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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
Paolo Valente46d556e2017-07-29 12:42:56 +020074 * intermediate queue in a hierarchical setup.
Paolo Valenteea25da42017-04-19 08:48:24 -060075 *
76 * The supported ioprio_classes are the same as in CFQ, in descending
77 * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
78 * Requests from higher priority queues are served before all the
79 * requests from lower priority queues; among requests of the same
80 * queue requests are served according to B-WF2Q+.
Paolo Valente46d556e2017-07-29 12:42:56 +020081 *
82 * The schedule is implemented by the service trees, plus the field
83 * @next_in_service, which points to the entity on the active trees
84 * that will be served next, if 1) no changes in the schedule occurs
85 * before the current in-service entity is expired, 2) the in-service
86 * queue becomes idle when it expires, and 3) if the entity pointed by
87 * in_service_entity is not a queue, then the in-service child entity
88 * of the entity pointed by in_service_entity becomes idle on
89 * expiration. This peculiar definition allows for the following
90 * optimization, not yet exploited: while a given entity is still in
91 * service, we already know which is the best candidate for next
92 * service among the other active entitities in the same parent
93 * entity. We can then quickly compare the timestamps of the
94 * in-service entity with those of such best candidate.
95 *
96 * All fields are protected by the lock of the containing bfqd.
Paolo Valenteea25da42017-04-19 08:48:24 -060097 */
98struct bfq_sched_data {
99 /* entity in service */
100 struct bfq_entity *in_service_entity;
101 /* head-of-line entity (see comments above) */
102 struct bfq_entity *next_in_service;
103 /* array of service trees, one per ioprio_class */
104 struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES];
105 /* last time CLASS_IDLE was served */
106 unsigned long bfq_class_idle_last_service;
107
108};
109
110/**
111 * struct bfq_weight_counter - counter of the number of all active entities
112 * with a given weight.
113 */
114struct bfq_weight_counter {
115 unsigned int weight; /* weight of the entities this counter refers to */
116 unsigned int num_active; /* nr of active entities with this weight */
117 /*
118 * Weights tree member (see bfq_data's @queue_weights_tree and
119 * @group_weights_tree)
120 */
121 struct rb_node weights_node;
122};
123
124/**
125 * struct bfq_entity - schedulable entity.
126 *
127 * A bfq_entity is used to represent either a bfq_queue (leaf node in the
128 * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each
129 * entity belongs to the sched_data of the parent group in the cgroup
130 * hierarchy. Non-leaf entities have also their own sched_data, stored
131 * in @my_sched_data.
132 *
133 * Each entity stores independently its priority values; this would
134 * allow different weights on different devices, but this
135 * functionality is not exported to userspace by now. Priorities and
136 * weights are updated lazily, first storing the new values into the
137 * new_* fields, then setting the @prio_changed flag. As soon as
138 * there is a transition in the entity state that allows the priority
139 * update to take place the effective and the requested priority
140 * values are synchronized.
141 *
142 * Unless cgroups are used, the weight value is calculated from the
143 * ioprio to export the same interface as CFQ. When dealing with
144 * ``well-behaved'' queues (i.e., queues that do not spend too much
145 * time to consume their budget and have true sequential behavior, and
146 * when there are no external factors breaking anticipation) the
147 * relative weights at each level of the cgroups hierarchy should be
148 * guaranteed. All the fields are protected by the queue lock of the
149 * containing bfqd.
150 */
151struct bfq_entity {
152 /* service_tree member */
153 struct rb_node rb_node;
154 /* pointer to the weight counter associated with this entity */
155 struct bfq_weight_counter *weight_counter;
156
157 /*
158 * Flag, true if the entity is on a tree (either the active or
159 * the idle one of its service_tree) or is in service.
