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a497ee34 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
ea25da48 PV |
2 | /* |
3 | * Hierarchical Budget Worst-case Fair Weighted Fair Queueing | |
4 | * (B-WF2Q+): hierarchical scheduling algorithm by which the BFQ I/O | |
5 | * scheduler schedules generic entities. The latter can represent | |
6 | * either single bfq queues (associated with processes) or groups of | |
7 | * bfq queues (associated with cgroups). | |
ea25da48 PV |
8 | */ |
9 | #include "bfq-iosched.h" | |
10 | ||
11 | /** | |
12 | * bfq_gt - compare two timestamps. | |
13 | * @a: first ts. | |
14 | * @b: second ts. | |
15 | * | |
16 | * Return @a > @b, dealing with wrapping correctly. | |
17 | */ | |
18 | static int bfq_gt(u64 a, u64 b) | |
19 | { | |
20 | return (s64)(a - b) > 0; | |
21 | } | |
22 | ||
23 | static struct bfq_entity *bfq_root_active_entity(struct rb_root *tree) | |
24 | { | |
25 | struct rb_node *node = tree->rb_node; | |
26 | ||
27 | return rb_entry(node, struct bfq_entity, rb_node); | |
28 | } | |
29 | ||
30 | static unsigned int bfq_class_idx(struct bfq_entity *entity) | |
31 | { | |
32 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
33 | ||
34 | return bfqq ? bfqq->ioprio_class - 1 : | |
35 | BFQ_DEFAULT_GRP_CLASS - 1; | |
36 | } | |
37 | ||
73d58118 PV |
38 | unsigned int bfq_tot_busy_queues(struct bfq_data *bfqd) |
39 | { | |
40 | return bfqd->busy_queues[0] + bfqd->busy_queues[1] + | |
41 | bfqd->busy_queues[2]; | |
42 | } | |
43 | ||
80294c3b PV |
44 | static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, |
45 | bool expiration); | |
ea25da48 PV |
46 | |
47 | static bool bfq_update_parent_budget(struct bfq_entity *next_in_service); | |
48 | ||
49 | /** | |
50 | * bfq_update_next_in_service - update sd->next_in_service | |
51 | * @sd: sched_data for which to perform the update. | |
52 | * @new_entity: if not NULL, pointer to the entity whose activation, | |
636b8fe8 | 53 | * requeueing or repositioning triggered the invocation of |
ea25da48 | 54 | * this function. |
80294c3b PV |
55 | * @expiration: id true, this function is being invoked after the |
56 | * expiration of the in-service entity | |
ea25da48 PV |
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, | |
80294c3b PV |
75 | struct bfq_entity *new_entity, |
76 | bool expiration) | |
ea25da48 PV |
77 | { |
78 | struct bfq_entity *next_in_service = sd->next_in_service; | |
79 | bool parent_sched_may_change = false; | |
24d90bb2 | 80 | bool change_without_lookup = false; |
ea25da48 PV |
81 | |
82 | /* | |
83 | * If this update is triggered by the activation, requeueing | |
636b8fe8 | 84 | * or repositioning of an entity that does not coincide with |
ea25da48 PV |
85 | * sd->next_in_service, then a full lookup in the active tree |
86 | * can be avoided. In fact, it is enough to check whether the | |
a02195ce PV |
87 | * just-modified entity has the same priority as |
88 | * sd->next_in_service, is eligible and has a lower virtual | |
ea25da48 PV |
89 | * finish time than sd->next_in_service. If this compound |
90 | * condition holds, then the new entity becomes the new | |
91 | * next_in_service. Otherwise no change is needed. | |
92 | */ | |
93 | if (new_entity && new_entity != sd->next_in_service) { | |
94 | /* | |
95 | * Flag used to decide whether to replace | |
96 | * sd->next_in_service with new_entity. Tentatively | |
97 | * set to true, and left as true if | |
98 | * sd->next_in_service is NULL. | |
99 | */ | |
24d90bb2 | 100 | change_without_lookup = true; |
ea25da48 PV |
101 | |
102 | /* | |
103 | * If there is already a next_in_service candidate | |
a02195ce PV |
104 | * entity, then compare timestamps to decide whether |
105 | * to replace sd->service_tree with new_entity. | |
ea25da48 PV |
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 | ||
24d90bb2 | 113 | change_without_lookup = |
ea25da48 PV |
114 | (new_entity_class_idx == |
115 | bfq_class_idx(next_in_service) | |
116 | && | |
117 | !bfq_gt(new_entity->start, st->vtime) | |
118 | && | |
119 | bfq_gt(next_in_service->finish, | |
a02195ce | 120 | new_entity->finish)); |
ea25da48 PV |
121 | } |
122 | ||
24d90bb2 | 123 | if (change_without_lookup) |
ea25da48 | 124 | next_in_service = new_entity; |
24d90bb2 PV |
125 | } |
126 | ||
127 | if (!change_without_lookup) /* lookup needed */ | |
80294c3b | 128 | next_in_service = bfq_lookup_next_entity(sd, expiration); |
ea25da48 | 129 | |
e02a0aa2 PV |
130 | if (next_in_service) { |
131 | bool new_budget_triggers_change = | |
ea25da48 | 132 | bfq_update_parent_budget(next_in_service); |
ea25da48 | 133 | |
e02a0aa2 PV |
134 | parent_sched_may_change = !sd->next_in_service || |
135 | new_budget_triggers_change; | |
136 | } | |
137 | ||
ea25da48 PV |
138 | sd->next_in_service = next_in_service; |
139 | ||
ea25da48 PV |
140 | return parent_sched_may_change; |
141 | } | |
142 | ||
143 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
144 | ||
145 | struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) | |
146 | { | |
147 | struct bfq_entity *group_entity = bfqq->entity.parent; | |
148 | ||
149 | if (!group_entity) | |
150 | group_entity = &bfqq->bfqd->root_group->entity; | |
151 | ||
152 | return container_of(group_entity, struct bfq_group, entity); | |
153 | } | |
154 | ||
155 | /* | |
156 | * Returns true if this budget changes may let next_in_service->parent | |
157 | * become the next_in_service entity for its parent entity. | |
158 | */ | |
159 | static bool bfq_update_parent_budget(struct bfq_entity *next_in_service) | |
160 | { | |
161 | struct bfq_entity *bfqg_entity; | |
162 | struct bfq_group *bfqg; | |
163 | struct bfq_sched_data *group_sd; | |
164 | bool ret = false; | |
165 | ||
166 | group_sd = next_in_service->sched_data; | |
167 | ||
168 | bfqg = container_of(group_sd, struct bfq_group, sched_data); | |
169 | /* | |
170 | * bfq_group's my_entity field is not NULL only if the group | |
171 | * is not the root group. We must not touch the root entity | |
172 | * as it must never become an in-service entity. | |
173 | */ | |
174 | bfqg_entity = bfqg->my_entity; | |
175 | if (bfqg_entity) { | |
176 | if (bfqg_entity->budget > next_in_service->budget) | |
177 | ret = true; | |
178 | bfqg_entity->budget = next_in_service->budget; | |
179 | } | |
180 | ||
181 | return ret; | |
182 | } | |
183 | ||
184 | /* | |
185 | * This function tells whether entity stops being a candidate for next | |
46d556e6 PV |
186 | * service, according to the restrictive definition of the field |
187 | * next_in_service. In particular, this function is invoked for an | |
188 | * entity that is about to be set in service. | |
ea25da48 | 189 | * |
46d556e6 PV |
190 | * If entity is a queue, then the entity is no longer a candidate for |
191 | * next service according to the that definition, because entity is | |
192 | * about to become the in-service queue. This function then returns | |
193 | * true if entity is a queue. | |
ea25da48 | 194 | * |
46d556e6 PV |
195 | * In contrast, entity could still be a candidate for next service if |
196 | * it is not a queue, and has more than one active child. In fact, | |
197 | * even if one of its children is about to be set in service, other | |
198 | * active children may still be the next to serve, for the parent | |
199 | * entity, even according to the above definition. As a consequence, a | |
200 | * non-queue entity is not a candidate for next-service only if it has | |
201 | * only one active child. And only if this condition holds, then this | |
202 | * function returns true for a non-queue entity. | |
ea25da48 PV |
203 | */ |
204 | static bool bfq_no_longer_next_in_service(struct bfq_entity *entity) | |
205 | { | |
206 | struct bfq_group *bfqg; | |
207 | ||
208 | if (bfq_entity_to_bfqq(entity)) | |
209 | return true; | |
210 | ||
211 | bfqg = container_of(entity, struct bfq_group, entity); | |
212 | ||
46d556e6 PV |
213 | /* |
214 | * The field active_entities does not always contain the | |
215 | * actual number of active children entities: it happens to | |
216 | * not account for the in-service entity in case the latter is | |
217 | * removed from its active tree (which may get done after | |
218 | * invoking the function bfq_no_longer_next_in_service in | |
219 | * bfq_get_next_queue). Fortunately, here, i.e., while | |
220 | * bfq_no_longer_next_in_service is not yet completed in | |
221 | * bfq_get_next_queue, bfq_active_extract has not yet been | |
222 | * invoked, and thus active_entities still coincides with the | |
223 | * actual number of active entities. | |
224 | */ | |
ea25da48 PV |
225 | if (bfqg->active_entities == 1) |
226 | return true; | |
227 | ||
