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Paolo Valenteea25da42017-04-19 08:48:24 -06001/*
2 * Header file for the BFQ I/O scheduler: data structures and
3 * prototypes of interface functions among BFQ components.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 */
15#ifndef _BFQ_H
16#define _BFQ_H
17
18#include <linux/blktrace_api.h>
19#include <linux/hrtimer.h>
20#include <linux/blk-cgroup.h>
21
22#define BFQ_IOPRIO_CLASSES 3
23#define BFQ_CL_IDLE_TIMEOUT (HZ/5)
24
25#define BFQ_MIN_WEIGHT 1
26#define BFQ_MAX_WEIGHT 1000
27#define BFQ_WEIGHT_CONVERSION_COEFF 10
28
29#define BFQ_DEFAULT_QUEUE_IOPRIO 4
30
31#define BFQ_WEIGHT_LEGACY_DFL 100
32#define BFQ_DEFAULT_GRP_IOPRIO 0
33#define BFQ_DEFAULT_GRP_CLASS IOPRIO_CLASS_BE
34
35/*
36 * Soft real-time applications are extremely more latency sensitive
37 * than interactive ones. Over-raise the weight of the former to
38 * privilege them against the latter.
39 */
40#define BFQ_SOFTRT_WEIGHT_FACTOR 100
41
42struct bfq_entity;
43
44/**
45 * struct bfq_service_tree - per ioprio_class service tree.
46 *
47 * Each service tree represents a B-WF2Q+ scheduler on its own. Each
48 * ioprio_class has its own independent scheduler, and so its own
49 * bfq_service_tree. All the fields are protected by the queue lock
50 * of the containing bfqd.
51 */
52struct bfq_service_tree {
53 /* tree for active entities (i.e., those backlogged) */
54 struct rb_root active;
Hou Tao38c91402017-07-12 15:25:01 +080055 /* tree for idle entities (i.e., not backlogged, with V < F_i)*/
Paolo Valenteea25da42017-04-19 08:48:24 -060056 struct rb_root idle;
57
58 /* idle entity with minimum F_i */
59 struct bfq_entity *first_idle;
60 /* idle entity with maximum F_i */
61 struct bfq_entity *last_idle;
62
63 /* scheduler virtual time */
64 u64 vtime;
65 /* scheduler weight sum; active and idle entities contribute to it */
66 unsigned long wsum;
67};
68
69/**
70 * struct bfq_sched_data - multi-class scheduler.
71 *
72 * bfq_sched_data is the basic scheduler queue. It supports three
73 * ioprio_classes, and can be used either as a toplevel queue or as an
74 * intermediate queue on a hierarchical setup. @next_in_service
75 * points to the active entity of the sched_data service trees that
76 * will be scheduled next. It is used to reduce the number of steps
77 * needed for each hierarchical-schedule update.
78 *
79 * The supported ioprio_classes are the same as in CFQ, in descending
80 * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
81 * Requests from higher priority queues are served before all the
82 * requests from lower priority queues; among requests of the same
83 * queue requests are served according to B-WF2Q+.
84 * All the fields are protected by the queue lock of the containing bfqd.
85 */
86struct bfq_sched_data {
87 /* entity in service */
88 struct bfq_entity *in_service_entity;
89 /* head-of-line entity (see comments above) */
90 struct bfq_entity *next_in_service;
91 /* array of service trees, one per ioprio_class */
92 struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES];
93 /* last time CLASS_IDLE was served */
94 unsigned long bfq_class_idle_last_service;
95
96};
97
98/**
99 * struct bfq_weight_counter - counter of the number of all active entities
100 * with a given weight.
101 */
102struct bfq_weight_counter {
103 unsigned int weight; /* weight of the entities this counter refers to */
104 unsigned int num_active; /* nr of active entities with this weight */
105 /*
106 * Weights tree member (see bfq_data's @queue_weights_tree and
107 * @group_weights_tree)
108 */
109 struct rb_node weights_node;
110};
111
112/**
113 * struct bfq_entity - schedulable entity.
