Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Hierarchical Budget Worst-case Fair Weighted Fair Queueing |
| 3 | * (B-WF2Q+): hierarchical scheduling algorithm by which the BFQ I/O |
| 4 | * scheduler schedules generic entities. The latter can represent |
| 5 | * either single bfq queues (associated with processes) or groups of |
| 6 | * bfq queues (associated with cgroups). |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License as |
| 10 | * published by the Free Software Foundation; either version 2 of the |
| 11 | * License, or (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * General Public License for more details. |
| 17 | */ |
| 18 | #include "bfq-iosched.h" |
| 19 | |
| 20 | /** |
| 21 | * bfq_gt - compare two timestamps. |
| 22 | * @a: first ts. |
| 23 | * @b: second ts. |
| 24 | * |
| 25 | * Return @a > @b, dealing with wrapping correctly. |
| 26 | */ |
| 27 | static int bfq_gt(u64 a, u64 b) |
| 28 | { |
| 29 | return (s64)(a - b) > 0; |
| 30 | } |
| 31 | |
| 32 | static struct bfq_entity *bfq_root_active_entity(struct rb_root *tree) |
| 33 | { |
| 34 | struct rb_node *node = tree->rb_node; |
| 35 | |
| 36 | return rb_entry(node, struct bfq_entity, rb_node); |
| 37 | } |
| 38 | |
| 39 | static unsigned int bfq_class_idx(struct bfq_entity *entity) |
| 40 | { |
| 41 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 42 | |
| 43 | return bfqq ? bfqq->ioprio_class - 1 : |
| 44 | BFQ_DEFAULT_GRP_CLASS - 1; |
| 45 | } |
| 46 | |
| 47 | static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd); |
| 48 | |
| 49 | static bool bfq_update_parent_budget(struct bfq_entity *next_in_service); |
| 50 | |
| 51 | /** |
| 52 | * bfq_update_next_in_service - update sd->next_in_service |
| 53 | * @sd: sched_data for which to perform the update. |
| 54 | * @new_entity: if not NULL, pointer to the entity whose activation, |
| 55 | * requeueing or repositionig triggered the invocation of |
| 56 | * this function. |
| 57 | * |
| 58 | * This function is called to update sd->next_in_service, which, in |
| 59 | * its turn, may change as a consequence of the insertion or |
| 60 | * extraction of an entity into/from one of the active trees of |
| 61 | * sd. These insertions/extractions occur as a consequence of |
| 62 | * activations/deactivations of entities, with some activations being |
| 63 | * 'true' activations, and other activations being requeueings (i.e., |
| 64 | * implementing the second, requeueing phase of the mechanism used to |
| 65 | * reposition an entity in its active tree; see comments on |
| 66 | * __bfq_activate_entity and __bfq_requeue_entity for details). In |
| 67 | * both the last two activation sub-cases, new_entity points to the |
| 68 | * just activated or requeued entity. |
| 69 | * |
| 70 | * Returns true if sd->next_in_service changes in such a way that |
| 71 | * entity->parent may become the next_in_service for its parent |
| 72 | * entity. |
| 73 | */ |
| 74 | static bool bfq_update_next_in_service(struct bfq_sched_data *sd, |
| 75 | struct bfq_entity *new_entity) |
| 76 | { |
| 77 | struct bfq_entity *next_in_service = sd->next_in_service; |
| 78 | bool parent_sched_may_change = false; |
| 79 | |
| 80 | /* |
| 81 | * If this update is triggered by the activation, requeueing |
| 82 | * or repositiong of an entity that does not coincide with |
| 83 | * sd->next_in_service, then a full lookup in the active tree |
| 84 | * can be avoided. In fact, it is enough to check whether the |
| 85 | * just-modified entity has a higher priority than |
| 86 | * sd->next_in_service, or, even if it has the same priority |
| 87 | * as sd->next_in_service, is eligible and has a lower virtual |
| 88 | * finish time than sd->next_in_service. If this compound |
| 89 | * condition holds, then the new entity becomes the new |
| 90 | * next_in_service. Otherwise no change is needed. |
| 91 | */ |
| 92 | if (new_entity && new_entity != sd->next_in_service) { |
| 93 | /* |
| 94 | * Flag used to decide whether to replace |
| 95 | * sd->next_in_service with new_entity. Tentatively |
| 96 | * set to true, and left as true if |
| 97 | * sd->next_in_service is NULL. |
| 98 | */ |
| 99 | bool replace_next = true; |
| 100 | |
| 101 | /* |
| 102 | * If there is already a next_in_service candidate |
| 103 | * entity, then compare class priorities or timestamps |
| 104 | * to decide whether to replace sd->service_tree with |
| 105 | * new_entity. |
| 106 | */ |
| 107 | if (next_in_service) { |
| 108 | unsigned int new_entity_class_idx = |
| 109 | bfq_class_idx(new_entity); |
| 110 | struct bfq_service_tree *st = |
| 111 | sd->service_tree + new_entity_class_idx; |
| 112 | |
| 113 | /* |
| 114 | * For efficiency, evaluate the most likely |
| 115 | * sub-condition first. |
| 116 | */ |
| 117 | replace_next = |
| 118 | (new_entity_class_idx == |
| 119 | bfq_class_idx(next_in_service) |
| 120 | && |
| 121 | !bfq_gt(new_entity->start, st->vtime) |
| 122 | && |
| 123 | bfq_gt(next_in_service->finish, |
| 124 | new_entity->finish)) |
| 125 | || |
| 126 | new_entity_class_idx < |
| 127 | bfq_class_idx(next_in_service); |
| 128 | } |
| 129 | |
| 130 | if (replace_next) |
| 131 | next_in_service = new_entity; |
| 132 | } else /* invoked because of a deactivation: lookup needed */ |
| 133 | next_in_service = bfq_lookup_next_entity(sd); |
| 134 | |
| 135 | if (next_in_service) { |
| 136 | parent_sched_may_change = !sd->next_in_service || |
| 137 | bfq_update_parent_budget(next_in_service); |
| 138 | } |
| 139 | |
| 140 | sd->next_in_service = next_in_service; |
| 141 | |
| 142 | if (!next_in_service) |
| 143 | return parent_sched_may_change; |
| 144 | |
| 145 | return parent_sched_may_change; |
| 146 | } |
| 147 | |
| 148 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 149 | |
| 150 | struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) |
| 151 | { |
| 152 | struct bfq_entity *group_entity = bfqq->entity.parent; |
| 153 | |
| 154 | if (!group_entity) |
| 155 | group_entity = &bfqq->bfqd->root_group->entity; |
| 156 | |
| 157 | return container_of(group_entity, struct bfq_group, entity); |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Returns true if this budget changes may let next_in_service->parent |
| 162 | * become the next_in_service entity for its parent entity. |
| 163 | */ |
| 164 | static bool bfq_update_parent_budget(struct bfq_entity *next_in_service) |
| 165 | { |
| 166 | struct bfq_entity *bfqg_entity; |
| 167 | struct bfq_group *bfqg; |
| 168 | struct bfq_sched_data *group_sd; |
| 169 | bool ret = false; |
| 170 | |
| 171 | group_sd = next_in_service->sched_data; |
| 172 | |
| 173 | bfqg = container_of(group_sd, struct bfq_group, sched_data); |
| 174 | /* |
| 175 | * bfq_group's my_entity field is not NULL only if the group |
| 176 | * is not the root group. We must not touch the root entity |
| 177 | * as it must never become an in-service entity. |
| 178 | */ |
| 179 | bfqg_entity = bfqg->my_entity; |
| 180 | if (bfqg_entity) { |
| 181 | if (bfqg_entity->budget > next_in_service->budget) |
| 182 | ret = true; |
| 183 | bfqg_entity->budget = next_in_service->budget; |
| 184 | } |
| 185 | |
| 186 | return ret; |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * This function tells whether entity stops being a candidate for next |
| 191 | * service, according to the following logic. |
| 192 | * |
| 193 | * This function is invoked for an entity that is about to be set in |
| 194 | * service. If such an entity is a queue, then the entity is no longer |
| 195 | * a candidate for next service (i.e, a candidate entity to serve |
| 196 | * after the in-service entity is expired). The function then returns |
| 197 | * true. |
| 198 | * |
| 199 | * In contrast, the entity could stil be a candidate for next service |
| 200 | * if it is not a queue, and has more than one child. In fact, even if |
| 201 | * one of its children is about to be set in service, other children |
| 202 | * may still be the next to serve. As a consequence, a non-queue |
| 203 | * entity is not a candidate for next-service only if it has only one |
| 204 | * child. And only if this condition holds, then the function returns |
| 205 | * true for a non-queue entity. |
| 206 | */ |
| 207 | static bool bfq_no_longer_next_in_service(struct bfq_entity *entity) |
| 208 | { |