228 | return false; | |
229 | } | |
230 | ||
231 | #else /* CONFIG_BFQ_GROUP_IOSCHED */ | |
232 | ||
233 | struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) | |
234 | { | |
235 | return bfqq->bfqd->root_group; | |
236 | } | |
237 | ||
238 | static bool bfq_update_parent_budget(struct bfq_entity *next_in_service) | |
239 | { | |
240 | return false; | |
241 | } | |
242 | ||
243 | static bool bfq_no_longer_next_in_service(struct bfq_entity *entity) | |
244 | { | |
245 | return true; | |
246 | } | |
247 | ||
248 | #endif /* CONFIG_BFQ_GROUP_IOSCHED */ | |
249 | ||
250 | /* | |
251 | * Shift for timestamp calculations. This actually limits the maximum | |
252 | * service allowed in one timestamp delta (small shift values increase it), | |
253 | * the maximum total weight that can be used for the queues in the system | |
254 | * (big shift values increase it), and the period of virtual time | |
255 | * wraparounds. | |
256 | */ | |
257 | #define WFQ_SERVICE_SHIFT 22 | |
258 | ||
259 | struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) | |
260 | { | |
261 | struct bfq_queue *bfqq = NULL; | |
262 | ||
263 | if (!entity->my_sched_data) | |
264 | bfqq = container_of(entity, struct bfq_queue, entity); | |
265 | ||
266 | return bfqq; | |
267 | } | |
268 | ||
269 | ||
270 | /** | |
271 | * bfq_delta - map service into the virtual time domain. | |
272 | * @service: amount of service. | |
273 | * @weight: scale factor (weight of an entity or weight sum). | |
274 | */ | |
275 | static u64 bfq_delta(unsigned long service, unsigned long weight) | |
276 | { | |
554d21ef | 277 | return div64_ul((u64)service << WFQ_SERVICE_SHIFT, weight); |
ea25da48 PV |
278 | } |
279 | ||
280 | /** | |
281 | * bfq_calc_finish - assign the finish time to an entity. | |
282 | * @entity: the entity to act upon. | |
283 | * @service: the service to be charged to the entity. | |
284 | */ | |
285 | static void bfq_calc_finish(struct bfq_entity *entity, unsigned long service) | |
286 | { | |
287 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
288 | ||
289 | entity->finish = entity->start + | |
290 | bfq_delta(service, entity->weight); | |
291 | ||
292 | if (bfqq) { | |
293 | bfq_log_bfqq(bfqq->bfqd, bfqq, | |
294 | "calc_finish: serv %lu, w %d", | |
295 | service, entity->weight); | |
296 | bfq_log_bfqq(bfqq->bfqd, bfqq, | |
297 | "calc_finish: start %llu, finish %llu, delta %llu", | |
298 | entity->start, entity->finish, | |
299 | bfq_delta(service, entity->weight)); | |
300 | } | |
301 | } | |
302 | ||
303 | /** | |
304 | * bfq_entity_of - get an entity from a node. | |
305 | * @node: the node field of the entity. | |
306 | * | |
307 | * Convert a node pointer to the relative entity. This is used only | |
308 | * to simplify the logic of some functions and not as the generic | |
309 | * conversion mechanism because, e.g., in the tree walking functions, | |
310 | * the check for a %NULL value would be redundant. | |
311 | */ | |
312 | struct bfq_entity *bfq_entity_of(struct rb_node *node) | |
313 | { | |
314 | struct bfq_entity *entity = NULL; | |
315 | ||
316 | if (node) | |
317 | entity = rb_entry(node, struct bfq_entity, rb_node); | |
318 | ||
319 | return entity; | |
320 | } | |
321 | ||
322 | /** | |
323 | * bfq_extract - remove an entity from a tree. | |
324 | * @root: the tree root. | |
325 | * @entity: the entity to remove. | |
326 | */ | |
327 | static void bfq_extract(struct rb_root *root, struct bfq_entity *entity) | |
328 | { | |
329 | entity->tree = NULL; | |
330 | rb_erase(&entity->rb_node, root); | |
331 | } | |
332 | ||
333 | /** | |
334 | * bfq_idle_extract - extract an entity from the idle tree. | |
335 | * @st: the service tree of the owning @entity. | |
336 | * @entity: the entity being removed. | |
337 | */ | |
338 | static void bfq_idle_extract(struct bfq_service_tree *st, | |
339 | struct bfq_entity *entity) | |
340 | { | |
341 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
342 | struct rb_node *next; | |
343 | ||
344 | if (entity == st->first_idle) { | |
345 | next = rb_next(&entity->rb_node); | |
346 | st->first_idle = bfq_entity_of(next); | |
347 | } | |
348 | ||
349 | if (entity == st->last_idle) { | |
350 | next = rb_prev(&entity->rb_node); | |
351 | st->last_idle = bfq_entity_of(next); | |
352 | } | |
353 | ||
354 | bfq_extract(&st->idle, entity); | |
355 | ||
356 | if (bfqq) | |
357 | list_del(&bfqq->bfqq_list); | |
358 | } | |
359 | ||
360 | /** | |
361 | * bfq_insert - generic tree insertion. | |
362 | * @root: tree root. | |
363 | * @entity: entity to insert. | |
364 | * | |
365 | * This is used for the idle and the active tree, since they are both | |
366 | * ordered by finish time. | |
367 | */ | |
368 | static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) | |
369 | { | |
370 | struct bfq_entity *entry; | |
371 | struct rb_node **node = &root->rb_node; | |
372 | struct rb_node *parent = NULL; | |
373 | ||
374 | while (*node) { | |
375 | parent = *node; | |
376 | entry = rb_entry(parent, struct bfq_entity, rb_node); | |
377 | ||
378 | if (bfq_gt(entry->finish, entity->finish)) | |
379 | node = &parent->rb_left; | |
380 | else | |
381 | node = &parent->rb_right; | |
382 | } | |
383 | ||
384 | rb_link_node(&entity->rb_node, parent, node); | |
385 | rb_insert_color(&entity->rb_node, root); | |
386 | ||
387 | entity->tree = root; | |
388 | } | |
389 | ||
390 | /** | |
391 | * bfq_update_min - update the min_start field of a entity. | |
392 | * @entity: the entity to update. | |
393 | * @node: one of its children. | |
394 | * | |
395 | * This function is called when @entity may store an invalid value for | |
396 | * min_start due to updates to the active tree. The function assumes | |
397 | * that the subtree rooted at @node (which may be its left or its right | |
398 | * child) has a valid min_start value. | |
399 | */ | |
400 | static void bfq_update_min(struct bfq_entity *entity, struct rb_node *node) | |
401 | { | |
402 | struct bfq_entity *child; | |
403 | ||
404 | if (node) { | |
405 | child = rb_entry(node, struct bfq_entity, rb_node); | |
406 | if (bfq_gt(entity->min_start, child->min_start)) | |
407 | entity->min_start = child->min_start; | |
408 | } | |
409 | } | |
410 | ||
411 | /** | |
412 | * bfq_update_active_node - recalculate min_start. | |
413 | * @node: the node to update. | |
414 | * | |
415 | * @node may have changed position or one of its children may have moved, | |
416 | * this function updates its min_start value. The left and right subtrees | |
417 | * are assumed to hold a correct min_start value. | |
418 | */ | |
419 | static void bfq_update_active_node(struct rb_node *node) | |
420 | { | |
421 | struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node); | |
422 | ||
423 | entity->min_start = entity->start; | |
424 | bfq_update_min(entity, node->rb_right); | |
425 | bfq_update_min(entity, node->rb_left); | |
426 | } | |
427 | ||
428 | /** | |
429 | * bfq_update_active_tree - update min_start for the whole active tree. | |
430 | * @node: the starting node. | |
431 | * | |
432 | * @node must be the deepest modified node after an update. This function | |
433 | * updates its min_start using the values held by its children, assuming | |
434 | * that they did not change, and then updates all the nodes that may have | |
435 | * changed in the path to the root. The only nodes that may have changed | |
436 | * are the ones in the path or their siblings. | |
437 | */ | |
438 | static void bfq_update_active_tree(struct rb_node *node) | |
439 | { | |
440 | struct rb_node *parent; | |
441 | ||
442 | up: | |
443 | bfq_update_active_node(node); | |
444 | ||
445 | parent = rb_parent(node); | |
446 | if (!parent) | |
447 | return; | |
448 | ||
449 | if (node == parent->rb_left && parent->rb_right) | |
450 | bfq_update_active_node(parent->rb_right); | |
451 | else if (parent->rb_left) | |
452 | bfq_update_active_node(parent->rb_left); | |
453 | ||
454 | node = parent; | |
455 | goto up; | |
456 | } | |
457 | ||
458 | /** | |
459 | * bfq_active_insert - insert an entity in the active tree of its | |
460 | * group/device. | |
461 | * @st: the service tree of the entity. | |
462 | * @entity: the entity being inserted. | |
463 | * | |
464 | * The active tree is ordered by finish time, but an extra key is kept | |
465 | * per each node, containing the minimum value for the start times of | |
466 | * its children (and the node itself), so it's possible to search for | |
467 | * the eligible node with the lowest finish time in logarithmic time. | |
468 | */ | |
469 | static void bfq_active_insert(struct bfq_service_tree *st, | |
470 | struct bfq_entity *entity) | |
471 | { | |
472 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