114 *
115 * A bfq_entity is used to represent either a bfq_queue (leaf node in the
116 * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each
117 * entity belongs to the sched_data of the parent group in the cgroup
118 * hierarchy. Non-leaf entities have also their own sched_data, stored
119 * in @my_sched_data.
120 *
121 * Each entity stores independently its priority values; this would
122 * allow different weights on different devices, but this
123 * functionality is not exported to userspace by now. Priorities and
124 * weights are updated lazily, first storing the new values into the
125 * new_* fields, then setting the @prio_changed flag. As soon as
126 * there is a transition in the entity state that allows the priority
127 * update to take place the effective and the requested priority
128 * values are synchronized.
129 *
130 * Unless cgroups are used, the weight value is calculated from the
131 * ioprio to export the same interface as CFQ. When dealing with
132 * ``well-behaved'' queues (i.e., queues that do not spend too much
133 * time to consume their budget and have true sequential behavior, and
134 * when there are no external factors breaking anticipation) the
135 * relative weights at each level of the cgroups hierarchy should be
136 * guaranteed. All the fields are protected by the queue lock of the
137 * containing bfqd.
138 */
139struct bfq_entity {
140 /* service_tree member */
141 struct rb_node rb_node;
142 /* pointer to the weight counter associated with this entity */
143 struct bfq_weight_counter *weight_counter;
144
145 /*
146 * Flag, true if the entity is on a tree (either the active or
147 * the idle one of its service_tree) or is in service.
148 */
149 bool on_st;
150
151 /* B-WF2Q+ start and finish timestamps [sectors/weight] */
152 u64 start, finish;
153
154 /* tree the entity is enqueued into; %NULL if not on a tree */
155 struct rb_root *tree;
156
157 /*
158 * minimum start time of the (active) subtree rooted at this
159 * entity; used for O(log N) lookups into active trees
160 */
161 u64 min_start;
162
163 /* amount of service received during the last service slot */
164 int service;
165
166 /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */
167 int budget;
168
169 /* weight of the queue */
170 int weight;
171 /* next weight if a change is in progress */
172 int new_weight;
173
174 /* original weight, used to implement weight boosting */
175 int orig_weight;
176
177 /* parent entity, for hierarchical scheduling */
178 struct bfq_entity *parent;
179
180 /*
181 * For non-leaf nodes in the hierarchy, the associated
182 * scheduler queue, %NULL on leaf nodes.
183 */
184 struct bfq_sched_data *my_sched_data;
185 /* the scheduler queue this entity belongs to */
186 struct bfq_sched_data *sched_data;
187
188 /* flag, set to request a weight, ioprio or ioprio_class change */
189 int prio_changed;
190};
191
192struct bfq_group;
193
194/**
195 * struct bfq_ttime - per process thinktime stats.
196 */
197struct bfq_ttime {
198 /* completion time of the last request */
199 u64 last_end_request;
200
201 /* total process thinktime */
202 u64 ttime_total;
203 /* number of thinktime samples */
204 unsigned long ttime_samples;
205 /* average process thinktime */
206 u64 ttime_mean;
207};
208
209/**
210 * struct bfq_queue - leaf schedulable entity.
211 *
212 * A bfq_queue is a leaf request queue; it can be associated with an
213 * io_context or more, if it is async or shared between cooperating
214 * processes. @cgroup holds a reference to the cgroup, to be sure that it
215 * does not disappear while a bfqq still references it (mostly to avoid
216 * races between request issuing and task migration followed by cgroup
217 * destruction).
218 * All the fields are protected by the queue lock of the containing bfqd.
219 */
220struct bfq_queue {
221 /* reference counter */
222 int ref;
223 /* parent bfq_data */
224 struct bfq_data *bfqd;
225
226 /* current ioprio and ioprio class */
227 unsigned short ioprio, ioprio_class;
228 /* next ioprio and ioprio class if a change is in progress */
229 unsigned short new_ioprio, new_ioprio_class;
230
231 /*
232 * Shared bfq_queue if queue is cooperating with one or more
233 * other queues.