160 */
161 bool on_st;
162
163 /* B-WF2Q+ start and finish timestamps [sectors/weight] */
164 u64 start, finish;
165
166 /* tree the entity is enqueued into; %NULL if not on a tree */
167 struct rb_root *tree;
168
169 /*
170 * minimum start time of the (active) subtree rooted at this
171 * entity; used for O(log N) lookups into active trees
172 */
173 u64 min_start;
174
175 /* amount of service received during the last service slot */
176 int service;
177
178 /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */
179 int budget;
180
181 /* weight of the queue */
182 int weight;
183 /* next weight if a change is in progress */
184 int new_weight;
185
186 /* original weight, used to implement weight boosting */
187 int orig_weight;
188
189 /* parent entity, for hierarchical scheduling */
190 struct bfq_entity *parent;
191
192 /*
193 * For non-leaf nodes in the hierarchy, the associated
194 * scheduler queue, %NULL on leaf nodes.
195 */
196 struct bfq_sched_data *my_sched_data;
197 /* the scheduler queue this entity belongs to */
198 struct bfq_sched_data *sched_data;
199
200 /* flag, set to request a weight, ioprio or ioprio_class change */
201 int prio_changed;
202};
203
204struct bfq_group;
205
206/**
207 * struct bfq_ttime - per process thinktime stats.
208 */
209struct bfq_ttime {
210 /* completion time of the last request */
211 u64 last_end_request;
212
213 /* total process thinktime */
214 u64 ttime_total;
215 /* number of thinktime samples */
216 unsigned long ttime_samples;
217 /* average process thinktime */
218 u64 ttime_mean;
219};
220
221/**
222 * struct bfq_queue - leaf schedulable entity.
223 *
224 * A bfq_queue is a leaf request queue; it can be associated with an
225 * io_context or more, if it is async or shared between cooperating
226 * processes. @cgroup holds a reference to the cgroup, to be sure that it
227 * does not disappear while a bfqq still references it (mostly to avoid
228 * races between request issuing and task migration followed by cgroup
229 * destruction).
230 * All the fields are protected by the queue lock of the containing bfqd.
231 */
232struct bfq_queue {
233 /* reference counter */
234 int ref;
235 /* parent bfq_data */
236 struct bfq_data *bfqd;
237
238 /* current ioprio and ioprio class */
239 unsigned short ioprio, ioprio_class;
240 /* next ioprio and ioprio class if a change is in progress */
241 unsigned short new_ioprio, new_ioprio_class;
242
243 /*
244 * Shared bfq_queue if queue is cooperating with one or more
245 * other queues.
246 */
247 struct bfq_queue *new_bfqq;
248 /* request-position tree member (see bfq_group's @rq_pos_tree) */
249 struct rb_node pos_node;
250 /* request-position tree root (see bfq_group's @rq_pos_tree) */
251 struct rb_root *pos_root;
252
253 /* sorted list of pending requests */
254 struct rb_root sort_list;
255 /* if fifo isn't expired, next request to serve */
256 struct request *next_rq;
257 /* number of sync and async requests queued */
258 int queued[2];
259 /* number of requests currently allocated */
260 int allocated;
261 /* number of pending metadata requests */
262 int meta_pending;
263 /* fifo list of requests in sort_list */
264 struct list_head fifo;
265
266 /* entity representing this queue in the scheduler */
267 struct bfq_entity entity;
268
269 /* maximum budget allowed from the feedback mechanism */
270 int max_budget;
271 /* budget expiration (in jiffies) */
272 unsigned long budget_timeout;
273
274 /* number of requests on the dispatch list or inside driver */
275 int dispatched;
276
277 /* status flags */
278 unsigned long flags;
279
280 /* node for active/idle bfqq list inside parent bfqd */
281 struct list_head bfqq_list;
282
283 /* associated @bfq_ttime struct */
284 struct bfq_ttime ttime;
285
286 /* bit vector: a 1 for each seeky requests in history */
287 u32 seek_history;
288
289 /* node for the device's burst list */
290 struct hlist_node burst_list_node;
291
292 /* position of the last request enqueued */
293 sector_t last_request_pos;
294
295 /* Number of consecutive pairs of request completion and
296 * arrival, such that the queue becomes idle after the
297 * completion, but the next request arrives within an idle
298 * time slice; used only if the queue's IO_bound flag has been
299 * cleared.
