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 in a hierarchical setup. 75 * 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+. 81 * 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. 97 */ 98 struct 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 queues 112 * with a given weight. 113 */ 114 struct bfq_weight_counter { 115 unsigned int weight; /* weight of the queues this counter refers to */ 116 unsigned int num_active; /* nr of active queues with this weight */ 117 /* 118 * Weights tree member (see bfq_data's @queue_weights_tree) 119 */ 120 struct rb_node weights_node; 121 }; 122 123 /** 124 * struct bfq_entity - schedulable entity. 125 * 126 * A bfq_entity is used to represent either a bfq_queue (leaf node in the 127 * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each 128 * entity belongs to the sched_data of the parent group in the cgroup 129 * hierarchy. Non-leaf entities have also their own sched_data, stored 130 * in @my_sched_data. 131 * 132 * Each entity stores independently its priority values; this would 133 * allow different weights on different devices, but this 134 * functionality is not exported to userspace by now. Priorities and 135 * weights are updated lazily, first storing the new values into the 136 * new_* fields, then setting the @prio_changed flag. As soon as 137 * there is a transition in the entity state that allows the priority 138 * update to take place the effective and the requested priority 139 * values are synchronized. 140 * 141 * Unless cgroups are used, the weight value is calculated from the 142 * ioprio to export the same interface as CFQ. When dealing with 143 * ``well-behaved'' queues (i.e., queues that do not spend too much 144 * time to consume their budget and have true sequential behavior, and 145 * when there are no external factors breaking anticipation) the 146 * relative weights at each level of the cgroups hierarchy should be 147 * guaranteed. All the fields are protected by the queue lock of the 148 * containing bfqd. 149 */ 150 struct bfq_entity { 151 /* service_tree member */ 152 struct rb_node rb_node; 153 154 /* 155 * Flag, true if the entity is on a tree (either the active or 156 * the idle one of its service_tree) or is in service. 157 */ 158 bool on_st; 159 160 /* B-WF2Q+ start and finish timestamps [sectors/weight] */ 161 u64 start, finish; 162 163 /* tree the entity is enqueued into; %NULL if not on a tree */ 164 struct rb_root *tree; 165 166 /* 167 * minimum start time of the (active) subtree rooted at this 168 * entity; used for O(log N) lookups into active trees 169 */ 170 u64 min_start; 171 172 /* amount of service received during the last service slot */ 173 int service; 174 175 /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */ 176 int budget; 177 178 /* weight of the queue */ 179 int weight; 180 /* next weight if a change is in progress */ 181 int new_weight; 182 183 /* original weight, used to implement weight boosting */ 184 int orig_weight; 185 186 /* parent entity, for hierarchical scheduling */ 187 struct bfq_entity *parent; 188 189 /* 190 * For non-leaf nodes in the hierarchy, the associated 191 * scheduler queue, %NULL on leaf nodes. 192 */ 193 struct bfq_sched_data *my_sched_data; 194 /* the scheduler queue this entity belongs to */ 195 struct bfq_sched_data *sched_data; 196 197 /* flag, set to request a weight, ioprio or ioprio_class change */ 198 int prio_changed; 199 }; 200 201 struct bfq_group; 202 203 /** 204 * struct bfq_ttime - per process thinktime stats. 205 */ 206 struct bfq_ttime { 207 /* completion time of the last request */ 208 u64 last_end_request; 209 210 /* total process thinktime */ 211 u64 ttime_total; 212 /* number of thinktime samples */ 213 unsigned long ttime_samples; 214 /* average process thinktime */ 215 u64 ttime_mean; 216 }; 217 218 /** 219 * struct bfq_queue - leaf schedulable entity. 220 * 221 * A bfq_queue is a leaf request queue; it can be associated with an 222 * io_context or more, if it is async or shared between cooperating 223 * processes. @cgroup holds a reference to the cgroup, to be sure that it 224 * does not disappear while a bfqq still references it (mostly to avoid 225 * races between request issuing and task migration followed by cgroup 226 * destruction). 