| 209 | struct bfq_group *bfqg; |
| 210 | |
| 211 | if (bfq_entity_to_bfqq(entity)) |
| 212 | return true; |
| 213 | |
| 214 | bfqg = container_of(entity, struct bfq_group, entity); |
| 215 | |
| 216 | if (bfqg->active_entities == 1) |
| 217 | return true; |
| 218 | |
| 219 | return false; |
| 220 | } |
| 221 | |
| 222 | #else /* CONFIG_BFQ_GROUP_IOSCHED */ |
| 223 | |
| 224 | struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) |
| 225 | { |
| 226 | return bfqq->bfqd->root_group; |
| 227 | } |
| 228 | |
| 229 | static bool bfq_update_parent_budget(struct bfq_entity *next_in_service) |
| 230 | { |
| 231 | return false; |
| 232 | } |
| 233 | |
| 234 | static bool bfq_no_longer_next_in_service(struct bfq_entity *entity) |
| 235 | { |
| 236 | return true; |
| 237 | } |
| 238 | |
| 239 | #endif /* CONFIG_BFQ_GROUP_IOSCHED */ |
| 240 | |
| 241 | /* |
| 242 | * Shift for timestamp calculations. This actually limits the maximum |
| 243 | * service allowed in one timestamp delta (small shift values increase it), |
| 244 | * the maximum total weight that can be used for the queues in the system |
| 245 | * (big shift values increase it), and the period of virtual time |
| 246 | * wraparounds. |
| 247 | */ |
| 248 | #define WFQ_SERVICE_SHIFT 22 |
| 249 | |
| 250 | struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) |
| 251 | { |
| 252 | struct bfq_queue *bfqq = NULL; |
| 253 | |
| 254 | if (!entity->my_sched_data) |
| 255 | bfqq = container_of(entity, struct bfq_queue, entity); |
| 256 | |
| 257 | return bfqq; |
| 258 | } |
| 259 | |
| 260 | |
| 261 | /** |
| 262 | * bfq_delta - map service into the virtual time domain. |
| 263 | * @service: amount of service. |
| 264 | * @weight: scale factor (weight of an entity or weight sum). |
| 265 | */ |
| 266 | static u64 bfq_delta(unsigned long service, unsigned long weight) |
| 267 | { |
| 268 | u64 d = (u64)service << WFQ_SERVICE_SHIFT; |
| 269 | |
| 270 | do_div(d, weight); |
| 271 | return d; |
| 272 | } |
| 273 | |
| 274 | /** |
| 275 | * bfq_calc_finish - assign the finish time to an entity. |
| 276 | * @entity: the entity to act upon. |
| 277 | * @service: the service to be charged to the entity. |
| 278 | */ |
| 279 | static void bfq_calc_finish(struct bfq_entity *entity, unsigned long service) |
| 280 | { |
| 281 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 282 | |
| 283 | entity->finish = entity->start + |
| 284 | bfq_delta(service, entity->weight); |
| 285 | |
| 286 | if (bfqq) { |
| 287 | bfq_log_bfqq(bfqq->bfqd, bfqq, |
| 288 | "calc_finish: serv %lu, w %d", |
| 289 | service, entity->weight); |
| 290 | bfq_log_bfqq(bfqq->bfqd, bfqq, |
| 291 | "calc_finish: start %llu, finish %llu, delta %llu", |
| 292 | entity->start, entity->finish, |
| 293 | bfq_delta(service, entity->weight)); |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | /** |
| 298 | * bfq_entity_of - get an entity from a node. |
| 299 | * @node: the node field of the entity. |
| 300 | * |
| 301 | * Convert a node pointer to the relative entity. This is used only |
| 302 | * to simplify the logic of some functions and not as the generic |
| 303 | * conversion mechanism because, e.g., in the tree walking functions, |
| 304 | * the check for a %NULL value would be redundant. |
| 305 | */ |
| 306 | struct bfq_entity *bfq_entity_of(struct rb_node *node) |
| 307 | { |
| 308 | struct bfq_entity *entity = NULL; |
| 309 | |
| 310 | if (node) |
| 311 | entity = rb_entry(node, struct bfq_entity, rb_node); |
| 312 | |
| 313 | return entity; |
| 314 | } |
| 315 | |
| 316 | /** |
| 317 | * bfq_extract - remove an entity from a tree. |
| 318 | * @root: the tree root. |
| 319 | * @entity: the entity to remove. |
| 320 | */ |
| 321 | static void bfq_extract(struct rb_root *root, struct bfq_entity *entity) |
| 322 | { |
| 323 | entity->tree = NULL; |
| 324 | rb_erase(&entity->rb_node, root); |
| 325 | } |
| 326 | |
| 327 | /** |
| 328 | * bfq_idle_extract - extract an entity from the idle tree. |
| 329 | * @st: the service tree of the owning @entity. |
| 330 | * @entity: the entity being removed. |
| 331 | */ |
| 332 | static void bfq_idle_extract(struct bfq_service_tree *st, |
| 333 | struct bfq_entity *entity) |
| 334 | { |
| 335 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 336 | struct rb_node *next; |
| 337 | |
| 338 | if (entity == st->first_idle) { |
| 339 | next = rb_next(&entity->rb_node); |
| 340 | st->first_idle = bfq_entity_of(next); |
| 341 | } |
| 342 | |
| 343 | if (entity == st->last_idle) { |
| 344 | next = rb_prev(&entity->rb_node); |
| 345 | st->last_idle = bfq_entity_of(next); |
| 346 | } |
| 347 | |
| 348 | bfq_extract(&st->idle, entity); |
| 349 | |
| 350 | if (bfqq) |
| 351 | list_del(&bfqq->bfqq_list); |
| 352 | } |
| 353 | |
| 354 | /** |
| 355 | * bfq_insert - generic tree insertion. |
| 356 | * @root: tree root. |
| 357 | * @entity: entity to insert. |
| 358 | * |
| 359 | * This is used for the idle and the active tree, since they are both |
| 360 | * ordered by finish time. |
| 361 | */ |
| 362 | static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) |
| 363 | { |
| 364 | struct bfq_entity *entry; |
| 365 | struct rb_node **node = &root->rb_node; |
| 366 | struct rb_node *parent = NULL; |
| 367 | |
| 368 | while (*node) { |
| 369 | parent = *node; |
| 370 | entry = rb_entry(parent, struct bfq_entity, rb_node); |
| 371 | |
| 372 | if (bfq_gt(entry->finish, entity->finish)) |
| 373 | node = &parent->rb_left; |
| 374 | else |
| 375 | node = &parent->rb_right; |
| 376 | } |
| 377 | |
| 378 | rb_link_node(&entity->rb_node, parent, node); |
| 379 | rb_insert_color(&entity->rb_node, root); |
| 380 | |
| 381 | entity->tree = root; |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * bfq_update_min - update the min_start field of a entity. |
| 386 | * @entity: the entity to update. |
| 387 | * @node: one of its children. |
| 388 | * |
| 389 | * This function is called when @entity may store an invalid value for |
| 390 | * min_start due to updates to the active tree. The function assumes |
| 391 | * that the subtree rooted at @node (which may be its left or its right |
| 392 | * child) has a valid min_start value. |
| 393 | */ |
| 394 | static void bfq_update_min(struct bfq_entity *entity, struct rb_node *node) |
| 395 | { |
| 396 | struct bfq_entity *child; |
| 397 | |
| 398 | if (node) { |
| 399 | child = rb_entry(node, struct bfq_entity, rb_node); |
| 400 | if (bfq_gt(entity->min_start, child->min_start)) |
| 401 | entity->min_start = child->min_start; |
| 402 | } |
| 403 | } |
| 404 | |
| 405 | /** |
| 406 | * bfq_update_active_node - recalculate min_start. |
| 407 | * @node: the node to update. |
| 408 | * |
| 409 | * @node may have changed position or one of its children may have moved, |
| 410 | * this function updates its min_start value. The left and right subtrees |
| 411 | * are assumed to hold a correct min_start value. |
| 412 | */ |
| 413 | static void bfq_update_active_node(struct rb_node *node) |
| 414 | { |
| 415 | struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node); |
| 416 | |
| 417 | entity->min_start = entity->start; |
| 418 | bfq_update_min(entity, node->rb_right); |
| 419 | bfq_update_min(entity, node->rb_left); |
| 420 | } |
| 421 | |
| 422 | /** |
| 423 | * bfq_update_active_tree - update min_start for the whole active tree. |
| 424 | * @node: the starting node. |
| 425 | * |
| 426 | * @node must be the deepest modified node after an update. This function |
| 427 | * updates its min_start using the values held by its children, assuming |
| 428 | * that they did not change, and then updates all the nodes that may have |
| 429 | * changed in the path to the root. The only nodes that may have changed |
| 430 | * are the ones in the path or their siblings. |
| 431 | */ |
| 432 | static void bfq_update_active_tree(struct rb_node *node) |
| 433 | { |
| 434 | struct rb_node *parent; |
| 435 | |
| 436 | up: |
| 437 | bfq_update_active_node(node); |
| 438 | |
| 439 | parent = rb_parent(node); |
| 440 | if (!parent) |
| 441 | return; |
| 442 | |
| 443 | if (node == parent->rb_left && parent->rb_right) |
| 444 | bfq_update_active_node(parent->rb_right); |
| 445 | else if (parent->rb_left) |
| 446 | bfq_update_active_node(parent->rb_left); |
| 447 | |
| 448 | node = parent; |
| 449 | goto up; |
