block/bfq-iosched.h

   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, struct bfq_entity *entity,
 831                              struct rb_root *root);
 832 void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 833                      bool compensate, enum bfqq_expiration reason);
 834 void bfq_put_queue(struct bfq_queue *bfqq);
 835 void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
 836 void bfq_schedule_dispatch(struct bfq_data *bfqd);
 837 void bfq_put_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg);
 838
 839 /* ------------ end of main algorithm interface -------------- */
 840
 841 /* ---------------- cgroups-support interface ---------------- */
 842
 843 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
 844                               unsigned int op);
 845 void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op);
 846 void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op);
 847 void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
 848                                   u64 io_start_time_ns, unsigned int op);
 849 void bfqg_stats_update_dequeue(struct bfq_group *bfqg);
 850 void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);
 851 void bfqg_stats_update_idle_time(struct bfq_group *bfqg);
 852 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg);
 853 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg);
 854 void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 855                    struct bfq_group *bfqg);
 856
 857 void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg);
 858 void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio);
 859 void bfq_end_wr_async(struct bfq_data *bfqd);
 860 struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
 861                                      struct blkcg *blkcg);
 862 struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
 863 struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
 864 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
 865 void bfqg_and_blkg_put(struct bfq_group *bfqg);
 866
 867 #ifdef CONFIG_BFQ_GROUP_IOSCHED
 868 extern struct cftype bfq_blkcg_legacy_files[];
 869 extern struct cftype bfq_blkg_files[];
 870 extern struct blkcg_policy blkcg_policy_bfq;
 871 #endif
 872
 873 /* ------------- end of cgroups-support interface ------------- */
 874
 875 /* - interface of the internal hierarchical B-WF2Q+ scheduler - */
 876
 877 #ifdef CONFIG_BFQ_GROUP_IOSCHED
 878 /* both next loops stop at one of the child entities of the root group */
 879 #define for_each_entity(entity) \
 880         for (; entity ; entity = entity->parent)
 881
 882 /*
 883  * For each iteration, compute parent in advance, so as to be safe if
 884  * entity is deallocated during the iteration. Such a deallocation may
 885  * happen as a consequence of a bfq_put_queue that frees the bfq_queue
 886  * containing entity.
 887  */
 888 #define for_each_entity_safe(entity, parent) \
 889         for (; entity && ({ parent = entity->parent; 1; }); entity = parent)
 890
 891 #else /* CONFIG_BFQ_GROUP_IOSCHED */
 892 /*
 893  * Next two macros are fake loops when cgroups support is not
 894  * enabled. I fact, in such a case, there is only one level to go up
 895  * (to reach the root group).
 896  */
 897 #define for_each_entity(entity) \
 898         for (; entity ; entity = NULL)
 899
 900 #define for_each_entity_safe(entity, parent) \
 901         for (parent = NULL; entity ; entity = parent)
 902 #endif /* CONFIG_BFQ_GROUP_IOSCHED */
 903
 904 struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq);
 905 struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity);
 906 struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity);
 907 struct bfq_entity *bfq_entity_of(struct rb_node *node);
 908 unsigned short bfq_ioprio_to_weight(int ioprio);
 909 void bfq_put_idle_entity(struct bfq_service_tree *st,
 910                          struct bfq_entity *entity);
 911 struct bfq_service_tree *
 912 __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
 913                                 struct bfq_entity *entity,
 914                                 bool update_class_too);
 915 void bfq_bfqq_served(struct bfq_queue *bfqq, int served);
 916 void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 917                           unsigned long time_ms);
 918 bool __bfq_deactivate_entity(struct bfq_entity *entity,
 919                              bool ins_into_idle_tree);
 920 bool next_queue_may_preempt(struct bfq_data *bfqd);
 921 struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd);
 922 void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd);
 923 void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 924                          bool ins_into_idle_tree, bool expiration);
 925 void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq);
 926 void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 927                       bool expiration);
 928 void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 929                        bool expiration);
 930 void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq);
 931
 932 /* --------------- end of interface of B-WF2Q+ ---------------- */
 933
 934 /* Logging facilities. */
 935 #ifdef CONFIG_BFQ_GROUP_IOSCHED
 936 struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
 937
 938 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...)  do {                    \
 939         blk_add_cgroup_trace_msg((bfqd)->queue,                         \
 940                         bfqg_to_blkg(bfqq_group(bfqq))->blkcg,          \
 941                         "bfq%d%c " fmt, (bfqq)->pid,                    \
 942                         bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args);     \
 943 } while (0)
 944
 945 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...)  do {                    \
 946         blk_add_cgroup_trace_msg((bfqd)->queue,                         \
 947                 bfqg_to_blkg(bfqg)->blkcg, fmt, ##args);                \
 948 } while (0)
 949
 950 #else /* CONFIG_BFQ_GROUP_IOSCHED */
 951
 952 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...)  \
 953         blk_add_trace_msg((bfqd)->queue, "bfq%d%c " fmt, (bfqq)->pid,   \
 954                         bfq_bfqq_sync((bfqq)) ? 'S' : 'A',              \
 955                                 ##args)
 956 #define bfq_log_bfqg(bfqd, bfqg, fmt, args...)          do {} while (0)
 957
 958 #endif /* CONFIG_BFQ_GROUP_IOSCHED */
 959
 960 #define bfq_log(bfqd, fmt, args...) \
 961         blk_add_trace_msg((bfqd)->queue, "bfq " fmt, ##args)
 962
 963 #endif /* _BFQ_H */