xref: /openbmc/linux/block/bfq-iosched.h (revision e9f2f3f5)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * Header file for the BFQ I/O scheduler: data structures and
4  * prototypes of interface functions among BFQ components.
5  */
6 #ifndef _BFQ_H
7 #define _BFQ_H
8 
9 #include <linux/blktrace_api.h>
10 #include <linux/hrtimer.h>
11 
12 #include "blk-cgroup-rwstat.h"
13 
14 #define BFQ_IOPRIO_CLASSES	3
15 #define BFQ_CL_IDLE_TIMEOUT	(HZ/5)
16 
17 #define BFQ_MIN_WEIGHT			1
18 #define BFQ_MAX_WEIGHT			1000
19 #define BFQ_WEIGHT_CONVERSION_COEFF	10
20 
21 #define BFQ_DEFAULT_QUEUE_IOPRIO	4
22 
23 #define BFQ_DEFAULT_GRP_IOPRIO	0
24 #define BFQ_DEFAULT_GRP_CLASS	IOPRIO_CLASS_BE
25 
26 #define MAX_BFQQ_NAME_LENGTH 16
27 
28 /*
29  * Soft real-time applications are extremely more latency sensitive
30  * than interactive ones. Over-raise the weight of the former to
31  * privilege them against the latter.
32  */
33 #define BFQ_SOFTRT_WEIGHT_FACTOR	100
34 
35 /*
36  * Maximum number of actuators supported. This constant is used simply
37  * to define the size of the static array that will contain
38  * per-actuator data. The current value is hopefully a good upper
39  * bound to the possible number of actuators of any actual drive.
40  */
41 #define BFQ_MAX_ACTUATORS 8
42 
43 struct bfq_entity;
44 
45 /**
46  * struct bfq_service_tree - per ioprio_class service tree.
47  *
48  * Each service tree represents a B-WF2Q+ scheduler on its own.  Each
49  * ioprio_class has its own independent scheduler, and so its own
50  * bfq_service_tree.  All the fields are protected by the queue lock
51  * of the containing bfqd.
52  */
53 struct bfq_service_tree {
54 	/* tree for active entities (i.e., those backlogged) */
55 	struct rb_root active;
56 	/* tree for idle entities (i.e., not backlogged, with V < F_i)*/
57 	struct rb_root idle;
58 
59 	/* idle entity with minimum F_i */
60 	struct bfq_entity *first_idle;
61 	/* idle entity with maximum F_i */
62 	struct bfq_entity *last_idle;
63 
64 	/* scheduler virtual time */
65 	u64 vtime;
66 	/* scheduler weight sum; active and idle entities contribute to it */
67 	unsigned long wsum;
68 };
69 
70 /**
71  * struct bfq_sched_data - multi-class scheduler.
72  *
73  * bfq_sched_data is the basic scheduler queue.  It supports three
74  * ioprio_classes, and can be used either as a toplevel queue or as an
75  * intermediate queue in a hierarchical setup.
76  *
77  * The supported ioprio_classes are the same as in CFQ, in descending
78  * priority order, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE.
79  * Requests from higher priority queues are served before all the
80  * requests from lower priority queues; among requests of the same
81  * queue requests are served according to B-WF2Q+.
82  *
83  * The schedule is implemented by the service trees, plus the field
84  * @next_in_service, which points to the entity on the active trees
85  * that will be served next, if 1) no changes in the schedule occurs
86  * before the current in-service entity is expired, 2) the in-service
87  * queue becomes idle when it expires, and 3) if the entity pointed by
88  * in_service_entity is not a queue, then the in-service child entity
89  * of the entity pointed by in_service_entity becomes idle on
90  * expiration. This peculiar definition allows for the following
91  * optimization, not yet exploited: while a given entity is still in
92  * service, we already know which is the best candidate for next
93  * service among the other active entities in the same parent
94  * entity. We can then quickly compare the timestamps of the
95  * in-service entity with those of such best candidate.
96  *
97  * All fields are protected by the lock of the containing bfqd.
98  */
99 struct bfq_sched_data {
100 	/* entity in service */
101 	struct bfq_entity *in_service_entity;
102 	/* head-of-line entity (see comments above) */
103 	struct bfq_entity *next_in_service;
104 	/* array of service trees, one per ioprio_class */
105 	struct bfq_service_tree service_tree[BFQ_IOPRIO_CLASSES];
106 	/* last time CLASS_IDLE was served */
107 	unsigned long bfq_class_idle_last_service;
108 
109 };
110 
111 /**
112  * struct bfq_weight_counter - counter of the number of all active queues
113  *                             with a given weight.
114  */
115 struct bfq_weight_counter {
116 	unsigned int weight; /* weight of the queues this counter refers to */
117 	unsigned int num_active; /* nr of active queues with this weight */
118 	/*
119 	 * Weights tree member (see bfq_data's @queue_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  */
151 struct bfq_entity {
152 	/* service_tree member */
153 	struct rb_node rb_node;
154 
155 	/*
156 	 * Flag, true if the entity is on a tree (either the active or
157 	 * the idle one of its service_tree) or is in service.
158 	 */
159 	bool on_st_or_in_serv;
160 
161 	/* B-WF2Q+ start and finish timestamps [sectors/weight] */
162 	u64 start, finish;
163 
164 	/* tree the entity is enqueued into; %NULL if not on a tree */
165 	struct rb_root *tree;
166 
167 	/*
168 	 * minimum start time of the (active) subtree rooted at this
169 	 * entity; used for O(log N) lookups into active trees
170 	 */
171 	u64 min_start;
172 
173 	/* amount of service received during the last service slot */
174 	int service;
175 
176 	/* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */
177 	int budget;
178 
179 	/* Number of requests allocated in the subtree of this entity */
180 	int allocated;
181 
182 	/* device weight, if non-zero, it overrides the default weight of
183 	 * bfq_group_data */
184 	int dev_weight;
185 	/* weight of the queue */
186 	int weight;
187 	/* next weight if a change is in progress */
188 	int new_weight;
189 
190 	/* original weight, used to implement weight boosting */
191 	int orig_weight;
192 
193 	/* parent entity, for hierarchical scheduling */
194 	struct bfq_entity *parent;
195 
196 	/*
197 	 * For non-leaf nodes in the hierarchy, the associated
198 	 * scheduler queue, %NULL on leaf nodes.