| 450 | } |
| 451 | |
| 452 | /** |
| 453 | * bfq_active_insert - insert an entity in the active tree of its |
| 454 | * group/device. |
| 455 | * @st: the service tree of the entity. |
| 456 | * @entity: the entity being inserted. |
| 457 | * |
| 458 | * The active tree is ordered by finish time, but an extra key is kept |
| 459 | * per each node, containing the minimum value for the start times of |
| 460 | * its children (and the node itself), so it's possible to search for |
| 461 | * the eligible node with the lowest finish time in logarithmic time. |
| 462 | */ |
| 463 | static void bfq_active_insert(struct bfq_service_tree *st, |
| 464 | struct bfq_entity *entity) |
| 465 | { |
| 466 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 467 | struct rb_node *node = &entity->rb_node; |
| 468 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 469 | struct bfq_sched_data *sd = NULL; |
| 470 | struct bfq_group *bfqg = NULL; |
| 471 | struct bfq_data *bfqd = NULL; |
| 472 | #endif |
| 473 | |
| 474 | bfq_insert(&st->active, entity); |
| 475 | |
| 476 | if (node->rb_left) |
| 477 | node = node->rb_left; |
| 478 | else if (node->rb_right) |
| 479 | node = node->rb_right; |
| 480 | |
| 481 | bfq_update_active_tree(node); |
| 482 | |
| 483 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 484 | sd = entity->sched_data; |
| 485 | bfqg = container_of(sd, struct bfq_group, sched_data); |
| 486 | bfqd = (struct bfq_data *)bfqg->bfqd; |
| 487 | #endif |
| 488 | if (bfqq) |
| 489 | list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list); |
| 490 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 491 | else /* bfq_group */ |
| 492 | bfq_weights_tree_add(bfqd, entity, &bfqd->group_weights_tree); |
| 493 | |
| 494 | if (bfqg != bfqd->root_group) |
| 495 | bfqg->active_entities++; |
| 496 | #endif |
| 497 | } |
| 498 | |
| 499 | /** |
| 500 | * bfq_ioprio_to_weight - calc a weight from an ioprio. |
| 501 | * @ioprio: the ioprio value to convert. |
| 502 | */ |
| 503 | unsigned short bfq_ioprio_to_weight(int ioprio) |
| 504 | { |
| 505 | return (IOPRIO_BE_NR - ioprio) * BFQ_WEIGHT_CONVERSION_COEFF; |
| 506 | } |
| 507 | |
| 508 | /** |
| 509 | * bfq_weight_to_ioprio - calc an ioprio from a weight. |
| 510 | * @weight: the weight value to convert. |
| 511 | * |
| 512 | * To preserve as much as possible the old only-ioprio user interface, |
| 513 | * 0 is used as an escape ioprio value for weights (numerically) equal or |
| 514 | * larger than IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF. |
| 515 | */ |
| 516 | static unsigned short bfq_weight_to_ioprio(int weight) |
| 517 | { |
| 518 | return max_t(int, 0, |
| 519 | IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight); |
| 520 | } |
| 521 | |
| 522 | static void bfq_get_entity(struct bfq_entity *entity) |
| 523 | { |
| 524 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 525 | |
| 526 | if (bfqq) { |
| 527 | bfqq->ref++; |
| 528 | bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d", |
| 529 | bfqq, bfqq->ref); |
| 530 | } |
| 531 | } |
| 532 | |
| 533 | /** |
| 534 | * bfq_find_deepest - find the deepest node that an extraction can modify. |
| 535 | * @node: the node being removed. |
| 536 | * |
| 537 | * Do the first step of an extraction in an rb tree, looking for the |
| 538 | * node that will replace @node, and returning the deepest node that |
| 539 | * the following modifications to the tree can touch. If @node is the |
| 540 | * last node in the tree return %NULL. |
| 541 | */ |
| 542 | static struct rb_node *bfq_find_deepest(struct rb_node *node) |
| 543 | { |
| 544 | struct rb_node *deepest; |
| 545 | |
| 546 | if (!node->rb_right && !node->rb_left) |
| 547 | deepest = rb_parent(node); |
| 548 | else if (!node->rb_right) |
| 549 | deepest = node->rb_left; |
| 550 | else if (!node->rb_left) |
| 551 | deepest = node->rb_right; |
| 552 | else { |
| 553 | deepest = rb_next(node); |
| 554 | if (deepest->rb_right) |
| 555 | deepest = deepest->rb_right; |
| 556 | else if (rb_parent(deepest) != node) |
| 557 | deepest = rb_parent(deepest); |
| 558 | } |
| 559 | |
| 560 | return deepest; |
| 561 | } |
| 562 | |
| 563 | /** |
| 564 | * bfq_active_extract - remove an entity from the active tree. |
| 565 | * @st: the service_tree containing the tree. |
| 566 | * @entity: the entity being removed. |
| 567 | */ |
| 568 | static void bfq_active_extract(struct bfq_service_tree *st, |
| 569 | struct bfq_entity *entity) |
| 570 | { |
| 571 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 572 | struct rb_node *node; |
| 573 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 574 | struct bfq_sched_data *sd = NULL; |
| 575 | struct bfq_group *bfqg = NULL; |
| 576 | struct bfq_data *bfqd = NULL; |
| 577 | #endif |
| 578 | |
| 579 | node = bfq_find_deepest(&entity->rb_node); |
| 580 | bfq_extract(&st->active, entity); |
| 581 | |
| 582 | if (node) |
| 583 | bfq_update_active_tree(node); |
| 584 | |
| 585 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 586 | sd = entity->sched_data; |
| 587 | bfqg = container_of(sd, struct bfq_group, sched_data); |
| 588 | bfqd = (struct bfq_data *)bfqg->bfqd; |
| 589 | #endif |
| 590 | if (bfqq) |
| 591 | list_del(&bfqq->bfqq_list); |
| 592 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 593 | else /* bfq_group */ |
| 594 | bfq_weights_tree_remove(bfqd, entity, |
| 595 | &bfqd->group_weights_tree); |
| 596 | |
| 597 | if (bfqg != bfqd->root_group) |
| 598 | bfqg->active_entities--; |
| 599 | #endif |
| 600 | } |
| 601 | |
| 602 | /** |
| 603 | * bfq_idle_insert - insert an entity into the idle tree. |
| 604 | * @st: the service tree containing the tree. |
| 605 | * @entity: the entity to insert. |
| 606 | */ |
| 607 | static void bfq_idle_insert(struct bfq_service_tree *st, |
| 608 | struct bfq_entity *entity) |
| 609 | { |
| 610 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 611 | struct bfq_entity *first_idle = st->first_idle; |
| 612 | struct bfq_entity *last_idle = st->last_idle; |
| 613 | |
| 614 | if (!first_idle || bfq_gt(first_idle->finish, entity->finish)) |
| 615 | st->first_idle = entity; |
| 616 | if (!last_idle || bfq_gt(entity->finish, last_idle->finish)) |
| 617 | st->last_idle = entity; |
| 618 | |
| 619 | bfq_insert(&st->idle, entity); |
| 620 | |
| 621 | if (bfqq) |
| 622 | list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list); |
| 623 | } |
| 624 | |
| 625 | /** |
| 626 | * bfq_forget_entity - do not consider entity any longer for scheduling |
| 627 | * @st: the service tree. |
| 628 | * @entity: the entity being removed. |
| 629 | * @is_in_service: true if entity is currently the in-service entity. |
| 630 | * |
| 631 | * Forget everything about @entity. In addition, if entity represents |
| 632 | * a queue, and the latter is not in service, then release the service |
| 633 | * reference to the queue (the one taken through bfq_get_entity). In |
| 634 | * fact, in this case, there is really no more service reference to |
| 635 | * the queue, as the latter is also outside any service tree. If, |
| 636 | * instead, the queue is in service, then __bfq_bfqd_reset_in_service |
| 637 | * will take care of putting the reference when the queue finally |
| 638 | * stops being served. |
| 639 | */ |
| 640 | static void bfq_forget_entity(struct bfq_service_tree *st, |
| 641 | struct bfq_entity *entity, |
| 642 | bool is_in_service) |
| 643 | { |
| 644 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 645 | |
| 646 | entity->on_st = false; |
| 647 | st->wsum -= entity->weight; |
| 648 | if (bfqq && !is_in_service) |
| 649 | bfq_put_queue(bfqq); |
| 650 | } |
| 651 | |
| 652 | /** |
| 653 | * bfq_put_idle_entity - release the idle tree ref of an entity. |
| 654 | * @st: service tree for the entity. |
| 655 | * @entity: the entity being released. |
| 656 | */ |
| 657 | void bfq_put_idle_entity(struct bfq_service_tree *st, struct bfq_entity *entity) |
| 658 | { |
| 659 | bfq_idle_extract(st, entity); |
| 660 | bfq_forget_entity(st, entity, |
| 661 | entity == entity->sched_data->in_service_entity); |
| 662 | } |
| 663 | |
| 664 | /** |
| 665 | * bfq_forget_idle - update the idle tree if necessary. |
| 666 | * @st: the service tree to act upon. |
| 667 | * |
| 668 | * To preserve the global O(log N) complexity we only remove one entry here; |