473 | struct rb_node *node = &entity->rb_node; | |
474 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
475 | struct bfq_sched_data *sd = NULL; | |
476 | struct bfq_group *bfqg = NULL; | |
477 | struct bfq_data *bfqd = NULL; | |
478 | #endif | |
479 | ||
480 | bfq_insert(&st->active, entity); | |
481 | ||
482 | if (node->rb_left) | |
483 | node = node->rb_left; | |
484 | else if (node->rb_right) | |
485 | node = node->rb_right; | |
486 | ||
487 | bfq_update_active_tree(node); | |
488 | ||
489 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
490 | sd = entity->sched_data; | |
491 | bfqg = container_of(sd, struct bfq_group, sched_data); | |
492 | bfqd = (struct bfq_data *)bfqg->bfqd; | |
493 | #endif | |
494 | if (bfqq) | |
495 | list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list); | |
496 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
ea25da48 PV |
497 | if (bfqg != bfqd->root_group) |
498 | bfqg->active_entities++; | |
499 | #endif | |
500 | } | |
501 | ||
502 | /** | |
503 | * bfq_ioprio_to_weight - calc a weight from an ioprio. | |
504 | * @ioprio: the ioprio value to convert. | |
505 | */ | |
506 | unsigned short bfq_ioprio_to_weight(int ioprio) | |
507 | { | |
202bc942 | 508 | return (IOPRIO_NR_LEVELS - ioprio) * BFQ_WEIGHT_CONVERSION_COEFF; |
ea25da48 PV |
509 | } |
510 | ||
511 | /** | |
512 | * bfq_weight_to_ioprio - calc an ioprio from a weight. | |
513 | * @weight: the weight value to convert. | |
514 | * | |
515 | * To preserve as much as possible the old only-ioprio user interface, | |
516 | * 0 is used as an escape ioprio value for weights (numerically) equal or | |
202bc942 | 517 | * larger than IOPRIO_NR_LEVELS * BFQ_WEIGHT_CONVERSION_COEFF. |
ea25da48 PV |
518 | */ |
519 | static unsigned short bfq_weight_to_ioprio(int weight) | |
520 | { | |
521 | return max_t(int, 0, | |
202bc942 | 522 | IOPRIO_NR_LEVELS * BFQ_WEIGHT_CONVERSION_COEFF - weight); |
ea25da48 PV |
523 | } |
524 | ||
525 | static void bfq_get_entity(struct bfq_entity *entity) | |
526 | { | |
527 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
528 | ||
529 | if (bfqq) { | |
530 | bfqq->ref++; | |
531 | bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d", | |
532 | bfqq, bfqq->ref); | |
2de791ab | 533 | } |
ea25da48 PV |
534 | } |
535 | ||
536 | /** | |
537 | * bfq_find_deepest - find the deepest node that an extraction can modify. | |
538 | * @node: the node being removed. | |
539 | * | |
540 | * Do the first step of an extraction in an rb tree, looking for the | |
541 | * node that will replace @node, and returning the deepest node that | |
542 | * the following modifications to the tree can touch. If @node is the | |
543 | * last node in the tree return %NULL. | |
544 | */ | |
545 | static struct rb_node *bfq_find_deepest(struct rb_node *node) | |
546 | { | |
547 | struct rb_node *deepest; | |
548 | ||
549 | if (!node->rb_right && !node->rb_left) | |
550 | deepest = rb_parent(node); | |
551 | else if (!node->rb_right) | |
552 | deepest = node->rb_left; | |
553 | else if (!node->rb_left) | |
554 | deepest = node->rb_right; | |
555 | else { | |
556 | deepest = rb_next(node); | |
557 | if (deepest->rb_right) | |
558 | deepest = deepest->rb_right; | |
559 | else if (rb_parent(deepest) != node) | |
560 | deepest = rb_parent(deepest); | |
561 | } | |
562 | ||
563 | return deepest; | |
564 | } | |
565 | ||
566 | /** | |
567 | * bfq_active_extract - remove an entity from the active tree. | |
568 | * @st: the service_tree containing the tree. | |
569 | * @entity: the entity being removed. | |
570 | */ | |
571 | static void bfq_active_extract(struct bfq_service_tree *st, | |
572 | struct bfq_entity *entity) | |
573 | { | |
574 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
575 | struct rb_node *node; | |
576 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
577 | struct bfq_sched_data *sd = NULL; | |
578 | struct bfq_group *bfqg = NULL; | |
579 | struct bfq_data *bfqd = NULL; | |
580 | #endif | |
581 | ||
582 | node = bfq_find_deepest(&entity->rb_node); | |
583 | bfq_extract(&st->active, entity); | |
584 | ||
585 | if (node) | |
586 | bfq_update_active_tree(node); | |
587 | ||
588 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
589 | sd = entity->sched_data; | |
590 | bfqg = container_of(sd, struct bfq_group, sched_data); | |
591 | bfqd = (struct bfq_data *)bfqg->bfqd; | |
592 | #endif | |
593 | if (bfqq) | |
594 | list_del(&bfqq->bfqq_list); | |
595 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
ea25da48 PV |
596 | if (bfqg != bfqd->root_group) |
597 | bfqg->active_entities--; | |
598 | #endif | |
599 | } | |
600 | ||
601 | /** | |
602 | * bfq_idle_insert - insert an entity into the idle tree. | |
603 | * @st: the service tree containing the tree. | |
604 | * @entity: the entity to insert. | |
605 | */ | |
606 | static void bfq_idle_insert(struct bfq_service_tree *st, | |
607 | struct bfq_entity *entity) | |
608 | { | |
609 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
610 | struct bfq_entity *first_idle = st->first_idle; | |
611 | struct bfq_entity *last_idle = st->last_idle; | |
612 | ||
613 | if (!first_idle || bfq_gt(first_idle->finish, entity->finish)) | |
614 | st->first_idle = entity; | |
615 | if (!last_idle || bfq_gt(entity->finish, last_idle->finish)) | |
616 | st->last_idle = entity; | |
617 | ||
618 | bfq_insert(&st->idle, entity); | |
619 | ||
620 | if (bfqq) | |
621 | list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list); | |
622 | } | |
623 | ||
624 | /** | |
625 | * bfq_forget_entity - do not consider entity any longer for scheduling | |
626 | * @st: the service tree. | |
627 | * @entity: the entity being removed. | |
628 | * @is_in_service: true if entity is currently the in-service entity. | |
629 | * | |
630 | * Forget everything about @entity. In addition, if entity represents | |
631 | * a queue, and the latter is not in service, then release the service | |
632 | * reference to the queue (the one taken through bfq_get_entity). In | |
633 | * fact, in this case, there is really no more service reference to | |
634 | * the queue, as the latter is also outside any service tree. If, | |
635 | * instead, the queue is in service, then __bfq_bfqd_reset_in_service | |
636 | * will take care of putting the reference when the queue finally | |
637 | * stops being served. | |
638 | */ | |
639 | static void bfq_forget_entity(struct bfq_service_tree *st, | |
640 | struct bfq_entity *entity, | |
641 | bool is_in_service) | |
642 | { | |
643 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
644 | ||
33a16a98 | 645 | entity->on_st_or_in_serv = false; |
ea25da48 | 646 | st->wsum -= entity->weight; |
2de791ab | 647 | if (bfqq && !is_in_service) |
ea25da48 PV |
648 | bfq_put_queue(bfqq); |
649 | } | |
650 | ||
651 | /** | |
652 | * bfq_put_idle_entity - release the idle tree ref of an entity. | |
653 | * @st: service tree for the entity. | |
654 | * @entity: the entity being released. | |
655 | */ | |
656 | void bfq_put_idle_entity(struct bfq_service_tree *st, struct bfq_entity *entity) | |
657 | { | |
658 | bfq_idle_extract(st, entity); | |
659 | bfq_forget_entity(st, entity, | |
660 | entity == entity->sched_data->in_service_entity); | |
661 | } | |
662 | ||
663 | /** | |
664 | * bfq_forget_idle - update the idle tree if necessary. | |
665 | * @st: the service tree to act upon. | |
666 | * | |
667 | * To preserve the global O(log N) complexity we only remove one entry here; | |
668 | * as the idle tree will not grow indefinitely this can be done safely. | |
669 | */ | |
670 | static void bfq_forget_idle(struct bfq_service_tree *st) | |
671 | { | |
672 | struct bfq_entity *first_idle = st->first_idle; | |
673 | struct bfq_entity *last_idle = st->last_idle; | |
674 | ||
675 | if (RB_EMPTY_ROOT(&st->active) && last_idle && | |
676 | !bfq_gt(last_idle->finish, st->vtime)) { | |
677 | /* | |
678 | * Forget the whole idle tree, increasing the vtime past | |
679 | * the last finish time of idle entities. | |
680 | */ | |
681 | st->vtime = last_idle->finish; | |
682 | } | |
683 | ||
684 | if (first_idle && !bfq_gt(first_idle->finish, st->vtime)) | |
685 | bfq_put_idle_entity(st, first_idle); | |
686 | } | |
687 | ||
688 | struct bfq_service_tree *bfq_entity_service_tree(struct bfq_entity *entity) | |
689 | { | |
690 | struct bfq_sched_data *sched_data = entity->sched_data; | |
691 | unsigned int idx = bfq_class_idx(entity); | |
692 | ||
693 | return sched_data->service_tree + idx; | |
694 | } | |
695 | ||
431b17f9 PV |
696 | /* |
697 | * Update weight and priority of entity. If update_class_too is true, | |
698 | * then update the ioprio_class of entity too. | |
699 | * | |