234 */
235 struct bfq_queue *new_bfqq;
236 /* request-position tree member (see bfq_group's @rq_pos_tree) */
237 struct rb_node pos_node;
238 /* request-position tree root (see bfq_group's @rq_pos_tree) */
239 struct rb_root *pos_root;
240
241 /* sorted list of pending requests */
242 struct rb_root sort_list;
243 /* if fifo isn't expired, next request to serve */
244 struct request *next_rq;
245 /* number of sync and async requests queued */
246 int queued[2];
247 /* number of requests currently allocated */
248 int allocated;
249 /* number of pending metadata requests */
250 int meta_pending;
251 /* fifo list of requests in sort_list */
252 struct list_head fifo;
253
254 /* entity representing this queue in the scheduler */
255 struct bfq_entity entity;
256
257 /* maximum budget allowed from the feedback mechanism */
258 int max_budget;
259 /* budget expiration (in jiffies) */
260 unsigned long budget_timeout;
261
262 /* number of requests on the dispatch list or inside driver */
263 int dispatched;
264
265 /* status flags */
266 unsigned long flags;
267
268 /* node for active/idle bfqq list inside parent bfqd */
269 struct list_head bfqq_list;
270
271 /* associated @bfq_ttime struct */
272 struct bfq_ttime ttime;
273
274 /* bit vector: a 1 for each seeky requests in history */
275 u32 seek_history;
276
277 /* node for the device's burst list */
278 struct hlist_node burst_list_node;
279
280 /* position of the last request enqueued */
281 sector_t last_request_pos;
282
283 /* Number of consecutive pairs of request completion and
284 * arrival, such that the queue becomes idle after the
285 * completion, but the next request arrives within an idle
286 * time slice; used only if the queue's IO_bound flag has been
287 * cleared.
288 */
289 unsigned int requests_within_timer;
290
291 /* pid of the process owning the queue, used for logging purposes */
292 pid_t pid;
293
294 /*
295 * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL
296 * if the queue is shared.
297 */
298 struct bfq_io_cq *bic;
299
300 /* current maximum weight-raising time for this queue */
301 unsigned long wr_cur_max_time;
302 /*
303 * Minimum time instant such that, only if a new request is
304 * enqueued after this time instant in an idle @bfq_queue with
305 * no outstanding requests, then the task associated with the
306 * queue it is deemed as soft real-time (see the comments on
307 * the function bfq_bfqq_softrt_next_start())
308 */
309 unsigned long soft_rt_next_start;
310 /*
311 * Start time of the current weight-raising period if
312 * the @bfq-queue is being weight-raised, otherwise
313 * finish time of the last weight-raising period.
314 */
315 unsigned long last_wr_start_finish;
316 /* factor by which the weight of this queue is multiplied */
317 unsigned int wr_coeff;
318 /*
319 * Time of the last transition of the @bfq_queue from idle to
320 * backlogged.
321 */
322 unsigned long last_idle_bklogged;
323 /*
324 * Cumulative service received from the @bfq_queue since the
325 * last transition from idle to backlogged.
326 */
327 unsigned long service_from_backlogged;
328
329 /*
330 * Value of wr start time when switching to soft rt
331 */
332 unsigned long wr_start_at_switch_to_srt;
333
334 unsigned long split_time; /* time of last split */
335};
336
337/**
338 * struct bfq_io_cq - per (request_queue, io_context) structure.
339 */
340struct bfq_io_cq {
341 /* associated io_cq structure */
342 struct io_cq icq; /* must be the first member */
343 /* array of two process queues, the sync and the async */
344 struct bfq_queue *bfqq[2];
345 /* per (request_queue, blkcg) ioprio */
346 int ioprio;
347#ifdef CONFIG_BFQ_GROUP_IOSCHED
348 uint64_t blkcg_serial_nr; /* the current blkcg serial */
349#endif
350 /*
351 * Snapshot of the idle window before merging; taken to
352 * remember this value while the queue is merged, so as to be
353 * able to restore it in case of split.
354 */
355 bool saved_idle_window;
356 /*
357 * Same purpose as the previous two fields for the I/O bound
358 * classification of a queue.
359 */
360 bool saved_IO_bound;
361
362 /*
363 * Same purpose as the previous fields for the value of the
364 * field keeping the queue's belonging to a large burst
365 */
366 bool saved_in_large_burst;
367 /*
368 * True if the queue belonged to a burst list before its merge
369 * with another cooperating queue.