| 669 | * as the idle tree will not grow indefinitely this can be done safely. |
| 670 | */ |
| 671 | static void bfq_forget_idle(struct bfq_service_tree *st) |
| 672 | { |
| 673 | struct bfq_entity *first_idle = st->first_idle; |
| 674 | struct bfq_entity *last_idle = st->last_idle; |
| 675 | |
| 676 | if (RB_EMPTY_ROOT(&st->active) && last_idle && |
| 677 | !bfq_gt(last_idle->finish, st->vtime)) { |
| 678 | /* |
| 679 | * Forget the whole idle tree, increasing the vtime past |
| 680 | * the last finish time of idle entities. |
| 681 | */ |
| 682 | st->vtime = last_idle->finish; |
| 683 | } |
| 684 | |
| 685 | if (first_idle && !bfq_gt(first_idle->finish, st->vtime)) |
| 686 | bfq_put_idle_entity(st, first_idle); |
| 687 | } |
| 688 | |
| 689 | struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity) |
| 690 | { |
| 691 | struct bfq_sched_data *sched_data = entity->sched_data; |
| 692 | unsigned int idx = bfq_class_idx(entity); |
| 693 | |
| 694 | return sched_data->service_tree + idx; |
| 695 | } |
| 696 | |
Paolo Valente | 431b17f | 2017-07-03 10:00:10 +0200 | [diff] [blame] | 697 | /* |
| 698 | * Update weight and priority of entity. If update_class_too is true, |
| 699 | * then update the ioprio_class of entity too. |
| 700 | * |
| 701 | * The reason why the update of ioprio_class is controlled through the |
| 702 | * last parameter is as follows. Changing the ioprio class of an |
| 703 | * entity implies changing the destination service trees for that |
| 704 | * entity. If such a change occurred when the entity is already on one |
| 705 | * of the service trees for its previous class, then the state of the |
| 706 | * entity would become more complex: none of the new possible service |
| 707 | * trees for the entity, according to bfq_entity_service_tree(), would |
| 708 | * match any of the possible service trees on which the entity |
| 709 | * is. Complex operations involving these trees, such as entity |
| 710 | * activations and deactivations, should take into account this |
| 711 | * additional complexity. To avoid this issue, this function is |
| 712 | * invoked with update_class_too unset in the points in the code where |
| 713 | * entity may happen to be on some tree. |
| 714 | */ |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 715 | struct bfq_service_tree * |
| 716 | __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, |
Paolo Valente | 431b17f | 2017-07-03 10:00:10 +0200 | [diff] [blame] | 717 | struct bfq_entity *entity, |
| 718 | bool update_class_too) |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 719 | { |
| 720 | struct bfq_service_tree *new_st = old_st; |
| 721 | |
| 722 | if (entity->prio_changed) { |
| 723 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 724 | unsigned int prev_weight, new_weight; |
| 725 | struct bfq_data *bfqd = NULL; |
| 726 | struct rb_root *root; |
| 727 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 728 | struct bfq_sched_data *sd; |
| 729 | struct bfq_group *bfqg; |
| 730 | #endif |
| 731 | |
| 732 | if (bfqq) |
| 733 | bfqd = bfqq->bfqd; |
| 734 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
| 735 | else { |
| 736 | sd = entity->my_sched_data; |
| 737 | bfqg = container_of(sd, struct bfq_group, sched_data); |
| 738 | bfqd = (struct bfq_data *)bfqg->bfqd; |
| 739 | } |
| 740 | #endif |
| 741 | |
| 742 | old_st->wsum -= entity->weight; |
| 743 | |
| 744 | if (entity->new_weight != entity->orig_weight) { |
| 745 | if (entity->new_weight < BFQ_MIN_WEIGHT || |
| 746 | entity->new_weight > BFQ_MAX_WEIGHT) { |
| 747 | pr_crit("update_weight_prio: new_weight %d\n", |
| 748 | entity->new_weight); |
| 749 | if (entity->new_weight < BFQ_MIN_WEIGHT) |
| 750 | entity->new_weight = BFQ_MIN_WEIGHT; |
| 751 | else |
| 752 | entity->new_weight = BFQ_MAX_WEIGHT; |
| 753 | } |
| 754 | entity->orig_weight = entity->new_weight; |
| 755 | if (bfqq) |
| 756 | bfqq->ioprio = |
| 757 | bfq_weight_to_ioprio(entity->orig_weight); |
| 758 | } |
| 759 | |
Paolo Valente | 431b17f | 2017-07-03 10:00:10 +0200 | [diff] [blame] | 760 | if (bfqq && update_class_too) |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 761 | bfqq->ioprio_class = bfqq->new_ioprio_class; |
Paolo Valente | 431b17f | 2017-07-03 10:00:10 +0200 | [diff] [blame] | 762 | |
| 763 | /* |
| 764 | * Reset prio_changed only if the ioprio_class change |
| 765 | * is not pending any longer. |
| 766 | */ |
| 767 | if (!bfqq || bfqq->ioprio_class == bfqq->new_ioprio_class) |
| 768 | entity->prio_changed = 0; |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 769 | |
| 770 | /* |
| 771 | * NOTE: here we may be changing the weight too early, |
| 772 | * this will cause unfairness. The correct approach |
| 773 | * would have required additional complexity to defer |
| 774 | * weight changes to the proper time instants (i.e., |
| 775 | * when entity->finish <= old_st->vtime). |
| 776 | */ |
| 777 | new_st = bfq_entity_service_tree(entity); |
| 778 | |
| 779 | prev_weight = entity->weight; |
| 780 | new_weight = entity->orig_weight * |
| 781 | (bfqq ? bfqq->wr_coeff : 1); |
| 782 | /* |
| 783 | * If the weight of the entity changes, remove the entity |
| 784 | * from its old weight counter (if there is a counter |
| 785 | * associated with the entity), and add it to the counter |
| 786 | * associated with its new weight. |
| 787 | */ |
| 788 | if (prev_weight != new_weight) { |
| 789 | root = bfqq ? &bfqd->queue_weights_tree : |
| 790 | &bfqd->group_weights_tree; |
| 791 | bfq_weights_tree_remove(bfqd, entity, root); |
| 792 | } |
| 793 | entity->weight = new_weight; |
| 794 | /* |
| 795 | * Add the entity to its weights tree only if it is |
| 796 | * not associated with a weight-raised queue. |
| 797 | */ |
| 798 | if (prev_weight != new_weight && |
| 799 | (bfqq ? bfqq->wr_coeff == 1 : 1)) |
| 800 | /* If we get here, root has been initialized. */ |
| 801 | bfq_weights_tree_add(bfqd, entity, root); |
| 802 | |
| 803 | new_st->wsum += entity->weight; |
| 804 | |
| 805 | if (new_st != old_st) |
| 806 | entity->start = new_st->vtime; |
| 807 | } |
| 808 | |
| 809 | return new_st; |
| 810 | } |
| 811 | |
| 812 | /** |
| 813 | * bfq_bfqq_served - update the scheduler status after selection for |
| 814 | * service. |
| 815 | * @bfqq: the queue being served. |
| 816 | * @served: bytes to transfer. |
| 817 | * |
| 818 | * NOTE: this can be optimized, as the timestamps of upper level entities |
| 819 | * are synchronized every time a new bfqq is selected for service. By now, |
| 820 | * we keep it to better check consistency. |
| 821 | */ |
| 822 | void bfq_bfqq_served(struct bfq_queue *bfqq, int served) |
| 823 | { |
| 824 | struct bfq_entity *entity = &bfqq->entity; |
| 825 | struct bfq_service_tree *st; |
| 826 | |
| 827 | for_each_entity(entity) { |
| 828 | st = bfq_entity_service_tree(entity); |
| 829 | |
| 830 | entity->service += served; |
| 831 | |
| 832 | st->vtime += bfq_delta(served, st->wsum); |
| 833 | bfq_forget_idle(st); |
| 834 | } |
| 835 | bfqg_stats_set_start_empty_time(bfqq_group(bfqq)); |
| 836 | bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs", served); |
| 837 | } |
| 838 | |
| 839 | /** |
| 840 | * bfq_bfqq_charge_time - charge an amount of service equivalent to the length |
| 841 | * of the time interval during which bfqq has been in |
| 842 | * service. |
| 843 | * @bfqd: the device |
| 844 | * @bfqq: the queue that needs a service update. |
| 845 | * @time_ms: the amount of time during which the queue has received service |
| 846 | * |
| 847 | * If a queue does not consume its budget fast enough, then providing |
| 848 | * the queue with service fairness may impair throughput, more or less |
| 849 | * severely. For this reason, queues that consume their budget slowly |
| 850 | * are provided with time fairness instead of service fairness. This |
| 851 | * goal is achieved through the BFQ scheduling engine, even if such an |
| 852 | * engine works in the service, and not in the time domain. The trick |
| 853 | * is charging these queues with an inflated amount of service, equal |
| 854 | * to the amount of service that they would have received during their |
| 855 | * service slot if they had been fast, i.e., if their requests had |
| 856 | * been dispatched at a rate equal to the estimated peak rate. |
