1 /* 2 * net/sched/sch_qfq.c Quick Fair Queueing Plus Scheduler. 3 * 4 * Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente. 5 * Copyright (c) 2012 Paolo Valente. 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * version 2 as published by the Free Software Foundation. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/bitops.h> 15 #include <linux/errno.h> 16 #include <linux/netdevice.h> 17 #include <linux/pkt_sched.h> 18 #include <net/sch_generic.h> 19 #include <net/pkt_sched.h> 20 #include <net/pkt_cls.h> 21 22 23 /* Quick Fair Queueing Plus 24 ======================== 25 26 Sources: 27 28 [1] Paolo Valente, 29 "Reducing the Execution Time of Fair-Queueing Schedulers." 30 http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdf 31 32 Sources for QFQ: 33 34 [2] Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient 35 Packet Scheduling with Tight Bandwidth Distribution Guarantees." 36 37 See also: 38 http://retis.sssup.it/~fabio/linux/qfq/ 39 */ 40 41 /* 42 43 QFQ+ divides classes into aggregates of at most MAX_AGG_CLASSES 44 classes. Each aggregate is timestamped with a virtual start time S 45 and a virtual finish time F, and scheduled according to its 46 timestamps. S and F are computed as a function of a system virtual 47 time function V. The classes within each aggregate are instead 48 scheduled with DRR. 49 50 To speed up operations, QFQ+ divides also aggregates into a limited 51 number of groups. Which group a class belongs to depends on the 52 ratio between the maximum packet length for the class and the weight 53 of the class. Groups have their own S and F. In the end, QFQ+ 54 schedules groups, then aggregates within groups, then classes within 55 aggregates. See [1] and [2] for a full description. 56 57 Virtual time computations. 58 59 S, F and V are all computed in fixed point arithmetic with 60 FRAC_BITS decimal bits. 61 62 QFQ_MAX_INDEX is the maximum index allowed for a group. We need 63 one bit per index. 64 QFQ_MAX_WSHIFT is the maximum power of two supported as a weight. 65 66 The layout of the bits is as below: 67 68 [ MTU_SHIFT ][ FRAC_BITS ] 69 [ MAX_INDEX ][ MIN_SLOT_SHIFT ] 70 ^.__grp->index = 0 71 *.__grp->slot_shift 72 73 where MIN_SLOT_SHIFT is derived by difference from the others. 74 75 The max group index corresponds to Lmax/w_min, where 76 Lmax=1<<MTU_SHIFT, w_min = 1 . 77 From this, and knowing how many groups (MAX_INDEX) we want, 78 we can derive the shift corresponding to each group. 79 80 Because we often need to compute 81 F = S + len/w_i and V = V + len/wsum 82 instead of storing w_i store the value 83 inv_w = (1<<FRAC_BITS)/w_i 84 so we can do F = S + len * inv_w * wsum. 85 We use W_TOT in the formulas so we can easily move between 86 static and adaptive weight sum. 87 88 The per-scheduler-instance data contain all the data structures 89 for the scheduler: bitmaps and bucket lists. 90 91 */ 92 93 /* 94 * Maximum number of consecutive slots occupied by backlogged classes 95 * inside a group. 96 */ 97 #define QFQ_MAX_SLOTS 32 98 99 /* 100 * Shifts used for aggregate<->group mapping. We allow class weights that are 101 * in the range [1, 2^MAX_WSHIFT], and we try to map each aggregate i to the 102 * group with the smallest index that can support the L_i / r_i configured 103 * for the classes in the aggregate. 104 * 105 * grp->index is the index of the group; and grp->slot_shift 106 * is the shift for the corresponding (scaled) sigma_i. 107 */ 108 #define QFQ_MAX_INDEX 24 109 #define QFQ_MAX_WSHIFT 10 110 111 #define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) /* see qfq_slot_insert */ 112 #define QFQ_MAX_WSUM (64*QFQ_MAX_WEIGHT) 113 114 #define FRAC_BITS 30 /* fixed point arithmetic */ 115 #define ONE_FP (1UL << FRAC_BITS) 116 117 #define QFQ_MTU_SHIFT 16 /* to support TSO/GSO */ 118 #define QFQ_MIN_LMAX 512 /* see qfq_slot_insert */ 119 120 #define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */ 121 122 /* 123 * Possible group states. These values are used as indexes for the bitmaps 124 * array of struct qfq_queue. 125 */ 126 enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE }; 127 128 struct qfq_group; 129 130 struct qfq_aggregate; 131 132 struct qfq_class { 133 struct Qdisc_class_common common; 134 135 unsigned int refcnt; 136 unsigned int filter_cnt; 137 138 struct gnet_stats_basic_packed bstats; 139 struct gnet_stats_queue qstats; 140 struct gnet_stats_rate_est64 rate_est; 141 struct Qdisc *qdisc; 142 struct list_head alist; /* Link for active-classes list. */ 143 struct qfq_aggregate *agg; /* Parent aggregate. */ 144 int deficit; /* DRR deficit counter. */ 145 }; 146 147 struct qfq_aggregate { 148 struct hlist_node next; /* Link for the slot list. */ 149 u64 S, F; /* flow timestamps (exact) */ 150 151 /* group we belong to. In principle we would need the index, 152 * which is log_2(lmax/weight), but we never reference it 153 * directly, only the group. 154 */ 155 struct qfq_group *grp; 156 157 /* these are copied from the flowset. */ 158 u32 class_weight; /* Weight of each class in this aggregate. */ 159 /* Max pkt size for the classes in this aggregate, DRR quantum. */ 160 int lmax; 161 162 u32 inv_w; /* ONE_FP/(sum of weights of classes in aggr.). */ 163 u32 budgetmax; /* Max budget for this aggregate. */ 164 u32 initial_budget, budget; /* Initial and current budget. */ 165 166 int num_classes; /* Number of classes in this aggr. */ 167 struct list_head active; /* DRR queue of active classes. */ 168 169 struct hlist_node nonfull_next; /* See nonfull_aggs in qfq_sched. */ 170 }; 171 172 struct qfq_group { 173 u64 S, F; /* group timestamps (approx). */ 174 unsigned int slot_shift; /* Slot shift. */ 175 unsigned int index; /* Group index. */ 176 unsigned int front; /* Index of the front slot. */ 177 unsigned long full_slots; /* non-empty slots */ 178 179 /* Array of RR lists of active aggregates. */ 