199 	 */
200 	struct bfq_sched_data *my_sched_data;
201 	/* the scheduler queue this entity belongs to */
202 	struct bfq_sched_data *sched_data;
203 
204 	/* flag, set to request a weight, ioprio or ioprio_class change  */
205 	int prio_changed;
206 
207 #ifdef CONFIG_BFQ_GROUP_IOSCHED
208 	/* flag, set if the entity is counted in groups_with_pending_reqs */
209 	bool in_groups_with_pending_reqs;
210 #endif
211 
212 	/* last child queue of entity created (for non-leaf entities) */
213 	struct bfq_queue *last_bfqq_created;
214 };
215 
216 struct bfq_group;
217 
218 /**
219  * struct bfq_ttime - per process thinktime stats.
220  */
221 struct bfq_ttime {
222 	/* completion time of the last request */
223 	u64 last_end_request;
224 
225 	/* total process thinktime */
226 	u64 ttime_total;
227 	/* number of thinktime samples */
228 	unsigned long ttime_samples;
229 	/* average process thinktime */
230 	u64 ttime_mean;
231 };
232 
233 /**
234  * struct bfq_queue - leaf schedulable entity.
235  *
236  * A bfq_queue is a leaf request queue; it can be associated with an
237  * io_context or more, if it is async or shared between cooperating
238  * processes. Besides, it contains I/O requests for only one actuator
239  * (an io_context is associated with a different bfq_queue for each
240  * actuator it generates I/O for). @cgroup holds a reference to the
241  * cgroup, to be sure that it does not disappear while a bfqq still
242  * references it (mostly to avoid races between request issuing and
243  * task migration followed by cgroup destruction).  All the fields are
244  * protected by the queue lock of the containing bfqd.
245  */
246 struct bfq_queue {
247 	/* reference counter */
248 	int ref;
249 	/* counter of references from other queues for delayed stable merge */
250 	int stable_ref;
251 	/* parent bfq_data */
252 	struct bfq_data *bfqd;
253 
254 	/* current ioprio and ioprio class */
255 	unsigned short ioprio, ioprio_class;
256 	/* next ioprio and ioprio class if a change is in progress */
257 	unsigned short new_ioprio, new_ioprio_class;
258 
259 	/* last total-service-time sample, see bfq_update_inject_limit() */
260 	u64 last_serv_time_ns;
261 	/* limit for request injection */
262 	unsigned int inject_limit;
263 	/* last time the inject limit has been decreased, in jiffies */
264 	unsigned long decrease_time_jif;
265 
266 	/*
267 	 * Shared bfq_queue if queue is cooperating with one or more
268 	 * other queues.
269 	 */
270 	struct bfq_queue *new_bfqq;
271 	/* request-position tree member (see bfq_group's @rq_pos_tree) */
272 	struct rb_node pos_node;
273 	/* request-position tree root (see bfq_group's @rq_pos_tree) */
274 	struct rb_root *pos_root;
275 
276 	/* sorted list of pending requests */
277 	struct rb_root sort_list;
278 	/* if fifo isn't expired, next request to serve */
279 	struct request *next_rq;
280 	/* number of sync and async requests queued */
281 	int queued[2];
282 	/* number of pending metadata requests */
283 	int meta_pending;
284 	/* fifo list of requests in sort_list */
285 	struct list_head fifo;
286 
287 	/* entity representing this queue in the scheduler */
288 	struct bfq_entity entity;
289 
290 	/* pointer to the weight counter associated with this entity */
291 	struct bfq_weight_counter *weight_counter;
292 
293 	/* maximum budget allowed from the feedback mechanism */
294 	int max_budget;
295 	/* budget expiration (in jiffies) */
296 	unsigned long budget_timeout;
297 
298 	/* number of requests on the dispatch list or inside driver */
299 	int dispatched;
300 
301 	/* status flags */
302 	unsigned long flags;
303 
304 	/* node for active/idle bfqq list inside parent bfqd */
305 	struct list_head bfqq_list;
306 
307 	/* associated @bfq_ttime struct */
308 	struct bfq_ttime ttime;
309 
310 	/* when bfqq started to do I/O within the last observation window */
311 	u64 io_start_time;
312 	/* how long bfqq has remained empty during the last observ. window */
313 	u64 tot_idle_time;
314 
315 	/* bit vector: a 1 for each seeky requests in history */
316 	u32 seek_history;
317 
318 	/* node for the device's burst list */
319 	struct hlist_node burst_list_node;
320 
321 	/* position of the last request enqueued */
322 	sector_t last_request_pos;
323 
324 	/* Number of consecutive pairs of request completion and
325 	 * arrival, such that the queue becomes idle after the
326 	 * completion, but the next request arrives within an idle
327 	 * time slice; used only if the queue's IO_bound flag has been
328 	 * cleared.
329 	 */
330 	unsigned int requests_within_timer;
331 
332 	/* pid of the process owning the queue, used for logging purposes */
333 	pid_t pid;
334 
335 	/*
336 	 * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL
337 	 * if the queue is shared.
338 	 */
339 	struct bfq_io_cq *bic;
340 
341 	/* current maximum weight-raising time for this queue */
342 	unsigned long wr_cur_max_time;
343 	/*
344 	 * Minimum time instant such that, only if a new request is
345 	 * enqueued after this time instant in an idle @bfq_queue with
346 	 * no outstanding requests, then the task associated with the
347 	 * queue it is deemed as soft real-time (see the comments on
348 	 * the function bfq_bfqq_softrt_next_start())
349 	 */
350 	unsigned long soft_rt_next_start;
351 	/*
352 	 * Start time of the current weight-raising period if
353 	 * the @bfq-queue is being weight-raised, otherwise
354 	 * finish time of the last weight-raising period.