| 857 | * |
| 858 | * It is worth noting that time fairness can cause important |
| 859 | * distortions in terms of bandwidth distribution, on devices with |
| 860 | * internal queueing. The reason is that I/O requests dispatched |
| 861 | * during the service slot of a queue may be served after that service |
| 862 | * slot is finished, and may have a total processing time loosely |
| 863 | * correlated with the duration of the service slot. This is |
| 864 | * especially true for short service slots. |
| 865 | */ |
| 866 | void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
| 867 | unsigned long time_ms) |
| 868 | { |
| 869 | struct bfq_entity *entity = &bfqq->entity; |
| 870 | int tot_serv_to_charge = entity->service; |
| 871 | unsigned int timeout_ms = jiffies_to_msecs(bfq_timeout); |
| 872 | |
| 873 | if (time_ms > 0 && time_ms < timeout_ms) |
| 874 | tot_serv_to_charge = |
| 875 | (bfqd->bfq_max_budget * time_ms) / timeout_ms; |
| 876 | |
| 877 | if (tot_serv_to_charge < entity->service) |
| 878 | tot_serv_to_charge = entity->service; |
| 879 | |
| 880 | /* Increase budget to avoid inconsistencies */ |
| 881 | if (tot_serv_to_charge > entity->budget) |
| 882 | entity->budget = tot_serv_to_charge; |
| 883 | |
| 884 | bfq_bfqq_served(bfqq, |
| 885 | max_t(int, 0, tot_serv_to_charge - entity->service)); |
| 886 | } |
| 887 | |
| 888 | static void bfq_update_fin_time_enqueue(struct bfq_entity *entity, |
| 889 | struct bfq_service_tree *st, |
| 890 | bool backshifted) |
| 891 | { |
| 892 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); |
| 893 | |
Paolo Valente | 431b17f | 2017-07-03 10:00:10 +0200 | [diff] [blame] | 894 | /* |
| 895 | * When this function is invoked, entity is not in any service |
| 896 | * tree, then it is safe to invoke next function with the last |
| 897 | * parameter set (see the comments on the function). |
| 898 | */ |
| 899 | st = __bfq_entity_update_weight_prio(st, entity, true); |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 900 | bfq_calc_finish(entity, entity->budget); |
| 901 | |
| 902 | /* |
| 903 | * If some queues enjoy backshifting for a while, then their |
| 904 | * (virtual) finish timestamps may happen to become lower and |
| 905 | * lower than the system virtual time. In particular, if |
| 906 | * these queues often happen to be idle for short time |
| 907 | * periods, and during such time periods other queues with |
| 908 | * higher timestamps happen to be busy, then the backshifted |
| 909 | * timestamps of the former queues can become much lower than |
| 910 | * the system virtual time. In fact, to serve the queues with |
| 911 | * higher timestamps while the ones with lower timestamps are |
| 912 | * idle, the system virtual time may be pushed-up to much |
| 913 | * higher values than the finish timestamps of the idle |
| 914 | * queues. As a consequence, the finish timestamps of all new |
| 915 | * or newly activated queues may end up being much larger than |
| 916 | * those of lucky queues with backshifted timestamps. The |
| 917 | * latter queues may then monopolize the device for a lot of |
| 918 | * time. This would simply break service guarantees. |
| 919 | * |
| 920 | * To reduce this problem, push up a little bit the |
| 921 | * backshifted timestamps of the queue associated with this |
| 922 | * entity (only a queue can happen to have the backshifted |
| 923 | * flag set): just enough to let the finish timestamp of the |
| 924 | * queue be equal to the current value of the system virtual |
| 925 | * time. This may introduce a little unfairness among queues |
| 926 | * with backshifted timestamps, but it does not break |
| 927 | * worst-case fairness guarantees. |
| 928 | * |
| 929 | * As a special case, if bfqq is weight-raised, push up |
| 930 | * timestamps much less, to keep very low the probability that |
| 931 | * this push up causes the backshifted finish timestamps of |
| 932 | * weight-raised queues to become higher than the backshifted |
| 933 | * finish timestamps of non weight-raised queues. |
| 934 | */ |
| 935 | if (backshifted && bfq_gt(st->vtime, entity->finish)) { |
| 936 | unsigned long delta = st->vtime - entity->finish; |
| 937 | |
| 938 | if (bfqq) |
| 939 | delta /= bfqq->wr_coeff; |
| 940 | |
| 941 | entity->start += delta; |
| 942 | entity->finish += delta; |
| 943 | } |
| 944 | |
| 945 | bfq_active_insert(st, entity); |
| 946 | } |
| 947 | |
| 948 | /** |
| 949 | * __bfq_activate_entity - handle activation of entity. |
| 950 | * @entity: the entity being activated. |
| 951 | * @non_blocking_wait_rq: true if entity was waiting for a request |
| 952 | * |
| 953 | * Called for a 'true' activation, i.e., if entity is not active and |
| 954 | * one of its children receives a new request. |
| 955 | * |
| 956 | * Basically, this function updates the timestamps of entity and |
| 957 | * inserts entity into its active tree, ater possible extracting it |
| 958 | * from its idle tree. |
| 959 | */ |
| 960 | static void __bfq_activate_entity(struct bfq_entity *entity, |
| 961 | bool non_blocking_wait_rq) |
| 962 | { |
| 963 | struct bfq_service_tree *st = bfq_entity_service_tree(entity); |
| 964 | bool backshifted = false; |
| 965 | unsigned long long min_vstart; |
| 966 | |
| 967 | /* See comments on bfq_fqq_update_budg_for_activation */ |
| 968 | if (non_blocking_wait_rq && bfq_gt(st->vtime, entity->finish)) { |
| 969 | backshifted = true; |
| 970 | min_vstart = entity->finish; |
| 971 | } else |
| 972 | min_vstart = st->vtime; |
| 973 | |
| 974 | if (entity->tree == &st->idle) { |
| 975 | /* |
| 976 | * Must be on the idle tree, bfq_idle_extract() will |
| 977 | * check for that. |
| 978 | */ |
| 979 | bfq_idle_extract(st, entity); |
| 980 | entity->start = bfq_gt(min_vstart, entity->finish) ? |
| 981 | min_vstart : entity->finish; |
| 982 | } else { |
| 983 | /* |
| 984 | * The finish time of the entity may be invalid, and |
| 985 | * it is in the past for sure, otherwise the queue |
| 986 | * would have been on the idle tree. |
| 987 | */ |
| 988 | entity->start = min_vstart; |
| 989 | st->wsum += entity->weight; |
| 990 | /* |
| 991 | * entity is about to be inserted into a service tree, |
| 992 | * and then set in service: get a reference to make |
| 993 | * sure entity does not disappear until it is no |
| 994 | * longer in service or scheduled for service. |
| 995 | */ |
| 996 | bfq_get_entity(entity); |
| 997 | |
| 998 | entity->on_st = true; |
| 999 | } |
| 1000 | |
| 1001 | bfq_update_fin_time_enqueue(entity, st, backshifted); |
| 1002 | } |
| 1003 | |
| 1004 | /** |
| 1005 | * __bfq_requeue_entity - handle requeueing or repositioning of an entity. |
| 1006 | * @entity: the entity being requeued or repositioned. |
| 1007 | * |
| 1008 | * Requeueing is needed if this entity stops being served, which |
| 1009 | * happens if a leaf descendant entity has expired. On the other hand, |
| 1010 | * repositioning is needed if the next_inservice_entity for the child |
| 1011 | * entity has changed. See the comments inside the function for |
| 1012 | * details. |
| 1013 | * |
| 1014 | * Basically, this function: 1) removes entity from its active tree if |
| 1015 | * present there, 2) updates the timestamps of entity and 3) inserts |
| 1016 | * entity back into its active tree (in the new, right position for |
| 1017 | * the new values of the timestamps). |
| 1018 | */ |
| 1019 | static void __bfq_requeue_entity(struct bfq_entity *entity) |
| 1020 | { |
| 1021 | struct bfq_sched_data *sd = entity->sched_data; |
| 1022 | struct bfq_service_tree *st = bfq_entity_service_tree(entity); |
| 1023 | |
| 1024 | if (entity == sd->in_service_entity) { |
| 1025 | /* |
| 1026 | * We are requeueing the current in-service entity, |
| 1027 | * which may have to be done for one of the following |
| 1028 | * reasons: |
| 1029 | * - entity represents the in-service queue, and the |
| 1030 | * in-service queue is being requeued after an |
| 1031 | * expiration; |
| 1032 | * - entity represents a group, and its budget has |
| 1033 | * changed because one of its child entities has |
| 1034 | * just been either activated or requeued for some |
| 1035 | * reason; the timestamps of the entity need then to |
| 1036 | * be updated, and the entity needs to be enqueued |
| 1037 | * or repositioned accordingly. |