180 struct hlist_head slots[QFQ_MAX_SLOTS]; 181 }; 182 183 struct qfq_sched { 184 struct tcf_proto __rcu *filter_list; 185 struct Qdisc_class_hash clhash; 186 187 u64 oldV, V; /* Precise virtual times. */ 188 struct qfq_aggregate *in_serv_agg; /* Aggregate being served. */ 189 u32 wsum; /* weight sum */ 190 u32 iwsum; /* inverse weight sum */ 191 192 unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */ 193 struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */ 194 u32 min_slot_shift; /* Index of the group-0 bit in the bitmaps. */ 195 196 u32 max_agg_classes; /* Max number of classes per aggr. */ 197 struct hlist_head nonfull_aggs; /* Aggs with room for more classes. */ 198 }; 199 200 /* 201 * Possible reasons why the timestamps of an aggregate are updated 202 * enqueue: the aggregate switches from idle to active and must scheduled 203 * for service 204 * requeue: the aggregate finishes its budget, so it stops being served and 205 * must be rescheduled for service 206 */ 207 enum update_reason {enqueue, requeue}; 208 209 static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid) 210 { 211 struct qfq_sched *q = qdisc_priv(sch); 212 struct Qdisc_class_common *clc; 213 214 clc = qdisc_class_find(&q->clhash, classid); 215 if (clc == NULL) 216 return NULL; 217 return container_of(clc, struct qfq_class, common); 218 } 219 220 static void qfq_purge_queue(struct qfq_class *cl) 221 { 222 unsigned int len = cl->qdisc->q.qlen; 223 unsigned int backlog = cl->qdisc->qstats.backlog; 224 225 qdisc_reset(cl->qdisc); 226 qdisc_tree_reduce_backlog(cl->qdisc, len, backlog); 227 } 228 229 static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = { 230 [TCA_QFQ_WEIGHT] = { .type = NLA_U32 }, 231 [TCA_QFQ_LMAX] = { .type = NLA_U32 }, 232 }; 233 234 /* 235 * Calculate a flow index, given its weight and maximum packet length. 236 * index = log_2(maxlen/weight) but we need to apply the scaling. 237 * This is used only once at flow creation. 238 */ 239 static int qfq_calc_index(u32 inv_w, unsigned int maxlen, u32 min_slot_shift) 240 { 241 u64 slot_size = (u64)maxlen * inv_w; 242 unsigned long size_map; 243 int index = 0; 244 245 size_map = slot_size >> min_slot_shift; 246 if (!size_map) 247 goto out; 248 249 index = __fls(size_map) + 1; /* basically a log_2 */ 250 index -= !(slot_size - (1ULL << (index + min_slot_shift - 1))); 251 252 if (index < 0) 253 index = 0; 254 out: 255 pr_debug("qfq calc_index: W = %lu, L = %u, I = %d\n", 256 (unsigned long) ONE_FP/inv_w, maxlen, index); 257 258 return index; 259 } 260 261 static void qfq_deactivate_agg(struct qfq_sched *, struct qfq_aggregate *); 262 static void qfq_activate_agg(struct qfq_sched *, struct qfq_aggregate *, 263 enum update_reason); 264 265 static void qfq_init_agg(struct qfq_sched *q, struct qfq_aggregate *agg, 266 u32 lmax, u32 weight) 267 { 268 INIT_LIST_HEAD(&agg->active); 269 hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs); 270 271 agg->lmax = lmax; 272 agg->class_weight = weight; 273 } 274 275 static struct qfq_aggregate *qfq_find_agg(struct qfq_sched *q, 276 u32 lmax, u32 weight) 277 { 278 struct qfq_aggregate *agg; 279 280 hlist_for_each_entry(agg, &q->nonfull_aggs, nonfull_next) 281 if (agg->lmax == lmax && agg->class_weight == weight) 282 return agg; 283 284 return NULL; 285 } 286 287 288 /* Update aggregate as a function of the new number of classes. */ 289 static void qfq_update_agg(struct qfq_sched *q, struct qfq_aggregate *agg, 290 int new_num_classes) 291 { 292 u32 new_agg_weight; 293 294 if (new_num_classes == q->max_agg_classes) 295 hlist_del_init(&agg->nonfull_next); 296 297 if (agg->num_classes > new_num_classes && 298 new_num_classes == q->max_agg_classes - 1) /* agg no more full */ 299 hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs); 300 301 /* The next assignment may let 302 * agg->initial_budget > agg->budgetmax 303 * hold, we will take it into account in charge_actual_service(). 304 */ 305 agg->budgetmax = new_num_classes * agg->lmax; 306 new_agg_weight = agg->class_weight * new_num_classes; 307 agg->inv_w = ONE_FP/new_agg_weight; 308 309 if (agg->grp == NULL) { 310 int i = qfq_calc_index(agg->inv_w, agg->budgetmax, 311 q->min_slot_shift); 312 agg->grp = &q->groups[i]; 313 } 314 315 q->wsum += 316 (int) agg->class_weight * (new_num_classes - agg->num_classes); 317 q->iwsum = ONE_FP / q->wsum; 318 319 agg->num_classes = new_num_classes; 320 } 321 322 /* Add class to aggregate. */ 323 static void qfq_add_to_agg(struct qfq_sched *q, 324 struct qfq_aggregate *agg, 325 struct qfq_class *cl) 326 { 327 cl->agg = agg; 328 329 qfq_update_agg(q, agg, agg->num_classes+1); 330 if (cl->qdisc->q.qlen > 0) { /* adding an active class */ 331 list_add_tail(&cl->alist, &agg->active); 332 if (list_first_entry(&agg->active, struct qfq_class, alist) == 333 cl && q->in_serv_agg != agg) /* agg was inactive */ 334 qfq_activate_agg(q, agg, enqueue); /* schedule agg */ 335 } 336 } 337 338 static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *); 339 340 static void qfq_destroy_agg(struct qfq_sched *q, struct qfq_aggregate *agg) 341 { 342 hlist_del_init(&agg->nonfull_next); 343 q->wsum -= agg->class_weight; 344 if (q->wsum != 0) 345 q->iwsum = ONE_FP / q->wsum; 346 347 if (q->in_serv_agg == agg) 348 q->in_serv_agg = qfq_choose_next_agg(q); 349 kfree(agg); 350 } 351 352 /* Deschedule class from within its parent aggregate. */ 353 static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) 354 { 355 struct qfq_aggregate *agg = cl->agg; 356 357 358 list_del(&cl->alist); /* remove from RR queue of the aggregate */ 359 if (list_empty(&agg->active)) /* agg is now inactive */ 360 qfq_deactivate_agg(q, agg); 361 } 362 363 /* Remove class from its parent aggregate. */ 364 static void qfq_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl) 365 { 366 struct qfq_aggregate *agg = cl->agg; 367 368 cl->agg = NULL; 