300 */
301 unsigned int requests_within_timer;
302
303 /* pid of the process owning the queue, used for logging purposes */
304 pid_t pid;
305
306 /*
307 * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL
308 * if the queue is shared.
309 */
310 struct bfq_io_cq *bic;
311
312 /* current maximum weight-raising time for this queue */
313 unsigned long wr_cur_max_time;
314 /*
315 * Minimum time instant such that, only if a new request is
316 * enqueued after this time instant in an idle @bfq_queue with
317 * no outstanding requests, then the task associated with the
318 * queue it is deemed as soft real-time (see the comments on
319 * the function bfq_bfqq_softrt_next_start())
320 */
321 unsigned long soft_rt_next_start;
322 /*
323 * Start time of the current weight-raising period if
324 * the @bfq-queue is being weight-raised, otherwise
325 * finish time of the last weight-raising period.
326 */
327 unsigned long last_wr_start_finish;
328 /* factor by which the weight of this queue is multiplied */
329 unsigned int wr_coeff;
330 /*
331 * Time of the last transition of the @bfq_queue from idle to
332 * backlogged.
333 */
334 unsigned long last_idle_bklogged;
335 /*
336 * Cumulative service received from the @bfq_queue since the
337 * last transition from idle to backlogged.
338 */
339 unsigned long service_from_backlogged;
340
341 /*
342 * Value of wr start time when switching to soft rt
343 */
344 unsigned long wr_start_at_switch_to_srt;
345
346 unsigned long split_time; /* time of last split */
347};
348
349/**
350 * struct bfq_io_cq - per (request_queue, io_context) structure.
351 */
352struct bfq_io_cq {
353 /* associated io_cq structure */
354 struct io_cq icq; /* must be the first member */
355 /* array of two process queues, the sync and the async */
356 struct bfq_queue *bfqq[2];
357 /* per (request_queue, blkcg) ioprio */
358 int ioprio;
359#ifdef CONFIG_BFQ_GROUP_IOSCHED
360 uint64_t blkcg_serial_nr; /* the current blkcg serial */
361#endif
362 /*
Paolo Valented5be3fe2017-08-04 07:35:10 +0200363 * Snapshot of the has_short_time flag before merging; taken
364 * to remember its value while the queue is merged, so as to
365 * be able to restore it in case of split.
Paolo Valenteea25da42017-04-19 08:48:24 -0600366 */
Paolo Valented5be3fe2017-08-04 07:35:10 +0200367 bool saved_has_short_ttime;
Paolo Valenteea25da42017-04-19 08:48:24 -0600368 /*
369 * Same purpose as the previous two fields for the I/O bound
370 * classification of a queue.
371 */
372 bool saved_IO_bound;
373
374 /*
375 * Same purpose as the previous fields for the value of the
376 * field keeping the queue's belonging to a large burst
377 */
378 bool saved_in_large_burst;
379 /*
380 * True if the queue belonged to a burst list before its merge
381 * with another cooperating queue.
382 */
383 bool was_in_burst_list;
384
385 /*
386 * Similar to previous fields: save wr information.
387 */
388 unsigned long saved_wr_coeff;
389 unsigned long saved_last_wr_start_finish;
390 unsigned long saved_wr_start_at_switch_to_srt;
391 unsigned int saved_wr_cur_max_time;
392 struct bfq_ttime saved_ttime;
393};
394
395enum bfq_device_speed {
396 BFQ_BFQD_FAST,
397 BFQ_BFQD_SLOW,
398};
399
400/**
401 * struct bfq_data - per-device data structure.
402 *
403 * All the fields are protected by @lock.
404 */
405struct bfq_data {
406 /* device request queue */
407 struct request_queue *queue;
408 /* dispatch queue */
409 struct list_head dispatch;
410
411 /* root bfq_group for the device */
412 struct bfq_group *root_group;
413
414 /*
415 * rbtree of weight counters of @bfq_queues, sorted by
416 * weight. Used to keep track of whether all @bfq_queues have
417 * the same weight. The tree contains one counter for each
418 * distinct weight associated to some active and not
419 * weight-raised @bfq_queue (see the comments to the functions
420 * bfq_weights_tree_[add|remove] for further details).