370 */
371 bool was_in_burst_list;
372
373 /*
374 * Similar to previous fields: save wr information.
375 */
376 unsigned long saved_wr_coeff;
377 unsigned long saved_last_wr_start_finish;
378 unsigned long saved_wr_start_at_switch_to_srt;
379 unsigned int saved_wr_cur_max_time;
380 struct bfq_ttime saved_ttime;
381};
382
383enum bfq_device_speed {
384 BFQ_BFQD_FAST,
385 BFQ_BFQD_SLOW,
386};
387
388/**
389 * struct bfq_data - per-device data structure.
390 *
391 * All the fields are protected by @lock.
392 */
393struct bfq_data {
394 /* device request queue */
395 struct request_queue *queue;
396 /* dispatch queue */
397 struct list_head dispatch;
398
399 /* root bfq_group for the device */
400 struct bfq_group *root_group;
401
402 /*
403 * rbtree of weight counters of @bfq_queues, sorted by
404 * weight. Used to keep track of whether all @bfq_queues have
405 * the same weight. The tree contains one counter for each
406 * distinct weight associated to some active and not
407 * weight-raised @bfq_queue (see the comments to the functions
408 * bfq_weights_tree_[add|remove] for further details).
409 */
410 struct rb_root queue_weights_tree;
411 /*
412 * rbtree of non-queue @bfq_entity weight counters, sorted by
413 * weight. Used to keep track of whether all @bfq_groups have
414 * the same weight. The tree contains one counter for each
415 * distinct weight associated to some active @bfq_group (see
416 * the comments to the functions bfq_weights_tree_[add|remove]
417 * for further details).
418 */
419 struct rb_root group_weights_tree;
420
421 /*
422 * Number of bfq_queues containing requests (including the
423 * queue in service, even if it is idling).
424 */
425 int busy_queues;
426 /* number of weight-raised busy @bfq_queues */
427 int wr_busy_queues;
428 /* number of queued requests */
429 int queued;
430 /* number of requests dispatched and waiting for completion */
431 int rq_in_driver;
432
433 /*
434 * Maximum number of requests in driver in the last
435 * @hw_tag_samples completed requests.
436 */
437 int max_rq_in_driver;
438 /* number of samples used to calculate hw_tag */
439 int hw_tag_samples;
440 /* flag set to one if the driver is showing a queueing behavior */
441 int hw_tag;
442
443 /* number of budgets assigned */
444 int budgets_assigned;
445
446 /*
447 * Timer set when idling (waiting) for the next request from
448 * the queue in service.
449 */
450 struct hrtimer idle_slice_timer;
451
452 /* bfq_queue in service */
453 struct bfq_queue *in_service_queue;
454
455 /* on-disk position of the last served request */
456 sector_t last_position;
457
458 /* time of last request completion (ns) */
459 u64 last_completion;
460
461 /* time of first rq dispatch in current observation interval (ns) */
462 u64 first_dispatch;
463 /* time of last rq dispatch in current observation interval (ns) */
464 u64 last_dispatch;
465
466 /* beginning of the last budget */
467 ktime_t last_budget_start;
468 /* beginning of the last idle slice */
469 ktime_t last_idling_start;
470
471 /* number of samples in current observation interval */
472 int peak_rate_samples;
473 /* num of samples of seq dispatches in current observation interval */
474 u32 sequential_samples;
475 /* total num of sectors transferred in current observation interval */
476 u64 tot_sectors_dispatched;
477 /* max rq size seen during current observation interval (sectors) */
478 u32 last_rq_max_size;
479 /* time elapsed from first dispatch in current observ. interval (us) */
480 u64 delta_from_first;
481 /*
482 * Current estimate of the device peak rate, measured in
483 * [BFQ_RATE_SHIFT * sectors/usec]. The left-shift by
484 * BFQ_RATE_SHIFT is performed to increase precision in
485 * fixed-point calculations.