369 if (agg->num_classes == 1) { /* agg being emptied, destroy it */ 370 qfq_destroy_agg(q, agg); 371 return; 372 } 373 qfq_update_agg(q, agg, agg->num_classes-1); 374 } 375 376 /* Deschedule class and remove it from its parent aggregate. */ 377 static void qfq_deact_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl) 378 { 379 if (cl->qdisc->q.qlen > 0) /* class is active */ 380 qfq_deactivate_class(q, cl); 381 382 qfq_rm_from_agg(q, cl); 383 } 384 385 /* Move class to a new aggregate, matching the new class weight and/or lmax */ 386 static int qfq_change_agg(struct Qdisc *sch, struct qfq_class *cl, u32 weight, 387 u32 lmax) 388 { 389 struct qfq_sched *q = qdisc_priv(sch); 390 struct qfq_aggregate *new_agg = qfq_find_agg(q, lmax, weight); 391 392 if (new_agg == NULL) { /* create new aggregate */ 393 new_agg = kzalloc(sizeof(*new_agg), GFP_ATOMIC); 394 if (new_agg == NULL) 395 return -ENOBUFS; 396 qfq_init_agg(q, new_agg, lmax, weight); 397 } 398 qfq_deact_rm_from_agg(q, cl); 399 qfq_add_to_agg(q, new_agg, cl); 400 401 return 0; 402 } 403 404 static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, 405 struct nlattr **tca, unsigned long *arg) 406 { 407 struct qfq_sched *q = qdisc_priv(sch); 408 struct qfq_class *cl = (struct qfq_class *)*arg; 409 bool existing = false; 410 struct nlattr *tb[TCA_QFQ_MAX + 1]; 411 struct qfq_aggregate *new_agg = NULL; 412 u32 weight, lmax, inv_w; 413 int err; 414 int delta_w; 415 416 if (tca[TCA_OPTIONS] == NULL) { 417 pr_notice("qfq: no options\n"); 418 return -EINVAL; 419 } 420 421 err = nla_parse_nested(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS], qfq_policy); 422 if (err < 0) 423 return err; 424 425 if (tb[TCA_QFQ_WEIGHT]) { 426 weight = nla_get_u32(tb[TCA_QFQ_WEIGHT]); 427 if (!weight || weight > (1UL << QFQ_MAX_WSHIFT)) { 428 pr_notice("qfq: invalid weight %u\n", weight); 429 return -EINVAL; 430 } 431 } else 432 weight = 1; 433 434 if (tb[TCA_QFQ_LMAX]) { 435 lmax = nla_get_u32(tb[TCA_QFQ_LMAX]); 436 if (lmax < QFQ_MIN_LMAX || lmax > (1UL << QFQ_MTU_SHIFT)) { 437 pr_notice("qfq: invalid max length %u\n", lmax); 438 return -EINVAL; 439 } 440 } else 441 lmax = psched_mtu(qdisc_dev(sch)); 442 443 inv_w = ONE_FP / weight; 444 weight = ONE_FP / inv_w; 445 446 if (cl != NULL && 447 lmax == cl->agg->lmax && 448 weight == cl->agg->class_weight) 449 return 0; /* nothing to change */ 450 451 delta_w = weight - (cl ? cl->agg->class_weight : 0); 452 453 if (q->wsum + delta_w > QFQ_MAX_WSUM) { 454 pr_notice("qfq: total weight out of range (%d + %u)\n", 455 delta_w, q->wsum); 456 return -EINVAL; 457 } 458 459 if (cl != NULL) { /* modify existing class */ 460 if (tca[TCA_RATE]) { 461 err = gen_replace_estimator(&cl->bstats, NULL, 462 &cl->rate_est, 463 NULL, 464 qdisc_root_sleeping_running(sch), 465 tca[TCA_RATE]); 466 if (err) 467 return err; 468 } 469 existing = true; 470 goto set_change_agg; 471 } 472 473 /* create and init new class */ 474 cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL); 475 if (cl == NULL) 476 return -ENOBUFS; 477 478 cl->refcnt = 1; 479 cl->common.classid = classid; 480 cl->deficit = lmax; 481 482 cl->qdisc = qdisc_create_dflt(sch->dev_queue, 483 &pfifo_qdisc_ops, classid); 484 if (cl->qdisc == NULL) 485 cl->qdisc = &noop_qdisc; 486 487 if (tca[TCA_RATE]) { 488 err = gen_new_estimator(&cl->bstats, NULL, 489 &cl->rate_est, 490 NULL, 491 qdisc_root_sleeping_running(sch), 492 tca[TCA_RATE]); 493 if (err) 494 goto destroy_class; 495 } 496 497 sch_tree_lock(sch); 498 qdisc_class_hash_insert(&q->clhash, &cl->common); 499 sch_tree_unlock(sch); 500 501 qdisc_class_hash_grow(sch, &q->clhash); 502 503 set_change_agg: 504 sch_tree_lock(sch); 505 new_agg = qfq_find_agg(q, lmax, weight); 506 if (new_agg == NULL) { /* create new aggregate */ 507 sch_tree_unlock(sch); 508 new_agg = kzalloc(sizeof(*new_agg), GFP_KERNEL); 509 if (new_agg == NULL) { 510 err = -ENOBUFS; 511 gen_kill_estimator(&cl->bstats, &cl->rate_est); 512 goto destroy_class; 513 } 514 sch_tree_lock(sch); 515 qfq_init_agg(q, new_agg, lmax, weight); 516 } 517 if (existing) 518 qfq_deact_rm_from_agg(q, cl); 519 qfq_add_to_agg(q, new_agg, cl); 520 sch_tree_unlock(sch); 521 522 *arg = (unsigned long)cl; 523 return 0; 524 525 destroy_class: 526 qdisc_destroy(cl->qdisc); 527 kfree(cl); 528 return err; 529 } 530 531 static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl) 532 { 533 struct qfq_sched *q = qdisc_priv(sch); 534 535 qfq_rm_from_agg(q, cl); 536 gen_kill_estimator(&cl->bstats, &cl->rate_est); 537 qdisc_destroy(cl->qdisc); 538 kfree(cl); 539 } 540 541 static int qfq_delete_class(struct Qdisc *sch, unsigned long arg) 542 { 543 struct qfq_sched *q = qdisc_priv(sch); 544 struct qfq_class *cl = (struct qfq_class *)arg; 545 546 if (cl->filter_cnt > 0) 547 return -EBUSY; 548 549 sch_tree_lock(sch); 550 551 qfq_purge_queue(cl); 552 qdisc_class_hash_remove(&q->clhash, &cl->common); 553 554 BUG_ON(--cl->refcnt == 0); 555 /* 556 * This shouldn't happen: we "hold" one cops->get() when called 557 * from tc_ctl_tclass; the destroy method is done from cops->put(). 