignored).
897 * @my_entity: pointer to @entity, %NULL for the toplevel group; used
898 * to avoid too many special cases during group creation/
900 * @stats: stats for this bfqg.
901 * @active_entities: number of active entities belonging to the group;
902 * unused for the root group. Used to know whether there
903 * are groups with more than one active @bfq_entity
904 * (see the comments to the function
905 * bfq_bfqq_may_idle()).
906 * @rq_pos_tree: rbtree sorted by next_request position, used when
907 * determining if two or more queues have interleaving
908 * requests (see bfq_find_close_cooperator()).
910 * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup
911 * there is a set of bfq_groups, each one collecting the lower-level
912 * entities belonging to the group that are acting on the same device.
914 * Locking works as follows:
915 * o @bfqd is protected by the queue lock, RCU is used to access it
917 * o All the other fields are protected by the @bfqd queue lock.
920 /* must be the first member */
921 struct blkg_policy_data pd
;
923 /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */
926 /* reference counter (see comments in bfq_bic_update_cgroup) */
928 /* Is bfq_group still online? */
931 struct bfq_entity entity
;
932 struct bfq_sched_data sched_data
;
934 struct bfq_data
*bfqd
;
936 struct bfq_queue
*async_bfqq
[2][IOPRIO_NR_LEVELS
];
937 struct bfq_queue
*async_idle_bfqq
;
939 struct bfq_entity
*my_entity
;
942 int num_queues_with_pending_reqs
;
944 struct rb_root rq_pos_tree
;
946 struct bfqg_stats stats
;
951 struct bfq_entity entity
;
952 struct bfq_sched_data sched_data
;
954 struct bfq_queue
*async_bfqq
[2][IOPRIO_NR_LEVELS
];
955 struct bfq_queue
*async_idle_bfqq
;
957 struct rb_root rq_pos_tree
;
961 /* --------------- main algorithm interface ----------------- */
963 #define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \
964 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 })
966 extern const int bfq_timeout
;
968 struct bfq_queue
*bic_to_bfqq(struct bfq_io_cq
*bic
, bool is_sync
);
969 void bic_set_bfqq(struct bfq_io_cq
*bic
, struct bfq_queue
*bfqq
, bool is_sync
);
970 struct bfq_data
*bic_to_bfqd(struct bfq_io_cq
*bic
);
971 void bfq_pos_tree_add_move(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
);
972 void bfq_weights_tree_add(struct bfq_queue
*bfqq
);
973 void bfq_weights_tree_remove(struct bfq_queue
*bfqq
);
974 void bfq_bfqq_expire(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
,
975 bool compensate
, enum bfqq_expiration reason
);
976 void bfq_put_queue(struct bfq_queue
*bfqq
);
977 void bfq_put_cooperator(struct bfq_queue
*bfqq
);
978 void bfq_end_wr_async_queues(struct bfq_data
*bfqd
, struct bfq_group
*bfqg
);
979 void bfq_release_process_ref(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
);
980 void bfq_schedule_dispatch(struct bfq_data
*bfqd
);
981 void bfq_put_async_queues(struct bfq_data
*bfqd
, struct bfq_group
*bfqg
);
983 /* ------------ end of main algorithm interface -------------- */
985 /* ---------------- cgroups-support interface ---------------- */
987 void bfqg_stats_update_legacy_io(struct request_queue
*q
, struct request
*rq
);
988 void bfqg_stats_update_io_remove(struct bfq_group
*bfqg
, blk_opf_t opf
);
989 void bfqg_stats_update_io_merged(struct bfq_group
*bfqg
, blk_opf_t opf
);
990 void bfqg_stats_update_completion(struct bfq_group
*bfqg
, u64 start_time_ns
,
991 u64 io_start_time_ns
, blk_opf_t opf
);
992 void bfqg_stats_update_dequeue(struct bfq_group
*bfqg
);
993 void bfqg_stats_set_start_idle_time(struct bfq_group
*bfqg
);
994 void bfq_bfqq_move(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
,
995 struct bfq_group
*bfqg
);
997 #ifdef CONFIG_BFQ_CGROUP_DEBUG
998 void bfqg_stats_update_io_add(struct bfq_group
*bfqg
, struct bfq_queue
*bfqq
,
1000 void bfqg_stats_set_start_empty_time(struct bfq_group
*bfqg
);
1001 void bfqg_stats_update_idle_time(struct bfq_group
*bfqg
);
1002 void bfqg_stats_update_avg_queue_size(struct bfq_group
*bfqg
);
1005 void bfq_init_entity(struct bfq_entity
*entity
, struct bfq_group
*bfqg
);
1006 void bfq_bic_update_cgroup(struct bfq_io_cq
*bic
, struct bio
*bio
);
1007 void bfq_end_wr_async(struct bfq_data
*bfqd
);
1008 struct bfq_group
*bfq_bio_bfqg(struct bfq_data
*bfqd
, struct bio
*bio
);
1009 struct blkcg_gq
*bfqg_to_blkg(struct bfq_group
*bfqg
);
1010 struct bfq_group
*bfqq_group(struct bfq_queue
*bfqq
);
1011 struct bfq_group
*bfq_create_group_hierarchy(struct bfq_data
*bfqd
, int node
);
1012 void bfqg_and_blkg_put(struct bfq_group
*bfqg
);
1014 #ifdef CONFIG_BFQ_GROUP_IOSCHED
1015 extern struct cftype bfq_blkcg_legacy_files
[];
1016 extern struct cftype bfq_blkg_files
[];
1017 extern struct blkcg_policy blkcg_policy_bfq
;
1020 /* ------------- end of cgroups-support interface ------------- */
1022 /* - interface of the internal hierarchical B-WF2Q+ scheduler - */
1024 #ifdef CONFIG_BFQ_GROUP_IOSCHED
1025 /* both next loops stop at one of the child entities of the root group */
1026 #define for_each_entity(entity) \
1027 for (; entity ; entity = entity->parent)
1030 * For each iteration, compute parent in advance, so as to be safe if
1031 * entity is deallocated during the iteration. Such a deallocation may
1032 * happen as a consequence of a bfq_put_queue that frees the bfq_queue
1033 * containing entity.