421 */
422 struct rb_root queue_weights_tree;
423 /*
424 * rbtree of non-queue @bfq_entity weight counters, sorted by
425 * weight. Used to keep track of whether all @bfq_groups have
426 * the same weight. The tree contains one counter for each
427 * distinct weight associated to some active @bfq_group (see
428 * the comments to the functions bfq_weights_tree_[add|remove]
429 * for further details).
430 */
431 struct rb_root group_weights_tree;
432
433 /*
434 * Number of bfq_queues containing requests (including the
435 * queue in service, even if it is idling).
436 */
437 int busy_queues;
438 /* number of weight-raised busy @bfq_queues */
439 int wr_busy_queues;
440 /* number of queued requests */
441 int queued;
442 /* number of requests dispatched and waiting for completion */
443 int rq_in_driver;
444
445 /*
446 * Maximum number of requests in driver in the last
447 * @hw_tag_samples completed requests.
448 */
449 int max_rq_in_driver;
450 /* number of samples used to calculate hw_tag */
451 int hw_tag_samples;
452 /* flag set to one if the driver is showing a queueing behavior */
453 int hw_tag;
454
455 /* number of budgets assigned */
456 int budgets_assigned;
457
458 /*
459 * Timer set when idling (waiting) for the next request from
460 * the queue in service.
461 */
462 struct hrtimer idle_slice_timer;
463
464 /* bfq_queue in service */
465 struct bfq_queue *in_service_queue;
466
467 /* on-disk position of the last served request */
468 sector_t last_position;
469
470 /* time of last request completion (ns) */
471 u64 last_completion;
472
473 /* time of first rq dispatch in current observation interval (ns) */
474 u64 first_dispatch;
475 /* time of last rq dispatch in current observation interval (ns) */
476 u64 last_dispatch;
477
478 /* beginning of the last budget */
479 ktime_t last_budget_start;
480 /* beginning of the last idle slice */
481 ktime_t last_idling_start;
482
483 /* number of samples in current observation interval */
484 int peak_rate_samples;
485 /* num of samples of seq dispatches in current observation interval */
486 u32 sequential_samples;
487 /* total num of sectors transferred in current observation interval */
488 u64 tot_sectors_dispatched;
489 /* max rq size seen during current observation interval (sectors) */
490 u32 last_rq_max_size;
491 /* time elapsed from first dispatch in current observ. interval (us) */
492 u64 delta_from_first;
493 /*
494 * Current estimate of the device peak rate, measured in
495 * [BFQ_RATE_SHIFT * sectors/usec]. The left-shift by
496 * BFQ_RATE_SHIFT is performed to increase precision in
497 * fixed-point calculations.
498 */
499 u32 peak_rate;
500
501 /* maximum budget allotted to a bfq_queue before rescheduling */
502 int bfq_max_budget;
503
504 /* list of all the bfq_queues active on the device */
505 struct list_head active_list;
506 /* list of all the bfq_queues idle on the device */
507 struct list_head idle_list;
508
509 /*
510 * Timeout for async/sync requests; when it fires, requests
511 * are served in fifo order.
512 */
513 u64 bfq_fifo_expire[2];
514 /* weight of backward seeks wrt forward ones */
515 unsigned int bfq_back_penalty;
516 /* maximum allowed backward seek */
517 unsigned int bfq_back_max;
518 /* maximum idling time */
519 u32 bfq_slice_idle;
520
521 /* user-configured max budget value (0 for auto-tuning) */
522 int bfq_user_max_budget;
523 /*
524 * Timeout for bfq_queues to consume their budget; used to
525 * prevent seeky queues from imposing long latencies to
526 * sequential or quasi-sequential ones (this also implies that
527 * seeky queues cannot receive guarantees in the service
528 * domain; after a timeout they are charged for the time they
529 * have been in service, to preserve fairness among them, but
530 * without service-domain guarantees).
531 */
532 unsigned int bfq_timeout;
533
534 /*
535 * Number of consecutive requests that must be issued within
536 * the idle time slice to set again idling to a queue which
537 * was marked as non-I/O-bound (see the definition of the
538 * IO_bound flag for further details).