558 */ 559 560 sch_tree_unlock(sch); 561 return 0; 562 } 563 564 static unsigned long qfq_get_class(struct Qdisc *sch, u32 classid) 565 { 566 struct qfq_class *cl = qfq_find_class(sch, classid); 567 568 if (cl != NULL) 569 cl->refcnt++; 570 571 return (unsigned long)cl; 572 } 573 574 static void qfq_put_class(struct Qdisc *sch, unsigned long arg) 575 { 576 struct qfq_class *cl = (struct qfq_class *)arg; 577 578 if (--cl->refcnt == 0) 579 qfq_destroy_class(sch, cl); 580 } 581 582 static struct tcf_proto __rcu **qfq_tcf_chain(struct Qdisc *sch, 583 unsigned long cl) 584 { 585 struct qfq_sched *q = qdisc_priv(sch); 586 587 if (cl) 588 return NULL; 589 590 return &q->filter_list; 591 } 592 593 static unsigned long qfq_bind_tcf(struct Qdisc *sch, unsigned long parent, 594 u32 classid) 595 { 596 struct qfq_class *cl = qfq_find_class(sch, classid); 597 598 if (cl != NULL) 599 cl->filter_cnt++; 600 601 return (unsigned long)cl; 602 } 603 604 static void qfq_unbind_tcf(struct Qdisc *sch, unsigned long arg) 605 { 606 struct qfq_class *cl = (struct qfq_class *)arg; 607 608 cl->filter_cnt--; 609 } 610 611 static int qfq_graft_class(struct Qdisc *sch, unsigned long arg, 612 struct Qdisc *new, struct Qdisc **old) 613 { 614 struct qfq_class *cl = (struct qfq_class *)arg; 615 616 if (new == NULL) { 617 new = qdisc_create_dflt(sch->dev_queue, 618 &pfifo_qdisc_ops, cl->common.classid); 619 if (new == NULL) 620 new = &noop_qdisc; 621 } 622 623 *old = qdisc_replace(sch, new, &cl->qdisc); 624 return 0; 625 } 626 627 static struct Qdisc *qfq_class_leaf(struct Qdisc *sch, unsigned long arg) 628 { 629 struct qfq_class *cl = (struct qfq_class *)arg; 630 631 return cl->qdisc; 632 } 633 634 static int qfq_dump_class(struct Qdisc *sch, unsigned long arg, 635 struct sk_buff *skb, struct tcmsg *tcm) 636 { 637 struct qfq_class *cl = (struct qfq_class *)arg; 638 struct nlattr *nest; 639 640 tcm->tcm_parent = TC_H_ROOT; 641 tcm->tcm_handle = cl->common.classid; 642 tcm->tcm_info = cl->qdisc->handle; 643 644 nest = nla_nest_start(skb, TCA_OPTIONS); 645 if (nest == NULL) 646 goto nla_put_failure; 647 if (nla_put_u32(skb, TCA_QFQ_WEIGHT, cl->agg->class_weight) || 648 nla_put_u32(skb, TCA_QFQ_LMAX, cl->agg->lmax)) 649 goto nla_put_failure; 650 return nla_nest_end(skb, nest); 651 652 nla_put_failure: 653 nla_nest_cancel(skb, nest); 654 return -EMSGSIZE; 655 } 656 657 static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg, 658 struct gnet_dump *d) 659 { 660 struct qfq_class *cl = (struct qfq_class *)arg; 661 struct tc_qfq_stats xstats; 662 663 memset(&xstats, 0, sizeof(xstats)); 664 665 xstats.weight = cl->agg->class_weight; 666 xstats.lmax = cl->agg->lmax; 667 668 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), 669 d, NULL, &cl->bstats) < 0 || 670 gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || 671 gnet_stats_copy_queue(d, NULL, 672 &cl->qdisc->qstats, cl->qdisc->q.qlen) < 0) 673 return -1; 674 675 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 676 } 677 678 static void qfq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 679 { 680 struct qfq_sched *q = qdisc_priv(sch); 681 struct qfq_class *cl; 682 unsigned int i; 683 684 if (arg->stop) 685 return; 686 687 for (i = 0; i < q->clhash.hashsize; i++) { 688 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { 689 if (arg->count < arg->skip) { 690 arg->count++; 691 continue; 692 } 693 if (arg->fn(sch, (unsigned long)cl, arg) < 0) { 694 arg->stop = 1; 695 return; 696 } 697 arg->count++; 698 } 699 } 700 } 701 702 static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch, 703 int *qerr) 704 { 705 struct qfq_sched *q = qdisc_priv(sch); 706 struct qfq_class *cl; 707 struct tcf_result res; 708 struct tcf_proto *fl; 709 int result; 710 711 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { 712 pr_debug("qfq_classify: found %d\n", skb->priority); 713 cl = qfq_find_class(sch, skb->priority); 714 if (cl != NULL) 715 return cl; 716 } 717 718 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 719 fl = rcu_dereference_bh(q->filter_list); 720 result = tc_classify(skb, fl, &res, false); 721 if (result >= 0) { 722 #ifdef CONFIG_NET_CLS_ACT 723 switch (result) { 724 case TC_ACT_QUEUED: 725 case TC_ACT_STOLEN: 726 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 727 case TC_ACT_SHOT: 728 return NULL; 729 } 730 #endif 731 cl = (struct qfq_class *)res.class; 732 if (cl == NULL) 733 cl = qfq_find_class(sch, res.classid); 734 return cl; 735 } 736 737 return NULL; 738 } 739 740 /* Generic comparison function, handling wraparound. */ 741 static inline int qfq_gt(u64 a, u64 b) 742 { 743 return (s64)(a - b) > 0; 744 } 745 746 /* Round a precise timestamp to its slotted value. */ 747 static inline u64 qfq_round_down(u64 ts, unsigned int shift) 748 { 749 return ts & ~((1ULL << shift) - 1); 750 } 751 752 /* return the pointer to the group with lowest index in the bitmap */ 753 static inline struct qfq_group *qfq_ffs(struct qfq_sched *q, 754 unsigned long bitmap) 755 { 756 int index = __ffs(bitmap); 757 return &q->groups[index]; 758 } 759 /* Calculate a mask to mimic what would be ffs_from(). */ 760 static inline unsigned long mask_from(unsigned long bitmap, int from) 761 { 762 return bitmap & ~((1UL << from) - 1); 763 } 764 765 /* 766 * The state computation relies on ER=0, IR=1, EB=2, IB=3 767 * First compute eligibility comparing grp->S, q->V, 768 * then check if someone is blocking us and possibly add EB 769 */ 770 static int qfq_calc_state(struct qfq_sched *q, const struct qfq_group *grp) 771 { 772 /* if S > V we are not eligible */ 773 unsigned int state = qfq_gt(grp->S, q->V); 774 unsigned long mask = mask_from(q->bitmaps[ER], grp->index); 775 struct qfq_group *next; 776 777 if (mask) { 778 next = qfq_ffs(q, mask); 779 if (qfq_gt(grp->F, next->F)) 780 state |= EB; 781 } 782 783 return state; 784 } 785 786 787 /* 788 * In principle 789 * q->bitmaps[dst] |= q->bitmaps[src] & mask; 790 * q->bitmaps[src] &= ~mask; 791 * but we should make sure that src != dst 792 */ 793 static inline void qfq_move_groups(struct qfq_sched *q, unsigned long mask, 794 int src, int dst) 795 { 796 q->bitmaps[dst] |= q->bitmaps[src] & mask; 797 q->bitmaps[src] &= ~mask; 798 } 799 800 static void qfq_unblock_groups(struct qfq_sched *q, int index, u64 old_F) 801 { 802 unsigned long mask = mask_from(q->bitmaps[ER], index + 1); 803 struct qfq_group *next; 804 805 if (mask) { 806 next = qfq_ffs(q, mask); 807 if (!qfq_gt(next->F, old_F)) 808 return; 809 } 810 811 mask = (1UL << index) - 1; 812 qfq_move_groups(q, mask, EB, ER); 813 qfq_move_groups(q, mask, IB, IR); 814 } 815 816 /* 817 * perhaps 818 * 819 old_V ^= q->V; 820 old_V >>= q->min_slot_shift; 821 if (old_V) { 822 ... 