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 entities 112 * with a given weight. 113 */ 114 struct bfq_weight_counter { 115 unsigned int weight; /* weight of the entities this counter refers to */ 116 unsigned int num_active; /* nr of active entities with this weight */ 117 /* 118 * Weights tree member (see bfq_data's @queue_weights_tree and 119 * @group_weights_tree) 120 */ 121 struct rb_node weights_node; 122 }; 123 124 /** 125 * struct bfq_entity - schedulable entity. 126 * 127 * A bfq_entity is used to represent either a bfq_queue (leaf node in the 128 * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each 129 * entity belongs to the sched_data of the parent group in the cgroup 130 * hierarchy. Non-leaf entities have also their own sched_data, stored 131 * in @my_sched_data. 132 * 133 * Each entity stores independently its priority values; this would 134 * allow different weights on different devices, but this 135 * functionality is not exported to userspace by now. Priorities and 136 * weights are updated lazily, first storing the new values into the 137 * new_* fields, then setting the @prio_changed flag. As soon as 138 * there is a transition in the entity state that allows the priority 139 * update to take place the effective and the requested priority 140 * values are synchronized. 141 * 142 * Unless cgroups are used, the weight value is calculated from the 143 * ioprio to export the same interface as CFQ. When dealing with 144 * ``well-behaved'' queues (i.e., queues that do not spend too much 145 * time to consume their budget and have true sequential behavior, and 146 * when there are no external factors breaking anticipation) the 147 * relative weights at each level of the cgroups hierarchy should be 148 * guaranteed. All the fields are protected by the queue lock of the 149 * containing bfqd. 150 */ 151 struct bfq_entity { 152 /* service_tree member */ 153 struct rb_node rb_node; 154 /* pointer to the weight counter associated with this entity */ 155 struct bfq_weight_counter *weight_counter; 156 157 /* 158 * Flag, true if the entity is on a tree (either the active or 159 * the idle one of its service_tree) or is in service. 160 */ 161 bool on_st; 162 163 /* B-WF2Q+ start and finish timestamps [sectors/weight] */ 164 u64 start, finish; 165 166 /* tree the entity is enqueued into; %NULL if not on a tree */ 167 struct rb_root *tree; 168 169 /* 170 * minimum start time of the (active) subtree rooted at this 171 * entity; used for O(log N) lookups into active trees 172 */ 173 u64 min_start; 174 175 /* amount of service received during the last service slot */ 176 int service; 177 178 /* budget, used also to calculate F_i: F_i = S_i + @budget / @weight */ 179 int budget; 180 181 /* weight of the queue */ 182 int weight; 183 /* next weight if a change is in progress */ 184 int new_weight; 185 186 /* original weight, used to implement weight boosting */ 187 int orig_weight; 188 189 /* parent entity, for hierarchical scheduling */ 190 struct bfq_entity *parent; 191 192 /* 193 * For non-leaf nodes in the hierarchy, the associated 194 * scheduler queue, %NULL on leaf nodes. 195 */ 196 struct bfq_sched_data *my_sched_data; 197 /* the scheduler queue this entity belongs to */ 198 struct bfq_sched_data *sched_data; 199 200 /* flag, set to request a weight, ioprio or ioprio_class change */ 201 int prio_changed; 202 }; 203 204 struct bfq_group; 205 206 /** 207 * struct bfq_ttime - per process thinktime stats. 208 */ 209 struct bfq_ttime { 210 /* completion time of the last request */ 211 u64 last_end_request; 212 213 /* total process thinktime */ 214 u64 ttime_total; 215 /* number of thinktime samples */ 216 unsigned long ttime_samples; 217 /* average process thinktime */ 218 u64 ttime_mean; 219 }; 220 221 /** 222 * struct bfq_queue - leaf schedulable entity. 223 * 224 * A bfq_queue is a leaf request queue; it can be associated with an 225 * io_context or more, if it is async or shared between cooperating 226 * processes. @cgroup holds a reference to the cgroup, to be sure that it 227 * does not disappear while a bfqq still references it (mostly to avoid 228 * races between request issuing and task migration followed by cgroup 229 * destruction). 