539 */
540 unsigned int bfq_requests_within_timer;
541
542 /*
543 * Force device idling whenever needed to provide accurate
544 * service guarantees, without caring about throughput
545 * issues. CAVEAT: this may even increase latencies, in case
546 * of useless idling for processes that did stop doing I/O.
547 */
548 bool strict_guarantees;
549
550 /*
551 * Last time at which a queue entered the current burst of
552 * queues being activated shortly after each other; for more
553 * details about this and the following parameters related to
554 * a burst of activations, see the comments on the function
555 * bfq_handle_burst.
556 */
557 unsigned long last_ins_in_burst;
558 /*
559 * Reference time interval used to decide whether a queue has
560 * been activated shortly after @last_ins_in_burst.
561 */
562 unsigned long bfq_burst_interval;
563 /* number of queues in the current burst of queue activations */
564 int burst_size;
565
566 /* common parent entity for the queues in the burst */
567 struct bfq_entity *burst_parent_entity;
568 /* Maximum burst size above which the current queue-activation
569 * burst is deemed as 'large'.
570 */
571 unsigned long bfq_large_burst_thresh;
572 /* true if a large queue-activation burst is in progress */
573 bool large_burst;
574 /*
575 * Head of the burst list (as for the above fields, more
576 * details in the comments on the function bfq_handle_burst).
577 */
578 struct hlist_head burst_list;
579
580 /* if set to true, low-latency heuristics are enabled */
581 bool low_latency;
582 /*
583 * Maximum factor by which the weight of a weight-raised queue
584 * is multiplied.
585 */
586 unsigned int bfq_wr_coeff;
587 /* maximum duration of a weight-raising period (jiffies) */
588 unsigned int bfq_wr_max_time;
589
590 /* Maximum weight-raising duration for soft real-time processes */
591 unsigned int bfq_wr_rt_max_time;
592 /*
593 * Minimum idle period after which weight-raising may be
594 * reactivated for a queue (in jiffies).
595 */
596 unsigned int bfq_wr_min_idle_time;
597 /*
598 * Minimum period between request arrivals after which
599 * weight-raising may be reactivated for an already busy async
600 * queue (in jiffies).
601 */
602 unsigned long bfq_wr_min_inter_arr_async;
603
604 /* Max service-rate for a soft real-time queue, in sectors/sec */
605 unsigned int bfq_wr_max_softrt_rate;
606 /*
607 * Cached value of the product R*T, used for computing the
608 * maximum duration of weight raising automatically.
609 */
610 u64 RT_prod;
611 /* device-speed class for the low-latency heuristic */
612 enum bfq_device_speed device_speed;
613
614 /* fallback dummy bfqq for extreme OOM conditions */
615 struct bfq_queue oom_bfqq;
616
617 spinlock_t lock;
618
619 /*
620 * bic associated with the task issuing current bio for
621 * merging. This and the next field are used as a support to
622 * be able to perform the bic lookup, needed by bio-merge
623 * functions, before the scheduler lock is taken, and thus
624 * avoid taking the request-queue lock while the scheduler
625 * lock is being held.
626 */
627 struct bfq_io_cq *bio_bic;
628 /* bfqq associated with the task issuing current bio for merging */
629 struct bfq_queue *bio_bfqq;
630};
631
632enum bfqq_state_flags {
633 BFQQF_just_created = 0, /* queue just allocated */
634 BFQQF_busy, /* has requests or is in service */
635 BFQQF_wait_request, /* waiting for a request */
636 BFQQF_non_blocking_wait_rq, /*
637 * waiting for a request
638 * without idling the device
639 */
640 BFQQF_fifo_expire, /* FIFO checked in this slice */
Paolo Valented5be3fe2017-08-04 07:35:10 +0200641 BFQQF_has_short_ttime, /* queue has a short think time */
Paolo Valenteea25da42017-04-19 08:48:24 -0600642 BFQQF_sync, /* synchronous queue */
643 BFQQF_IO_bound, /*
644 * bfqq has timed-out at least once
645 * having consumed at most 2/10 of
646 * its budget
647 */
648 BFQQF_in_large_burst, /*
649 * bfqq activated in a large burst,
650 * see comments to bfq_handle_burst.