823 } 824 * 825 */ 826 static void qfq_make_eligible(struct qfq_sched *q) 827 { 828 unsigned long vslot = q->V >> q->min_slot_shift; 829 unsigned long old_vslot = q->oldV >> q->min_slot_shift; 830 831 if (vslot != old_vslot) { 832 unsigned long mask; 833 int last_flip_pos = fls(vslot ^ old_vslot); 834 835 if (last_flip_pos > 31) /* higher than the number of groups */ 836 mask = ~0UL; /* make all groups eligible */ 837 else 838 mask = (1UL << last_flip_pos) - 1; 839 840 qfq_move_groups(q, mask, IR, ER); 841 qfq_move_groups(q, mask, IB, EB); 842 } 843 } 844 845 /* 846 * The index of the slot in which the input aggregate agg is to be 847 * inserted must not be higher than QFQ_MAX_SLOTS-2. There is a '-2' 848 * and not a '-1' because the start time of the group may be moved 849 * backward by one slot after the aggregate has been inserted, and 850 * this would cause non-empty slots to be right-shifted by one 851 * position. 852 * 853 * QFQ+ fully satisfies this bound to the slot index if the parameters 854 * of the classes are not changed dynamically, and if QFQ+ never 855 * happens to postpone the service of agg unjustly, i.e., it never 856 * happens that the aggregate becomes backlogged and eligible, or just 857 * eligible, while an aggregate with a higher approximated finish time 858 * is being served. In particular, in this case QFQ+ guarantees that 859 * the timestamps of agg are low enough that the slot index is never 860 * higher than 2. Unfortunately, QFQ+ cannot provide the same 861 * guarantee if it happens to unjustly postpone the service of agg, or 862 * if the parameters of some class are changed. 863 * 864 * As for the first event, i.e., an out-of-order service, the 865 * upper bound to the slot index guaranteed by QFQ+ grows to 866 * 2 + 867 * QFQ_MAX_AGG_CLASSES * ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) * 868 * (current_max_weight/current_wsum) <= 2 + 8 * 128 * 1. 869 * 870 * The following function deals with this problem by backward-shifting 871 * the timestamps of agg, if needed, so as to guarantee that the slot 872 * index is never higher than QFQ_MAX_SLOTS-2. This backward-shift may 873 * cause the service of other aggregates to be postponed, yet the 874 * worst-case guarantees of these aggregates are not violated. In 875 * fact, in case of no out-of-order service, the timestamps of agg 876 * would have been even lower than they are after the backward shift, 877 * because QFQ+ would have guaranteed a maximum value equal to 2 for 878 * the slot index, and 2 < QFQ_MAX_SLOTS-2. Hence the aggregates whose 879 * service is postponed because of the backward-shift would have 880 * however waited for the service of agg before being served. 881 * 882 * The other event that may cause the slot index to be higher than 2 883 * for agg is a recent change of the parameters of some class. If the 884 * weight of a class is increased or the lmax (max_pkt_size) of the 885 * class is decreased, then a new aggregate with smaller slot size 886 * than the original parent aggregate of the class may happen to be 887 * activated. The activation of this aggregate should be properly 888 * delayed to when the service of the class has finished in the ideal 889 * system tracked by QFQ+. If the activation of the aggregate is not 890 * delayed to this reference time instant, then this aggregate may be 891 * unjustly served before other aggregates waiting for service. This 892 * may cause the above bound to the slot index to be violated for some 893 * of these unlucky aggregates. 894 * 895 * Instead of delaying the activation of the new aggregate, which is 896 * quite complex, the above-discussed capping of the slot index is 897 * used to handle also the consequences of a change of the parameters 898 * of a class. 899 */ 900 static void qfq_slot_insert(struct qfq_group *grp, struct qfq_aggregate *agg, 901 u64 roundedS) 902 { 903 u64 slot = (roundedS - grp->S) >> grp->slot_shift; 904 unsigned int i; /* slot index in the bucket list */ 905 906 if (unlikely(slot > QFQ_MAX_SLOTS - 2)) { 907 u64 deltaS = roundedS - grp->S - 908 ((u64)(QFQ_MAX_SLOTS - 2)<<grp->slot_shift); 909 agg->S -= deltaS; 910 agg->F -= deltaS; 911 slot = QFQ_MAX_SLOTS - 2; 912 } 913 914 i = (grp->front + slot) % QFQ_MAX_SLOTS; 915 916 hlist_add_head(&agg->next, &grp->slots[i]); 917 __set_bit(slot, &grp->full_slots); 918 } 919 920 /* Maybe introduce hlist_first_entry?? */ 921 static struct qfq_aggregate *qfq_slot_head(struct qfq_group *grp) 922 { 923 return hlist_entry(grp->slots[grp->front].first, 924 struct qfq_aggregate, next); 925 } 926 927 /* 928 * remove the entry from the slot 929 */ 930 static void qfq_front_slot_remove(struct qfq_group *grp) 931 { 932 struct qfq_aggregate *agg = qfq_slot_head(grp); 933 934 BUG_ON(!agg); 935 hlist_del(&agg->next); 936 if (hlist_empty(&grp->slots[grp->front])) 937 __clear_bit(0, &grp->full_slots); 938 } 939 940 /* 941 * Returns the first aggregate in the first non-empty bucket of the 942 * group. As a side effect, adjusts the bucket list so the first 943 * non-empty bucket is at position 0 in full_slots. 944 */ 945 static struct qfq_aggregate *qfq_slot_scan(struct qfq_group *grp) 946 { 947 unsigned int i; 948 949 pr_debug("qfq slot_scan: grp %u full %#lx\n", 950 grp->index, grp->full_slots); 951 952 if (grp->full_slots == 0) 953 return NULL; 954 955 i = __ffs(grp->full_slots); /* zero based */ 956 if (i > 0) { 957 grp->front = (grp->front + i) % QFQ_MAX_SLOTS; 958 grp->full_slots >>= i; 959 } 960 961 return qfq_slot_head(grp); 962 } 963 964 /* 965 * adjust the bucket list. When the start time of a group decreases, 966 * we move the index down (modulo QFQ_MAX_SLOTS) so we don't need to 967 * move the objects. The mask of occupied slots must be shifted 968 * because we use ffs() to find the first non-empty slot. 969 * This covers decreases in the group's start time, but what about 970 * increases of the start time ? 