355 	 */
356 	unsigned long last_wr_start_finish;
357 	/* factor by which the weight of this queue is multiplied */
358 	unsigned int wr_coeff;
359 	/*
360 	 * Time of the last transition of the @bfq_queue from idle to
361 	 * backlogged.
362 	 */
363 	unsigned long last_idle_bklogged;
364 	/*
365 	 * Cumulative service received from the @bfq_queue since the
366 	 * last transition from idle to backlogged.
367 	 */
368 	unsigned long service_from_backlogged;
369 	/*
370 	 * Cumulative service received from the @bfq_queue since its
371 	 * last transition to weight-raised state.
372 	 */
373 	unsigned long service_from_wr;
374 
375 	/*
376 	 * Value of wr start time when switching to soft rt
377 	 */
378 	unsigned long wr_start_at_switch_to_srt;
379 
380 	unsigned long split_time; /* time of last split */
381 
382 	unsigned long first_IO_time; /* time of first I/O for this queue */
383 	unsigned long creation_time; /* when this queue is created */
384 
385 	/*
386 	 * Pointer to the waker queue for this queue, i.e., to the
387 	 * queue Q such that this queue happens to get new I/O right
388 	 * after some I/O request of Q is completed. For details, see
389 	 * the comments on the choice of the queue for injection in
390 	 * bfq_select_queue().
391 	 */
392 	struct bfq_queue *waker_bfqq;
393 	/* pointer to the curr. tentative waker queue, see bfq_check_waker() */
394 	struct bfq_queue *tentative_waker_bfqq;
395 	/* number of times the same tentative waker has been detected */
396 	unsigned int num_waker_detections;
397 	/* time when we started considering this waker */
398 	u64 waker_detection_started;
399 
400 	/* node for woken_list, see below */
401 	struct hlist_node woken_list_node;
402 	/*
403 	 * Head of the list of the woken queues for this queue, i.e.,
404 	 * of the list of the queues for which this queue is a waker
405 	 * queue. This list is used to reset the waker_bfqq pointer in
406 	 * the woken queues when this queue exits.
407 	 */
408 	struct hlist_head woken_list;
409 
410 	/* index of the actuator this queue is associated with */
411 	unsigned int actuator_idx;
412 };
413 
414 /**
415 * struct bfq_data - bfqq data unique and persistent for associated bfq_io_cq
416 */
417 struct bfq_iocq_bfqq_data {
418 	/*
419 	 * Snapshot of the has_short_time flag before merging; taken
420 	 * to remember its values while the queue is merged, so as to
421 	 * be able to restore it in case of split.
422 	 */
423 	bool saved_has_short_ttime;
424 	/*
425 	 * Same purpose as the previous two fields for the I/O bound
426 	 * classification of a queue.
427 	 */
428 	bool saved_IO_bound;
429 
430 	u64 saved_io_start_time;
431 	u64 saved_tot_idle_time;
432 
433 	/*
434 	 * Same purpose as the previous fields for the values of the
435 	 * field keeping the queue's belonging to a large burst
436 	 */
437 	bool saved_in_large_burst;
438 	/*
439 	 * True if the queue belonged to a burst list before its merge
440 	 * with another cooperating queue.
441 	 */
442 	bool was_in_burst_list;
443 
444 	/*
445 	 * Save the weight when a merge occurs, to be able
446 	 * to restore it in case of split. If the weight is not
447 	 * correctly resumed when the queue is recycled,
448 	 * then the weight of the recycled queue could differ
449 	 * from the weight of the original queue.
450 	 */
451 	unsigned int saved_weight;
452 
453 	/*
454 	 * Similar to previous fields: save wr information.
455 	 */
456 	unsigned long saved_wr_coeff;
457 	unsigned long saved_last_wr_start_finish;
458 	unsigned long saved_service_from_wr;
459 	unsigned long saved_wr_start_at_switch_to_srt;
460 	unsigned int saved_wr_cur_max_time;
461 	struct bfq_ttime saved_ttime;
462 
463 	/* Save also injection state */
464 	u64 saved_last_serv_time_ns;
465 	unsigned int saved_inject_limit;
466 	unsigned long saved_decrease_time_jif;
467 
468 	/* candidate queue for a stable merge (due to close creation time) */
469 	struct bfq_queue *stable_merge_bfqq;
470 
471 	bool stably_merged;	/* non splittable if true */
472 };
473 
474 /**
475  * struct bfq_io_cq - per (request_queue, io_context) structure.
476  */
477 struct bfq_io_cq {
478 	/* associated io_cq structure */
479 	struct io_cq icq; /* must be the first member */
480 	/*
481 	 * Matrix of associated process queues: first row for async
482 	 * queues, second row sync queues. Each row contains one
483 	 * column for each actuator. An I/O request generated by the
484 	 * process is inserted into the queue pointed by bfqq[i][j] if
485 	 * the request is to be served by the j-th actuator of the
486 	 * drive, where i==0 or i==1, depending on whether the request
487 	 * is async or sync. So there is a distinct queue for each
488 	 * actuator.
489 	 */
490 	struct bfq_queue *bfqq[2][BFQ_MAX_ACTUATORS];
491 	/* per (request_queue, blkcg) ioprio */
492 	int ioprio;
493 #ifdef CONFIG_BFQ_GROUP_IOSCHED
494 	uint64_t blkcg_serial_nr; /* the current blkcg serial */
495 #endif
496 
497 	/*
498 	 * Persistent data for associated synchronous process queues
499 	 * (one queue per actuator, see field bfqq above). In
500 	 * particular, each of these queues may undergo a merge.
501 	 */
502 	struct bfq_iocq_bfqq_data bfqq_data[BFQ_MAX_ACTUATORS];
503 
504 	unsigned int requests;	/* Number of requests this process has in flight */
505 };
506 
507 /**
508  * struct bfq_data - per-device data structure.