| 1038 | * |
| 1039 | * In particular, before requeueing, the start time of |
| 1040 | * the entity must be moved forward to account for the |
| 1041 | * service that the entity has received while in |
| 1042 | * service. This is done by the next instructions. The |
| 1043 | * finish time will then be updated according to this |
| 1044 | * new value of the start time, and to the budget of |
| 1045 | * the entity. |
| 1046 | */ |
| 1047 | bfq_calc_finish(entity, entity->service); |
| 1048 | entity->start = entity->finish; |
| 1049 | /* |
| 1050 | * In addition, if the entity had more than one child |
| 1051 | * when set in service, then was not extracted from |
| 1052 | * the active tree. This implies that the position of |
| 1053 | * the entity in the active tree may need to be |
| 1054 | * changed now, because we have just updated the start |
| 1055 | * time of the entity, and we will update its finish |
| 1056 | * time in a moment (the requeueing is then, more |
| 1057 | * precisely, a repositioning in this case). To |
| 1058 | * implement this repositioning, we: 1) dequeue the |
| 1059 | * entity here, 2) update the finish time and |
| 1060 | * requeue the entity according to the new |
| 1061 | * timestamps below. |
| 1062 | */ |
| 1063 | if (entity->tree) |
| 1064 | bfq_active_extract(st, entity); |
| 1065 | } else { /* The entity is already active, and not in service */ |
| 1066 | /* |
| 1067 | * In this case, this function gets called only if the |
| 1068 | * next_in_service entity below this entity has |
| 1069 | * changed, and this change has caused the budget of |
| 1070 | * this entity to change, which, finally implies that |
| 1071 | * the finish time of this entity must be |
| 1072 | * updated. Such an update may cause the scheduling, |
| 1073 | * i.e., the position in the active tree, of this |
| 1074 | * entity to change. We handle this change by: 1) |
| 1075 | * dequeueing the entity here, 2) updating the finish |
| 1076 | * time and requeueing the entity according to the new |
| 1077 | * timestamps below. This is the same approach as the |
| 1078 | * non-extracted-entity sub-case above. |
| 1079 | */ |
| 1080 | bfq_active_extract(st, entity); |
| 1081 | } |
| 1082 | |
| 1083 | bfq_update_fin_time_enqueue(entity, st, false); |
| 1084 | } |
| 1085 | |
| 1086 | static void __bfq_activate_requeue_entity(struct bfq_entity *entity, |
| 1087 | struct bfq_sched_data *sd, |
| 1088 | bool non_blocking_wait_rq) |
| 1089 | { |
| 1090 | struct bfq_service_tree *st = bfq_entity_service_tree(entity); |
| 1091 | |
| 1092 | if (sd->in_service_entity == entity || entity->tree == &st->active) |
| 1093 | /* |
| 1094 | * in service or already queued on the active tree, |
| 1095 | * requeue or reposition |
| 1096 | */ |
| 1097 | __bfq_requeue_entity(entity); |
| 1098 | else |
| 1099 | /* |
| 1100 | * Not in service and not queued on its active tree: |
| 1101 | * the activity is idle and this is a true activation. |
| 1102 | */ |
| 1103 | __bfq_activate_entity(entity, non_blocking_wait_rq); |
| 1104 | } |
| 1105 | |
| 1106 | |
| 1107 | /** |
| 1108 | * bfq_activate_entity - activate or requeue an entity representing a bfq_queue, |
| 1109 | * and activate, requeue or reposition all ancestors |
| 1110 | * for which such an update becomes necessary. |
| 1111 | * @entity: the entity to activate. |
| 1112 | * @non_blocking_wait_rq: true if this entity was waiting for a request |
| 1113 | * @requeue: true if this is a requeue, which implies that bfqq is |
| 1114 | * being expired; thus ALL its ancestors stop being served and must |
| 1115 | * therefore be requeued |
| 1116 | */ |
| 1117 | static void bfq_activate_requeue_entity(struct bfq_entity *entity, |
| 1118 | bool non_blocking_wait_rq, |
| 1119 | bool requeue) |
| 1120 | { |
| 1121 | struct bfq_sched_data *sd; |
| 1122 | |
| 1123 | for_each_entity(entity) { |
| 1124 | sd = entity->sched_data; |
| 1125 | __bfq_activate_requeue_entity(entity, sd, non_blocking_wait_rq); |
| 1126 | |
| 1127 | if (!bfq_update_next_in_service(sd, entity) && !requeue) |
| 1128 | break; |
| 1129 | } |
| 1130 | } |
| 1131 | |
| 1132 | /** |
| 1133 | * __bfq_deactivate_entity - deactivate an entity from its service tree. |
| 1134 | * @entity: the entity to deactivate. |
| 1135 | * @ins_into_idle_tree: if false, the entity will not be put into the |
| 1136 | * idle tree. |
| 1137 | * |
| 1138 | * Deactivates an entity, independently from its previous state. Must |
| 1139 | * be invoked only if entity is on a service tree. Extracts the entity |
| 1140 | * from that tree, and if necessary and allowed, puts it on the idle |
| 1141 | * tree. |
| 1142 | */ |
| 1143 | bool __bfq_deactivate_entity(struct bfq_entity *entity, bool ins_into_idle_tree) |
| 1144 | { |
| 1145 | struct bfq_sched_data *sd = entity->sched_data; |
Paolo Valente | a66c38a | 2017-05-09 11:37:27 +0200 | [diff] [blame] | 1146 | struct bfq_service_tree *st; |
| 1147 | bool is_in_service; |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 1148 | |
| 1149 | if (!entity->on_st) /* entity never activated, or already inactive */ |
| 1150 | return false; |
| 1151 | |
Paolo Valente | a66c38a | 2017-05-09 11:37:27 +0200 | [diff] [blame] | 1152 | /* |
| 1153 | * If we get here, then entity is active, which implies that |
| 1154 | * bfq_group_set_parent has already been invoked for the group |
| 1155 | * represented by entity. Therefore, the field |
| 1156 | * entity->sched_data has been set, and we can safely use it. |
| 1157 | */ |
| 1158 | st = bfq_entity_service_tree(entity); |
| 1159 | is_in_service = entity == sd->in_service_entity; |
| 1160 | |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 1161 | if (is_in_service) |
| 1162 | bfq_calc_finish(entity, entity->service); |
| 1163 | |
| 1164 | if (entity->tree == &st->active) |
| 1165 | bfq_active_extract(st, entity); |
| 1166 | else if (!is_in_service && entity->tree == &st->idle) |
| 1167 | bfq_idle_extract(st, entity); |
| 1168 | |
| 1169 | if (!ins_into_idle_tree || !bfq_gt(entity->finish, st->vtime)) |
| 1170 | bfq_forget_entity(st, entity, is_in_service); |
| 1171 | else |
| 1172 | bfq_idle_insert(st, entity); |
| 1173 | |
| 1174 | return true; |
| 1175 | } |
| 1176 | |
| 1177 | /** |
| 1178 | * bfq_deactivate_entity - deactivate an entity representing a bfq_queue. |
| 1179 | * @entity: the entity to deactivate. |
| 1180 | * @ins_into_idle_tree: true if the entity can be put on the idle tree |
| 1181 | */ |
| 1182 | static void bfq_deactivate_entity(struct bfq_entity *entity, |
| 1183 | bool ins_into_idle_tree, |
| 1184 | bool expiration) |
| 1185 | { |
| 1186 | struct bfq_sched_data *sd; |
| 1187 | struct bfq_entity *parent = NULL; |
| 1188 | |
| 1189 | for_each_entity_safe(entity, parent) { |
| 1190 | sd = entity->sched_data; |
| 1191 | |
| 1192 | if (!__bfq_deactivate_entity(entity, ins_into_idle_tree)) { |
| 1193 | /* |
| 1194 | * entity is not in any tree any more, so |
| 1195 | * this deactivation is a no-op, and there is |
| 1196 | * nothing to change for upper-level entities |
| 1197 | * (in case of expiration, this can never |
| 1198 | * happen). |
| 1199 | */ |
| 1200 | return; |
| 1201 | } |
| 1202 | |
| 1203 | if (sd->next_in_service == entity) |
| 1204 | /* |
| 1205 | * entity was the next_in_service entity, |
| 1206 | * then, since entity has just been |
| 1207 | * deactivated, a new one must be found. |
| 1208 | */ |
| 1209 | bfq_update_next_in_service(sd, NULL); |
| 1210 | |
| 1211 | if (sd->next_in_service) |
| 1212 | /* |
| 1213 | * The parent entity is still backlogged, |
| 1214 | * because next_in_service is not NULL. So, no |
| 1215 | * further upwards deactivation must be |
| 1216 | * performed. Yet, next_in_service has |
| 1217 | * changed. Then the schedule does need to be |
| 1218 | * updated upwards. |
| 1219 | */ |
| 1220 | break; |
| 1221 | |
| 1222 | /* |
| 1223 | * If we get here, then the parent is no more |
| 1224 | * backlogged and we need to propagate the |
| 1225 | * deactivation upwards. Thus let the loop go on. |
| 1226 | */ |
| 1227 | |
| 1228 | /* |
| 1229 | * Also let parent be queued into the idle tree on |
| 1230 | * deactivation, to preserve service guarantees, and |
| 1231 | * assuming that who invoked this function does not |
| 1232 | * need parent entities too to be removed completely. |