971 * Here too we should make sure that i is less than 32 972 */ 973 static void qfq_slot_rotate(struct qfq_group *grp, u64 roundedS) 974 { 975 unsigned int i = (grp->S - roundedS) >> grp->slot_shift; 976 977 grp->full_slots <<= i; 978 grp->front = (grp->front - i) % QFQ_MAX_SLOTS; 979 } 980 981 static void qfq_update_eligible(struct qfq_sched *q) 982 { 983 struct qfq_group *grp; 984 unsigned long ineligible; 985 986 ineligible = q->bitmaps[IR] | q->bitmaps[IB]; 987 if (ineligible) { 988 if (!q->bitmaps[ER]) { 989 grp = qfq_ffs(q, ineligible); 990 if (qfq_gt(grp->S, q->V)) 991 q->V = grp->S; 992 } 993 qfq_make_eligible(q); 994 } 995 } 996 997 /* Dequeue head packet of the head class in the DRR queue of the aggregate. */ 998 static void agg_dequeue(struct qfq_aggregate *agg, 999 struct qfq_class *cl, unsigned int len) 1000 { 1001 qdisc_dequeue_peeked(cl->qdisc); 1002 1003 cl->deficit -= (int) len; 1004 1005 if (cl->qdisc->q.qlen == 0) /* no more packets, remove from list */ 1006 list_del(&cl->alist); 1007 else if (cl->deficit < qdisc_pkt_len(cl->qdisc->ops->peek(cl->qdisc))) { 1008 cl->deficit += agg->lmax; 1009 list_move_tail(&cl->alist, &agg->active); 1010 } 1011 } 1012 1013 static inline struct sk_buff *qfq_peek_skb(struct qfq_aggregate *agg, 1014 struct qfq_class **cl, 1015 unsigned int *len) 1016 { 1017 struct sk_buff *skb; 1018 1019 *cl = list_first_entry(&agg->active, struct qfq_class, alist); 1020 skb = (*cl)->qdisc->ops->peek((*cl)->qdisc); 1021 if (skb == NULL) 1022 WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n"); 1023 else 1024 *len = qdisc_pkt_len(skb); 1025 1026 return skb; 1027 } 1028 1029 /* Update F according to the actual service received by the aggregate. */ 1030 static inline void charge_actual_service(struct qfq_aggregate *agg) 1031 { 1032 /* Compute the service received by the aggregate, taking into 1033 * account that, after decreasing the number of classes in 1034 * agg, it may happen that 1035 * agg->initial_budget - agg->budget > agg->bugdetmax 1036 */ 1037 u32 service_received = min(agg->budgetmax, 1038 agg->initial_budget - agg->budget); 1039 1040 agg->F = agg->S + (u64)service_received * agg->inv_w; 1041 } 1042 1043 /* Assign a reasonable start time for a new aggregate in group i. 1044 * Admissible values for \hat(F) are multiples of \sigma_i 1045 * no greater than V+\sigma_i . Larger values mean that 1046 * we had a wraparound so we consider the timestamp to be stale. 1047 * 1048 * If F is not stale and F >= V then we set S = F. 1049 * Otherwise we should assign S = V, but this may violate 1050 * the ordering in EB (see [2]). So, if we have groups in ER, 1051 * set S to the F_j of the first group j which would be blocking us. 1052 * We are guaranteed not to move S backward because 1053 * otherwise our group i would still be blocked. 1054 */ 1055 static void qfq_update_start(struct qfq_sched *q, struct qfq_aggregate *agg) 1056 { 1057 unsigned long mask; 1058 u64 limit, roundedF; 1059 int slot_shift = agg->grp->slot_shift; 1060 1061 roundedF = qfq_round_down(agg->F, slot_shift); 1062 limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift); 1063 1064 if (!qfq_gt(agg->F, q->V) || qfq_gt(roundedF, limit)) { 1065 /* timestamp was stale */ 1066 mask = mask_from(q->bitmaps[ER], agg->grp->index); 1067 if (mask) { 1068 struct qfq_group *next = qfq_ffs(q, mask); 1069 if (qfq_gt(roundedF, next->F)) { 1070 if (qfq_gt(limit, next->F)) 1071 agg->S = next->F; 1072 else /* preserve timestamp correctness */ 1073 agg->S = limit; 1074 return; 1075 } 1076 } 1077 agg->S = q->V; 1078 } else /* timestamp is not stale */ 1079 agg->S = agg->F; 1080 } 1081 1082 /* Update the timestamps of agg before scheduling/rescheduling it for 1083 * service. In particular, assign to agg->F its maximum possible 1084 * value, i.e., the virtual finish time with which the aggregate 1085 * should be labeled if it used all its budget once in service. 1086 */ 1087 static inline void 1088 qfq_update_agg_ts(struct qfq_sched *q, 1089 struct qfq_aggregate *agg, enum update_reason reason) 1090 { 1091 if (reason != requeue) 1092 qfq_update_start(q, agg); 1093 else /* just charge agg for the service received */ 1094 agg->S = agg->F; 1095 1096 agg->F = agg->S + (u64)agg->budgetmax * agg->inv_w; 1097 } 1098 1099 static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg); 1100 1101 static struct sk_buff *qfq_dequeue(struct Qdisc *sch) 1102 { 1103 struct qfq_sched *q = qdisc_priv(sch); 1104 struct qfq_aggregate *in_serv_agg = q->in_serv_agg; 1105 struct qfq_class *cl; 1106 struct sk_buff *skb = NULL; 1107 /* next-packet len, 0 means no more active classes in in-service agg */ 1108 unsigned int len = 0; 1109 1110 if (in_serv_agg == NULL) 1111 return NULL; 1112 1113 if (!list_empty(&in_serv_agg->active)) 1114 skb = qfq_peek_skb(in_serv_agg, &cl, &len); 1115 1116 /* 1117 * If there are no active classes in the in-service aggregate, 1118 * or if the aggregate has not enough budget to serve its next 1119 * class, then choose the next aggregate to serve. 1120 */ 1121 if (len == 0 || in_serv_agg->budget < len) { 1122 charge_actual_service(in_serv_agg); 1123 1124 /* recharge the budget of the aggregate */ 1125 in_serv_agg->initial_budget = in_serv_agg->budget = 1126 in_serv_agg->budgetmax; 1127 1128 if (!list_empty(&in_serv_agg->active)) { 1129 /* 1130 * Still active: reschedule for 1131 * service. Possible optimization: if no other 1132 * aggregate is active, then there is no point 1133 * in rescheduling this aggregate, and we can 1134 * just keep it as the in-service one. This 1135 * should be however a corner case, and to 1136 * handle it, we would need to maintain an 1137 * extra num_active_aggs field. 