509  *
510  * All the fields are protected by @lock.
511  */
512 struct bfq_data {
513 	/* device request queue */
514 	struct request_queue *queue;
515 	/* dispatch queue */
516 	struct list_head dispatch;
517 
518 	/* root bfq_group for the device */
519 	struct bfq_group *root_group;
520 
521 	/*
522 	 * rbtree of weight counters of @bfq_queues, sorted by
523 	 * weight. Used to keep track of whether all @bfq_queues have
524 	 * the same weight. The tree contains one counter for each
525 	 * distinct weight associated to some active and not
526 	 * weight-raised @bfq_queue (see the comments to the functions
527 	 * bfq_weights_tree_[add|remove] for further details).
528 	 */
529 	struct rb_root_cached queue_weights_tree;
530 
531 #ifdef CONFIG_BFQ_GROUP_IOSCHED
532 	/*
533 	 * Number of groups with at least one process that
534 	 * has at least one request waiting for completion. Note that
535 	 * this accounts for also requests already dispatched, but not
536 	 * yet completed. Therefore this number of groups may differ
537 	 * (be larger) than the number of active groups, as a group is
538 	 * considered active only if its corresponding entity has
539 	 * queues with at least one request queued. This
540 	 * number is used to decide whether a scenario is symmetric.
541 	 * For a detailed explanation see comments on the computation
542 	 * of the variable asymmetric_scenario in the function
543 	 * bfq_better_to_idle().
544 	 *
545 	 * However, it is hard to compute this number exactly, for
546 	 * groups with multiple processes. Consider a group
547 	 * that is inactive, i.e., that has no process with
548 	 * pending I/O inside BFQ queues. Then suppose that
549 	 * num_groups_with_pending_reqs is still accounting for this
550 	 * group, because the group has processes with some
551 	 * I/O request still in flight. num_groups_with_pending_reqs
552 	 * should be decremented when the in-flight request of the
553 	 * last process is finally completed (assuming that
554 	 * nothing else has changed for the group in the meantime, in
555 	 * terms of composition of the group and active/inactive state of child
556 	 * groups and processes). To accomplish this, an additional
557 	 * pending-request counter must be added to entities, and must
558 	 * be updated correctly. To avoid this additional field and operations,
559 	 * we resort to the following tradeoff between simplicity and
560 	 * accuracy: for an inactive group that is still counted in
561 	 * num_groups_with_pending_reqs, we decrement
562 	 * num_groups_with_pending_reqs when the first
563 	 * process of the group remains with no request waiting for
564 	 * completion.
565 	 *
566 	 * Even this simpler decrement strategy requires a little
567 	 * carefulness: to avoid multiple decrements, we flag a group,
568 	 * more precisely an entity representing a group, as still
569 	 * counted in num_groups_with_pending_reqs when it becomes
570 	 * inactive. Then, when the first queue of the
571 	 * entity remains with no request waiting for completion,
572 	 * num_groups_with_pending_reqs is decremented, and this flag
573 	 * is reset. After this flag is reset for the entity,
574 	 * num_groups_with_pending_reqs won't be decremented any
575 	 * longer in case a new queue of the entity remains
576 	 * with no request waiting for completion.
577 	 */
578 	unsigned int num_groups_with_pending_reqs;
579 #endif
580 
581 	/*
582 	 * Per-class (RT, BE, IDLE) number of bfq_queues containing
583 	 * requests (including the queue in service, even if it is
584 	 * idling).
585 	 */
586 	unsigned int busy_queues[3];
587 	/* number of weight-raised busy @bfq_queues */
588 	int wr_busy_queues;
589 	/* number of queued requests */
590 	int queued;
591 	/* number of requests dispatched and waiting for completion */
592 	int tot_rq_in_driver;
593 	/*
594 	 * number of requests dispatched and waiting for completion
595 	 * for each actuator
596 	 */
597 	int rq_in_driver[BFQ_MAX_ACTUATORS];
598 
599 	/* true if the device is non rotational and performs queueing */
600 	bool nonrot_with_queueing;
601 
602 	/*
603 	 * Maximum number of requests in driver in the last
604 	 * @hw_tag_samples completed requests.
605 	 */
606 	int max_rq_in_driver;
607 	/* number of samples used to calculate hw_tag */
608 	int hw_tag_samples;
609 	/* flag set to one if the driver is showing a queueing behavior */
610 	int hw_tag;
611 
612 	/* number of budgets assigned */
613 	int budgets_assigned;
614 
615 	/*
616 	 * Timer set when idling (waiting) for the next request from
617 	 * the queue in service.
618 	 */
619 	struct hrtimer idle_slice_timer;
620 
621 	/* bfq_queue in service */
622 	struct bfq_queue *in_service_queue;
623 
624 	/* on-disk position of the last served request */
625 	sector_t last_position;
626 
627 	/* position of the last served request for the in-service queue */
628 	sector_t in_serv_last_pos;
629 
630 	/* time of last request completion (ns) */
631 	u64 last_completion;
632 
633 	/* bfqq owning the last completed rq */
634 	struct bfq_queue *last_completed_rq_bfqq;
635 
636 	/* last bfqq created, among those in the root group */
637 	struct bfq_queue *last_bfqq_created;
638 
639 	/* time of last transition from empty to non-empty (ns) */
640 	u64 last_empty_occupied_ns;
641 
642 	/*
643 	 * Flag set to activate the sampling of the total service time
644 	 * of a just-arrived first I/O request (see
645 	 * bfq_update_inject_limit()). This will cause the setting of
646 	 * waited_rq when the request is finally dispatched.
647 	 */
648 	bool wait_dispatch;
649 	/*
650 	 *  If set, then bfq_update_inject_limit() is invoked when
651 	 *  waited_rq is eventually completed.
652 	 */
653 	struct request *waited_rq;
654 	/*
655 	 * True if some request has been injected during the last service hole.