| 1233 | */ |
| 1234 | ins_into_idle_tree = true; |
| 1235 | } |
| 1236 | |
| 1237 | /* |
| 1238 | * If the deactivation loop is fully executed, then there are |
| 1239 | * no more entities to touch and next loop is not executed at |
| 1240 | * all. Otherwise, requeue remaining entities if they are |
| 1241 | * about to stop receiving service, or reposition them if this |
| 1242 | * is not the case. |
| 1243 | */ |
| 1244 | entity = parent; |
| 1245 | for_each_entity(entity) { |
| 1246 | /* |
| 1247 | * Invoke __bfq_requeue_entity on entity, even if |
| 1248 | * already active, to requeue/reposition it in the |
| 1249 | * active tree (because sd->next_in_service has |
| 1250 | * changed) |
| 1251 | */ |
| 1252 | __bfq_requeue_entity(entity); |
| 1253 | |
| 1254 | sd = entity->sched_data; |
| 1255 | if (!bfq_update_next_in_service(sd, entity) && |
| 1256 | !expiration) |
| 1257 | /* |
| 1258 | * next_in_service unchanged or not causing |
| 1259 | * any change in entity->parent->sd, and no |
| 1260 | * requeueing needed for expiration: stop |
| 1261 | * here. |
| 1262 | */ |
| 1263 | break; |
| 1264 | } |
| 1265 | } |
| 1266 | |
| 1267 | /** |
| 1268 | * bfq_calc_vtime_jump - compute the value to which the vtime should jump, |
| 1269 | * if needed, to have at least one entity eligible. |
| 1270 | * @st: the service tree to act upon. |
| 1271 | * |
| 1272 | * Assumes that st is not empty. |
| 1273 | */ |
| 1274 | static u64 bfq_calc_vtime_jump(struct bfq_service_tree *st) |
| 1275 | { |
| 1276 | struct bfq_entity *root_entity = bfq_root_active_entity(&st->active); |
| 1277 | |
| 1278 | if (bfq_gt(root_entity->min_start, st->vtime)) |
| 1279 | return root_entity->min_start; |
| 1280 | |
| 1281 | return st->vtime; |
| 1282 | } |
| 1283 | |
| 1284 | static void bfq_update_vtime(struct bfq_service_tree *st, u64 new_value) |
| 1285 | { |
| 1286 | if (new_value > st->vtime) { |
| 1287 | st->vtime = new_value; |
| 1288 | bfq_forget_idle(st); |
| 1289 | } |
| 1290 | } |
| 1291 | |
| 1292 | /** |
| 1293 | * bfq_first_active_entity - find the eligible entity with |
| 1294 | * the smallest finish time |
| 1295 | * @st: the service tree to select from. |
| 1296 | * @vtime: the system virtual to use as a reference for eligibility |
| 1297 | * |
| 1298 | * This function searches the first schedulable entity, starting from the |
| 1299 | * root of the tree and going on the left every time on this side there is |
Hou Tao | 38c9140 | 2017-07-12 15:25:01 +0800 | [diff] [blame] | 1300 | * a subtree with at least one eligible (start <= vtime) entity. The path on |
Paolo Valente | ea25da4 | 2017-04-19 08:48:24 -0600 | [diff] [blame] | 1301 | * the right is followed only if a) the left subtree contains no eligible |
| 1302 | * entities and b) no eligible entity has been found yet. |
| 1303 | */ |
| 1304 | static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st, |
| 1305 | u64 vtime) |
| 1306 | { |
| 1307 | struct bfq_entity *entry, *first = NULL; |
| 1308 | struct rb_node *node = st->active.rb_node; |
| 1309 | |
| 1310 | while (node) { |
| 1311 | entry = rb_entry(node, struct bfq_entity, rb_node); |
| 1312 | left: |
| 1313 | if (!bfq_gt(entry->start, vtime)) |
| 1314 | first = entry; |
| 1315 | |
| 1316 | if (node->rb_left) { |
| 1317 | entry = rb_entry(node->rb_left, |
| 1318 | struct bfq_entity, rb_node); |
| 1319 | if (!bfq_gt(entry->min_start, vtime)) { |
| 1320 | node = node->rb_left; |
| 1321 | goto left; |
| 1322 | } |
| 1323 | } |
| 1324 | if (first) |
| 1325 | break; |
| 1326 | node = node->rb_right; |
| 1327 | } |
| 1328 | |
| 1329 | return first; |
| 1330 | } |
| 1331 | |
| 1332 | /** |
| 1333 | * __bfq_lookup_next_entity - return the first eligible entity in @st. |
| 1334 | * @st: the service tree. |
| 1335 | * |
| 1336 | * If there is no in-service entity for the sched_data st belongs to, |
| 1337 | * then return the entity that will be set in service if: |
| 1338 | * 1) the parent entity this st belongs to is set in service; |
| 1339 | * 2) no entity belonging to such parent entity undergoes a state change |
| 1340 | * that would influence the timestamps of the entity (e.g., becomes idle, |
| 1341 | * becomes backlogged, changes its budget, ...). |
| 1342 | * |
| 1343 | * In this first case, update the virtual time in @st too (see the |
| 1344 | * comments on this update inside the function). |
| 1345 | * |
| 1346 | * In constrast, if there is an in-service entity, then return the |
| 1347 | * entity that would be set in service if not only the above |
| 1348 | * conditions, but also the next one held true: the currently |
| 1349 | * in-service entity, on expiration, |
| 1350 | * 1) gets a finish time equal to the current one, or |
| 1351 | * 2) is not eligible any more, or |
| 1352 | * 3) is idle. |
| 1353 | */ |
| 1354 | static struct bfq_entity * |
| 1355 | __bfq_lookup_next_entity(struct bfq_service_tree *st, bool in_service) |
| 1356 | { |
| 1357 | struct bfq_entity *entity; |
| 1358 | u64 new_vtime; |
| 1359 | |
| 1360 | if (RB_EMPTY_ROOT(&st->active)) |
| 1361 | return NULL; |
| 1362 | |
| 1363 | /* |
| 1364 | * Get the value of the system virtual time for which at |
| 1365 | * least one entity is eligible. |
| 1366 | */ |
| 1367 | new_vtime = bfq_calc_vtime_jump(st); |
| 1368 | |
| 1369 | /* |
| 1370 | * If there is no in-service entity for the sched_data this |
| 1371 | * active tree belongs to, then push the system virtual time |
| 1372 | * up to the value that guarantees that at least one entity is |
| 1373 | * eligible. If, instead, there is an in-service entity, then |
| 1374 | * do not make any such update, because there is already an |
| 1375 | * eligible entity, namely the in-service one (even if the |
| 1376 | * entity is not on st, because it was extracted when set in |
| 1377 | * service). |
| 1378 | */ |
| 1379 | if (!in_service) |
| 1380 | bfq_update_vtime(st, new_vtime); |
| 1381 | |
| 1382 | entity = bfq_first_active_entity(st, new_vtime); |
| 1383 | |
| 1384 | return entity; |
| 1385 | } |
| 1386 | |
| 1387 | /** |
| 1388 | * bfq_lookup_next_entity - return the first eligible entity in @sd. |
| 1389 | * @sd: the sched_data. |
| 1390 | * |
| 1391 | * This function is invoked when there has been a change in the trees |
| 1392 | * for sd, and we need know what is the new next entity after this |
| 1393 | * change. |
| 1394 | */ |
| 1395 | static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd) |
| 1396 | { |
| 1397 | struct bfq_service_tree *st = sd->service_tree; |
| 1398 | struct bfq_service_tree *idle_class_st = st + (BFQ_IOPRIO_CLASSES - 1); |
| 1399 | struct bfq_entity *entity = NULL; |
| 1400 | int class_idx = 0; |
| 1401 | |
| 1402 | /* |
| 1403 | * Choose from idle class, if needed to guarantee a minimum |
| 1404 | * bandwidth to this class (and if there is some active entity |
| 1405 | * in idle class). This should also mitigate |
| 1406 | * priority-inversion problems in case a low priority task is |
| 1407 | * holding file system resources. |
| 1408 | */ |
| 1409 | if (time_is_before_jiffies(sd->bfq_class_idle_last_service + |
| 1410 | BFQ_CL_IDLE_TIMEOUT)) { |
| 1411 | if (!RB_EMPTY_ROOT(&idle_class_st->active)) |
| 1412 | class_idx = BFQ_IOPRIO_CLASSES - 1; |
| 1413 | /* About to be served if backlogged, or not yet backlogged */ |
| 1414 | sd->bfq_class_idle_last_service = jiffies; |
| 1415 | } |
| 1416 | |
| 1417 | /* |
| 1418 | * Find the next entity to serve for the highest-priority |
| 1419 | * class, unless the idle class needs to be served. |
| 1420 | */ |
| 1421 | for (; class_idx < BFQ_IOPRIO_CLASSES; class_idx++) { |
| 1422 | entity = __bfq_lookup_next_entity(st + class_idx, |
| 1423 | sd->in_service_entity); |
| 1424 | |
| 1425 | if (entity) |
| 1426 | break; |
| 1427 | } |
| 1428 | |
| 1429 | if (!entity) |
| 1430 | return NULL; |
| 1431 | |
| 1432 | return entity; |
| 1433 | } |
| 1434 | |
| 1435 | bool next_queue_may_preempt(struct bfq_data *bfqd) |
| 1436 | { |
| 1437 | struct bfq_sched_data *sd = &bfqd->root_group->sched_data; |
| 1438 | |
| 1439 | return sd->next_in_service != sd->in_service_entity; |
| 1440 | } |
| 1441 | |
| 1442 | /* |
| 1443 | * Get next queue for service. |
| 1444 | */ |
| 1445 | struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd) |
| 1446 | { |
| 1447 | struct bfq_entity *entity = NULL; |