230 * All the fields are protected by the queue lock of the containing bfqd. 231 */ 232 struct bfq_queue { 233 /* reference counter */ 234 int ref; 235 /* parent bfq_data */ 236 struct bfq_data *bfqd; 237 238 /* current ioprio and ioprio class */ 239 unsigned short ioprio, ioprio_class; 240 /* next ioprio and ioprio class if a change is in progress */ 241 unsigned short new_ioprio, new_ioprio_class; 242 243 /* 244 * Shared bfq_queue if queue is cooperating with one or more 245 * other queues. 246 */ 247 struct bfq_queue *new_bfqq; 248 /* request-position tree member (see bfq_group's @rq_pos_tree) */ 249 struct rb_node pos_node; 250 /* request-position tree root (see bfq_group's @rq_pos_tree) */ 251 struct rb_root *pos_root; 252 253 /* sorted list of pending requests */ 254 struct rb_root sort_list; 255 /* if fifo isn't expired, next request to serve */ 256 struct request *next_rq; 257 /* number of sync and async requests queued */ 258 int queued[2]; 259 /* number of requests currently allocated */ 260 int allocated; 261 /* number of pending metadata requests */ 262 int meta_pending; 263 /* fifo list of requests in sort_list */ 264 struct list_head fifo; 265 266 /* entity representing this queue in the scheduler */ 267 struct bfq_entity entity; 268 269 /* maximum budget allowed from the feedback mechanism */ 270 int max_budget; 271 /* budget expiration (in jiffies) */ 272 unsigned long budget_timeout; 273 274 /* number of requests on the dispatch list or inside driver */ 275 int dispatched; 276 277 /* status flags */ 278 unsigned long flags; 279 280 /* node for active/idle bfqq list inside parent bfqd */ 281 struct list_head bfqq_list; 282 283 /* associated @bfq_ttime struct */ 284 struct bfq_ttime ttime; 285 286 /* bit vector: a 1 for each seeky requests in history */ 287 u32 seek_history; 288 289 /* node for the device's burst list */ 290 struct hlist_node burst_list_node; 291 292 /* position of the last request enqueued */ 293 sector_t last_request_pos; 294 295 /* Number of consecutive pairs of request completion and 296 * arrival, such that the queue becomes idle after the 297 * completion, but the next request arrives within an idle 298 * time slice; used only if the queue's IO_bound flag has been 299 * cleared. 300 */ 301 unsigned int requests_within_timer; 302 303 /* pid of the process owning the queue, used for logging purposes */ 304 pid_t pid; 305 306 /* 307 * Pointer to the bfq_io_cq owning the bfq_queue, set to %NULL 308 * if the queue is shared. 309 */ 310 struct bfq_io_cq *bic; 311 312 /* current maximum weight-raising time for this queue */ 313 unsigned long wr_cur_max_time; 314 /* 315 * Minimum time instant such that, only if a new request is 316 * enqueued after this time instant in an idle @bfq_queue with 317 * no outstanding requests, then the task associated with the 318 * queue it is deemed as soft real-time (see the comments on 319 * the function bfq_bfqq_softrt_next_start()) 320 */ 321 unsigned long soft_rt_next_start; 322 /* 323 * Start time of the current weight-raising period if 324 * the @bfq-queue is being weight-raised, otherwise 325 * finish time of the last weight-raising period. 326 */ 327 unsigned long last_wr_start_finish; 328 /* factor by which the weight of this queue is multiplied */ 329 unsigned int wr_coeff; 330 /* 331 * Time of the last transition of the @bfq_queue from idle to 332 * backlogged. 333 */ 334 unsigned long last_idle_bklogged; 335 /* 336 * Cumulative service received from the @bfq_queue since the 337 * last transition from idle to backlogged. 338 */ 339 unsigned long service_from_backlogged; 340 /* 341 * 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 }; 355 356 /** 357 * struct bfq_io_cq - per (request_queue, io_context) structure. 358 */ 359 struct bfq_io_cq { 360 /* associated io_cq structure */ 361 struct io_cq icq; /* must be the first member */ 362 /* array of two process queues, the sync and the async */ 363 struct bfq_queue *bfqq[2]; 364 /* per (request_queue, blkcg) ioprio */ 365 int ioprio; 366 #ifdef CONFIG_BFQ_GROUP_IOSCHED 367 uint64_t blkcg_serial_nr; /* the current blkcg serial */ 368 #endif 369 /* 370 * Snapshot of the has_short_time flag before merging; taken 371 * to remember its value while the queue is merged, so as to 372 * be able to restore it in case of split. 