656 	 */
657 	bool rqs_injected;
658 
659 	/* time of first rq dispatch in current observation interval (ns) */
660 	u64 first_dispatch;
661 	/* time of last rq dispatch in current observation interval (ns) */
662 	u64 last_dispatch;
663 
664 	/* beginning of the last budget */
665 	ktime_t last_budget_start;
666 	/* beginning of the last idle slice */
667 	ktime_t last_idling_start;
668 	unsigned long last_idling_start_jiffies;
669 
670 	/* number of samples in current observation interval */
671 	int peak_rate_samples;
672 	/* num of samples of seq dispatches in current observation interval */
673 	u32 sequential_samples;
674 	/* total num of sectors transferred in current observation interval */
675 	u64 tot_sectors_dispatched;
676 	/* max rq size seen during current observation interval (sectors) */
677 	u32 last_rq_max_size;
678 	/* time elapsed from first dispatch in current observ. interval (us) */
679 	u64 delta_from_first;
680 	/*
681 	 * Current estimate of the device peak rate, measured in
682 	 * [(sectors/usec) / 2^BFQ_RATE_SHIFT]. The left-shift by
683 	 * BFQ_RATE_SHIFT is performed to increase precision in
684 	 * fixed-point calculations.
685 	 */
686 	u32 peak_rate;
687 
688 	/* maximum budget allotted to a bfq_queue before rescheduling */
689 	int bfq_max_budget;
690 
691 	/*
692 	 * List of all the bfq_queues active for a specific actuator
693 	 * on the device. Keeping active queues separate on a
694 	 * per-actuator basis helps implementing per-actuator
695 	 * injection more efficiently.
696 	 */
697 	struct list_head active_list[BFQ_MAX_ACTUATORS];
698 	/* list of all the bfq_queues idle on the device */
699 	struct list_head idle_list;
700 
701 	/*
702 	 * Timeout for async/sync requests; when it fires, requests
703 	 * are served in fifo order.
704 	 */
705 	u64 bfq_fifo_expire[2];
706 	/* weight of backward seeks wrt forward ones */
707 	unsigned int bfq_back_penalty;
708 	/* maximum allowed backward seek */
709 	unsigned int bfq_back_max;
710 	/* maximum idling time */
711 	u32 bfq_slice_idle;
712 
713 	/* user-configured max budget value (0 for auto-tuning) */
714 	int bfq_user_max_budget;
715 	/*
716 	 * Timeout for bfq_queues to consume their budget; used to
717 	 * prevent seeky queues from imposing long latencies to
718 	 * sequential or quasi-sequential ones (this also implies that
719 	 * seeky queues cannot receive guarantees in the service
720 	 * domain; after a timeout they are charged for the time they
721 	 * have been in service, to preserve fairness among them, but
722 	 * without service-domain guarantees).
723 	 */
724 	unsigned int bfq_timeout;
725 
726 	/*
727 	 * Force device idling whenever needed to provide accurate
728 	 * service guarantees, without caring about throughput
729 	 * issues. CAVEAT: this may even increase latencies, in case
730 	 * of useless idling for processes that did stop doing I/O.
731 	 */
732 	bool strict_guarantees;
733 
734 	/*
735 	 * Last time at which a queue entered the current burst of
736 	 * queues being activated shortly after each other; for more
737 	 * details about this and the following parameters related to
738 	 * a burst of activations, see the comments on the function
739 	 * bfq_handle_burst.
740 	 */
741 	unsigned long last_ins_in_burst;
742 	/*
743 	 * Reference time interval used to decide whether a queue has
744 	 * been activated shortly after @last_ins_in_burst.
745 	 */
746 	unsigned long bfq_burst_interval;
747 	/* number of queues in the current burst of queue activations */
748 	int burst_size;
749 
750 	/* common parent entity for the queues in the burst */
751 	struct bfq_entity *burst_parent_entity;
752 	/* Maximum burst size above which the current queue-activation
753 	 * burst is deemed as 'large'.
754 	 */
755 	unsigned long bfq_large_burst_thresh;
756 	/* true if a large queue-activation burst is in progress */
757 	bool large_burst;
758 	/*
759 	 * Head of the burst list (as for the above fields, more
760 	 * details in the comments on the function bfq_handle_burst).
761 	 */
762 	struct hlist_head burst_list;
763 
764 	/* if set to true, low-latency heuristics are enabled */
765 	bool low_latency;
766 	/*
767 	 * Maximum factor by which the weight of a weight-raised queue
768 	 * is multiplied.
769 	 */
770 	unsigned int bfq_wr_coeff;
771 
772 	/* Maximum weight-raising duration for soft real-time processes */
773 	unsigned int bfq_wr_rt_max_time;
774 	/*
775 	 * Minimum idle period after which weight-raising may be
776 	 * reactivated for a queue (in jiffies).
777 	 */
778 	unsigned int bfq_wr_min_idle_time;
779 	/*
780 	 * Minimum period between request arrivals after which
781 	 * weight-raising may be reactivated for an already busy async
782 	 * queue (in jiffies).
783 	 */
784 	unsigned long bfq_wr_min_inter_arr_async;
785 
786 	/* Max service-rate for a soft real-time queue, in sectors/sec */
787 	unsigned int bfq_wr_max_softrt_rate;
788 	/*
789 	 * Cached value of the product ref_rate*ref_wr_duration, used
790 	 * for computing the maximum duration of weight raising
791 	 * automatically.
792 	 */
793 	u64 rate_dur_prod;
794 
795 	/* fallback dummy bfqq for extreme OOM conditions */
796 	struct bfq_queue oom_bfqq;
797 
798 	spinlock_t lock;
799 
800 	/*
801 	 * bic associated with the task issuing current bio for
802 	 * merging. This and the next field are used as a support to
803 	 * be able to perform the bic lookup, needed by bio-merge
804 	 * functions, before the scheduler lock is taken, and thus
805 	 * avoid taking the request-queue lock while the scheduler
806 	 * lock is being held.