700 | * The reason why the update of ioprio_class is controlled through the | |
701 | * last parameter is as follows. Changing the ioprio class of an | |
702 | * entity implies changing the destination service trees for that | |
703 | * entity. If such a change occurred when the entity is already on one | |
704 | * of the service trees for its previous class, then the state of the | |
705 | * entity would become more complex: none of the new possible service | |
706 | * trees for the entity, according to bfq_entity_service_tree(), would | |
707 | * match any of the possible service trees on which the entity | |
708 | * is. Complex operations involving these trees, such as entity | |
709 | * activations and deactivations, should take into account this | |
710 | * additional complexity. To avoid this issue, this function is | |
711 | * invoked with update_class_too unset in the points in the code where | |
712 | * entity may happen to be on some tree. | |
713 | */ | |
ea25da48 PV |
714 | struct bfq_service_tree * |
715 | __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, | |
431b17f9 PV |
716 | struct bfq_entity *entity, |
717 | bool update_class_too) | |
ea25da48 PV |
718 | { |
719 | struct bfq_service_tree *new_st = old_st; | |
720 | ||
721 | if (entity->prio_changed) { | |
722 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
723 | unsigned int prev_weight, new_weight; | |
724 | struct bfq_data *bfqd = NULL; | |
fb53ac6c | 725 | struct rb_root_cached *root; |
ea25da48 PV |
726 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
727 | struct bfq_sched_data *sd; | |
728 | struct bfq_group *bfqg; | |
729 | #endif | |
730 | ||
731 | if (bfqq) | |
732 | bfqd = bfqq->bfqd; | |
733 | #ifdef CONFIG_BFQ_GROUP_IOSCHED | |
734 | else { | |
735 | sd = entity->my_sched_data; | |
736 | bfqg = container_of(sd, struct bfq_group, sched_data); | |
737 | bfqd = (struct bfq_data *)bfqg->bfqd; | |
738 | } | |
739 | #endif | |
740 | ||
e9d3c866 FZ |
741 | /* Matches the smp_wmb() in bfq_group_set_weight. */ |
742 | smp_rmb(); | |
ea25da48 PV |
743 | old_st->wsum -= entity->weight; |
744 | ||
745 | if (entity->new_weight != entity->orig_weight) { | |
746 | if (entity->new_weight < BFQ_MIN_WEIGHT || | |
747 | entity->new_weight > BFQ_MAX_WEIGHT) { | |
748 | pr_crit("update_weight_prio: new_weight %d\n", | |
749 | entity->new_weight); | |
750 | if (entity->new_weight < BFQ_MIN_WEIGHT) | |
751 | entity->new_weight = BFQ_MIN_WEIGHT; | |
752 | else | |
753 | entity->new_weight = BFQ_MAX_WEIGHT; | |
754 | } | |
755 | entity->orig_weight = entity->new_weight; | |
756 | if (bfqq) | |
757 | bfqq->ioprio = | |
758 | bfq_weight_to_ioprio(entity->orig_weight); | |
759 | } | |
760 | ||
431b17f9 | 761 | if (bfqq && update_class_too) |
ea25da48 | 762 | bfqq->ioprio_class = bfqq->new_ioprio_class; |
431b17f9 PV |
763 | |
764 | /* | |
765 | * Reset prio_changed only if the ioprio_class change | |
766 | * is not pending any longer. | |
767 | */ | |
768 | if (!bfqq || bfqq->ioprio_class == bfqq->new_ioprio_class) | |
769 | entity->prio_changed = 0; | |
ea25da48 PV |
770 | |
771 | /* | |
772 | * NOTE: here we may be changing the weight too early, | |
773 | * this will cause unfairness. The correct approach | |
774 | * would have required additional complexity to defer | |
775 | * weight changes to the proper time instants (i.e., | |
776 | * when entity->finish <= old_st->vtime). | |
777 | */ | |
778 | new_st = bfq_entity_service_tree(entity); | |
779 | ||
780 | prev_weight = entity->weight; | |
781 | new_weight = entity->orig_weight * | |
782 | (bfqq ? bfqq->wr_coeff : 1); | |
783 | /* | |
2d29c9f8 FM |
784 | * If the weight of the entity changes, and the entity is a |
785 | * queue, remove the entity from its old weight counter (if | |
786 | * there is a counter associated with the entity). | |
ea25da48 | 787 | */ |
98fa7a3e FM |
788 | if (prev_weight != new_weight && bfqq) { |
789 | root = &bfqd->queue_weights_tree; | |
790 | __bfq_weights_tree_remove(bfqd, bfqq, root); | |
ea25da48 PV |
791 | } |
792 | entity->weight = new_weight; | |
793 | /* | |
2d29c9f8 FM |
794 | * Add the entity, if it is not a weight-raised queue, |
795 | * to the counter associated with its new weight. | |
ea25da48 | 796 | */ |
98fa7a3e FM |
797 | if (prev_weight != new_weight && bfqq && bfqq->wr_coeff == 1) { |
798 | /* If we get here, root has been initialized. */ | |
799 | bfq_weights_tree_add(bfqd, bfqq, root); | |
2d29c9f8 | 800 | } |
ea25da48 PV |
801 | |
802 | new_st->wsum += entity->weight; | |
803 | ||
804 | if (new_st != old_st) | |
805 | entity->start = new_st->vtime; | |
806 | } | |
807 | ||
808 | return new_st; | |
809 | } | |
810 | ||
811 | /** | |
812 | * bfq_bfqq_served - update the scheduler status after selection for | |
813 | * service. | |
814 | * @bfqq: the queue being served. | |
815 | * @served: bytes to transfer. | |
816 | * | |
817 | * NOTE: this can be optimized, as the timestamps of upper level entities | |
818 | * are synchronized every time a new bfqq is selected for service. By now, | |
819 | * we keep it to better check consistency. | |
820 | */ | |
821 | void bfq_bfqq_served(struct bfq_queue *bfqq, int served) | |
822 | { | |
823 | struct bfq_entity *entity = &bfqq->entity; | |
824 | struct bfq_service_tree *st; | |
825 | ||
7b8fa3b9 PV |
826 | if (!bfqq->service_from_backlogged) |
827 | bfqq->first_IO_time = jiffies; | |
828 | ||
8a8747dc PV |
829 | if (bfqq->wr_coeff > 1) |
830 | bfqq->service_from_wr += served; | |
831 | ||
7b8fa3b9 | 832 | bfqq->service_from_backlogged += served; |
ea25da48 PV |
833 | for_each_entity(entity) { |
834 | st = bfq_entity_service_tree(entity); | |
835 | ||
836 | entity->service += served; | |
837 | ||
838 | st->vtime += bfq_delta(served, st->wsum); | |
839 | bfq_forget_idle(st); | |
840 | } | |
ea25da48 PV |
841 | bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs", served); |
842 | } | |
843 | ||
844 | /** | |
845 | * bfq_bfqq_charge_time - charge an amount of service equivalent to the length | |
846 | * of the time interval during which bfqq has been in | |
847 | * service. | |
848 | * @bfqd: the device | |
849 | * @bfqq: the queue that needs a service update. | |
850 | * @time_ms: the amount of time during which the queue has received service | |
851 | * | |
852 | * If a queue does not consume its budget fast enough, then providing | |
853 | * the queue with service fairness may impair throughput, more or less | |
854 | * severely. For this reason, queues that consume their budget slowly | |
855 | * are provided with time fairness instead of service fairness. This | |
856 | * goal is achieved through the BFQ scheduling engine, even if such an | |
857 | * engine works in the service, and not in the time domain. The trick | |
858 | * is charging these queues with an inflated amount of service, equal | |
859 | * to the amount of service that they would have received during their | |
860 | * service slot if they had been fast, i.e., if their requests had | |
861 | * been dispatched at a rate equal to the estimated peak rate. | |
862 | * | |
863 | * It is worth noting that time fairness can cause important | |
864 | * distortions in terms of bandwidth distribution, on devices with | |
865 | * internal queueing. The reason is that I/O requests dispatched | |
866 | * during the service slot of a queue may be served after that service | |
867 | * slot is finished, and may have a total processing time loosely | |
868 | * correlated with the duration of the service slot. This is | |
869 | * especially true for short service slots. | |
870 | */ | |
871 | void bfq_bfqq_charge_time(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
872 | unsigned long time_ms) | |
873 | { | |
874 | struct bfq_entity *entity = &bfqq->entity; | |
f8121648 PV |
875 | unsigned long timeout_ms = jiffies_to_msecs(bfq_timeout); |
876 | unsigned long bounded_time_ms = min(time_ms, timeout_ms); | |
877 | int serv_to_charge_for_time = | |
878 | (bfqd->bfq_max_budget * bounded_time_ms) / timeout_ms; | |
879 | int tot_serv_to_charge = max(serv_to_charge_for_time, entity->service); | |
ea25da48 PV |
880 | |
881 | /* Increase budget to avoid inconsistencies */ | |
882 | if (tot_serv_to_charge > entity->budget) | |
883 | entity->budget = tot_serv_to_charge; | |
884 | ||
885 | bfq_bfqq_served(bfqq, | |
886 | max_t(int, 0, tot_serv_to_charge - entity->service)); | |
887 | } | |
888 | ||
889 | static void bfq_update_fin_time_enqueue(struct bfq_entity *entity, | |
890 | struct bfq_service_tree *st, | |
891 | bool backshifted) | |
892 | { | |
893 | struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); | |
894 | ||
431b17f9 PV |
895 | /* |
896 | * When this function is invoked, entity is not in any service | |