651 */
652 BFQQF_softrt_update, /*
653 * may need softrt-next-start
654 * update
655 */
656 BFQQF_coop, /* bfqq is shared */
657 BFQQF_split_coop /* shared bfqq will be split */
658};
659
660#define BFQ_BFQQ_FNS(name) \
661void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \
662void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \
663int bfq_bfqq_##name(const struct bfq_queue *bfqq);
664
665BFQ_BFQQ_FNS(just_created);
666BFQ_BFQQ_FNS(busy);
667BFQ_BFQQ_FNS(wait_request);
668BFQ_BFQQ_FNS(non_blocking_wait_rq);
669BFQ_BFQQ_FNS(fifo_expire);
Paolo Valented5be3fe2017-08-04 07:35:10 +0200670BFQ_BFQQ_FNS(has_short_ttime);
Paolo Valenteea25da42017-04-19 08:48:24 -0600671BFQ_BFQQ_FNS(sync);
672BFQ_BFQQ_FNS(IO_bound);
673BFQ_BFQQ_FNS(in_large_burst);
674BFQ_BFQQ_FNS(coop);
675BFQ_BFQQ_FNS(split_coop);
676BFQ_BFQQ_FNS(softrt_update);
677#undef BFQ_BFQQ_FNS
678
679/* Expiration reasons. */
680enum bfqq_expiration {
681 BFQQE_TOO_IDLE = 0, /*
682 * queue has been idling for
683 * too long
684 */
685 BFQQE_BUDGET_TIMEOUT, /* budget took too long to be used */
686 BFQQE_BUDGET_EXHAUSTED, /* budget consumed */
687 BFQQE_NO_MORE_REQUESTS, /* the queue has no more requests */
688 BFQQE_PREEMPTED /* preemption in progress */
689};
690
691struct bfqg_stats {
Luca Miccioa33801e2017-11-13 07:34:10 +0100692#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
Paolo Valenteea25da42017-04-19 08:48:24 -0600693 /* number of ios merged */
694 struct blkg_rwstat merged;
695 /* total time spent on device in ns, may not be accurate w/ queueing */
696 struct blkg_rwstat service_time;
697 /* total time spent waiting in scheduler queue in ns */
698 struct blkg_rwstat wait_time;
699 /* number of IOs queued up */
700 struct blkg_rwstat queued;
701 /* total disk time and nr sectors dispatched by this group */
702 struct blkg_stat time;
703 /* sum of number of ios queued across all samples */
704 struct blkg_stat avg_queue_size_sum;
705 /* count of samples taken for average */
706 struct blkg_stat avg_queue_size_samples;
707 /* how many times this group has been removed from service tree */
708 struct blkg_stat dequeue;
709 /* total time spent waiting for it to be assigned a timeslice. */
710 struct blkg_stat group_wait_time;
711 /* time spent idling for this blkcg_gq */
712 struct blkg_stat idle_time;
713 /* total time with empty current active q with other requests queued */
714 struct blkg_stat empty_time;
715 /* fields after this shouldn't be cleared on stat reset */
716 uint64_t start_group_wait_time;
717 uint64_t start_idle_time;
718 uint64_t start_empty_time;
719 uint16_t flags;
Luca Miccioa33801e2017-11-13 07:34:10 +0100720#endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
Paolo Valenteea25da42017-04-19 08:48:24 -0600721};
722
723#ifdef CONFIG_BFQ_GROUP_IOSCHED
724
725/*
726 * struct bfq_group_data - per-blkcg storage for the blkio subsystem.
727 *
728 * @ps: @blkcg_policy_storage that this structure inherits
729 * @weight: weight of the bfq_group
730 */
731struct bfq_group_data {
732 /* must be the first member */
733 struct blkcg_policy_data pd;
734
735 unsigned int weight;
736};
737
738/**
739 * struct bfq_group - per (device, cgroup) data structure.