807 	 */
808 	struct bfq_io_cq *bio_bic;
809 	/* bfqq associated with the task issuing current bio for merging */
810 	struct bfq_queue *bio_bfqq;
811 
812 	/*
813 	 * Depth limits used in bfq_limit_depth (see comments on the
814 	 * function)
815 	 */
816 	unsigned int word_depths[2][2];
817 	unsigned int full_depth_shift;
818 
819 	/*
820 	 * Number of independent actuators. This is equal to 1 in
821 	 * case of single-actuator drives.
822 	 */
823 	unsigned int num_actuators;
824 	/*
825 	 * Disk independent access ranges for each actuator
826 	 * in this device.
827 	 */
828 	sector_t sector[BFQ_MAX_ACTUATORS];
829 	sector_t nr_sectors[BFQ_MAX_ACTUATORS];
830 	struct blk_independent_access_range ia_ranges[BFQ_MAX_ACTUATORS];
831 
832 	/*
833 	 * If the number of I/O requests queued in the device for a
834 	 * given actuator is below next threshold, then the actuator
835 	 * is deemed as underutilized. If this condition is found to
836 	 * hold for some actuator upon a dispatch, but (i) the
837 	 * in-service queue does not contain I/O for that actuator,
838 	 * while (ii) some other queue does contain I/O for that
839 	 * actuator, then the head I/O request of the latter queue is
840 	 * returned (injected), instead of the head request of the
841 	 * currently in-service queue.
842 	 *
843 	 * We set the threshold, empirically, to the minimum possible
844 	 * value for which an actuator is fully utilized, or close to
845 	 * be fully utilized. By doing so, injected I/O 'steals' as
846 	 * few drive-queue slots as possibile to the in-service
847 	 * queue. This reduces as much as possible the probability
848 	 * that the service of I/O from the in-service bfq_queue gets
849 	 * delayed because of slot exhaustion, i.e., because all the
850 	 * slots of the drive queue are filled with I/O injected from
851 	 * other queues (NCQ provides for 32 slots).
852 	 */
853 	unsigned int actuator_load_threshold;
854 };
855 
856 enum bfqq_state_flags {
857 	BFQQF_just_created = 0,	/* queue just allocated */
858 	BFQQF_busy,		/* has requests or is in service */
859 	BFQQF_wait_request,	/* waiting for a request */
860 	BFQQF_non_blocking_wait_rq, /*
861 				     * waiting for a request
862 				     * without idling the device
863 				     */
864 	BFQQF_fifo_expire,	/* FIFO checked in this slice */
865 	BFQQF_has_short_ttime,	/* queue has a short think time */
866 	BFQQF_sync,		/* synchronous queue */
867 	BFQQF_IO_bound,		/*
868 				 * bfqq has timed-out at least once
869 				 * having consumed at most 2/10 of
870 				 * its budget
871 				 */
872 	BFQQF_in_large_burst,	/*
873 				 * bfqq activated in a large burst,
874 				 * see comments to bfq_handle_burst.
875 				 */
876 	BFQQF_softrt_update,	/*
877 				 * may need softrt-next-start
878 				 * update
879 				 */
880 	BFQQF_coop,		/* bfqq is shared */
881 	BFQQF_split_coop,	/* shared bfqq will be split */
882 };
883 
884 #define BFQ_BFQQ_FNS(name)						\
885 void bfq_mark_bfqq_##name(struct bfq_queue *bfqq);			\
886 void bfq_clear_bfqq_##name(struct bfq_queue *bfqq);			\
887 int bfq_bfqq_##name(const struct bfq_queue *bfqq);
888 
889 BFQ_BFQQ_FNS(just_created);
890 BFQ_BFQQ_FNS(busy);
891 BFQ_BFQQ_FNS(wait_request);
892 BFQ_BFQQ_FNS(non_blocking_wait_rq);
893 BFQ_BFQQ_FNS(fifo_expire);
894 BFQ_BFQQ_FNS(has_short_ttime);
895 BFQ_BFQQ_FNS(sync);
896 BFQ_BFQQ_FNS(IO_bound);
897 BFQ_BFQQ_FNS(in_large_burst);
898 BFQ_BFQQ_FNS(coop);
899 BFQ_BFQQ_FNS(split_coop);
900 BFQ_BFQQ_FNS(softrt_update);
901 #undef BFQ_BFQQ_FNS
902 
903 /* Expiration reasons. */
904 enum bfqq_expiration {
905 	BFQQE_TOO_IDLE = 0,		/*
906 					 * queue has been idling for
907 					 * too long
908 					 */
909 	BFQQE_BUDGET_TIMEOUT,	/* budget took too long to be used */
910 	BFQQE_BUDGET_EXHAUSTED,	/* budget consumed */
911 	BFQQE_NO_MORE_REQUESTS,	/* the queue has no more requests */
912 	BFQQE_PREEMPTED		/* preemption in progress */
913 };
914 
915 struct bfq_stat {
916 	struct percpu_counter		cpu_cnt;
917 	atomic64_t			aux_cnt;
918 };
919 
920 struct bfqg_stats {
921 	/* basic stats */
922 	struct blkg_rwstat		bytes;
923 	struct blkg_rwstat		ios;
924 #ifdef CONFIG_BFQ_CGROUP_DEBUG
925 	/* number of ios merged */
926 	struct blkg_rwstat		merged;
927 	/* total time spent on device in ns, may not be accurate w/ queueing */
928 	struct blkg_rwstat		service_time;
929 	/* total time spent waiting in scheduler queue in ns */
930 	struct blkg_rwstat		wait_time;
931 	/* number of IOs queued up */
932 	struct blkg_rwstat		queued;
933 	/* total disk time and nr sectors dispatched by this group */
934 	struct bfq_stat		time;
935 	/* sum of number of ios queued across all samples */
936 	struct bfq_stat		avg_queue_size_sum;
937 	/* count of samples taken for average */
938 	struct bfq_stat		avg_queue_size_samples;
939 	/* how many times this group has been removed from service tree */
940 	struct bfq_stat		dequeue;
941 	/* total time spent waiting for it to be assigned a timeslice. */
942 	struct bfq_stat		group_wait_time;
943 	/* time spent idling for this blkcg_gq */
944 	struct bfq_stat		idle_time;
945 	/* total time with empty current active q with other requests queued */
946 	struct bfq_stat		empty_time;
947 	/* fields after this shouldn't be cleared on stat reset */
948 	u64				start_group_wait_time;
949 	u64				start_idle_time;
950 	u64				start_empty_time;
951 	uint16_t			flags;
952 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
953 };
954 
955 #ifdef CONFIG_BFQ_GROUP_IOSCHED
956 
957 /*
958  * struct bfq_group_data - per-blkcg storage for the blkio subsystem.