373 */ 374 bool saved_has_short_ttime; 375 /* 376 * Same purpose as the previous two fields for the I/O bound 377 * classification of a queue. 378 */ 379 bool saved_IO_bound; 380 381 /* 382 * Same purpose as the previous fields for the value of the 383 * field keeping the queue's belonging to a large burst 384 */ 385 bool saved_in_large_burst; 386 /* 387 * True if the queue belonged to a burst list before its merge 388 * with another cooperating queue. 389 */ 390 bool was_in_burst_list; 391 392 /* 393 * Similar to previous fields: save wr information. 394 */ 395 unsigned long saved_wr_coeff; 396 unsigned long saved_last_wr_start_finish; 397 unsigned long saved_wr_start_at_switch_to_srt; 398 unsigned int saved_wr_cur_max_time; 399 struct bfq_ttime saved_ttime; 400 }; 401 402 /** 403 * struct bfq_data - per-device data structure. 404 * 405 * All the fields are protected by @lock. 406 */ 407 struct bfq_data { 408 /* device request queue */ 409 struct request_queue *queue; 410 /* dispatch queue */ 411 struct list_head dispatch; 412 413 /* root bfq_group for the device */ 414 struct bfq_group *root_group; 415 416 /* 417 * rbtree of weight counters of @bfq_queues, sorted by 418 * weight. Used to keep track of whether all @bfq_queues have 419 * the same weight. The tree contains one counter for each 420 * distinct weight associated to some active and not 421 * weight-raised @bfq_queue (see the comments to the functions 422 * bfq_weights_tree_[add|remove] for further details). 423 */ 424 struct rb_root queue_weights_tree; 425 /* 426 * rbtree of non-queue @bfq_entity weight counters, sorted by 427 * weight. Used to keep track of whether all @bfq_groups have 428 * the same weight. The tree contains one counter for each 429 * distinct weight associated to some active @bfq_group (see 430 * the comments to the functions bfq_weights_tree_[add|remove] 431 * for further details). 432 */ 433 struct rb_root group_weights_tree; 434 435 /* 436 * Number of bfq_queues containing requests (including the 437 * queue in service, even if it is idling). 438 */ 439 int busy_queues; 440 /* number of weight-raised busy @bfq_queues */ 441 int wr_busy_queues; 442 /* number of queued requests */ 443 int queued; 444 /* number of requests dispatched and waiting for completion */ 445 int rq_in_driver; 446 447 /* 448 * Maximum number of requests in driver in the last 449 * @hw_tag_samples completed requests. 450 */ 451 int max_rq_in_driver; 452 /* number of samples used to calculate hw_tag */ 453 int hw_tag_samples; 454 /* flag set to one if the driver is showing a queueing behavior */ 455 int hw_tag; 456 457 /* number of budgets assigned */ 458 int budgets_assigned; 459 460 /* 461 * Timer set when idling (waiting) for the next request from 462 * the queue in service. 463 */ 464 struct hrtimer idle_slice_timer; 465 466 /* bfq_queue in service */ 467 struct bfq_queue *in_service_queue; 468 469 /* on-disk position of the last served request */ 470 sector_t last_position; 471 472 /* time of last request completion (ns) */ 473 u64 last_completion; 474 475 /* time of first rq dispatch in current observation interval (ns) */ 476 u64 first_dispatch; 477 /* time of last rq dispatch in current observation interval (ns) */ 478 u64 last_dispatch; 479 480 /* beginning of the last budget */ 481 ktime_t last_budget_start; 482 /* beginning of the last idle slice */ 483 ktime_t last_idling_start; 484 485 /* number of samples in current observation interval */ 486 int peak_rate_samples; 487 /* num of samples of seq dispatches in current observation interval */ 488 u32 sequential_samples; 489 /* total num of sectors transferred in current observation interval */ 490 u64 tot_sectors_dispatched; 491 /* max rq size seen during current observation interval (sectors) */ 492 u32 last_rq_max_size; 493 /* time elapsed from first dispatch in current observ. interval (us) */ 494 u64 delta_from_first; 495 /* 496 * Current estimate of the device peak rate, measured in 497 * [(sectors/usec) / 2^BFQ_RATE_SHIFT]. The left-shift by 498 * BFQ_RATE_SHIFT is performed to increase precision in 499 * fixed-point calculations. 