227 * All the fields are protected by the queue lock of the containing bfqd. 228 */ 229 struct bfq_queue { 230 /* reference counter */ 231 int ref; 232 /* parent bfq_data */ 233 struct bfq_data *bfqd; 234 235 /* current ioprio and ioprio class */ 236 unsigned short ioprio, ioprio_class; 237 /* next ioprio and ioprio class if a change is in progress */ 238 unsigned short new_ioprio, new_ioprio_class; 239 240 /* 241 * Shared bfq_queue if queue is cooperating with one or more 242 * other queues. 243 */ 244 struct bfq_queue *new_bfqq; 245 /* request-position tree member (see bfq_group's @rq_pos_tree) */ 246 struct rb_node pos_node; 247 /* request-position tree root (see bfq_group's @rq_pos_tree) */ 248 struct rb_root *pos_root; 249 250 /* sorted list of pending requests */ 251 struct rb_root sort_list; 252 /* if fifo isn't expired, next request to serve */ 253 struct request *next_rq; 254 /* number of sync and async requests queued */ 255 int queued[2]; 256 /* number of requests currently allocated */ 257 int allocated; 258 /* number of pending metadata requests */ 259 int meta_pending; 260 /* fifo list of requests in sort_list */ 261 struct list_head fifo; 262 263 /* entity representing this queue in the scheduler */ 264 struct bfq_entity entity; 265 266 /* pointer to the weight counter associated with this entity */ 267 struct bfq_weight_counter *weight_counter; 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 * Cumulative service received from the @bfq_queue since its 342 * last transition to weight-raised state. 343 */ 344 unsigned long service_from_wr; 345 346 /* 347 * Value of wr start time when switching to soft rt 348 */ 349 unsigned long wr_start_at_switch_to_srt; 350 351 unsigned long split_time; /* time of last split */ 352 353 unsigned long first_IO_time; /* time of first I/O for this queue */ 354 355 /* max service rate measured so far */ 356 u32 max_service_rate; 357 /* 358 * Ratio between the service received by bfqq while it is in 359 * service, and the cumulative service (of requests of other 360 * queues) that may be injected while bfqq is empty but still 361 * in service. To increase precision, the coefficient is 362 * measured in tenths of unit. Here are some example of (1) 363 * ratios, (2) resulting percentages of service injected 364 * w.r.t. to the total service dispatched while bfqq is in 365 * service, and (3) corresponding values of the coefficient: 366 * 1 (50%) -> 10 367 * 2 (33%) -> 20 368 * 10 (9%) -> 100 369 * 9.9 (9%) -> 99 370 * 1.5 (40%) -> 15 371 * 0.5 (66%) -> 5 372 * 0.1 (90%) -> 1 373 * 374 * So, if the coefficient is lower than 10, then 375 * injected service is more than bfqq service. 376 */ 377 unsigned int inject_coeff; 378 /* amount of service injected in current service slot */ 379 unsigned int injected_service; 380 }; 381 382 /** 383 * struct bfq_io_cq - per (request_queue, io_context) structure. 384 */ 385 struct bfq_io_cq { 386 /* associated io_cq structure */ 387 struct io_cq icq; /* must be the first member */ 388 /* array of two process queues, the sync and the async */ 389 struct bfq_queue *bfqq[2]; 390 /* per (request_queue, blkcg) ioprio */ 391 int ioprio; 392 #ifdef CONFIG_BFQ_GROUP_IOSCHED 393 uint64_t blkcg_serial_nr; /* the current blkcg serial */ 394 #endif 395 /* 396 * Snapshot of the has_short_time flag before merging; taken 397 * to remember its value while the queue is merged, so as to 398 * be able to restore it in case of split. 399 */ 400 bool saved_has_short_ttime; 401 /* 402 * Same purpose as the previous two fields for the I/O bound 403 * classification of a queue. 404 */ 405 bool saved_IO_bound; 406 407 /* 408 * Same purpose as the previous fields for the value of the 409 * field keeping the queue's belonging to a large burst 410 */ 411 bool saved_in_large_burst; 412 /* 413 * True if the queue belonged to a burst list before its merge 414 * with another cooperating queue. 