897 | * tree, then it is safe to invoke next function with the last | |
898 | * parameter set (see the comments on the function). | |
899 | */ | |
900 | st = __bfq_entity_update_weight_prio(st, entity, true); | |
ea25da48 PV |
901 | bfq_calc_finish(entity, entity->budget); |
902 | ||
903 | /* | |
904 | * If some queues enjoy backshifting for a while, then their | |
905 | * (virtual) finish timestamps may happen to become lower and | |
906 | * lower than the system virtual time. In particular, if | |
907 | * these queues often happen to be idle for short time | |
908 | * periods, and during such time periods other queues with | |
909 | * higher timestamps happen to be busy, then the backshifted | |
910 | * timestamps of the former queues can become much lower than | |
911 | * the system virtual time. In fact, to serve the queues with | |
912 | * higher timestamps while the ones with lower timestamps are | |
913 | * idle, the system virtual time may be pushed-up to much | |
914 | * higher values than the finish timestamps of the idle | |
915 | * queues. As a consequence, the finish timestamps of all new | |
916 | * or newly activated queues may end up being much larger than | |
917 | * those of lucky queues with backshifted timestamps. The | |
918 | * latter queues may then monopolize the device for a lot of | |
919 | * time. This would simply break service guarantees. | |
920 | * | |
921 | * To reduce this problem, push up a little bit the | |
922 | * backshifted timestamps of the queue associated with this | |
923 | * entity (only a queue can happen to have the backshifted | |
924 | * flag set): just enough to let the finish timestamp of the | |
925 | * queue be equal to the current value of the system virtual | |
926 | * time. This may introduce a little unfairness among queues | |
927 | * with backshifted timestamps, but it does not break | |
928 | * worst-case fairness guarantees. | |
929 | * | |
930 | * As a special case, if bfqq is weight-raised, push up | |
931 | * timestamps much less, to keep very low the probability that | |
932 | * this push up causes the backshifted finish timestamps of | |
933 | * weight-raised queues to become higher than the backshifted | |
934 | * finish timestamps of non weight-raised queues. | |
935 | */ | |
936 | if (backshifted && bfq_gt(st->vtime, entity->finish)) { | |
937 | unsigned long delta = st->vtime - entity->finish; | |
938 | ||
939 | if (bfqq) | |
940 | delta /= bfqq->wr_coeff; | |
941 | ||
942 | entity->start += delta; | |
943 | entity->finish += delta; | |
944 | } | |
945 | ||
946 | bfq_active_insert(st, entity); | |
947 | } | |
948 | ||
949 | /** | |
950 | * __bfq_activate_entity - handle activation of entity. | |
951 | * @entity: the entity being activated. | |
952 | * @non_blocking_wait_rq: true if entity was waiting for a request | |
953 | * | |
954 | * Called for a 'true' activation, i.e., if entity is not active and | |
955 | * one of its children receives a new request. | |
956 | * | |
957 | * Basically, this function updates the timestamps of entity and | |
0471559c | 958 | * inserts entity into its active tree, after possibly extracting it |
ea25da48 PV |
959 | * from its idle tree. |
960 | */ | |
961 | static void __bfq_activate_entity(struct bfq_entity *entity, | |
962 | bool non_blocking_wait_rq) | |
963 | { | |
964 | struct bfq_service_tree *st = bfq_entity_service_tree(entity); | |
965 | bool backshifted = false; | |
966 | unsigned long long min_vstart; | |
967 | ||
968 | /* See comments on bfq_fqq_update_budg_for_activation */ | |
969 | if (non_blocking_wait_rq && bfq_gt(st->vtime, entity->finish)) { | |
970 | backshifted = true; | |
971 | min_vstart = entity->finish; | |
972 | } else | |
973 | min_vstart = st->vtime; | |
974 | ||
975 | if (entity->tree == &st->idle) { | |
976 | /* | |
977 | * Must be on the idle tree, bfq_idle_extract() will | |
978 | * check for that. | |
979 | */ | |
980 | bfq_idle_extract(st, entity); | |
981 | entity->start = bfq_gt(min_vstart, entity->finish) ? | |
982 | min_vstart : entity->finish; | |
983 | } else { | |
984 | /* | |
985 | * The finish time of the entity may be invalid, and | |
986 | * it is in the past for sure, otherwise the queue | |
987 | * would have been on the idle tree. | |
988 | */ | |
989 | entity->start = min_vstart; | |
990 | st->wsum += entity->weight; | |
991 | /* | |
992 | * entity is about to be inserted into a service tree, | |
993 | * and then set in service: get a reference to make | |
994 | * sure entity does not disappear until it is no | |
995 | * longer in service or scheduled for service. | |
996 | */ | |
997 | bfq_get_entity(entity); | |
998 | ||
33a16a98 | 999 | entity->on_st_or_in_serv = true; |
ea25da48 PV |
1000 | } |
1001 | ||
42b1bd33 | 1002 | #ifdef CONFIG_BFQ_GROUP_IOSCHED |
0471559c PV |
1003 | if (!bfq_entity_to_bfqq(entity)) { /* bfq_group */ |
1004 | struct bfq_group *bfqg = | |
1005 | container_of(entity, struct bfq_group, entity); | |
2d29c9f8 | 1006 | struct bfq_data *bfqd = bfqg->bfqd; |
0471559c | 1007 | |
ba7aeae5 PV |
1008 | if (!entity->in_groups_with_pending_reqs) { |
1009 | entity->in_groups_with_pending_reqs = true; | |
1010 | bfqd->num_groups_with_pending_reqs++; | |
1011 | } | |
0471559c PV |
1012 | } |
1013 | #endif | |
1014 | ||
ea25da48 PV |
1015 | bfq_update_fin_time_enqueue(entity, st, backshifted); |
1016 | } | |
1017 | ||
1018 | /** | |
1019 | * __bfq_requeue_entity - handle requeueing or repositioning of an entity. | |
1020 | * @entity: the entity being requeued or repositioned. | |
1021 | * | |
1022 | * Requeueing is needed if this entity stops being served, which | |
1023 | * happens if a leaf descendant entity has expired. On the other hand, | |
1024 | * repositioning is needed if the next_inservice_entity for the child | |
1025 | * entity has changed. See the comments inside the function for | |
1026 | * details. | |
1027 | * | |
1028 | * Basically, this function: 1) removes entity from its active tree if | |
1029 | * present there, 2) updates the timestamps of entity and 3) inserts | |
1030 | * entity back into its active tree (in the new, right position for | |
1031 | * the new values of the timestamps). | |
1032 | */ | |
1033 | static void __bfq_requeue_entity(struct bfq_entity *entity) | |
1034 | { | |
1035 | struct bfq_sched_data *sd = entity->sched_data; | |
1036 | struct bfq_service_tree *st = bfq_entity_service_tree(entity); | |
1037 | ||
1038 | if (entity == sd->in_service_entity) { | |
1039 | /* | |
1040 | * We are requeueing the current in-service entity, | |
1041 | * which may have to be done for one of the following | |
1042 | * reasons: | |
1043 | * - entity represents the in-service queue, and the | |
1044 | * in-service queue is being requeued after an | |
1045 | * expiration; | |
1046 | * - entity represents a group, and its budget has | |
1047 | * changed because one of its child entities has | |
1048 | * just been either activated or requeued for some | |
1049 | * reason; the timestamps of the entity need then to | |
1050 | * be updated, and the entity needs to be enqueued | |
1051 | * or repositioned accordingly. | |
1052 | * | |
1053 | * In particular, before requeueing, the start time of | |
1054 | * the entity must be moved forward to account for the | |
1055 | * service that the entity has received while in | |
1056 | * service. This is done by the next instructions. The | |
1057 | * finish time will then be updated according to this | |
1058 | * new value of the start time, and to the budget of | |
1059 | * the entity. | |
1060 | */ | |
1061 | bfq_calc_finish(entity, entity->service); | |
1062 | entity->start = entity->finish; | |
1063 | /* | |
1064 | * In addition, if the entity had more than one child | |
46d556e6 | 1065 | * when set in service, then it was not extracted from |
ea25da48 PV |
1066 | * the active tree. This implies that the position of |
1067 | * the entity in the active tree may need to be | |
1068 | * changed now, because we have just updated the start | |
1069 | * time of the entity, and we will update its finish | |
1070 | * time in a moment (the requeueing is then, more | |
1071 | * precisely, a repositioning in this case). To | |
1072 | * implement this repositioning, we: 1) dequeue the | |
46d556e6 PV |
1073 | * entity here, 2) update the finish time and requeue |
1074 | * the entity according to the new timestamps below. | |
ea25da48 PV |
1075 | */ |
1076 | if (entity->tree) | |
1077 | bfq_active_extract(st, entity); | |
1078 | } else { /* The entity is already active, and not in service */ | |
1079 | /* | |
1080 | * In this case, this function gets called only if the | |
1081 | * next_in_service entity below this entity has | |