500 */ 501 u32 peak_rate; 502 503 /* maximum budget allotted to a bfq_queue before rescheduling */ 504 int bfq_max_budget; 505 506 /* list of all the bfq_queues active on the device */ 507 struct list_head active_list; 508 /* list of all the bfq_queues idle on the device */ 509 struct list_head idle_list; 510 511 /* 512 * Timeout for async/sync requests; when it fires, requests 513 * are served in fifo order. 514 */ 515 u64 bfq_fifo_expire[2]; 516 /* weight of backward seeks wrt forward ones */ 517 unsigned int bfq_back_penalty; 518 /* maximum allowed backward seek */ 519 unsigned int bfq_back_max; 520 /* maximum idling time */ 521 u32 bfq_slice_idle; 522 523 /* user-configured max budget value (0 for auto-tuning) */ 524 int bfq_user_max_budget; 525 /* 526 * Timeout for bfq_queues to consume their budget; used to 527 * prevent seeky queues from imposing long latencies to 528 * sequential or quasi-sequential ones (this also implies that 529 * seeky queues cannot receive guarantees in the service 530 * domain; after a timeout they are charged for the time they 531 * have been in service, to preserve fairness among them, but 532 * without service-domain guarantees). 533 */ 534 unsigned int bfq_timeout; 535 536 /* 537 * Number of consecutive requests that must be issued within 538 * the idle time slice to set again idling to a queue which 539 * was marked as non-I/O-bound (see the definition of the 540 * IO_bound flag for further details). 541 */ 542 unsigned int bfq_requests_within_timer; 543 544 /* 545 * Force device idling whenever needed to provide accurate 546 * service guarantees, without caring about throughput 547 * issues. CAVEAT: this may even increase latencies, in case 548 * of useless idling for processes that did stop doing I/O. 549 */ 550 bool strict_guarantees; 551 552 /* 553 * Last time at which a queue entered the current burst of 554 * queues being activated shortly after each other; for more 555 * details about this and the following parameters related to 556 * a burst of activations, see the comments on the function 557 * bfq_handle_burst. 558 */ 559 unsigned long last_ins_in_burst; 560 /* 561 * Reference time interval used to decide whether a queue has 562 * been activated shortly after @last_ins_in_burst. 563 */ 564 unsigned long bfq_burst_interval; 565 /* number of queues in the current burst of queue activations */ 566 int burst_size; 567 568 /* common parent entity for the queues in the burst */ 569 struct bfq_entity *burst_parent_entity; 570 /* Maximum burst size above which the current queue-activation 571 * burst is deemed as 'large'. 572 */ 573 unsigned long bfq_large_burst_thresh; 574 /* true if a large queue-activation burst is in progress */ 575 bool large_burst; 576 /* 577 * Head of the burst list (as for the above fields, more 578 * details in the comments on the function bfq_handle_burst). 579 */ 580 struct hlist_head burst_list; 581 582 /* if set to true, low-latency heuristics are enabled */ 583 bool low_latency; 584 /* 585 * Maximum factor by which the weight of a weight-raised queue 586 * is multiplied. 587 */ 588 unsigned int bfq_wr_coeff; 589 /* maximum duration of a weight-raising period (jiffies) */ 590 unsigned int bfq_wr_max_time; 591 592 /* Maximum weight-raising duration for soft real-time processes */ 593 unsigned int bfq_wr_rt_max_time; 594 /* 595 * Minimum idle period after which weight-raising may be 596 * reactivated for a queue (in jiffies). 597 */ 598 unsigned int bfq_wr_min_idle_time; 599 /* 600 * Minimum period between request arrivals after which 601 * weight-raising may be reactivated for an already busy async 602 * queue (in jiffies). 603 */ 604 unsigned long bfq_wr_min_inter_arr_async; 605 606 /* Max service-rate for a soft real-time queue, in sectors/sec */ 607 unsigned int bfq_wr_max_softrt_rate; 608 /* 609 * Cached value of the product ref_rate*ref_wr_duration, used 610 * for computing the maximum duration of weight raising 611 * automatically. 