486 */
487 u32 peak_rate;
488
489 /* maximum budget allotted to a bfq_queue before rescheduling */
490 int bfq_max_budget;
491
492 /* list of all the bfq_queues active on the device */
493 struct list_head active_list;
494 /* list of all the bfq_queues idle on the device */
495 struct list_head idle_list;
496
497 /*
498 * Timeout for async/sync requests; when it fires, requests
499 * are served in fifo order.
500 */
501 u64 bfq_fifo_expire[2];
502 /* weight of backward seeks wrt forward ones */
503 unsigned int bfq_back_penalty;
504 /* maximum allowed backward seek */
505 unsigned int bfq_back_max;
506 /* maximum idling time */
507 u32 bfq_slice_idle;
508
509 /* user-configured max budget value (0 for auto-tuning) */
510 int bfq_user_max_budget;
511 /*
512 * Timeout for bfq_queues to consume their budget; used to
513 * prevent seeky queues from imposing long latencies to
514 * sequential or quasi-sequential ones (this also implies that
515 * seeky queues cannot receive guarantees in the service
516 * domain; after a timeout they are charged for the time they
517 * have been in service, to preserve fairness among them, but
518 * without service-domain guarantees).
519 */
520 unsigned int bfq_timeout;
521
522 /*
523 * Number of consecutive requests that must be issued within
524 * the idle time slice to set again idling to a queue which
525 * was marked as non-I/O-bound (see the definition of the
526 * IO_bound flag for further details).
527 */
528 unsigned int bfq_requests_within_timer;
529
530 /*
531 * Force device idling whenever needed to provide accurate
532 * service guarantees, without caring about throughput
533 * issues. CAVEAT: this may even increase latencies, in case
534 * of useless idling for processes that did stop doing I/O.
535 */
536 bool strict_guarantees;
537
538 /*
539 * Last time at which a queue entered the current burst of
540 * queues being activated shortly after each other; for more
541 * details about this and the following parameters related to
542 * a burst of activations, see the comments on the function
543 * bfq_handle_burst.
544 */
545 unsigned long last_ins_in_burst;
546 /*
547 * Reference time interval used to decide whether a queue has
548 * been activated shortly after @last_ins_in_burst.
549 */
550 unsigned long bfq_burst_interval;
551 /* number of queues in the current burst of queue activations */
552 int burst_size;
553
554 /* common parent entity for the queues in the burst */
555 struct bfq_entity *burst_parent_entity;
556 /* Maximum burst size above which the current queue-activation
557 * burst is deemed as 'large'.
558 */
559 unsigned long bfq_large_burst_thresh;
560 /* true if a large queue-activation burst is in progress */
561 bool large_burst;
562 /*
563 * Head of the burst list (as for the above fields, more
564 * details in the comments on the function bfq_handle_burst).
565 */
566 struct hlist_head burst_list;
567
568 /* if set to true, low-latency heuristics are enabled */
569 bool low_latency;
570 /*
571 * Maximum factor by which the weight of a weight-raised queue
572 * is multiplied.
573 */
574 unsigned int bfq_wr_coeff;
575 /* maximum duration of a weight-raising period (jiffies) */
576 unsigned int bfq_wr_max_time;
577
578 /* Maximum weight-raising duration for soft real-time processes */
579 unsigned int bfq_wr_rt_max_time;
580 /*
581 * Minimum idle period after which weight-raising may be
582 * reactivated for a queue (in jiffies).
583 */
584 unsigned int bfq_wr_min_idle_time;
585 /*
586 * Minimum period between request arrivals after which
587 * weight-raising may be reactivated for an already busy async
588 * queue (in jiffies).
589 */
590 unsigned long bfq_wr_min_inter_arr_async;
591
592 /* Max service-rate for a soft real-time queue, in sectors/sec */
593 unsigned int bfq_wr_max_softrt_rate;
594 /*
595 * Cached value of the product R*T, used for computing the
596 * maximum duration of weight raising automatically.
597 */
598 u64 RT_prod;
599 /* device-speed class for the low-latency heuristic */
600 enum bfq_device_speed device_speed;
601
602 /* fallback dummy bfqq for extreme OOM conditions */
603 struct bfq_queue oom_bfqq;
604
605 spinlock_t lock;
606
607 /*
608 * bic associated with the task issuing current bio for
609 * merging. This and the next field are used as a support to
610 * be able to perform the bic lookup, needed by bio-merge
611 * functions, before the scheduler lock is taken, and thus
612 * avoid taking the request-queue lock while the scheduler
613 * lock is being held.