1082 | * changed, and this change has caused the budget of | |
1083 | * this entity to change, which, finally implies that | |
1084 | * the finish time of this entity must be | |
1085 | * updated. Such an update may cause the scheduling, | |
1086 | * i.e., the position in the active tree, of this | |
1087 | * entity to change. We handle this change by: 1) | |
1088 | * dequeueing the entity here, 2) updating the finish | |
1089 | * time and requeueing the entity according to the new | |
1090 | * timestamps below. This is the same approach as the | |
1091 | * non-extracted-entity sub-case above. | |
1092 | */ | |
1093 | bfq_active_extract(st, entity); | |
1094 | } | |
1095 | ||
1096 | bfq_update_fin_time_enqueue(entity, st, false); | |
1097 | } | |
1098 | ||
1099 | static void __bfq_activate_requeue_entity(struct bfq_entity *entity, | |
1100 | struct bfq_sched_data *sd, | |
1101 | bool non_blocking_wait_rq) | |
1102 | { | |
1103 | struct bfq_service_tree *st = bfq_entity_service_tree(entity); | |
1104 | ||
1105 | if (sd->in_service_entity == entity || entity->tree == &st->active) | |
1106 | /* | |
1107 | * in service or already queued on the active tree, | |
1108 | * requeue or reposition | |
1109 | */ | |
1110 | __bfq_requeue_entity(entity); | |
1111 | else | |
1112 | /* | |
1113 | * Not in service and not queued on its active tree: | |
1114 | * the activity is idle and this is a true activation. | |
1115 | */ | |
1116 | __bfq_activate_entity(entity, non_blocking_wait_rq); | |
1117 | } | |
1118 | ||
1119 | ||
1120 | /** | |
46d556e6 PV |
1121 | * bfq_activate_requeue_entity - activate or requeue an entity representing a |
1122 | * bfq_queue, and activate, requeue or reposition | |
1123 | * all ancestors for which such an update becomes | |
1124 | * necessary. | |
ea25da48 PV |
1125 | * @entity: the entity to activate. |
1126 | * @non_blocking_wait_rq: true if this entity was waiting for a request | |
1127 | * @requeue: true if this is a requeue, which implies that bfqq is | |
1128 | * being expired; thus ALL its ancestors stop being served and must | |
1129 | * therefore be requeued | |
80294c3b PV |
1130 | * @expiration: true if this function is being invoked in the expiration path |
1131 | * of the in-service queue | |
ea25da48 PV |
1132 | */ |
1133 | static void bfq_activate_requeue_entity(struct bfq_entity *entity, | |
1134 | bool non_blocking_wait_rq, | |
80294c3b | 1135 | bool requeue, bool expiration) |
ea25da48 PV |
1136 | { |
1137 | struct bfq_sched_data *sd; | |
1138 | ||
1139 | for_each_entity(entity) { | |
1140 | sd = entity->sched_data; | |
1141 | __bfq_activate_requeue_entity(entity, sd, non_blocking_wait_rq); | |
1142 | ||
80294c3b PV |
1143 | if (!bfq_update_next_in_service(sd, entity, expiration) && |
1144 | !requeue) | |
ea25da48 PV |
1145 | break; |
1146 | } | |
1147 | } | |
1148 | ||
1149 | /** | |
5bf85908 PV |
1150 | * __bfq_deactivate_entity - update sched_data and service trees for |
1151 | * entity, so as to represent entity as inactive | |
1152 | * @entity: the entity being deactivated. | |
ea25da48 PV |
1153 | * @ins_into_idle_tree: if false, the entity will not be put into the |
1154 | * idle tree. | |
1155 | * | |
5bf85908 PV |
1156 | * If necessary and allowed, puts entity into the idle tree. NOTE: |
1157 | * entity may be on no tree if in service. | |
ea25da48 PV |
1158 | */ |
1159 | bool __bfq_deactivate_entity(struct bfq_entity *entity, bool ins_into_idle_tree) | |
1160 | { | |
1161 | struct bfq_sched_data *sd = entity->sched_data; | |
a66c38a1 PV |
1162 | struct bfq_service_tree *st; |
1163 | bool is_in_service; | |
ea25da48 | 1164 | |
33a16a98 PV |
1165 | if (!entity->on_st_or_in_serv) /* |
1166 | * entity never activated, or | |
1167 | * already inactive | |
1168 | */ | |
ea25da48 PV |
1169 | return false; |
1170 | ||
a66c38a1 PV |
1171 | /* |
1172 | * If we get here, then entity is active, which implies that | |
1173 | * bfq_group_set_parent has already been invoked for the group | |
1174 | * represented by entity. Therefore, the field | |
1175 | * entity->sched_data has been set, and we can safely use it. | |
1176 | */ | |
1177 | st = bfq_entity_service_tree(entity); | |
1178 | is_in_service = entity == sd->in_service_entity; | |
1179 | ||
cbeb869a PV |
1180 | bfq_calc_finish(entity, entity->service); |
1181 | ||
1182 | if (is_in_service) | |
6ab1d8da | 1183 | sd->in_service_entity = NULL; |
cbeb869a PV |
1184 | else |
1185 | /* | |
1186 | * Non in-service entity: nobody will take care of | |
1187 | * resetting its service counter on expiration. Do it | |
1188 | * now. | |
1189 | */ | |
1190 | entity->service = 0; | |
ea25da48 PV |
1191 | |
1192 | if (entity->tree == &st->active) | |
1193 | bfq_active_extract(st, entity); | |
1194 | else if (!is_in_service && entity->tree == &st->idle) | |
1195 | bfq_idle_extract(st, entity); | |
1196 | ||
1197 | if (!ins_into_idle_tree || !bfq_gt(entity->finish, st->vtime)) | |
1198 | bfq_forget_entity(st, entity, is_in_service); | |
1199 | else | |
1200 | bfq_idle_insert(st, entity); | |
1201 | ||
1202 | return true; | |
1203 | } | |
1204 | ||
1205 | /** | |
1206 | * bfq_deactivate_entity - deactivate an entity representing a bfq_queue. | |
1207 | * @entity: the entity to deactivate. | |
46d556e6 | 1208 | * @ins_into_idle_tree: true if the entity can be put into the idle tree |
80294c3b PV |
1209 | * @expiration: true if this function is being invoked in the expiration path |
1210 | * of the in-service queue | |
ea25da48 PV |
1211 | */ |
1212 | static void bfq_deactivate_entity(struct bfq_entity *entity, | |
1213 | bool ins_into_idle_tree, | |
1214 | bool expiration) | |
1215 | { | |
1216 | struct bfq_sched_data *sd; | |
1217 | struct bfq_entity *parent = NULL; | |
1218 | ||
1219 | for_each_entity_safe(entity, parent) { | |
1220 | sd = entity->sched_data; | |
1221 | ||
1222 | if (!__bfq_deactivate_entity(entity, ins_into_idle_tree)) { | |
1223 | /* | |
1224 | * entity is not in any tree any more, so | |
1225 | * this deactivation is a no-op, and there is | |
1226 | * nothing to change for upper-level entities | |
1227 | * (in case of expiration, this can never | |
1228 | * happen). | |
1229 | */ | |
1230 | return; | |
1231 | } | |
1232 | ||
1233 | if (sd->next_in_service == entity) | |
1234 | /* | |
1235 | * entity was the next_in_service entity, | |
1236 | * then, since entity has just been | |
1237 | * deactivated, a new one must be found. | |
1238 | */ | |
80294c3b | 1239 | bfq_update_next_in_service(sd, NULL, expiration); |
ea25da48 | 1240 | |
46d556e6 | 1241 | if (sd->next_in_service || sd->in_service_entity) { |
ea25da48 | 1242 | /* |
46d556e6 PV |
1243 | * The parent entity is still active, because |
1244 | * either next_in_service or in_service_entity | |
1245 | * is not NULL. So, no further upwards | |
1246 | * deactivation must be performed. Yet, | |
1247 | * next_in_service has changed. Then the | |
1248 | * schedule does need to be updated upwards. | |
1249 | * | |
1250 | * NOTE If in_service_entity is not NULL, then | |
1251 | * next_in_service may happen to be NULL, | |
1252 | * although the parent entity is evidently | |
1253 | * active. This happens if 1) the entity | |
1254 | * pointed by in_service_entity is the only | |
1255 | * active entity in the parent entity, and 2) | |
1256 | * according to the definition of | |
1257 | * next_in_service, the in_service_entity | |
1258 | * cannot be considered as | |
1259 | * next_in_service. See the comments on the | |
1260 | * definition of next_in_service for details. | |
ea25da48 PV |
1261 | */ |
1262 | break; | |
46d556e6 | 1263 | } |
ea25da48 PV |
1264 | |
1265 | /* | |
1266 | * If we get here, then the parent is no more | |
1267 | * backlogged and we need to propagate the | |
1268 | * deactivation upwards. Thus let the loop go on. | |
1269 | */ | |
1270 | ||
1271 | /* | |
1272 | * Also let parent be queued into the idle tree on | |
1273 | * deactivation, to preserve service guarantees, and | |
1274 | * assuming that who invoked this function does not | |
1275 | * need parent entities too to be removed completely. | |
1276 | */ | |
1277 | ins_into_idle_tree = true; | |
1278 | } | |
1279 | ||
1280 | /* | |
1281 | * If the deactivation loop is fully executed, then there are | |
1282 | * no more entities to touch and next loop is not executed at | |
1283 | * all. Otherwise, requeue remaining entities if they are | |
1284 | * about to stop receiving service, or reposition them if this | |
1285 | * is not the case. | |
1286 | */ | |
1287 | entity = parent; | |
1288 | for_each_entity(entity) { | |
1289 | /* | |
1290 | * Invoke __bfq_requeue_entity on entity, even if | |
