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1 | /* |
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 | ||
42 | struct 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 | */ | |
52 | struct bfq_service_tree { | |
53 | /* tree for active entities (i.e., those backlogged) */ | |
54 | struct rb_root active; | |
55 | /* tree for idle entities (i.e., not backlogged, with V <= F_i)*/ | |
56 | 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 | */ | |
86 | struct 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 | */ | |
102 | struct 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 | */ | |
139 | struct 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 | ||
192 | struct bfq_group; | |
193 | ||
194 | /** | |
195 | * struct bfq_ttime - per process thinktime stats. | |
196 | */ | |
197 | struct 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 | */ | |
220 | struct 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 | */ | |
340 | struct 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 | ||
383 | enum 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 | */ | |
393 | struct 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 | ||
620 | enum 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) \ | |
649 | void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \ | |
650 | void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \ | |
651 | int bfq_bfqq_##name(const struct bfq_queue *bfqq); | |
652 | ||
653 | BFQ_BFQQ_FNS(just_created); | |
654 | BFQ_BFQQ_FNS(busy); | |
655 | BFQ_BFQQ_FNS(wait_request); | |
656 | BFQ_BFQQ_FNS(non_blocking_wait_rq); | |
657 | BFQ_BFQQ_FNS(fifo_expire); | |
658 | BFQ_BFQQ_FNS(idle_window); | |
659 | BFQ_BFQQ_FNS(sync); | |
660 | BFQ_BFQQ_FNS(IO_bound); | |
661 | BFQ_BFQQ_FNS(in_large_burst); | |
662 | BFQ_BFQQ_FNS(coop); | |
663 | BFQ_BFQQ_FNS(split_coop); | |
664 | BFQ_BFQQ_FNS(softrt_update); | |
665 | #undef BFQ_BFQQ_FNS | |
666 | ||
667 | /* Expiration reasons. */ | |
668 | enum 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 | ||
679 | struct 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 | */ | |
719 | struct 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 | */ | |
758 | struct bfq_group { | |
759 | /* must be the first member */ | |
760 | struct blkg_policy_data pd; | |
761 | ||
8f9bebc3 PV |
762 | /* 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 | ||
ea25da48 PV |
768 | 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 | |
786 | struct 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 | ||
796 | struct 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 | ||
803 | extern const int bfq_timeout; | |
804 | ||
805 | struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync); | |
806 | void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync); | |
807 | struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic); | |
808 | void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); | |
809 | void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); | |
810 | void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_entity *entity, | |
811 | struct rb_root *root); | |
812 | void bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_entity *entity, | |
813 | struct rb_root *root); | |
814 | void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
815 | bool compensate, enum bfqq_expiration reason); | |
816 | void bfq_put_queue(struct bfq_queue *bfqq); | |
817 | void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); | |
818 | void bfq_schedule_dispatch(struct bfq_data *bfqd); | |
819 | void 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 | ||
ea25da48 PV |
825 | void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, |
826 | unsigned int op); | |
827 | void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op); | |
828 | void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op); | |
829 | void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time, | |
830 | uint64_t io_start_time, unsigned int op); | |
831 | void bfqg_stats_update_dequeue(struct bfq_group *bfqg); | |
832 | void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); | |
833 | void bfqg_stats_update_idle_time(struct bfq_group *bfqg); | |
834 | void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg); | |
835 | void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg); | |
836 | void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
837 | struct bfq_group *bfqg); | |
838 | ||
839 | void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg); | |
840 | void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio); | |
841 | void bfq_end_wr_async(struct bfq_data *bfqd); | |
842 | struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, | |
843 | struct blkcg *blkcg); | |
844 | struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); | |
845 | struct bfq_group *bfqq_group(struct bfq_queue *bfqq); | |
846 | struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node); | |
8f9bebc3 | 847 | void bfqg_and_blkg_put(struct bfq_group *bfqg); |
ea25da48 PV |
848 | |
849 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
659b3394 JA |
850 | extern struct cftype bfq_blkcg_legacy_files[]; |
851 | extern struct cftype bfq_blkg_files[]; | |
ea25da48 PV |
852 | extern 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 | ||
886 | struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq); | |
887 | struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); | |
888 | struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity); | |
889 | struct bfq_entity *bfq_entity_of(struct rb_node *node); | |
890 | unsigned short bfq_ioprio_to_weight(int ioprio); | |
891 | void bfq_put_idle_entity(struct bfq_service_tree *st, | |
892 | struct bfq_entity *entity); | |
893 | struct bfq_service_tree * | |
894 | __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, | |
895 | struct bfq_entity *entity); | |
896 | void bfq_bfqq_served(struct bfq_queue *bfqq, int served); | |
897 | void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
898 | unsigned long time_ms); | |
899 | bool __bfq_deactivate_entity(struct bfq_entity *entity, | |
900 | bool ins_into_idle_tree); | |
901 | bool next_queue_may_preempt(struct bfq_data *bfqd); | |
902 | struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd); | |
903 | void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd); | |
904 | void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
905 | bool ins_into_idle_tree, bool expiration); | |
906 | void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); | |
907 | void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); | |
908 | void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
909 | bool expiration); | |
910 | void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); | |
911 | ||
912 | /* --------------- end of interface of B-WF2Q+ ---------------- */ | |
913 | ||
914 | /* Logging facilities. */ | |
915 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
916 | struct bfq_group *bfqq_group(struct bfq_queue *bfqq); | |
917 | ||
918 | #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ | |
8f9bebc3 | 919 | blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid,\ |
ea25da48 | 920 | bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ |
8f9bebc3 | 921 | bfqq_group(bfqq)->blkg_path, ##args); \ |
ea25da48 PV |
922 | } while (0) |
923 | ||
8f9bebc3 PV |
924 | #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) \ |
925 | blk_add_trace_msg((bfqd)->queue, "%s " fmt, (bfqg)->blkg_path, ##args) | |
ea25da48 PV |
926 | |
927 | #else /* CONFIG_BFQ_GROUP_IOSCHED */ | |
928 | ||
929 | #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ | |
930 | blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \ | |
931 | bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ | |
932 | ##args) | |
933 | #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) | |
934 | ||
935 | #endif /* CONFIG_BFQ_GROUP_IOSCHED */ | |
936 | ||
937 | #define bfq_log(bfqd, fmt, args...) \ | |
938 | blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) | |
939 | ||
940 | #endif /* _BFQ_H */ |