612 */ 613 u64 rate_dur_prod; 614 615 /* fallback dummy bfqq for extreme OOM conditions */ 616 struct bfq_queue oom_bfqq; 617 618 spinlock_t lock; 619 620 /* 621 * bic associated with the task issuing current bio for 622 * merging. This and the next field are used as a support to 623 * be able to perform the bic lookup, needed by bio-merge 624 * functions, before the scheduler lock is taken, and thus 625 * avoid taking the request-queue lock while the scheduler 626 * lock is being held. 627 */ 628 struct bfq_io_cq *bio_bic; 629 /* bfqq associated with the task issuing current bio for merging */ 630 struct bfq_queue *bio_bfqq; 631 632 /* 633 * Depth limits used in bfq_limit_depth (see comments on the 634 * function) 635 */ 636 unsigned int word_depths[2][2]; 637 }; 638 639 enum bfqq_state_flags { 640 BFQQF_just_created = 0, /* queue just allocated */ 641 BFQQF_busy, /* has requests or is in service */ 642 BFQQF_wait_request, /* waiting for a request */ 643 BFQQF_non_blocking_wait_rq, /* 644 * waiting for a request 645 * without idling the device 646 */ 647 BFQQF_fifo_expire, /* FIFO checked in this slice */ 648 BFQQF_has_short_ttime, /* queue has a short think time */ 649 BFQQF_sync, /* synchronous queue */ 650 BFQQF_IO_bound, /* 651 * bfqq has timed-out at least once 652 * having consumed at most 2/10 of 653 * its budget 654 */ 655 BFQQF_in_large_burst, /* 656 * bfqq activated in a large burst, 657 * see comments to bfq_handle_burst. 658 */ 659 BFQQF_softrt_update, /* 660 * may need softrt-next-start 661 * update 662 */ 663 BFQQF_coop, /* bfqq is shared */ 664 BFQQF_split_coop /* shared bfqq will be split */ 665 }; 666 667 #define BFQ_BFQQ_FNS(name) \ 668 void bfq_mark_bfqq_##name(struct bfq_queue *bfqq); \ 669 void bfq_clear_bfqq_##name(struct bfq_queue *bfqq); \ 670 int bfq_bfqq_##name(const struct bfq_queue *bfqq); 671 672 BFQ_BFQQ_FNS(just_created); 673 BFQ_BFQQ_FNS(busy); 674 BFQ_BFQQ_FNS(wait_request); 675 BFQ_BFQQ_FNS(non_blocking_wait_rq); 676 BFQ_BFQQ_FNS(fifo_expire); 677 BFQ_BFQQ_FNS(has_short_ttime); 678 BFQ_BFQQ_FNS(sync); 679 BFQ_BFQQ_FNS(IO_bound); 680 BFQ_BFQQ_FNS(in_large_burst); 681 BFQ_BFQQ_FNS(coop); 682 BFQ_BFQQ_FNS(split_coop); 683 BFQ_BFQQ_FNS(softrt_update); 684 #undef BFQ_BFQQ_FNS 685 686 /* Expiration reasons. */ 687 enum bfqq_expiration { 688 BFQQE_TOO_IDLE = 0, /* 689 * queue has been idling for 690 * too long 691 */ 692 BFQQE_BUDGET_TIMEOUT, /* budget took too long to be used */ 693 BFQQE_BUDGET_EXHAUSTED, /* budget consumed */ 694 BFQQE_NO_MORE_REQUESTS, /* the queue has no more requests */ 695 BFQQE_PREEMPTED /* preemption in progress */ 696 }; 697 698 struct bfqg_stats { 699 #if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP) 700 /* number of ios merged */ 701 struct blkg_rwstat merged; 702 /* total time spent on device in ns, may not be accurate w/ queueing */ 703 struct blkg_rwstat service_time; 704 /* total time spent waiting in scheduler queue in ns */ 705 struct blkg_rwstat wait_time; 706 /* number of IOs queued up */ 707 struct blkg_rwstat queued; 708 /* total disk time and nr sectors dispatched by this group */ 709 struct blkg_stat time; 710 /* sum of number of ios queued across all samples */ 711 struct blkg_stat avg_queue_size_sum; 712 /* count of samples taken for average */ 713 struct blkg_stat avg_queue_size_samples; 714 /* how many times this group has been removed from service tree */ 715 struct blkg_stat dequeue; 716 /* total time spent waiting for it to be assigned a timeslice. */ 717 struct blkg_stat group_wait_time; 718 /* time spent idling for this blkcg_gq */ 719 struct blkg_stat idle_time; 720 /* total time with empty current active q with other requests queued */ 721 struct blkg_stat empty_time; 722 /* fields after this shouldn't be cleared on stat reset */ 723 u64 start_group_wait_time; 724 u64 start_idle_time; 725 u64 start_empty_time; 726 uint16_t flags; 727 #endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ 728 }; 729 730 #ifdef CONFIG_BFQ_GROUP_IOSCHED 731 732 /* 733 * struct bfq_group_data - per-blkcg storage for the blkio subsystem. 734 * 735 * @ps: @blkcg_policy_storage that this structure inherits 736 * @weight: weight of the bfq_group 737 */ 738 struct bfq_group_data { 739 /* must be the first member */ 740 struct blkcg_policy_data pd; 741 742 unsigned int weight; 743 }; 744 745 /** 746 * struct bfq_group - per (device, cgroup) data structure. 747 * @entity: schedulable entity to insert into the parent group sched_data. 748 * @sched_data: own sched_data, to contain child entities (they may be 749 * both bfq_queues and bfq_groups). 750 * @bfqd: the bfq_data for the device this group acts upon. 751 * @async_bfqq: array of async queues for all the tasks belonging to 752 * the group, one queue per ioprio value per ioprio_class, 753 * except for the idle class that has only one queue. 