614 */
615 struct bfq_io_cq *bio_bic;
616 /* bfqq associated with the task issuing current bio for merging */
617 struct bfq_queue *bio_bfqq;
618};
619
620enum bfqq_state_flags {
621 BFQQF_just_created = 0, /* queue just allocated */
622 BFQQF_busy, /* has requests or is in service */
623 BFQQF_wait_request, /* waiting for a request */
624 BFQQF_non_blocking_wait_rq, /*
625 * waiting for a request
626 * without idling the device
627 */
628 BFQQF_fifo_expire, /* FIFO checked in this slice */
629 BFQQF_idle_window, /* slice idling enabled */
630 BFQQF_sync, /* synchronous queue */
631 BFQQF_IO_bound, /*
632 * bfqq has timed-out at least once
633 * having consumed at most 2/10 of
634 * its budget
635 */
636 BFQQF_in_large_burst, /*
637 * bfqq activated in a large burst,
638 * see comments to bfq_handle_burst.
639 */
640 BFQQF_softrt_update, /*
641 * may need softrt-next-start
642 * update
643 */
644 BFQQF_coop, /* bfqq is shared */
645 BFQQF_split_coop /* shared bfqq will be split */
646};
647
648#define BFQ_BFQQ_FNS(name) \
649void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \
650void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \
651int bfq_bfqq_##name(const struct bfq_queue *bfqq);
652
653BFQ_BFQQ_FNS(just_created);
654BFQ_BFQQ_FNS(busy);
655BFQ_BFQQ_FNS(wait_request);
656BFQ_BFQQ_FNS(non_blocking_wait_rq);
657BFQ_BFQQ_FNS(fifo_expire);
658BFQ_BFQQ_FNS(idle_window);
659BFQ_BFQQ_FNS(sync);
660BFQ_BFQQ_FNS(IO_bound);
661BFQ_BFQQ_FNS(in_large_burst);
662BFQ_BFQQ_FNS(coop);
663BFQ_BFQQ_FNS(split_coop);
664BFQ_BFQQ_FNS(softrt_update);
665#undef BFQ_BFQQ_FNS
666
667/* Expiration reasons. */
668enum bfqq_expiration {
669 BFQQE_TOO_IDLE = 0, /*
670 * queue has been idling for
671 * too long
672 */
673 BFQQE_BUDGET_TIMEOUT, /* budget took too long to be used */
674 BFQQE_BUDGET_EXHAUSTED, /* budget consumed */
675 BFQQE_NO_MORE_REQUESTS, /* the queue has no more requests */
676 BFQQE_PREEMPTED /* preemption in progress */
677};
678
679struct bfqg_stats {
680#ifdef CONFIG_BFQ_GROUP_IOSCHED
681 /* number of ios merged */
682 struct blkg_rwstat merged;
683 /* total time spent on device in ns, may not be accurate w/ queueing */
684 struct blkg_rwstat service_time;
685 /* total time spent waiting in scheduler queue in ns */
686 struct blkg_rwstat wait_time;
687 /* number of IOs queued up */
688 struct blkg_rwstat queued;
689 /* total disk time and nr sectors dispatched by this group */
690 struct blkg_stat time;
691 /* sum of number of ios queued across all samples */
692 struct blkg_stat avg_queue_size_sum;
693 /* count of samples taken for average */
694 struct blkg_stat avg_queue_size_samples;
695 /* how many times this group has been removed from service tree */
696 struct blkg_stat dequeue;
697 /* total time spent waiting for it to be assigned a timeslice. */
698 struct blkg_stat group_wait_time;
699 /* time spent idling for this blkcg_gq */
700 struct blkg_stat idle_time;
701 /* total time with empty current active q with other requests queued */
702 struct blkg_stat empty_time;
703 /* fields after this shouldn't be cleared on stat reset */
704 uint64_t start_group_wait_time;
705 uint64_t start_idle_time;
706 uint64_t start_empty_time;
707 uint16_t flags;
708#endif /* CONFIG_BFQ_GROUP_IOSCHED */
709};
710
711#ifdef CONFIG_BFQ_GROUP_IOSCHED
712
713/*
714 * struct bfq_group_data - per-blkcg storage for the blkio subsystem.