| 1448 | struct bfq_sched_data *sd; |
| 1449 | struct bfq_queue *bfqq; |
| 1450 | |
| 1451 | if (bfqd->busy_queues == 0) |
| 1452 | return NULL; |
| 1453 | |
| 1454 | /* |
| 1455 | * Traverse the path from the root to the leaf entity to |
| 1456 | * serve. Set in service all the entities visited along the |
| 1457 | * way. |
| 1458 | */ |
| 1459 | sd = &bfqd->root_group->sched_data; |
| 1460 | for (; sd ; sd = entity->my_sched_data) { |
| 1461 | /* |
| 1462 | * WARNING. We are about to set the in-service entity |
| 1463 | * to sd->next_in_service, i.e., to the (cached) value |
| 1464 | * returned by bfq_lookup_next_entity(sd) the last |
| 1465 | * time it was invoked, i.e., the last time when the |
| 1466 | * service order in sd changed as a consequence of the |
| 1467 | * activation or deactivation of an entity. In this |
| 1468 | * respect, if we execute bfq_lookup_next_entity(sd) |
| 1469 | * in this very moment, it may, although with low |
| 1470 | * probability, yield a different entity than that |
| 1471 | * pointed to by sd->next_in_service. This rare event |
| 1472 | * happens in case there was no CLASS_IDLE entity to |
| 1473 | * serve for sd when bfq_lookup_next_entity(sd) was |
| 1474 | * invoked for the last time, while there is now one |
| 1475 | * such entity. |
| 1476 | * |
| 1477 | * If the above event happens, then the scheduling of |
| 1478 | * such entity in CLASS_IDLE is postponed until the |
| 1479 | * service of the sd->next_in_service entity |
| 1480 | * finishes. In fact, when the latter is expired, |
| 1481 | * bfq_lookup_next_entity(sd) gets called again, |
| 1482 | * exactly to update sd->next_in_service. |
| 1483 | */ |
| 1484 | |
| 1485 | /* Make next_in_service entity become in_service_entity */ |
| 1486 | entity = sd->next_in_service; |
| 1487 | sd->in_service_entity = entity; |
| 1488 | |
| 1489 | /* |
| 1490 | * Reset the accumulator of the amount of service that |
| 1491 | * the entity is about to receive. |
| 1492 | */ |
| 1493 | entity->service = 0; |
| 1494 | |
| 1495 | /* |
| 1496 | * If entity is no longer a candidate for next |
| 1497 | * service, then we extract it from its active tree, |
| 1498 | * for the following reason. To further boost the |
| 1499 | * throughput in some special case, BFQ needs to know |
| 1500 | * which is the next candidate entity to serve, while |
| 1501 | * there is already an entity in service. In this |
| 1502 | * respect, to make it easy to compute/update the next |
| 1503 | * candidate entity to serve after the current |
| 1504 | * candidate has been set in service, there is a case |
| 1505 | * where it is necessary to extract the current |
| 1506 | * candidate from its service tree. Such a case is |
| 1507 | * when the entity just set in service cannot be also |
| 1508 | * a candidate for next service. Details about when |
| 1509 | * this conditions holds are reported in the comments |
| 1510 | * on the function bfq_no_longer_next_in_service() |
| 1511 | * invoked below. |
| 1512 | */ |
| 1513 | if (bfq_no_longer_next_in_service(entity)) |
| 1514 | bfq_active_extract(bfq_entity_service_tree(entity), |
| 1515 | entity); |
| 1516 | |
| 1517 | /* |
| 1518 | * For the same reason why we may have just extracted |
| 1519 | * entity from its active tree, we may need to update |
| 1520 | * next_in_service for the sched_data of entity too, |
| 1521 | * regardless of whether entity has been extracted. |
| 1522 | * In fact, even if entity has not been extracted, a |
| 1523 | * descendant entity may get extracted. Such an event |
| 1524 | * would cause a change in next_in_service for the |
| 1525 | * level of the descendant entity, and thus possibly |
| 1526 | * back to upper levels. |
| 1527 | * |
| 1528 | * We cannot perform the resulting needed update |
| 1529 | * before the end of this loop, because, to know which |
| 1530 | * is the correct next-to-serve candidate entity for |
| 1531 | * each level, we need first to find the leaf entity |
| 1532 | * to set in service. In fact, only after we know |
| 1533 | * which is the next-to-serve leaf entity, we can |
| 1534 | * discover whether the parent entity of the leaf |
| 1535 | * entity becomes the next-to-serve, and so on. |
| 1536 | */ |
| 1537 | |
| 1538 | } |
| 1539 | |
| 1540 | bfqq = bfq_entity_to_bfqq(entity); |
| 1541 | |
| 1542 | /* |
| 1543 | * We can finally update all next-to-serve entities along the |
| 1544 | * path from the leaf entity just set in service to the root. |
| 1545 | */ |
| 1546 | for_each_entity(entity) { |
| 1547 | struct bfq_sched_data *sd = entity->sched_data; |
| 1548 | |
| 1549 | if (!bfq_update_next_in_service(sd, NULL)) |
| 1550 | break; |
| 1551 | } |
| 1552 | |
| 1553 | return bfqq; |
| 1554 | } |
| 1555 | |
| 1556 | void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd) |
| 1557 | { |
| 1558 | struct bfq_queue *in_serv_bfqq = bfqd->in_service_queue; |
| 1559 | struct bfq_entity *in_serv_entity = &in_serv_bfqq->entity; |
| 1560 | struct bfq_entity *entity = in_serv_entity; |
| 1561 | |
| 1562 | bfq_clear_bfqq_wait_request(in_serv_bfqq); |
| 1563 | hrtimer_try_to_cancel(&bfqd->idle_slice_timer); |
| 1564 | bfqd->in_service_queue = NULL; |
| 1565 | |
| 1566 | /* |
| 1567 | * When this function is called, all in-service entities have |
| 1568 | * been properly deactivated or requeued, so we can safely |
| 1569 | * execute the final step: reset in_service_entity along the |
| 1570 | * path from entity to the root. |
| 1571 | */ |
| 1572 | for_each_entity(entity) |
| 1573 | entity->sched_data->in_service_entity = NULL; |
| 1574 | |
| 1575 | /* |
| 1576 | * in_serv_entity is no longer in service, so, if it is in no |
| 1577 | * service tree either, then release the service reference to |
| 1578 | * the queue it represents (taken with bfq_get_entity). |
| 1579 | */ |
| 1580 | if (!in_serv_entity->on_st) |
| 1581 | bfq_put_queue(in_serv_bfqq); |
| 1582 | } |
| 1583 | |
| 1584 | void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
| 1585 | bool ins_into_idle_tree, bool expiration) |
| 1586 | { |
| 1587 | struct bfq_entity *entity = &bfqq->entity; |
| 1588 | |
| 1589 | bfq_deactivate_entity(entity, ins_into_idle_tree, expiration); |
| 1590 | } |
| 1591 | |
| 1592 | void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) |
| 1593 | { |
| 1594 | struct bfq_entity *entity = &bfqq->entity; |
| 1595 | |
| 1596 | bfq_activate_requeue_entity(entity, bfq_bfqq_non_blocking_wait_rq(bfqq), |
| 1597 | false); |
| 1598 | bfq_clear_bfqq_non_blocking_wait_rq(bfqq); |
| 1599 | } |
| 1600 | |
| 1601 | void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) |
| 1602 | { |
| 1603 | struct bfq_entity *entity = &bfqq->entity; |
| 1604 | |
| 1605 | bfq_activate_requeue_entity(entity, false, |
| 1606 | bfqq == bfqd->in_service_queue); |
| 1607 | } |
| 1608 | |
| 1609 | /* |
| 1610 | * Called when the bfqq no longer has requests pending, remove it from |
| 1611 | * the service tree. As a special case, it can be invoked during an |
| 1612 | * expiration. |
| 1613 | */ |
| 1614 | void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
| 1615 | bool expiration) |
| 1616 | { |
| 1617 | bfq_log_bfqq(bfqd, bfqq, "del from busy"); |
| 1618 | |
| 1619 | bfq_clear_bfqq_busy(bfqq); |
| 1620 | |
| 1621 | bfqd->busy_queues--; |
| 1622 | |
| 1623 | if (!bfqq->dispatched) |
| 1624 | bfq_weights_tree_remove(bfqd, &bfqq->entity, |
| 1625 | &bfqd->queue_weights_tree); |
| 1626 | |
| 1627 | if (bfqq->wr_coeff > 1) |
| 1628 | bfqd->wr_busy_queues--; |
| 1629 | |
| 1630 | bfqg_stats_update_dequeue(bfqq_group(bfqq)); |
| 1631 | |
| 1632 | bfq_deactivate_bfqq(bfqd, bfqq, true, expiration); |
| 1633 | } |
| 1634 | |
| 1635 | /* |
| 1636 | * Called when an inactive queue receives a new request. |
| 1637 | */ |
| 1638 | void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq) |
| 1639 | { |
| 1640 | bfq_log_bfqq(bfqd, bfqq, "add to busy"); |
| 1641 | |
| 1642 | bfq_activate_bfqq(bfqd, bfqq); |
| 1643 | |
| 1644 | bfq_mark_bfqq_busy(bfqq); |
| 1645 | bfqd->busy_queues++; |
| 1646 | |
| 1647 | if (!bfqq->dispatched) |
| 1648 | if (bfqq->wr_coeff == 1) |
| 1649 | bfq_weights_tree_add(bfqd, &bfqq->entity, |
| 1650 | &bfqd->queue_weights_tree); |
| 1651 | |
| 1652 | if (bfqq->wr_coeff > 1) |
| 1653 | bfqd->wr_busy_queues++; |
| 1654 | } |