740 * @entity: schedulable entity to insert into the parent group sched_data.
741 * @sched_data: own sched_data, to contain child entities (they may be
742 * both bfq_queues and bfq_groups).
743 * @bfqd: the bfq_data for the device this group acts upon.
744 * @async_bfqq: array of async queues for all the tasks belonging to
745 * the group, one queue per ioprio value per ioprio_class,
746 * except for the idle class that has only one queue.
747 * @async_idle_bfqq: async queue for the idle class (ioprio is ignored).
748 * @my_entity: pointer to @entity, %NULL for the toplevel group; used
749 * to avoid too many special cases during group creation/
750 * migration.
751 * @stats: stats for this bfqg.
752 * @active_entities: number of active entities belonging to the group;
753 * unused for the root group. Used to know whether there
754 * are groups with more than one active @bfq_entity
755 * (see the comments to the function
756 * bfq_bfqq_may_idle()).
757 * @rq_pos_tree: rbtree sorted by next_request position, used when
758 * determining if two or more queues have interleaving
759 * requests (see bfq_find_close_cooperator()).
760 *
761 * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup
762 * there is a set of bfq_groups, each one collecting the lower-level
763 * entities belonging to the group that are acting on the same device.
764 *
765 * Locking works as follows:
766 * o @bfqd is protected by the queue lock, RCU is used to access it
767 * from the readers.
768 * o All the other fields are protected by the @bfqd queue lock.
769 */
770struct bfq_group {
771 /* must be the first member */
772 struct blkg_policy_data pd;
773
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200774 /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */
775 char blkg_path[128];
776
777 /* reference counter (see comments in bfq_bic_update_cgroup) */
778 int ref;
779
Paolo Valenteea25da42017-04-19 08:48:24 -0600780 struct bfq_entity entity;
781 struct bfq_sched_data sched_data;
782
783 void *bfqd;
784
785 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
786 struct bfq_queue *async_idle_bfqq;
787
788 struct bfq_entity *my_entity;
789
790 int active_entities;
791
792 struct rb_root rq_pos_tree;
793
794 struct bfqg_stats stats;
795};
796
797#else
798struct bfq_group {
799 struct bfq_sched_data sched_data;
800
801 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR];
802 struct bfq_queue *async_idle_bfqq;
803
804 struct rb_root rq_pos_tree;
805};
806#endif
807
808struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
809
810/* --------------- main algorithm interface ----------------- */
811
812#define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \
813 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 })
814
815extern const int bfq_timeout;
816
817struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync);
818void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync);
819struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic);
Paolo Valenteea25da42017-04-19 08:48:24 -0600820void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq);
821void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_entity *entity,
822 struct rb_root *root);
823void bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_entity *entity,
824 struct rb_root *root);
825void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq,
826 bool compensate, enum bfqq_expiration reason);
827void bfq_put_queue(struct bfq_queue *bfqq);
828void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
829void bfq_schedule_dispatch(struct bfq_data *bfqd);
830void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
831
832/* ------------ end of main algorithm interface -------------- */
833
834/* ---------------- cgroups-support interface ---------------- */
835
Paolo Valenteea25da42017-04-19 08:48:24 -0600836void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
837 unsigned int op);
838void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op);
839void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op);
840void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time,
841 uint64_t io_start_time, unsigned int op);
842void bfqg_stats_update_dequeue(struct bfq_group *bfqg);
843void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);
844void bfqg_stats_update_idle_time(struct bfq_group *bfqg);
845void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg);
846void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg);
847void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
848 struct bfq_group *bfqg);
849
850void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg);
851void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio);
852void bfq_end_wr_async(struct bfq_data *bfqd);
853struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
854 struct blkcg *blkcg);
855struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
856struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
857struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
Paolo Valente8f9bebc2017-06-05 10:11:15 +0200858void bfqg_and_blkg_put(struct bfq_group *bfqg);
Paolo Valenteea25da42017-04-19 08:48:24 -0600859
860#ifdef CONFIG_BFQ_GROUP_IOSCHED
Jens Axboe659b3392017-04-20 09:37:05 -0600861extern struct cftype bfq_blkcg_legacy_files[];
862extern struct cftype bfq_blkg_files[];
Paolo Valenteea25da42017-04-19 08:48:24 -0600863extern struct blkcg_policy blkcg_policy_bfq;
864#endif
865
866/* ------------- end of cgroups-support interface ------------- */
867
868/* - interface of the internal hierarchical B-WF2Q+ scheduler - */
869
870#ifdef CONFIG_BFQ_GROUP_IOSCHED
871/* both next loops stop at one of the child entities of the root group */
872#define for_each_entity(entity) \
873 for (; entity ; entity = entity->parent)
874
875/*
876 * For each iteration, compute parent in advance, so as to be safe if
877 * entity is deallocated during the iteration. Such a deallocation may
878 * happen as a consequence of a bfq_put_queue that frees the bfq_queue
879 * containing entity.