1291 | * already active, to requeue/reposition it in the | |
1292 | * active tree (because sd->next_in_service has | |
1293 | * changed) | |
1294 | */ | |
1295 | __bfq_requeue_entity(entity); | |
1296 | ||
1297 | sd = entity->sched_data; | |
80294c3b | 1298 | if (!bfq_update_next_in_service(sd, entity, expiration) && |
ea25da48 PV |
1299 | !expiration) |
1300 | /* | |
1301 | * next_in_service unchanged or not causing | |
1302 | * any change in entity->parent->sd, and no | |
1303 | * requeueing needed for expiration: stop | |
1304 | * here. | |
1305 | */ | |
1306 | break; | |
1307 | } | |
1308 | } | |
1309 | ||
1310 | /** | |
1311 | * bfq_calc_vtime_jump - compute the value to which the vtime should jump, | |
1312 | * if needed, to have at least one entity eligible. | |
1313 | * @st: the service tree to act upon. | |
1314 | * | |
1315 | * Assumes that st is not empty. | |
1316 | */ | |
1317 | static u64 bfq_calc_vtime_jump(struct bfq_service_tree *st) | |
1318 | { | |
1319 | struct bfq_entity *root_entity = bfq_root_active_entity(&st->active); | |
1320 | ||
1321 | if (bfq_gt(root_entity->min_start, st->vtime)) | |
1322 | return root_entity->min_start; | |
1323 | ||
1324 | return st->vtime; | |
1325 | } | |
1326 | ||
1327 | static void bfq_update_vtime(struct bfq_service_tree *st, u64 new_value) | |
1328 | { | |
1329 | if (new_value > st->vtime) { | |
1330 | st->vtime = new_value; | |
1331 | bfq_forget_idle(st); | |
1332 | } | |
1333 | } | |
1334 | ||
1335 | /** | |
1336 | * bfq_first_active_entity - find the eligible entity with | |
1337 | * the smallest finish time | |
1338 | * @st: the service tree to select from. | |
1339 | * @vtime: the system virtual to use as a reference for eligibility | |
1340 | * | |
1341 | * This function searches the first schedulable entity, starting from the | |
1342 | * root of the tree and going on the left every time on this side there is | |
38c91407 | 1343 | * a subtree with at least one eligible (start <= vtime) entity. The path on |
ea25da48 PV |
1344 | * the right is followed only if a) the left subtree contains no eligible |
1345 | * entities and b) no eligible entity has been found yet. | |
1346 | */ | |
1347 | static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st, | |
1348 | u64 vtime) | |
1349 | { | |
1350 | struct bfq_entity *entry, *first = NULL; | |
1351 | struct rb_node *node = st->active.rb_node; | |
1352 | ||
1353 | while (node) { | |
1354 | entry = rb_entry(node, struct bfq_entity, rb_node); | |
1355 | left: | |
1356 | if (!bfq_gt(entry->start, vtime)) | |
1357 | first = entry; | |
1358 | ||
1359 | if (node->rb_left) { | |
1360 | entry = rb_entry(node->rb_left, | |
1361 | struct bfq_entity, rb_node); | |
1362 | if (!bfq_gt(entry->min_start, vtime)) { | |
1363 | node = node->rb_left; | |
1364 | goto left; | |
1365 | } | |
1366 | } | |
1367 | if (first) | |
1368 | break; | |
1369 | node = node->rb_right; | |
1370 | } | |
1371 | ||
1372 | return first; | |
1373 | } | |
1374 | ||
1375 | /** | |
1376 | * __bfq_lookup_next_entity - return the first eligible entity in @st. | |
1377 | * @st: the service tree. | |
1378 | * | |
1379 | * If there is no in-service entity for the sched_data st belongs to, | |
1380 | * then return the entity that will be set in service if: | |
1381 | * 1) the parent entity this st belongs to is set in service; | |
1382 | * 2) no entity belonging to such parent entity undergoes a state change | |
1383 | * that would influence the timestamps of the entity (e.g., becomes idle, | |
1384 | * becomes backlogged, changes its budget, ...). | |
1385 | * | |
1386 | * In this first case, update the virtual time in @st too (see the | |
1387 | * comments on this update inside the function). | |
1388 | * | |
636b8fe8 | 1389 | * In contrast, if there is an in-service entity, then return the |
ea25da48 PV |
1390 | * entity that would be set in service if not only the above |
1391 | * conditions, but also the next one held true: the currently | |
1392 | * in-service entity, on expiration, | |
1393 | * 1) gets a finish time equal to the current one, or | |
1394 | * 2) is not eligible any more, or | |
1395 | * 3) is idle. | |
1396 | */ | |
1397 | static struct bfq_entity * | |
1398 | __bfq_lookup_next_entity(struct bfq_service_tree *st, bool in_service) | |
1399 | { | |
1400 | struct bfq_entity *entity; | |
1401 | u64 new_vtime; | |
1402 | ||
1403 | if (RB_EMPTY_ROOT(&st->active)) | |
1404 | return NULL; | |
1405 | ||
1406 | /* | |
1407 | * Get the value of the system virtual time for which at | |
1408 | * least one entity is eligible. | |
1409 | */ | |
1410 | new_vtime = bfq_calc_vtime_jump(st); | |
1411 | ||
1412 | /* | |
1413 | * If there is no in-service entity for the sched_data this | |
1414 | * active tree belongs to, then push the system virtual time | |
1415 | * up to the value that guarantees that at least one entity is | |
1416 | * eligible. If, instead, there is an in-service entity, then | |
1417 | * do not make any such update, because there is already an | |
1418 | * eligible entity, namely the in-service one (even if the | |
1419 | * entity is not on st, because it was extracted when set in | |
1420 | * service). | |
1421 | */ | |
1422 | if (!in_service) | |
1423 | bfq_update_vtime(st, new_vtime); | |
1424 | ||
1425 | entity = bfq_first_active_entity(st, new_vtime); | |
1426 | ||
1427 | return entity; | |
1428 | } | |
1429 | ||
1430 | /** | |
1431 | * bfq_lookup_next_entity - return the first eligible entity in @sd. | |
1432 | * @sd: the sched_data. | |
80294c3b | 1433 | * @expiration: true if we are on the expiration path of the in-service queue |
ea25da48 PV |
1434 | * |
1435 | * This function is invoked when there has been a change in the trees | |
80294c3b PV |
1436 | * for sd, and we need to know what is the new next entity to serve |
1437 | * after this change. | |
ea25da48 | 1438 | */ |
80294c3b PV |
1439 | static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, |
1440 | bool expiration) | |
ea25da48 PV |
1441 | { |
1442 | struct bfq_service_tree *st = sd->service_tree; | |
1443 | struct bfq_service_tree *idle_class_st = st + (BFQ_IOPRIO_CLASSES - 1); | |
1444 | struct bfq_entity *entity = NULL; | |
1445 | int class_idx = 0; | |
1446 | ||
1447 | /* | |
1448 | * Choose from idle class, if needed to guarantee a minimum | |
1449 | * bandwidth to this class (and if there is some active entity | |
1450 | * in idle class). This should also mitigate | |
1451 | * priority-inversion problems in case a low priority task is | |
1452 | * holding file system resources. | |
1453 | */ | |
1454 | if (time_is_before_jiffies(sd->bfq_class_idle_last_service + | |
1455 | BFQ_CL_IDLE_TIMEOUT)) { | |
1456 | if (!RB_EMPTY_ROOT(&idle_class_st->active)) | |
1457 | class_idx = BFQ_IOPRIO_CLASSES - 1; | |
1458 | /* About to be served if backlogged, or not yet backlogged */ | |
1459 | sd->bfq_class_idle_last_service = jiffies; | |
1460 | } | |
1461 | ||
1462 | /* | |
1463 | * Find the next entity to serve for the highest-priority | |
1464 | * class, unless the idle class needs to be served. | |
1465 | */ | |
1466 | for (; class_idx < BFQ_IOPRIO_CLASSES; class_idx++) { | |
80294c3b PV |
1467 | /* |
1468 | * If expiration is true, then bfq_lookup_next_entity | |
1469 | * is being invoked as a part of the expiration path | |
1470 | * of the in-service queue. In this case, even if | |
1471 | * sd->in_service_entity is not NULL, | |
636b8fe8 | 1472 | * sd->in_service_entity at this point is actually not |
80294c3b PV |
1473 | * in service any more, and, if needed, has already |
1474 | * been properly queued or requeued into the right | |
1475 | * tree. The reason why sd->in_service_entity is still | |
1476 | * not NULL here, even if expiration is true, is that | |
636b8fe8 | 1477 | * sd->in_service_entity is reset as a last step in the |
80294c3b PV |
1478 | * expiration path. So, if expiration is true, tell |
1479 | * __bfq_lookup_next_entity that there is no | |
1480 | * sd->in_service_entity. | |
1481 | */ | |
ea25da48 | 1482 | entity = __bfq_lookup_next_entity(st + class_idx, |
80294c3b PV |
1483 | sd->in_service_entity && |
1484 | !expiration); | |
ea25da48 PV |
1485 | |
1486 | if (entity) | |
1487 | break; | |
1488 | } | |
1489 | ||
1490 | if (!entity) | |
1491 | return NULL; | |
1492 | ||
1493 | return entity; | |
1494 | } | |
1495 | ||
1496 | bool next_queue_may_preempt(struct bfq_data *bfqd) | |
1497 | { | |
1498 | struct bfq_sched_data *sd = &bfqd->root_group->sched_data; | |
1499 | ||
1500 | return sd->next_in_service != sd->in_service_entity; | |
1501 | } | |
1502 | ||
1503 | /* | |
1504 | * Get next queue for service. | |
1505 | */ | |
1506 | struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd) | |