1035 #define for_each_entity_safe(entity, parent) \
1036 for (; entity && ({ parent = entity->parent; 1; }); entity = parent)
1038 #else /* CONFIG_BFQ_GROUP_IOSCHED */
1040 * Next two macros are fake loops when cgroups support is not
1041 * enabled. I fact, in such a case, there is only one level to go up
1042 * (to reach the root group).
1044 #define for_each_entity(entity) \
1045 for (; entity ; entity = NULL)
1047 #define for_each_entity_safe(entity, parent) \
1048 for (parent = NULL; entity ; entity = parent)
1049 #endif /* CONFIG_BFQ_GROUP_IOSCHED */
1051 struct bfq_queue
*bfq_entity_to_bfqq(struct bfq_entity
*entity
);
1052 unsigned int bfq_tot_busy_queues(struct bfq_data
*bfqd
);
1053 struct bfq_service_tree
*bfq_entity_service_tree(struct bfq_entity
*entity
);
1054 struct bfq_entity
*bfq_entity_of(struct rb_node
*node
);
1055 unsigned short bfq_ioprio_to_weight(int ioprio
);
1056 void bfq_put_idle_entity(struct bfq_service_tree
*st
,
1057 struct bfq_entity
*entity
);
1058 struct bfq_service_tree
*
1059 __bfq_entity_update_weight_prio(struct bfq_service_tree
*old_st
,
1060 struct bfq_entity
*entity
,
1061 bool update_class_too
);
1062 void bfq_bfqq_served(struct bfq_queue
*bfqq
, int served
);
1063 void bfq_bfqq_charge_time(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
,
1064 unsigned long time_ms
);
1065 bool __bfq_deactivate_entity(struct bfq_entity
*entity
,
1066 bool ins_into_idle_tree
);
1067 bool next_queue_may_preempt(struct bfq_data
*bfqd
);
1068 struct bfq_queue
*bfq_get_next_queue(struct bfq_data
*bfqd
);
1069 bool __bfq_bfqd_reset_in_service(struct bfq_data
*bfqd
);
1070 void bfq_deactivate_bfqq(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
,
1071 bool ins_into_idle_tree
, bool expiration
);
1072 void bfq_activate_bfqq(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
);
1073 void bfq_requeue_bfqq(struct bfq_data
*bfqd
, struct bfq_queue
*bfqq
,
1075 void bfq_del_bfqq_busy(struct bfq_queue
*bfqq
, bool expiration
);
1076 void bfq_add_bfqq_busy(struct bfq_queue
*bfqq
);
1077 void bfq_add_bfqq_in_groups_with_pending_reqs(struct bfq_queue
*bfqq
);
1078 void bfq_del_bfqq_in_groups_with_pending_reqs(struct bfq_queue
*bfqq
);
1080 /* --------------- end of interface of B-WF2Q+ ---------------- */
1082 /* Logging facilities. */
1083 static inline void bfq_bfqq_name(struct bfq_queue
*bfqq
, char *str
, int len
)
1085 char type
= bfq_bfqq_sync(bfqq
) ? 'S' : 'A';
1087 if (bfqq
->pid
!= -1)
1088 snprintf(str
, len
, "bfq%d%c", bfqq
->pid
, type
);
1090 snprintf(str
, len
, "bfqSHARED-%c", type
);
1093 #ifdef CONFIG_BFQ_GROUP_IOSCHED
1094 struct bfq_group
*bfqq_group(struct bfq_queue
*bfqq
);
1096 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
1097 char pid_str[MAX_BFQQ_NAME_LENGTH]; \
1098 if (likely(!blk_trace_note_message_enabled((bfqd)->queue))) \
1100 bfq_bfqq_name((bfqq), pid_str, MAX_BFQQ_NAME_LENGTH); \
1101 blk_add_cgroup_trace_msg((bfqd)->queue, \
1102 &bfqg_to_blkg(bfqq_group(bfqq))->blkcg->css, \
1103 "%s " fmt, pid_str, ##args); \
1106 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \
1107 blk_add_cgroup_trace_msg((bfqd)->queue, \
1108 &bfqg_to_blkg(bfqg)->blkcg->css, fmt, ##args); \
1111 #else /* CONFIG_BFQ_GROUP_IOSCHED */
1113 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
1114 char pid_str[MAX_BFQQ_NAME_LENGTH]; \
1115 if (likely(!blk_trace_note_message_enabled((bfqd)->queue))) \
1117 bfq_bfqq_name((bfqq), pid_str, MAX_BFQQ_NAME_LENGTH); \
1118 blk_add_trace_msg((bfqd)->queue, "%s " fmt, pid_str, ##args); \
1120 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0)
1122 #endif /* CONFIG_BFQ_GROUP_IOSCHED */
1124 #define bfq_log(bfqd, fmt, args...) \
1125 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)