880 */
881#define for_each_entity_safe(entity, parent) \
882 for (; entity && ({ parent = entity->parent; 1; }); entity = parent)
883
884#else /* CONFIG_BFQ_GROUP_IOSCHED */
885/*
886 * Next two macros are fake loops when cgroups support is not
887 * enabled. I fact, in such a case, there is only one level to go up
888 * (to reach the root group).
889 */
890#define for_each_entity(entity) \
891 for (; entity ; entity = NULL)
892
893#define for_each_entity_safe(entity, parent) \
894 for (parent = NULL; entity ; entity = parent)
895#endif /* CONFIG_BFQ_GROUP_IOSCHED */
896
897struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq);
898struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
899struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity);
900struct bfq_entity *bfq_entity_of(struct rb_node *node);
901unsigned short bfq_ioprio_to_weight(int ioprio);
902void bfq_put_idle_entity(struct bfq_service_tree *st,
903 struct bfq_entity *entity);
904struct bfq_service_tree *
905__bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
Paolo Valente431b17f2017-07-03 10:00:10 +0200906 struct bfq_entity *entity,
907 bool update_class_too);
Paolo Valenteea25da42017-04-19 08:48:24 -0600908void bfq_bfqq_served(struct bfq_queue *bfqq, int served);
909void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq,
910 unsigned long time_ms);
911bool __bfq_deactivate_entity(struct bfq_entity *entity,
912 bool ins_into_idle_tree);
913bool next_queue_may_preempt(struct bfq_data *bfqd);
914struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd);
915void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd);
916void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
917 bool ins_into_idle_tree, bool expiration);
918void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
Paolo Valente80294c32017-08-31 08:46:29 +0200919void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
920 bool expiration);
Paolo Valenteea25da42017-04-19 08:48:24 -0600921void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq,
922 bool expiration);
923void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq);
924
925/* --------------- end of interface of B-WF2Q+ ---------------- */
926
927/* Logging facilities. */
928#ifdef CONFIG_BFQ_GROUP_IOSCHED
929struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
930
931#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \
Shaohua Li35fe6d72017-07-12 11:49:56 -0700932 blk_add_cgroup_trace_msg((bfqd)->queue, \
933 bfqg_to_blkg(bfqq_group(bfqq))->blkcg, \
934 "bfq%d%c " fmt, (bfqq)->pid, \
935 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args); \
Paolo Valenteea25da42017-04-19 08:48:24 -0600936} while (0)
937
Shaohua Li35fe6d72017-07-12 11:49:56 -0700938#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \
939 blk_add_cgroup_trace_msg((bfqd)->queue, \
940 bfqg_to_blkg(bfqg)->blkcg, fmt, ##args); \
941} while (0)
Paolo Valenteea25da42017-04-19 08:48:24 -0600942
943#else /* CONFIG_BFQ_GROUP_IOSCHED */
944
945#define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \
946 blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \
947 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \
948 ##args)
949#define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0)
950
951#endif /* CONFIG_BFQ_GROUP_IOSCHED */
952
953#define bfq_log(bfqd, fmt, args...) \
954 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
955
956#endif /* _BFQ_H */