1507 | { | |
1508 | struct bfq_entity *entity = NULL; | |
1509 | struct bfq_sched_data *sd; | |
1510 | struct bfq_queue *bfqq; | |
1511 | ||
73d58118 | 1512 | if (bfq_tot_busy_queues(bfqd) == 0) |
ea25da48 PV |
1513 | return NULL; |
1514 | ||
1515 | /* | |
1516 | * Traverse the path from the root to the leaf entity to | |
1517 | * serve. Set in service all the entities visited along the | |
1518 | * way. | |
1519 | */ | |
1520 | sd = &bfqd->root_group->sched_data; | |
1521 | for (; sd ; sd = entity->my_sched_data) { | |
1522 | /* | |
1523 | * WARNING. We are about to set the in-service entity | |
1524 | * to sd->next_in_service, i.e., to the (cached) value | |
1525 | * returned by bfq_lookup_next_entity(sd) the last | |
1526 | * time it was invoked, i.e., the last time when the | |
1527 | * service order in sd changed as a consequence of the | |
1528 | * activation or deactivation of an entity. In this | |
1529 | * respect, if we execute bfq_lookup_next_entity(sd) | |
1530 | * in this very moment, it may, although with low | |
1531 | * probability, yield a different entity than that | |
1532 | * pointed to by sd->next_in_service. This rare event | |
1533 | * happens in case there was no CLASS_IDLE entity to | |
1534 | * serve for sd when bfq_lookup_next_entity(sd) was | |
1535 | * invoked for the last time, while there is now one | |
1536 | * such entity. | |
1537 | * | |
1538 | * If the above event happens, then the scheduling of | |
1539 | * such entity in CLASS_IDLE is postponed until the | |
1540 | * service of the sd->next_in_service entity | |
1541 | * finishes. In fact, when the latter is expired, | |
1542 | * bfq_lookup_next_entity(sd) gets called again, | |
1543 | * exactly to update sd->next_in_service. | |
1544 | */ | |
1545 | ||
1546 | /* Make next_in_service entity become in_service_entity */ | |
1547 | entity = sd->next_in_service; | |
1548 | sd->in_service_entity = entity; | |
1549 | ||
ea25da48 PV |
1550 | /* |
1551 | * If entity is no longer a candidate for next | |
46d556e6 PV |
1552 | * service, then it must be extracted from its active |
1553 | * tree, so as to make sure that it won't be | |
1554 | * considered when computing next_in_service. See the | |
1555 | * comments on the function | |
1556 | * bfq_no_longer_next_in_service() for details. | |
ea25da48 PV |
1557 | */ |
1558 | if (bfq_no_longer_next_in_service(entity)) | |
1559 | bfq_active_extract(bfq_entity_service_tree(entity), | |
1560 | entity); | |
1561 | ||
1562 | /* | |
46d556e6 PV |
1563 | * Even if entity is not to be extracted according to |
1564 | * the above check, a descendant entity may get | |
1565 | * extracted in one of the next iterations of this | |
1566 | * loop. Such an event could cause a change in | |
1567 | * next_in_service for the level of the descendant | |
1568 | * entity, and thus possibly back to this level. | |
ea25da48 | 1569 | * |
46d556e6 PV |
1570 | * However, we cannot perform the resulting needed |
1571 | * update of next_in_service for this level before the | |
1572 | * end of the whole loop, because, to know which is | |
1573 | * the correct next-to-serve candidate entity for each | |
1574 | * level, we need first to find the leaf entity to set | |
1575 | * in service. In fact, only after we know which is | |
1576 | * the next-to-serve leaf entity, we can discover | |
1577 | * whether the parent entity of the leaf entity | |
1578 | * becomes the next-to-serve, and so on. | |
ea25da48 | 1579 | */ |
ea25da48 PV |
1580 | } |
1581 | ||
1582 | bfqq = bfq_entity_to_bfqq(entity); | |
1583 | ||
1584 | /* | |
1585 | * We can finally update all next-to-serve entities along the | |
1586 | * path from the leaf entity just set in service to the root. | |
1587 | */ | |
1588 | for_each_entity(entity) { | |
1589 | struct bfq_sched_data *sd = entity->sched_data; | |
1590 | ||
80294c3b | 1591 | if (!bfq_update_next_in_service(sd, NULL, false)) |
ea25da48 PV |
1592 | break; |
1593 | } | |
1594 | ||
1595 | return bfqq; | |
1596 | } | |
1597 | ||
eed47d19 PV |
1598 | /* returns true if the in-service queue gets freed */ |
1599 | bool __bfq_bfqd_reset_in_service(struct bfq_data *bfqd) | |
ea25da48 PV |
1600 | { |
1601 | struct bfq_queue *in_serv_bfqq = bfqd->in_service_queue; | |
1602 | struct bfq_entity *in_serv_entity = &in_serv_bfqq->entity; | |
1603 | struct bfq_entity *entity = in_serv_entity; | |
1604 | ||
1605 | bfq_clear_bfqq_wait_request(in_serv_bfqq); | |
1606 | hrtimer_try_to_cancel(&bfqd->idle_slice_timer); | |
1607 | bfqd->in_service_queue = NULL; | |
1608 | ||
1609 | /* | |
1610 | * When this function is called, all in-service entities have | |
1611 | * been properly deactivated or requeued, so we can safely | |
1612 | * execute the final step: reset in_service_entity along the | |
1613 | * path from entity to the root. | |
1614 | */ | |
1615 | for_each_entity(entity) | |
1616 | entity->sched_data->in_service_entity = NULL; | |
1617 | ||
1618 | /* | |
1619 | * in_serv_entity is no longer in service, so, if it is in no | |
1620 | * service tree either, then release the service reference to | |
1621 | * the queue it represents (taken with bfq_get_entity). | |
1622 | */ | |
33a16a98 | 1623 | if (!in_serv_entity->on_st_or_in_serv) { |
eed47d19 PV |
1624 | /* |
1625 | * If no process is referencing in_serv_bfqq any | |
1626 | * longer, then the service reference may be the only | |
1627 | * reference to the queue. If this is the case, then | |
1628 | * bfqq gets freed here. | |
1629 | */ | |
1630 | int ref = in_serv_bfqq->ref; | |
ea25da48 | 1631 | bfq_put_queue(in_serv_bfqq); |
eed47d19 PV |
1632 | if (ref == 1) |
1633 | return true; | |
1634 | } | |
1635 | ||
1636 | return false; | |
ea25da48 PV |
1637 | } |
1638 | ||
1639 | void bfq_deactivate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
1640 | bool ins_into_idle_tree, bool expiration) | |
1641 | { | |
1642 | struct bfq_entity *entity = &bfqq->entity; | |
1643 | ||
1644 | bfq_deactivate_entity(entity, ins_into_idle_tree, expiration); | |
1645 | } | |
1646 | ||
1647 | void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) | |
1648 | { | |
1649 | struct bfq_entity *entity = &bfqq->entity; | |
1650 | ||
1651 | bfq_activate_requeue_entity(entity, bfq_bfqq_non_blocking_wait_rq(bfqq), | |
80294c3b | 1652 | false, false); |
ea25da48 PV |
1653 | bfq_clear_bfqq_non_blocking_wait_rq(bfqq); |
1654 | } | |
1655 | ||
80294c3b PV |
1656 | void bfq_requeue_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, |
1657 | bool expiration) | |
ea25da48 PV |
1658 | { |
1659 | struct bfq_entity *entity = &bfqq->entity; | |
1660 | ||
1661 | bfq_activate_requeue_entity(entity, false, | |
80294c3b | 1662 | bfqq == bfqd->in_service_queue, expiration); |
ea25da48 PV |
1663 | } |
1664 | ||
1665 | /* | |
1666 | * Called when the bfqq no longer has requests pending, remove it from | |
1667 | * the service tree. As a special case, it can be invoked during an | |
1668 | * expiration. | |
1669 | */ | |
1670 | void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, | |
1671 | bool expiration) | |
1672 | { | |
1673 | bfq_log_bfqq(bfqd, bfqq, "del from busy"); | |
1674 | ||
1675 | bfq_clear_bfqq_busy(bfqq); | |
1676 | ||
73d58118 | 1677 | bfqd->busy_queues[bfqq->ioprio_class - 1]--; |
ea25da48 | 1678 | |
ea25da48 PV |
1679 | if (bfqq->wr_coeff > 1) |
1680 | bfqd->wr_busy_queues--; | |
1681 | ||
1682 | bfqg_stats_update_dequeue(bfqq_group(bfqq)); | |
1683 | ||
1684 | bfq_deactivate_bfqq(bfqd, bfqq, true, expiration); | |
9dee8b3b PV |
1685 | |
1686 | if (!bfqq->dispatched) | |
1687 | bfq_weights_tree_remove(bfqd, bfqq); | |
ea25da48 PV |
1688 | } |
1689 | ||
1690 | /* | |
1691 | * Called when an inactive queue receives a new request. | |
1692 | */ | |
1693 | void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq) | |
1694 | { | |
1695 | bfq_log_bfqq(bfqd, bfqq, "add to busy"); | |
1696 | ||
1697 | bfq_activate_bfqq(bfqd, bfqq); | |
1698 | ||
1699 | bfq_mark_bfqq_busy(bfqq); | |
73d58118 | 1700 | bfqd->busy_queues[bfqq->ioprio_class - 1]++; |
ea25da48 PV |
1701 | |
1702 | if (!bfqq->dispatched) | |
1703 | if (bfqq->wr_coeff == 1) | |
2d29c9f8 | 1704 | bfq_weights_tree_add(bfqd, bfqq, |
ea25da48 PV |
1705 | &bfqd->queue_weights_tree); |
1706 | ||
1707 | if (bfqq->wr_coeff > 1) | |
1708 | bfqd->wr_busy_queues++; | |
2ec5a5c4 PV |
1709 | |
1710 | /* Move bfqq to the head of the woken list of its waker */ | |
1711 | if (!hlist_unhashed(&bfqq->woken_list_node) && | |
1712 | &bfqq->woken_list_node != bfqq->waker_bfqq->woken_list.first) { | |
1713 | hlist_del_init(&bfqq->woken_list_node); | |
1714 | hlist_add_head(&bfqq->woken_list_node, | |
1715 | &bfqq->waker_bfqq->woken_list); | |
1716 | } | |
ea25da48 | 1717 | } |