415 */ 416 bool was_in_burst_list; 417 418 /* 419 * Similar to previous fields: save wr information. 420 */ 421 unsigned long saved_wr_coeff; 422 unsigned long saved_last_wr_start_finish; 423 unsigned long saved_wr_start_at_switch_to_srt; 424 unsigned int saved_wr_cur_max_time; 425 struct bfq_ttime saved_ttime; 426 }; 427 428 /** 429 * struct bfq_data - per-device data structure. 430 * 431 * All the fields are protected by @lock. 432 */ 433 struct bfq_data { 434 /* device request queue */ 435 struct request_queue *queue; 436 /* dispatch queue */ 437 struct list_head dispatch; 438 439 /* root bfq_group for the device */ 440 struct bfq_group *root_group; 441 442 /* 443 * rbtree of weight counters of @bfq_queues, sorted by 444 * weight. Used to keep track of whether all @bfq_queues have 445 * the same weight. The tree contains one counter for each 446 * distinct weight associated to some active and not 447 * weight-raised @bfq_queue (see the comments to the functions 448 * bfq_weights_tree_[add|remove] for further details). 449 */ 450 struct rb_root queue_weights_tree; 451 /* 452 * number of groups with requests still waiting for completion 453 */ 454 unsigned int num_active_groups; 455 456 /* 457 * Number of bfq_queues containing requests (including the 458 * queue in service, even if it is idling). 459 */ 460 int busy_queues; 461 /* number of weight-raised busy @bfq_queues */ 462 int wr_busy_queues; 463 /* number of queued requests */ 464 int queued; 465 /* number of requests dispatched and waiting for completion */ 466 int rq_in_driver; 467 468 /* 469 * Maximum number of requests in driver in the last 470 * @hw_tag_samples completed requests. 471 */ 472 int max_rq_in_driver; 473 /* number of samples used to calculate hw_tag */ 474 int hw_tag_samples; 475 /* flag set to one if the driver is showing a queueing behavior */ 476 int hw_tag; 477 478 /* number of budgets assigned */ 479 int budgets_assigned; 480 481 /* 482 * Timer set when idling (waiting) for the next request from 483 * the queue in service. 484 */ 485 struct hrtimer idle_slice_timer; 486 487 /* bfq_queue in service */ 488 struct bfq_queue *in_service_queue; 489 490 /* on-disk position of the last served request */ 491 sector_t last_position; 492 493 /* time of last request completion (ns) */ 494 u64 last_completion; 495 496 /* time of first rq dispatch in current observation interval (ns) */ 497 u64 first_dispatch; 498 /* time of last rq dispatch in current observation interval (ns) */ 499 u64 last_dispatch; 500 501 /* beginning of the last budget */ 502 ktime_t last_budget_start; 503 /* beginning of the last idle slice */ 504 ktime_t last_idling_start; 505 506 /* number of samples in current observation interval */ 507 int peak_rate_samples; 508 /* num of samples of seq dispatches in current observation interval */ 509 u32 sequential_samples; 510 /* total num of sectors transferred in current observation interval */ 511 u64 tot_sectors_dispatched; 512 /* max rq size seen during current observation interval (sectors) */ 513 u32 last_rq_max_size; 514 /* time elapsed from first dispatch in current observ. interval (us) */ 515 u64 delta_from_first; 516 /* 517 * Current estimate of the device peak rate, measured in 518 * [(sectors/usec) / 2^BFQ_RATE_SHIFT]. The left-shift by 519 * BFQ_RATE_SHIFT is performed to increase precision in 520 * fixed-point calculations. 521 */ 522 u32 peak_rate; 523 524 /* maximum budget allotted to a bfq_queue before rescheduling */ 525 int bfq_max_budget; 526 527 /* list of all the bfq_queues active on the device */ 528 struct list_head active_list; 529 /* list of all the bfq_queues idle on the device */ 530 struct list_head idle_list; 531 532 /* 533 * Timeout for async/sync requests; when it fires, requests 534 * are served in fifo order. 