959  *
960  * @ps: @blkcg_policy_storage that this structure inherits
961  * @weight: weight of the bfq_group
962  */
963 struct bfq_group_data {
964 	/* must be the first member */
965 	struct blkcg_policy_data pd;
966 
967 	unsigned int weight;
968 };
969 
970 /**
971  * struct bfq_group - per (device, cgroup) data structure.
972  * @entity: schedulable entity to insert into the parent group sched_data.
973  * @sched_data: own sched_data, to contain child entities (they may be
974  *              both bfq_queues and bfq_groups).
975  * @bfqd: the bfq_data for the device this group acts upon.
976  * @async_bfqq: array of async queues for all the tasks belonging to
977  *              the group, one queue per ioprio value per ioprio_class,
978  *              except for the idle class that has only one queue.
979  * @async_idle_bfqq: async queue for the idle class (ioprio is ignored).
980  * @my_entity: pointer to @entity, %NULL for the toplevel group; used
981  *             to avoid too many special cases during group creation/
982  *             migration.
983  * @stats: stats for this bfqg.
984  * @active_entities: number of active entities belonging to the group;
985  *                   unused for the root group. Used to know whether there
986  *                   are groups with more than one active @bfq_entity
987  *                   (see the comments to the function
988  *                   bfq_bfqq_may_idle()).
989  * @rq_pos_tree: rbtree sorted by next_request position, used when
990  *               determining if two or more queues have interleaving
991  *               requests (see bfq_find_close_cooperator()).
992  *
993  * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup
994  * there is a set of bfq_groups, each one collecting the lower-level
995  * entities belonging to the group that are acting on the same device.
996  *
997  * Locking works as follows:
998  *    o @bfqd is protected by the queue lock, RCU is used to access it
999  *      from the readers.
1000  *    o All the other fields are protected by the @bfqd queue lock.
1001  */
1002 struct bfq_group {
1003 	/* must be the first member */
1004 	struct blkg_policy_data pd;
1005 
1006 	/* cached path for this blkg (see comments in bfq_bic_update_cgroup) */
1007 	char blkg_path[128];
1008 
1009 	/* reference counter (see comments in bfq_bic_update_cgroup) */
1010 	refcount_t ref;
1011 
1012 	struct bfq_entity entity;
1013 	struct bfq_sched_data sched_data;
1014 
1015 	struct bfq_data *bfqd;
1016 
1017 	struct bfq_queue *async_bfqq[2][IOPRIO_NR_LEVELS][BFQ_MAX_ACTUATORS];
1018 	struct bfq_queue *async_idle_bfqq[BFQ_MAX_ACTUATORS];
1019 
1020 	struct bfq_entity *my_entity;
1021 
1022 	int active_entities;
1023 	int num_queues_with_pending_reqs;
1024 
1025 	struct rb_root rq_pos_tree;
1026 
1027 	struct bfqg_stats stats;
1028 };
1029 
1030 #else
1031 struct bfq_group {
1032 	struct bfq_entity entity;
1033 	struct bfq_sched_data sched_data;
1034 
1035 	struct bfq_queue *async_bfqq[2][IOPRIO_NR_LEVELS][BFQ_MAX_ACTUATORS];
1036 	struct bfq_queue *async_idle_bfqq[BFQ_MAX_ACTUATORS];
1037 
1038 	struct rb_root rq_pos_tree;
1039 };
1040 #endif
1041 
1042 /* --------------- main algorithm interface ----------------- */
1043 
1044 #define BFQ_SERVICE_TREE_INIT	((struct bfq_service_tree)		\
1045 				{ RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 })
1046 
1047 extern const int bfq_timeout;
1048 
1049 struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync,
1050 				unsigned int actuator_idx);
1051 void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync,
1052 				unsigned int actuator_idx);
1053 struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic);
1054 void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq);
1055 void bfq_weights_tree_add(struct bfq_queue *bfqq);
1056 void bfq_weights_tree_remove(struct bfq_queue *bfqq);
1057 void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1058 		     bool compensate, enum bfqq_expiration reason);
1059 void bfq_put_queue(struct bfq_queue *bfqq);
1060 void bfq_put_cooperator(struct bfq_queue *bfqq);
1061 void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
1062 void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq);
1063 void bfq_schedule_dispatch(struct bfq_data *bfqd);
1064 void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
1065 
1066 /* ------------ end of main algorithm interface -------------- */
1067 
1068 /* ---------------- cgroups-support interface ---------------- */
1069 
1070 void bfqg_stats_update_legacy_io(struct request_queue *q, struct request *rq);
1071 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf);
1072 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf);
1073 void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
1074 				  u64 io_start_time_ns, blk_opf_t opf);
1075 void bfqg_stats_update_dequeue(struct bfq_group *bfqg);
1076 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg);
1077 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1078 		   struct bfq_group *bfqg);
1079 
1080 #ifdef CONFIG_BFQ_CGROUP_DEBUG
1081 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
1082 			      blk_opf_t opf);
1083 void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);
1084 void bfqg_stats_update_idle_time(struct bfq_group *bfqg);
1085 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg);
1086 #endif
1087 
1088 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg);
1089 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio);
1090 void bfq_end_wr_async(struct bfq_data *bfqd);
1091 struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio);
1092 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
1093 struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
1094 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
1095 void bfqg_and_blkg_put(struct bfq_group *bfqg);
1096 
1097 #ifdef CONFIG_BFQ_GROUP_IOSCHED
1098 extern struct cftype bfq_blkcg_legacy_files[];
1099 extern struct cftype bfq_blkg_files[];
1100 extern struct blkcg_policy blkcg_policy_bfq;
1101 #endif
1102 
1103 /* ------------- end of cgroups-support interface ------------- */
1104 
1105 /* - interface of the internal hierarchical B-WF2Q+ scheduler - */
1106 
1107 #ifdef CONFIG_BFQ_GROUP_IOSCHED
1108 /* both next loops stop at one of the child entities of the root group */
1109 #define for_each_entity(entity)	\
1110 	for (; entity ; entity = entity->parent)
1111 
1112 /*
1113  * For each iteration, compute parent in advance, so as to be safe if
1114  * entity is deallocated during the iteration. Such a deallocation may
1115  * happen as a consequence of a bfq_put_queue that frees the bfq_queue
1116  * containing entity.
