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; 761 762 struct bfq_entity entity; 763 struct bfq_sched_data sched_data; 764 765 void *bfqd; 766 767 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; 768 struct bfq_queue *async_idle_bfqq; 769 770 struct bfq_entity *my_entity; 771 772 int active_entities; 773 774 struct rb_root rq_pos_tree; 775 776 struct bfqg_stats stats; 777 }; 778 779 #else 780 struct bfq_group { 781 struct bfq_sched_data sched_data; 782 783 struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; 784 struct bfq_queue *async_idle_bfqq; 785 786 struct rb_root rq_pos_tree; 787 }; 788 #endif 789 790 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); 791 792 /* --------------- main algorithm interface ----------------- */ 793 794 #define BFQ_SERVICE_TREE_INIT ((struct bfq_service_tree) \ 795 { RB_ROOT, RB_ROOT, NULL, NULL, 0, 0 }) 796 797 extern const int bfq_timeout; 798 799 struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync); 800 void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, bool is_sync); 801 struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic); 802 void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); 803 void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); 804 void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_entity *entity, 805 struct rb_root *root); 806 void bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_entity *entity, 807 struct rb_root *root); 808 void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, 809 bool compensate, enum bfqq_expiration reason); 810 void bfq_put_queue(struct bfq_queue *bfqq); 811 void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); 812 void bfq_schedule_dispatch(struct bfq_data *bfqd); 813 void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); 814 815 /* ------------ end of main algorithm interface -------------- */ 816 817 /* ---------------- cgroups-support interface ---------------- */ 818 819 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, 820 unsigned int op); 821 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op); 822 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op); 823 void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time, 824 uint64_t io_start_time, unsigned int op); 825 void bfqg_stats_update_dequeue(struct bfq_group *bfqg); 826 void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); 827 void bfqg_stats_update_idle_time(struct bfq_group *bfqg); 828 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg); 829 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg); 830 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, 831 struct bfq_group *bfqg); 832 833 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg); 834 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio); 835 void bfq_end_wr_async(struct bfq_data *bfqd); 836 struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, 837 struct blkcg *blkcg); 838 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg); 839 struct bfq_group *bfqq_group(struct bfq_queue *bfqq); 840 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node); 841 void bfqg_put(struct bfq_group *bfqg); 842 843 #ifdef CONFIG_BFQ_GROUP_IOSCHED 844 extern struct cftype bfq_blkcg_legacy_files[]; 845 extern struct cftype bfq_blkg_files[]; 846 extern struct blkcg_policy blkcg_policy_bfq; 847 #endif 848 849 /* ------------- end of cgroups-support interface ------------- */ 850 851 /* - interface of the internal hierarchical B-WF2Q+ scheduler - */ 852 853 #ifdef CONFIG_BFQ_GROUP_IOSCHED 854 /* both next loops stop at one of the child entities of the root group */ 855 #define for_each_entity(entity) \ 856 for (; entity ; entity = entity->parent) 857 858 /* 859 * For each iteration, compute parent in advance, so as to be safe if 860 * entity is deallocated during the iteration. Such a deallocation may 861 * happen as a consequence of a bfq_put_queue that frees the bfq_queue 862 * containing entity. 863 */ 864 #define for_each_entity_safe(entity, parent) \ 865 for (; entity && ({ parent = entity->parent; 1; }); entity = parent) 866 867 #else /* CONFIG_BFQ_GROUP_IOSCHED */ 868 /* 869 * Next two macros are fake loops when cgroups support is not 870 * enabled. I fact, in such a case, there is only one level to go up 871 * (to reach the root group). 872 */ 873 #define for_each_entity(entity) \ 874 for (; entity ; entity = NULL) 875 876 #define for_each_entity_safe(entity, parent) \ 877 for (parent = NULL; entity ; entity = parent) 878 #endif /* CONFIG_BFQ_GROUP_IOSCHED */ 879 880 struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq); 881 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); 882 struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity); 883 struct bfq_entity *bfq_entity_of(struct rb_node *node); 884 unsigned short bfq_ioprio_to_weight(int ioprio); 885 void bfq_put_idle_entity(struct bfq_service_tree *st, 886 struct bfq_entity *entity); 887 struct bfq_service_tree * 888 __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, 889 struct bfq_entity *entity); 890 void bfq_bfqq_served(struct bfq_queue *bfqq, int served); 891 void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, 892 unsigned long time_ms); 893 bool __bfq_deactivate_entity(struct bfq_entity *entity, 894 bool ins_into_idle_tree); 895 bool next_queue_may_preempt(struct bfq_data *bfqd); 896 struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd); 897 void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd); 898 void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, 899 bool ins_into_idle_tree, bool expiration); 900 void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); 901 void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq); 902 void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, 903 bool expiration); 904 void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); 905 906 /* --------------- end of interface of B-WF2Q+ ---------------- */ 907 908 /* Logging facilities. */ 909 #ifdef CONFIG_BFQ_GROUP_IOSCHED 910 struct bfq_group *bfqq_group(struct bfq_queue *bfqq); 911 912 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ 913 char __pbuf[128]; \ 914 \ 915 blkg_path(bfqg_to_blkg(bfqq_group(bfqq)), __pbuf, sizeof(__pbuf)); \ 916 blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid, \ 917 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ 918 __pbuf, ##args); \ 919 } while (0) 920 921 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do { \ 922 char __pbuf[128]; \ 923 \ 924 blkg_path(bfqg_to_blkg(bfqg), __pbuf, sizeof(__pbuf)); \ 925 blk_add_trace_msg((bfqd)->queue, "%s " fmt, __pbuf, ##args); \ 926 } while (0) 927 928 #else /* CONFIG_BFQ_GROUP_IOSCHED */ 929 930 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) \ 931 blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid, \ 932 bfq_bfqq_sync((bfqq)) ? 'S' : 'A', \ 933 ##args) 934 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...) do {} while (0) 935 936 #endif /* CONFIG_BFQ_GROUP_IOSCHED */ 937 938 #define bfq_log(bfqd, fmt, args...) \ 939 blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args) 940 941 #endif /* _BFQ_H */ 942