535 */ 536 u64 bfq_fifo_expire[2]; 537 /* weight of backward seeks wrt forward ones */ 538 unsigned int bfq_back_penalty; 539 /* maximum allowed backward seek */ 540 unsigned int bfq_back_max; 541 /* maximum idling time */ 542 u32 bfq_slice_idle; 543 544 /* user-configured max budget value (0 for auto-tuning) */ 545 int bfq_user_max_budget; 546 /* 547 * Timeout for bfq_queues to consume their budget; used to 548 * prevent seeky queues from imposing long latencies to 549 * sequential or quasi-sequential ones (this also implies that 550 * seeky queues cannot receive guarantees in the service 551 * domain; after a timeout they are charged for the time they 552 * have been in service, to preserve fairness among them, but 553 * without service-domain guarantees). 554 */ 555 unsigned int bfq_timeout; 556 557 /* 558 * Number of consecutive requests that must be issued within 559 * the idle time slice to set again idling to a queue which 560 * was marked as non-I/O-bound (see the definition of the 561 * IO_bound flag for further details). 562 */ 563 unsigned int bfq_requests_within_timer; 564 565 /* 566 * Force device idling whenever needed to provide accurate 567 * service guarantees, without caring about throughput 568 * issues. CAVEAT: this may even increase latencies, in case 569 * of useless idling for processes that did stop doing I/O. 570 */ 571 bool strict_guarantees; 572 573 /* 574 * Last time at which a queue entered the current burst of 575 * queues being activated shortly after each other; for more 576 * details about this and the following parameters related to 577 * a burst of activations, see the comments on the function 578 * bfq_handle_burst. 579 */ 580 unsigned long last_ins_in_burst; 581 /* 582 * Reference time interval used to decide whether a queue has 583 * been activated shortly after @last_ins_in_burst. 584 */ 585 unsigned long bfq_burst_interval; 586 /* number of queues in the current burst of queue activations */ 587 int burst_size; 588 589 /* common parent entity for the queues in the burst */ 590 struct bfq_entity *burst_parent_entity; 591 /* Maximum burst size above which the current queue-activation 592 * burst is deemed as 'large'. 593 */ 594 unsigned long bfq_large_burst_thresh; 595 /* true if a large queue-activation burst is in progress */ 596 bool large_burst; 597 /* 598 * Head of the burst list (as for the above fields, more 599 * details in the comments on the function bfq_handle_burst). 600 */ 601 struct hlist_head burst_list; 602 603 /* if set to true, low-latency heuristics are enabled */ 604 bool low_latency; 605 /* 606 * Maximum factor by which the weight of a weight-raised queue 607 * is multiplied. 608 */ 609 unsigned int bfq_wr_coeff; 610 /* maximum duration of a weight-raising period (jiffies) */ 611 unsigned int bfq_wr_max_time; 612 613 /* Maximum weight-raising duration for soft real-time processes */ 614 unsigned int bfq_wr_rt_max_time; 615 /* 616 * Minimum idle period after which weight-raising may be 617 * reactivated for a queue (in jiffies). 618 */ 619 unsigned int bfq_wr_min_idle_time; 620 /* 621 * Minimum period between request arrivals after which 622 * weight-raising may be reactivated for an already busy async 623 * queue (in jiffies). 624 */ 625 unsigned long bfq_wr_min_inter_arr_async; 626 627 /* Max service-rate for a soft real-time queue, in sectors/sec */ 628 unsigned int bfq_wr_max_softrt_rate; 629 /* 630 * Cached value of the product ref_rate*ref_wr_duration, used 631 * for computing the maximum duration of weight raising 632 * automatically. 633 */ 634 u64 rate_dur_prod; 635 636 /* fallback dummy bfqq for extreme OOM conditions */ 637 struct bfq_queue oom_bfqq; 638 639 spinlock_t lock; 640 641 /* 642 * bic associated with the task issuing current bio for 643 * merging. This and the next field are used as a support to 644 * be able to perform the bic lookup, needed by bio-merge 645 * functions, before the scheduler lock is taken, and thus 646 * avoid taking the request-queue lock while the scheduler 647 * lock is being held. 648 */ 649 struct bfq_io_cq *bio_bic; 650 /* bfqq associated with the task issuing current bio for merging */ 651 struct bfq_queue *bio_bfqq; 652 653 /* 654 * Depth limits used in bfq_limit_depth (see comments on the 655 * function) 656 */ 657 unsigned int word_depths[2][2]; 658 }; 659 660 enum bfqq_state_flags { 661 BFQQF_just_created = 0, /* queue just allocated */ 662 BFQQF_busy, /* has requests or is in service */ 663 BFQQF_wait_request, /* waiting for a request */ 664 BFQQF_non_blocking_wait_rq, /* 665 * waiting for a request 666 * without idling the device 667 */ 668 BFQQF_fifo_expire, /* FIFO checked in this slice */ 669 BFQQF_has_short_ttime, /* queue has a short think time */ 670 BFQQF_sync, /* synchronous queue */ 671 BFQQF_IO_bound, /* 672 * bfqq has timed-out at least once 673 * having consumed at most 2/10 of 674 * its budget 675 */ 676 BFQQF_in_large_burst, /* 677 * bfqq activated in a large burst, 678 * see comments to bfq_handle_burst. 