1138 */ 1139 qfq_update_agg_ts(q, in_serv_agg, requeue); 1140 qfq_schedule_agg(q, in_serv_agg); 1141 } else if (sch->q.qlen == 0) { /* no aggregate to serve */ 1142 q->in_serv_agg = NULL; 1143 return NULL; 1144 } 1145 1146 /* 1147 * If we get here, there are other aggregates queued: 1148 * choose the new aggregate to serve. 1149 */ 1150 in_serv_agg = q->in_serv_agg = qfq_choose_next_agg(q); 1151 skb = qfq_peek_skb(in_serv_agg, &cl, &len); 1152 } 1153 if (!skb) 1154 return NULL; 1155 1156 sch->q.qlen--; 1157 qdisc_bstats_update(sch, skb); 1158 1159 agg_dequeue(in_serv_agg, cl, len); 1160 /* If lmax is lowered, through qfq_change_class, for a class 1161 * owning pending packets with larger size than the new value 1162 * of lmax, then the following condition may hold. 1163 */ 1164 if (unlikely(in_serv_agg->budget < len)) 1165 in_serv_agg->budget = 0; 1166 else 1167 in_serv_agg->budget -= len; 1168 1169 q->V += (u64)len * q->iwsum; 1170 pr_debug("qfq dequeue: len %u F %lld now %lld\n", 1171 len, (unsigned long long) in_serv_agg->F, 1172 (unsigned long long) q->V); 1173 1174 return skb; 1175 } 1176 1177 static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *q) 1178 { 1179 struct qfq_group *grp; 1180 struct qfq_aggregate *agg, *new_front_agg; 1181 u64 old_F; 1182 1183 qfq_update_eligible(q); 1184 q->oldV = q->V; 1185 1186 if (!q->bitmaps[ER]) 1187 return NULL; 1188 1189 grp = qfq_ffs(q, q->bitmaps[ER]); 1190 old_F = grp->F; 1191 1192 agg = qfq_slot_head(grp); 1193 1194 /* agg starts to be served, remove it from schedule */ 1195 qfq_front_slot_remove(grp); 1196 1197 new_front_agg = qfq_slot_scan(grp); 1198 1199 if (new_front_agg == NULL) /* group is now inactive, remove from ER */ 1200 __clear_bit(grp->index, &q->bitmaps[ER]); 1201 else { 1202 u64 roundedS = qfq_round_down(new_front_agg->S, 1203 grp->slot_shift); 1204 unsigned int s; 1205 1206 if (grp->S == roundedS) 1207 return agg; 1208 grp->S = roundedS; 1209 grp->F = roundedS + (2ULL << grp->slot_shift); 1210 __clear_bit(grp->index, &q->bitmaps[ER]); 1211 s = qfq_calc_state(q, grp); 1212 __set_bit(grp->index, &q->bitmaps[s]); 1213 } 1214 1215 qfq_unblock_groups(q, grp->index, old_F); 1216 1217 return agg; 1218 } 1219 1220 static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, 1221 struct sk_buff **to_free) 1222 { 1223 struct qfq_sched *q = qdisc_priv(sch); 1224 struct qfq_class *cl; 1225 struct qfq_aggregate *agg; 1226 int err = 0; 1227 1228 cl = qfq_classify(skb, sch, &err); 1229 if (cl == NULL) { 1230 if (err & __NET_XMIT_BYPASS) 1231 qdisc_qstats_drop(sch); 1232 kfree_skb(skb); 1233 return err; 1234 } 1235 pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); 1236 1237 if (unlikely(cl->agg->lmax < qdisc_pkt_len(skb))) { 1238 pr_debug("qfq: increasing maxpkt from %u to %u for class %u", 1239 cl->agg->lmax, qdisc_pkt_len(skb), cl->common.classid); 1240 err = qfq_change_agg(sch, cl, cl->agg->class_weight, 1241 qdisc_pkt_len(skb)); 1242 if (err) { 1243 cl->qstats.drops++; 1244 return qdisc_drop(skb, sch, to_free); 1245 } 1246 } 1247 1248 err = qdisc_enqueue(skb, cl->qdisc, to_free); 1249 if (unlikely(err != NET_XMIT_SUCCESS)) { 1250 pr_debug("qfq_enqueue: enqueue failed %d\n", err); 1251 if (net_xmit_drop_count(err)) { 1252 cl->qstats.drops++; 1253 qdisc_qstats_drop(sch); 1254 } 1255 return err; 1256 } 1257 1258 bstats_update(&cl->bstats, skb); 1259 ++sch->q.qlen; 1260 1261 agg = cl->agg; 1262 /* if the queue was not empty, then done here */ 1263 if (cl->qdisc->q.qlen != 1) { 1264 if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) && 1265 list_first_entry(&agg->active, struct qfq_class, alist) 1266 == cl && cl->deficit < qdisc_pkt_len(skb)) 1267 list_move_tail(&cl->alist, &agg->active); 1268 1269 return err; 1270 } 1271 1272 /* schedule class for service within the aggregate */ 1273 cl->deficit = agg->lmax; 1274 list_add_tail(&cl->alist, &agg->active); 1275 1276 if (list_first_entry(&agg->active, struct qfq_class, alist) != cl || 1277 q->in_serv_agg == agg) 1278 return err; /* non-empty or in service, nothing else to do */ 1279 1280 qfq_activate_agg(q, agg, enqueue); 1281 1282 return err; 1283 } 1284 1285 /* 1286 * Schedule aggregate according to its timestamps. 1287 */ 1288 static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg) 1289 { 1290 struct qfq_group *grp = agg->grp; 1291 u64 roundedS; 1292 int s; 1293 1294 roundedS = qfq_round_down(agg->S, grp->slot_shift); 1295 1296 /* 1297 * Insert agg in the correct bucket. 1298 * If agg->S >= grp->S we don't need to adjust the 1299 * bucket list and simply go to the insertion phase. 1300 * Otherwise grp->S is decreasing, we must make room 1301 * in the bucket list, and also recompute the group state. 1302 * Finally, if there were no flows in this group and nobody 1303 * was in ER make sure to adjust V. 1304 */ 1305 if (grp->full_slots) { 1306 if (!qfq_gt(grp->S, agg->S)) 1307 goto skip_update; 1308 1309 /* create a slot for this agg->S */ 1310 qfq_slot_rotate(grp, roundedS); 1311 /* group was surely ineligible, remove */ 1312 __clear_bit(grp->index, &q->bitmaps[IR]); 1313 __clear_bit(grp->index, &q->bitmaps[IB]); 1314 } else if (!q->bitmaps[ER] && qfq_gt(roundedS, q->V) && 1315 q->in_serv_agg == NULL) 1316 q->V = roundedS; 1317 1318 grp->S = roundedS; 1319 grp->F = roundedS + (2ULL << grp->slot_shift); 1320 s = qfq_calc_state(q, grp); 1321 __set_bit(grp->index, &q->bitmaps[s]); 1322 1323 pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n", 1324 s, q->bitmaps[s], 1325 (unsigned long long) agg->S, 1326 (unsigned long long) agg->F, 1327 (unsigned long long) q->V); 1328 1329 skip_update: 1330 qfq_slot_insert(grp, agg, roundedS); 1331 } 1332 1333 1334 /* Update agg ts and schedule agg for service */ 1335 static void qfq_activate_agg(struct qfq_sched *q, struct qfq_aggregate *agg, 1336 enum update_reason reason) 1337 { 1338 agg->initial_budget = agg->budget = agg->budgetmax; /* recharge budg. */ 1339 1340 qfq_update_agg_ts(q, agg, reason); 1341 if (q->in_serv_agg == NULL) { /* no aggr. in