715 *
716 * @ps: @blkcg_policy_storage that this structure inherits
717 * @weight: weight of the bfq_group
718 */
719struct bfq_group_data {
720 /* must be the first member */
721 struct blkcg_policy_data pd;
722
723 unsigned int weight;
724};
725
726/**
727 * struct bfq_group - per (device, cgroup) data structure.
728 * @entity: schedulable entity to insert into the parent group sched_data.
729 * @sched_data: own sched_data, to contain child entities (they may be
730 * both bfq_queues and bfq_groups).
731 * @bfqd: the bfq_data for the device this group acts upon.
732 * @async_bfqq: array of async queues for all the tasks belonging to
733 * the group, one queue per ioprio value per ioprio_class,
734 * except for the idle class that has only one queue.
735 * @async_idle_bfqq: async queue for the idle class (ioprio is ignored).
736 * @my_entity: pointer to @entity, %NULL for the toplevel group; used
737 * to avoid too many special cases during group creation/
738 * migration.
739 * @stats: stats for this bfqg.
740 * @active_entities: number of active entities belonging to the group;
741 * unused for the root group. Used to know whether there
742 * are groups with more than one active @bfq_entity
743 * (see the comments to the function
744 * bfq_bfqq_may_idle()).
745 * @rq_pos_tree: rbtree sorted by next_request position, used when
746 * determining if two or more queues have interleaving
747 * requests (see bfq_find_close_cooperator()).
748 *
749 * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup
750 * there is a set of bfq_groups, each one collecting the lower-level
751 * entities belonging to the group that are acting on the same device.
752 *
753 * Locking works as follows:
754 * o @bfqd is protected by the queue lock, RCU is used to access it
755 * from the readers.
756 * o All the other fields are protected by the @bfqd queue lock.
757 */
758struct bfq_group {
759 /* must be the first member */
760 struct blkg_policy_data pd;
761
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200762 /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */
763 char blkg_path[128];
764
765 /* reference counter (see comments in bfq_bic_update_cgroup) */
766 int ref;
767
Paolo Valenteea25da42017-04-19 08:48:24 -0600768 struct bfq_entity entity;
769 struct bfq_sched_data sched_data;
770
771 void *bfqd;
772
773 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
774 struct bfq_queue *async_idle_bfqq;
775
776 struct bfq_entity *my_entity;
777
778 int active_entities;
779
780 struct rb_root rq_pos_tree;
781
782 struct bfqg_stats stats;
783};
784
785#else
786struct bfq_group {
787 struct bfq_sched_data sched_data;
788
789 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
790 struct bfq_queue *async_idle_bfqq;
791
792 struct rb_root rq_pos_tree;
793};
794#endif
795
796struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
797
798/* --------------- main algorithm interface ----------------- */
799
800#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \
801 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 })
802
803extern const int bfq_timeout;
804
805struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync);
806void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync);
807struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic);
808void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
809void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq);
810void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_entity *entity,
811 struct rb_root *root);
812void bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_entity *entity,
813 struct rb_root *root);
814void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq,
815 bool compensate, enum bfqq_expiration reason);
816void bfq_put_queue(struct bfq_queue *bfqq);
817void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
818void bfq_schedule_dispatch(struct bfq_data *bfqd);
819void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
820
821/* ------------ end of main algorithm interface -------------- */
822
823/* ---------------- cgroups-support interface ---------------- */
824
Paolo Valenteea25da42017-04-19 08:48:24 -0600825void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
826 unsigned int op);
827void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op);
828void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op);
829void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time,
830 uint64_t io_start_time, unsigned int op);
831void bfqg_stats_update_dequeue(struct bfq_group *bfqg);
832void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);
833void bfqg_stats_update_idle_time(struct bfq_group *bfqg);
834void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg);
835void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg);