679 */ 680 BFQQF_softrt_update, /* 681 * may need softrt-next-start 682 * update 683 */ 684 BFQQF_coop, /* bfqq is shared */ 685 BFQQF_split_coop /* shared bfqq will be split */ 686 }; 687 688 #define BFQ_BFQQ_FNS(name) \ 689 void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \ 690 void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \ 691 int bfq_bfqq_##name(const struct bfq_queue *bfqq); 692 693 BFQ_BFQQ_FNS(just_created); 694 BFQ_BFQQ_FNS(busy); 695 BFQ_BFQQ_FNS(wait_request); 696 BFQ_BFQQ_FNS(non_blocking_wait_rq); 697 BFQ_BFQQ_FNS(fifo_expire); 698 BFQ_BFQQ_FNS(has_short_ttime); 699 BFQ_BFQQ_FNS(sync); 700 BFQ_BFQQ_FNS(IO_bound); 701 BFQ_BFQQ_FNS(in_large_burst); 702 BFQ_BFQQ_FNS(coop); 703 BFQ_BFQQ_FNS(split_coop); 704 BFQ_BFQQ_FNS(softrt_update); 705 #undef BFQ_BFQQ_FNS 706 707 /* Expiration reasons. */ 708 enum bfqq_expiration { 709 BFQQE_TOO_IDLE = 0, /* 710 * queue has been idling for 711 * too long 712 */ 713 BFQQE_BUDGET_TIMEOUT, /* budget took too long to be used */ 714 BFQQE_BUDGET_EXHAUSTED, /* budget consumed */ 715 BFQQE_NO_MORE_REQUESTS, /* the queue has no more requests */ 716 BFQQE_PREEMPTED /* preemption in progress */ 717 }; 718 719 struct bfqg_stats { 720 #if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP) 721 /* number of ios merged */ 722 struct blkg_rwstat merged; 723 /* total time spent on device in ns, may not be accurate w/ queueing */ 724 struct blkg_rwstat service_time; 725 /* total time spent waiting in scheduler queue in ns */ 726 struct blkg_rwstat wait_time; 727 /* number of IOs queued up */ 728 struct blkg_rwstat queued; 729 /* total disk time and nr sectors dispatched by this group */ 730 struct blkg_stat time; 731 /* sum of number of ios queued across all samples */ 732 struct blkg_stat avg_queue_size_sum; 733 /* count of samples taken for average */ 734 struct blkg_stat avg_queue_size_samples; 735 /* how many times this group has been removed from service tree */ 736 struct blkg_stat dequeue; 737 /* total time spent waiting for it to be assigned a timeslice. */ 738 struct blkg_stat group_wait_time; 739 /* time spent idling for this blkcg_gq */ 740 struct blkg_stat idle_time; 741 /* total time with empty current active q with other requests queued */ 742 struct blkg_stat empty_time; 743 /* fields after this shouldn't be cleared on stat reset */ 744 u64 start_group_wait_time; 745 u64 start_idle_time; 746 u64 start_empty_time; 747 uint16_t flags; 748 #endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ 749 }; 750 751 #ifdef CONFIG_BFQ_GROUP_IOSCHED 752 753 /* 754 * struct bfq_group_data - per-blkcg storage for the blkio subsystem. 755 * 756 * @ps: @blkcg_policy_storage that this structure inherits 757 * @weight: weight of the bfq_group 758 */ 759 struct bfq_group_data { 760 /* must be the first member */ 761 struct blkcg_policy_data pd; 762 763 unsigned int weight; 764 }; 765 766 /** 767 * struct bfq_group - per (device, cgroup) data structure. 768 * @entity: schedulable entity to insert into the parent group sched_data. 769 * @sched_data: own sched_data, to contain child entities (they may be 770 * both bfq_queues and bfq_groups). 771 * @bfqd: the bfq_data for the device this group acts upon. 772 * @async_bfqq: array of async queues for all the tasks belonging to 773 * the group, one queue per ioprio value per ioprio_class, 774 * except for the idle class that has only one queue. 775 * @async_idle_bfqq: async queue for the idle class (ioprio is ignored). 776 * @my_entity: pointer to @entity, %NULL for the toplevel group; used 777 * to avoid too many special cases during group creation/ 778 * migration. 