754 * @async_idle_bfqq: async queue for the idle class (ioprio is ignored). 755 * @my_entity: pointer to @entity, %NULL for the toplevel group; used 756 * to avoid too many special cases during group creation/ 757 * migration. 758 * @stats: stats for this bfqg. 759 * @active_entities: number of active entities belonging to the group; 760 * unused for the root group. Used to know whether there 761 * are groups with more than one active @bfq_entity 762 * (see the comments to the function 763 * bfq_bfqq_may_idle()). 764 * @rq_pos_tree: rbtree sorted by next_request position, used when 765 * determining if two or more queues have interleaving 766 * requests (see bfq_find_close_cooperator()). 767 * 768 * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup 769 * there is a set of bfq_groups, each one collecting the lower-level 770 * entities belonging to the group that are acting on the same device. 771 * 772 * Locking works as follows: 773 * o @bfqd is protected by the queue lock, RCU is used to access it 774 * from the readers. 775 * o All the other fields are protected by the @bfqd queue lock. 776 */ 777 struct bfq_group { 778 /* must be the first member */ 779 struct blkg_policy_data pd; 780 781 /* cached path for this blkg (see comments in bfq_bic_update_cgroup) */ 782 char blkg_path[128]; 783 784 /* reference counter (see comments in bfq_bic_update_cgroup) */ 785 int ref; 786 787 struct bfq_entity entity; 788 struct bfq_sched_data sched_data; 789 790 void *bfqd; 791 792 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; 793 struct bfq_queue *async_idle_bfqq; 794 795 struct bfq_entity *my_entity; 796 797 int active_entities; 798 799 struct rb_root rq_pos_tree; 800 801 struct bfqg_stats stats; 802 }; 803 804 #else 805 struct bfq_group { 806 struct bfq_sched_data sched_data; 807 808 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; 809 struct bfq_queue *async_idle_bfqq; 810 811 struct rb_root rq_pos_tree; 812 }; 813 #endif 814 815 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); 816 817 /* --------------- main algorithm interface ----------------- */ 818 819 #define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ 820 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) 821 822 extern const int bfq_timeout; 823 824 struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync); 825 void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync); 826 struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic); 827 void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); 828 void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_entity *entity, 829 struct rb_root *root); 830 void __bfq_weights_tree_remove(struct bfq_data *bfqd, 831 struct bfq_entity *entity, 832 struct rb_root *root); 833 void bfq_weights_tree_remove(struct bfq_data *bfqd, 834 struct bfq_queue *bfqq); 835 void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, 836 bool compensate, enum bfqq_expiration reason); 837 void bfq_put_queue(struct bfq_queue *bfqq); 838 void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); 839 void bfq_schedule_dispatch(struct bfq_data *bfqd); 840 void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); 841 842 /* ------------ end of main algorithm interface -------------- */ 843 844 /* ---------------- cgroups-support interface ---------------- */ 845 846 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, 847 unsigned int op); 848 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op); 849 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op); 850 void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, 851 u64 io_start_time_ns, unsigned int op); 852 void bfqg_stats_update_dequeue(struct bfq_group *bfqg); 853 void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); 854 void bfqg_stats_update_idle_time(struct bfq_group *bfqg); 855 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg); 856 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg); 857 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, 858 struct bfq_group *bfqg); 859 860 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg); 861 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio); 