1117  */
1118 #define for_each_entity_safe(entity, parent) \
1119 	for (; entity && ({ parent = entity->parent; 1; }); entity = parent)
1120 
1121 #else /* CONFIG_BFQ_GROUP_IOSCHED */
1122 /*
1123  * Next two macros are fake loops when cgroups support is not
1124  * enabled. I fact, in such a case, there is only one level to go up
1125  * (to reach the root group).
1126  */
1127 #define for_each_entity(entity)	\
1128 	for (; entity ; entity = NULL)
1129 
1130 #define for_each_entity_safe(entity, parent) \
1131 	for (parent = NULL; entity ; entity = parent)
1132 #endif /* CONFIG_BFQ_GROUP_IOSCHED */
1133 
1134 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
1135 unsigned int bfq_tot_busy_queues(struct bfq_data *bfqd);
1136 struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity);
1137 struct bfq_entity *bfq_entity_of(struct rb_node *node);
1138 unsigned short bfq_ioprio_to_weight(int ioprio);
1139 void bfq_put_idle_entity(struct bfq_service_tree *st,
1140 			 struct bfq_entity *entity);
1141 struct bfq_service_tree *
1142 __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
1143 				struct bfq_entity *entity,
1144 				bool update_class_too);
1145 void bfq_bfqq_served(struct bfq_queue *bfqq, int served);
1146 void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1147 			  unsigned long time_ms);
1148 bool __bfq_deactivate_entity(struct bfq_entity *entity,
1149 			     bool ins_into_idle_tree);
1150 bool next_queue_may_preempt(struct bfq_data *bfqd);
1151 struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd);
1152 bool __bfq_bfqd_reset_in_service(struct bfq_data *bfqd);
1153 void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1154 			 bool ins_into_idle_tree, bool expiration);
1155 void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
1156 void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
1157 		      bool expiration);
1158 void bfq_del_bfqq_busy(struct bfq_queue *bfqq, bool expiration);
1159 void bfq_add_bfqq_busy(struct bfq_queue *bfqq);
1160 void bfq_add_bfqq_in_groups_with_pending_reqs(struct bfq_queue *bfqq);
1161 void bfq_del_bfqq_in_groups_with_pending_reqs(struct bfq_queue *bfqq);
1162 
1163 /* --------------- end of interface of B-WF2Q+ ---------------- */
1164 
1165 /* Logging facilities. */
bfq_bfqq_name(struct bfq_queue * bfqq,char * str,int len)1166 static inline void bfq_bfqq_name(struct bfq_queue *bfqq, char *str, int len)
1167 {
1168 	char type = bfq_bfqq_sync(bfqq) ? 'S' : 'A';
1169 
1170 	if (bfqq->pid != -1)
1171 		snprintf(str, len, "bfq%d%c", bfqq->pid, type);
1172 	else
1173 		snprintf(str, len, "bfqSHARED-%c", type);
1174 }
1175 
1176 #ifdef CONFIG_BFQ_GROUP_IOSCHED
1177 struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
1178 
1179 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...)	do {			\
1180 	char pid_str[MAX_BFQQ_NAME_LENGTH];				\
1181 	if (likely(!blk_trace_note_message_enabled((bfqd)->queue)))	\
1182 		break;							\
1183 	bfq_bfqq_name((bfqq), pid_str, MAX_BFQQ_NAME_LENGTH);		\
1184 	blk_add_cgroup_trace_msg((bfqd)->queue,				\
1185 			&bfqg_to_blkg(bfqq_group(bfqq))->blkcg->css,	\
1186 			"%s " fmt, pid_str, ##args);			\
1187 } while (0)
1188 
1189 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...)	do {			\
1190 	blk_add_cgroup_trace_msg((bfqd)->queue,				\
1191 		&bfqg_to_blkg(bfqg)->blkcg->css, fmt, ##args);		\
1192 } while (0)
1193 
1194 #else /* CONFIG_BFQ_GROUP_IOSCHED */
1195 
1196 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do {	\
1197 	char pid_str[MAX_BFQQ_NAME_LENGTH];				\
1198 	if (likely(!blk_trace_note_message_enabled((bfqd)->queue)))	\
1199 		break;							\
1200 	bfq_bfqq_name((bfqq), pid_str, MAX_BFQQ_NAME_LENGTH);		\
1201 	blk_add_trace_msg((bfqd)->queue, "%s " fmt, pid_str, ##args);	\
1202 } while (0)
1203 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...)		do {} while (0)
1204 
1205 #endif /* CONFIG_BFQ_GROUP_IOSCHED */
1206 
1207 #define bfq_log(bfqd, fmt, args...) \
1208 	blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
1209 
1210 #endif /* _BFQ_H */
1211