779 * @stats: stats for this bfqg. 780 * @active_entities: number of active entities belonging to the group; 781 * unused for the root group. Used to know whether there 782 * are groups with more than one active @bfq_entity 783 * (see the comments to the function 784 * bfq_bfqq_may_idle()). 785 * @rq_pos_tree: rbtree sorted by next_request position, used when 786 * determining if two or more queues have interleaving 787 * requests (see bfq_find_close_cooperator()). 788 * 789 * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup 790 * there is a set of bfq_groups, each one collecting the lower-level 791 * entities belonging to the group that are acting on the same device. 792 * 793 * Locking works as follows: 794 * o @bfqd is protected by the queue lock, RCU is used to access it 795 * from the readers. 796 * o All the other fields are protected by the @bfqd queue lock. 797 */ 798 struct bfq_group { 799 /* must be the first member */ 800 struct blkg_policy_data pd; 801 802 /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */ 803 char blkg_path[128]; 804 805 /* reference counter (see comments in bfq_bic_update_cgroup) */ 806 int ref; 807 808 struct bfq_entity entity; 809 struct bfq_sched_data sched_data; 810 811 void *bfqd; 812 813 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; 814 struct bfq_queue *async_idle_bfqq; 815 816 struct bfq_entity *my_entity; 817 818 int active_entities; 819 820 struct rb_root rq_pos_tree; 821 822 struct bfqg_stats stats; 823 }; 824 825 #else 826 struct bfq_group { 827 struct bfq_sched_data sched_data; 828 829 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; 830 struct bfq_queue *async_idle_bfqq; 831 832 struct rb_root rq_pos_tree; 833 }; 834 #endif 835 836 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); 837 838 /* --------------- main algorithm interface ----------------- */ 839 840 #define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ 841 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) 842 843 extern const int bfq_timeout; 844 845 struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync); 846 void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync); 847 struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic); 848 void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); 849 void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq, 850 struct rb_root *root); 851 void __bfq_weights_tree_remove(struct bfq_data *bfqd, 852 struct bfq_queue *bfqq, 853 struct rb_root *root); 854 void bfq_weights_tree_remove(struct bfq_data *bfqd, 855 struct bfq_queue *bfqq); 856 void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, 857 bool compensate, enum bfqq_expiration reason); 858 void bfq_put_queue(struct bfq_queue *bfqq); 859 void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); 860 void bfq_schedule_dispatch(struct bfq_data *bfqd); 861 void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); 862 863 /* ------------ end of main algorithm interface -------------- */ 864 865 /* ---------------- cgroups-support interface ---------------- */ 866 867 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, 868 unsigned int op); 869 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op); 870 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op); 871 void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, 872 u64 io_start_time_ns, unsigned int op); 873 void bfqg_stats_update_dequeue(struct bfq_group *bfqg); 874 void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); 875 void bfqg_stats_update_idle_time(struct bfq_group *bfqg); 876 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg); 877 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg); 878 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, 879 struct bfq_group *bfqg); 880 881 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg); 882 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio); 883 void bfq_end_wr_async(struct bfq_data *bfqd); 884 struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, 885 struct blkcg *blkcg); 886 