836void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
837 struct bfq_group *bfqg);
838
839void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg);
840void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio);
841void bfq_end_wr_async(struct bfq_data *bfqd);
842struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
843 struct blkcg *blkcg);
844struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
845struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
846struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200847void bfqg_and_blkg_put(struct bfq_group *bfqg);
Paolo Valenteea25da42017-04-19 08:48:24 -0600848
849#ifdef CONFIG_BFQ_GROUP_IOSCHED
Jens Axboe659b3392017-04-20 09:37:05 -0600850extern struct cftype bfq_blkcg_legacy_files[];
851extern struct cftype bfq_blkg_files[];
Paolo Valenteea25da42017-04-19 08:48:24 -0600852extern struct blkcg_policy blkcg_policy_bfq;
853#endif
854
855/* ------------- end of cgroups-support interface ------------- */
856
857/* - interface of the internal hierarchical B-WF2Q+ scheduler - */
858
859#ifdef CONFIG_BFQ_GROUP_IOSCHED
860/* both next loops stop at one of the child entities of the root group */
861#define for_each_entity(entity) \
862 for (; entity ; entity = entity->parent)
863
864/*
865 * For each iteration, compute parent in advance, so as to be safe if
866 * entity is deallocated during the iteration. Such a deallocation may
867 * happen as a consequence of a bfq_put_queue that frees the bfq_queue
868 * containing entity.
869 */
870#define for_each_entity_safe(entity, parent) \
871 for (; entity && ({ parent = entity->parent; 1; }); entity = parent)
872
873#else /* CONFIG_BFQ_GROUP_IOSCHED */
874/*
875 * Next two macros are fake loops when cgroups support is not
876 * enabled. I fact, in such a case, there is only one level to go up
877 * (to reach the root group).
878 */
879#define for_each_entity(entity) \
880 for (; entity ; entity = NULL)
881
882#define for_each_entity_safe(entity, parent) \
883 for (parent = NULL; entity ; entity = parent)
884#endif /* CONFIG_BFQ_GROUP_IOSCHED */
885
886struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq);
887struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
888struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity);
889struct bfq_entity *bfq_entity_of(struct rb_node *node);
890unsigned short bfq_ioprio_to_weight(int ioprio);
891void bfq_put_idle_entity(struct bfq_service_tree *st,
892 struct bfq_entity *entity);
893struct bfq_service_tree *
894__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
Paolo Valente431b17f2017-07-03 10:00:10 +0200895 struct bfq_entity *entity,
896 bool update_class_too);
Paolo Valenteea25da42017-04-19 08:48:24 -0600897void bfq_bfqq_served(struct bfq_queue *bfqq, int served);
898void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq,
899 unsigned long time_ms);
900bool __bfq_deactivate_entity(struct bfq_entity *entity,
901 bool ins_into_idle_tree);
902bool next_queue_may_preempt(struct bfq_data *bfqd);
903struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd);
904void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd);
905void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
906 bool ins_into_idle_tree, bool expiration);
907void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
908void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
909void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq,
910 bool expiration);
911void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq);
912
913/* --------------- end of interface of B-WF2Q+ ---------------- */
914
915/* Logging facilities. */
916#ifdef CONFIG_BFQ_GROUP_IOSCHED
917struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
918
919#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200920 blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid,\
Paolo Valenteea25da42017-04-19 08:48:24 -0600921 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200922 bfqq_group(bfqq)->blkg_path, ##args); \
Paolo Valenteea25da42017-04-19 08:48:24 -0600923} while (0)
924
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200925#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) \
926 blk_add_trace_msg((bfqd)->queue, "%s " fmt, (bfqg)->blkg_path, ##args)
Paolo Valenteea25da42017-04-19 08:48:24 -0600927
928#else /* CONFIG_BFQ_GROUP_IOSCHED */
929
930#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \
931 blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \
932 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
933 ##args)
934#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0)
935
936#endif /* CONFIG_BFQ_GROUP_IOSCHED */
937
938#define bfq_log(bfqd, fmt, args...) \
939 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
940
941#endif /* _BFQ_H */