service or scheduled */ 1342 q->in_serv_agg = agg; /* start serving this aggregate */ 1343 /* update V: to be in service, agg must be eligible */ 1344 q->oldV = q->V = agg->S; 1345 } else if (agg != q->in_serv_agg) 1346 qfq_schedule_agg(q, agg); 1347 } 1348 1349 static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp, 1350 struct qfq_aggregate *agg) 1351 { 1352 unsigned int i, offset; 1353 u64 roundedS; 1354 1355 roundedS = qfq_round_down(agg->S, grp->slot_shift); 1356 offset = (roundedS - grp->S) >> grp->slot_shift; 1357 1358 i = (grp->front + offset) % QFQ_MAX_SLOTS; 1359 1360 hlist_del(&agg->next); 1361 if (hlist_empty(&grp->slots[i])) 1362 __clear_bit(offset, &grp->full_slots); 1363 } 1364 1365 /* 1366 * Called to forcibly deschedule an aggregate. If the aggregate is 1367 * not in the front bucket, or if the latter has other aggregates in 1368 * the front bucket, we can simply remove the aggregate with no other 1369 * side effects. 1370 * Otherwise we must propagate the event up. 1371 */ 1372 static void qfq_deactivate_agg(struct qfq_sched *q, struct qfq_aggregate *agg) 1373 { 1374 struct qfq_group *grp = agg->grp; 1375 unsigned long mask; 1376 u64 roundedS; 1377 int s; 1378 1379 if (agg == q->in_serv_agg) { 1380 charge_actual_service(agg); 1381 q->in_serv_agg = qfq_choose_next_agg(q); 1382 return; 1383 } 1384 1385 agg->F = agg->S; 1386 qfq_slot_remove(q, grp, agg); 1387 1388 if (!grp->full_slots) { 1389 __clear_bit(grp->index, &q->bitmaps[IR]); 1390 __clear_bit(grp->index, &q->bitmaps[EB]); 1391 __clear_bit(grp->index, &q->bitmaps[IB]); 1392 1393 if (test_bit(grp->index, &q->bitmaps[ER]) && 1394 !(q->bitmaps[ER] & ~((1UL << grp->index) - 1))) { 1395 mask = q->bitmaps[ER] & ((1UL << grp->index) - 1); 1396 if (mask) 1397 mask = ~((1UL << __fls(mask)) - 1); 1398 else 1399 mask = ~0UL; 1400 qfq_move_groups(q, mask, EB, ER); 1401 qfq_move_groups(q, mask, IB, IR); 1402 } 1403 __clear_bit(grp->index, &q->bitmaps[ER]); 1404 } else if (hlist_empty(&grp->slots[grp->front])) { 1405 agg = qfq_slot_scan(grp); 1406 roundedS = qfq_round_down(agg->S, grp->slot_shift); 1407 if (grp->S != roundedS) { 1408 __clear_bit(grp->index, &q->bitmaps[ER]); 1409 __clear_bit(grp->index, &q->bitmaps[IR]); 1410 __clear_bit(grp->index, &q->bitmaps[EB]); 1411 __clear_bit(grp->index, &q->bitmaps[IB]); 1412 grp->S = roundedS; 1413 grp->F = roundedS + (2ULL << grp->slot_shift); 1414 s = qfq_calc_state(q, grp); 1415 __set_bit(grp->index, &q->bitmaps[s]); 1416 } 1417 } 1418 } 1419 1420 static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg) 1421 { 1422 struct qfq_sched *q = qdisc_priv(sch); 1423 struct qfq_class *cl = (struct qfq_class *)arg; 1424 1425 if (cl->qdisc->q.qlen == 0) 1426 qfq_deactivate_class(q, cl); 1427 } 1428 1429 static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt) 1430 { 1431 struct qfq_sched *q = qdisc_priv(sch); 1432 struct qfq_group *grp; 1433 int i, j, err; 1434 u32 max_cl_shift, maxbudg_shift, max_classes; 1435 1436 err = qdisc_class_hash_init(&q->clhash); 1437 if (err < 0) 1438 return err; 1439 1440 if (qdisc_dev(sch)->tx_queue_len + 1 > QFQ_MAX_AGG_CLASSES) 1441 max_classes = QFQ_MAX_AGG_CLASSES; 1442 else 1443 max_classes = qdisc_dev(sch)->tx_queue_len + 1; 1444 /* max_cl_shift = floor(log_2(max_classes)) */ 1445 max_cl_shift = __fls(max_classes); 1446 q->max_agg_classes = 1<<max_cl_shift; 1447 1448 /* maxbudg_shift = log2(max_len * max_classes_per_agg) */ 1449 maxbudg_shift = QFQ_MTU_SHIFT + max_cl_shift; 1450 q->min_slot_shift = FRAC_BITS + maxbudg_shift - QFQ_MAX_INDEX; 1451 1452 for (i = 0; i <= QFQ_MAX_INDEX; i++) { 1453 grp = &q->groups[i]; 1454 grp->index = i; 1455 grp->slot_shift = q->min_slot_shift + i; 1456 for (j = 0; j < QFQ_MAX_SLOTS; j++) 1457 INIT_HLIST_HEAD(&grp->slots[j]); 1458 } 1459 1460 INIT_HLIST_HEAD(&q->nonfull_aggs); 1461 1462 return 0; 1463 } 1464 1465 static void qfq_reset_qdisc(struct Qdisc *sch) 1466 { 1467 struct qfq_sched *q = qdisc_priv(sch); 1468 struct qfq_class *cl; 1469 unsigned int i; 1470 1471 for (i = 0; i < q->clhash.hashsize; i++) { 1472 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { 1473 if (cl->qdisc->q.qlen > 0) 1474 qfq_deactivate_class(q, cl); 1475 1476 qdisc_reset(cl->qdisc); 1477 } 1478 } 1479 sch->q.qlen = 0; 1480 } 1481 1482 static void qfq_destroy_qdisc(struct Qdisc *sch) 1483 { 1484 struct qfq_sched *q = qdisc_priv(sch); 1485 struct qfq_class *cl; 1486 struct hlist_node *next; 1487 unsigned int i; 1488 1489 tcf_destroy_chain(&q->filter_list); 1490 1491 for (i = 0; i < q->clhash.hashsize; i++) { 1492 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i], 1493 common.hnode) { 1494 qfq_destroy_class(sch, cl); 1495 } 1496 } 1497 qdisc_class_hash_destroy(&q->clhash); 1498 } 1499 1500 static const struct Qdisc_class_ops qfq_class_ops = { 1501 .change = qfq_change_class, 1502 .delete = qfq_delete_class, 1503 .get = qfq_get_class, 1504 .put = qfq_put_class, 1505 .tcf_chain = qfq_tcf_chain, 1506 .bind_tcf = qfq_bind_tcf, 1507 .unbind_tcf = qfq_unbind_tcf, 1508 .graft = qfq_graft_class, 1509 .leaf = qfq_class_leaf, 1510 .qlen_notify = qfq_qlen_notify, 1511 .dump = qfq_dump_class, 1512 .dump_stats = qfq_dump_class_stats, 1513 .walk = qfq_walk, 1514 }; 1515 1516 static struct Qdisc_ops qfq_qdisc_ops __read_mostly = { 1517 .cl_ops = &qfq_class_ops, 1518 .id = "qfq", 1519 .priv_size = sizeof(struct qfq_sched), 1520 .enqueue = qfq_enqueue, 1521 .dequeue = qfq_dequeue, 1522 .peek = qdisc_peek_dequeued, 1523 .init = qfq_init_qdisc, 1524 .reset = qfq_reset_qdisc, 1525 .destroy = qfq_destroy_qdisc, 1526 .owner = THIS_MODULE, 1527 }; 1528 1529 static int __init qfq_init(void) 1530 { 1531 return register_qdisc(&qfq_qdisc_ops); 1532 } 1533 1534 static void __exit qfq_exit(void) 1535 { 1536 unregister_qdisc(&qfq_qdisc_ops); 1537 } 1538 1539 module_init(qfq_init); 1540 module_exit(qfq_exit); 1541 MODULE_LICENSE("GPL"); 1542