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); 887 struct bfq_group *bfqq_group(struct bfq_queue *bfqq); 888 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node); 889 void bfqg_and_blkg_put(struct bfq_group *bfqg); 890 891 #ifdef CONFIG_BFQ_GROUP_IOSCHED 892 extern struct cftype bfq_blkcg_legacy_files[]; 893 extern struct cftype bfq_blkg_files[]; 894 extern struct blkcg_policy blkcg_policy_bfq; 895 #endif 896 897 /* ------------- end of cgroups-support interface ------------- */ 898 899 /* - interface of the internal hierarchical B-WF2Q+ scheduler - */ 900 901 #ifdef CONFIG_BFQ_GROUP_IOSCHED 902 /* both next loops stop at one of the child entities of the root group */ 903 #define for_each_entity(entity) \ 904 for (; entity ; entity = entity->parent) 905 906 /* 907 * For each iteration, compute parent in advance, so as to be safe if 908 * entity is deallocated during the iteration. Such a deallocation may 909 * happen as a consequence of a bfq_put_queue that frees the bfq_queue 910 * containing entity. 911 */ 912 #define for_each_entity_safe(entity, parent) \ 913 for (; entity && ({ parent = entity->parent; 1; }); entity = parent) 914 915 #else /* CONFIG_BFQ_GROUP_IOSCHED */ 916 /* 917 * Next two macros are fake loops when cgroups support is not 918 * enabled. I fact, in such a case, there is only one level to go up 919 * (to reach the root group). 920 */ 921 #define for_each_entity(entity) \ 922 for (; entity ; entity = NULL) 923 924 #define for_each_entity_safe(entity, parent) \ 925 for (parent = NULL; entity ; entity = parent) 926 #endif /* CONFIG_BFQ_GROUP_IOSCHED */ 927 928 struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq); 929 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); 930 struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity); 931 struct bfq_entity *bfq_entity_of(struct rb_node *node); 932 unsigned short bfq_ioprio_to_weight(int ioprio); 933 void bfq_put_idle_entity(struct bfq_service_tree *st, 934 struct bfq_entity *entity); 935 struct bfq_service_tree * 936 __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, 937 struct bfq_entity *entity, 938 bool update_class_too); 939 void bfq_bfqq_served(struct bfq_queue *bfqq, int served); 940 void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, 941 unsigned long time_ms); 942 bool __bfq_deactivate_entity(struct bfq_entity *entity, 943 bool ins_into_idle_tree); 944 bool next_queue_may_preempt(struct bfq_data *bfqd); 945 struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd); 946 void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd); 947 void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, 948 bool ins_into_idle_tree, bool expiration); 949 void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); 950 void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, 951 bool expiration); 952 void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, 953 bool expiration); 954 void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); 955 956 /* --------------- end of interface of B-WF2Q+ ---------------- */ 957 958 /* Logging facilities. */ 959 #ifdef CONFIG_BFQ_GROUP_IOSCHED 960 struct bfq_group *bfqq_group(struct bfq_queue *bfqq); 961 962 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ 963 blk_add_cgroup_trace_msg((bfqd)->queue, \ 964 bfqg_to_blkg(bfqq_group(bfqq))->blkcg, \ 965 "bfq%d%c " fmt, (bfqq)->pid, \ 966 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args); \ 967 } while (0) 968 969 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ 970 blk_add_cgroup_trace_msg((bfqd)->queue, \ 971 bfqg_to_blkg(bfqg)->blkcg, fmt, ##args); \ 972 } while (0) 973 974 #else /* CONFIG_BFQ_GROUP_IOSCHED */ 975 976 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ 977 blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \ 978 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ 979 ##args) 980 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) 981 982 #endif /* CONFIG_BFQ_GROUP_IOSCHED */ 983 984 #define bfq_log(bfqd, fmt, args...) \ 985 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) 986 987 #endif /* _BFQ_H */ 988