862 void bfq_end_wr_async(struct bfq_data *bfqd); 863 struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, 864 struct blkcg *blkcg); 865 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); 866 struct bfq_group *bfqq_group(struct bfq_queue *bfqq); 867 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node); 868 void bfqg_and_blkg_put(struct bfq_group *bfqg); 869 870 #ifdef CONFIG_BFQ_GROUP_IOSCHED 871 extern struct cftype bfq_blkcg_legacy_files[]; 872 extern struct cftype bfq_blkg_files[]; 873 extern struct blkcg_policy blkcg_policy_bfq; 874 #endif 875 876 /* ------------- end of cgroups-support interface ------------- */ 877 878 /* - interface of the internal hierarchical B-WF2Q+ scheduler - */ 879 880 #ifdef CONFIG_BFQ_GROUP_IOSCHED 881 /* both next loops stop at one of the child entities of the root group */ 882 #define for_each_entity(entity) \ 883 for (; entity ; entity = entity->parent) 884 885 /* 886 * For each iteration, compute parent in advance, so as to be safe if 887 * entity is deallocated during the iteration. Such a deallocation may 888 * happen as a consequence of a bfq_put_queue that frees the bfq_queue 889 * containing entity. 890 */ 891 #define for_each_entity_safe(entity, parent) \ 892 for (; entity && ({ parent = entity->parent; 1; }); entity = parent) 893 894 #else /* CONFIG_BFQ_GROUP_IOSCHED */ 895 /* 896 * Next two macros are fake loops when cgroups support is not 897 * enabled. I fact, in such a case, there is only one level to go up 898 * (to reach the root group). 899 */ 900 #define for_each_entity(entity) \ 901 for (; entity ; entity = NULL) 902 903 #define for_each_entity_safe(entity, parent) \ 904 for (parent = NULL; entity ; entity = parent) 905 #endif /* CONFIG_BFQ_GROUP_IOSCHED */ 906 907 struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq); 908 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); 909 struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity); 910 struct bfq_entity *bfq_entity_of(struct rb_node *node); 911 unsigned short bfq_ioprio_to_weight(int ioprio); 912 void bfq_put_idle_entity(struct bfq_service_tree *st, 913 struct bfq_entity *entity); 914 struct bfq_service_tree * 915 __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, 916 struct bfq_entity *entity, 917 bool update_class_too); 918 void bfq_bfqq_served(struct bfq_queue *bfqq, int served); 919 void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, 920 unsigned long time_ms); 921 bool __bfq_deactivate_entity(struct bfq_entity *entity, 922 bool ins_into_idle_tree); 923 bool next_queue_may_preempt(struct bfq_data *bfqd); 924 struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd); 925 void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd); 926 void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, 927 bool ins_into_idle_tree, bool expiration); 928 void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); 929 void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, 930 bool expiration); 931 void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, 932 bool expiration); 933 void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); 934 935 /* --------------- end of interface of B-WF2Q+ ---------------- */ 936 937 /* Logging facilities. */ 938 #ifdef CONFIG_BFQ_GROUP_IOSCHED 939 struct bfq_group *bfqq_group(struct bfq_queue *bfqq); 940 941 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ 942 blk_add_cgroup_trace_msg((bfqd)->queue, \ 943 bfqg_to_blkg(bfqq_group(bfqq))->blkcg, \ 944 "bfq%d%c " fmt, (bfqq)->pid, \ 945 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args); \ 946 } while (0) 947 948 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ 949 blk_add_cgroup_trace_msg((bfqd)->queue, \ 950 bfqg_to_blkg(bfqg)->blkcg, fmt, ##args); \ 951 } while (0) 952 953 #else /* CONFIG_BFQ_GROUP_IOSCHED */ 954 955 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ 956 blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \ 957 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ 958 ##args) 959 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) 960 961 #endif /* CONFIG_BFQ_GROUP_IOSCHED */ 962 963 #define bfq_log(bfqd, fmt, args...) \ 964 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) 965 966 #endif /* _BFQ_H */ 967
