1 /* 2 * net/sched/sch_sfq.c Stochastic Fairness Queueing discipline. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 */ 11 12 #include <linux/module.h> 13 #include <linux/types.h> 14 #include <linux/kernel.h> 15 #include <linux/jiffies.h> 16 #include <linux/string.h> 17 #include <linux/in.h> 18 #include <linux/errno.h> 19 #include <linux/init.h> 20 #include <linux/skbuff.h> 21 #include <linux/jhash.h> 22 #include <linux/slab.h> 23 #include <linux/vmalloc.h> 24 #include <net/netlink.h> 25 #include <net/pkt_sched.h> 26 #include <net/red.h> 27 28 29 /* Stochastic Fairness Queuing algorithm. 30 ======================================= 31 32 Source: 33 Paul E. McKenney "Stochastic Fairness Queuing", 34 IEEE INFOCOMM'90 Proceedings, San Francisco, 1990. 35 36 Paul E. McKenney "Stochastic Fairness Queuing", 37 "Interworking: Research and Experience", v.2, 1991, p.113-131. 38 39 40 See also: 41 M. Shreedhar and George Varghese "Efficient Fair 42 Queuing using Deficit Round Robin", Proc. SIGCOMM 95. 43 44 45 This is not the thing that is usually called (W)FQ nowadays. 46 It does not use any timestamp mechanism, but instead 47 processes queues in round-robin order. 48 49 ADVANTAGE: 50 51 - It is very cheap. Both CPU and memory requirements are minimal. 52 53 DRAWBACKS: 54 55 - "Stochastic" -> It is not 100% fair. 56 When hash collisions occur, several flows are considered as one. 57 58 - "Round-robin" -> It introduces larger delays than virtual clock 59 based schemes, and should not be used for isolating interactive 60 traffic from non-interactive. It means, that this scheduler 61 should be used as leaf of CBQ or P3, which put interactive traffic 62 to higher priority band. 63 64 We still need true WFQ for top level CSZ, but using WFQ 65 for the best effort traffic is absolutely pointless: 66 SFQ is superior for this purpose. 67 68 IMPLEMENTATION: 69 This implementation limits : 70 - maximal queue length per flow to 127 packets. 71 - max mtu to 2^18-1; 72 - max 65408 flows, 73 - number of hash buckets to 65536. 74 75 It is easy to increase these values, but not in flight. */ 76 77 #define SFQ_MAX_DEPTH 127 /* max number of packets per flow */ 78 #define SFQ_DEFAULT_FLOWS 128 79 #define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */ 80 #define SFQ_EMPTY_SLOT 0xffff 81 #define SFQ_DEFAULT_HASH_DIVISOR 1024 82 83 /* We use 16 bits to store allot, and want to handle packets up to 64K 84 * Scale allot by 8 (1<<3) so that no overflow occurs. 85 */ 86 #define SFQ_ALLOT_SHIFT 3 87 #define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT) 88 89 /* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */ 90 typedef u16 sfq_index; 91 92 /* 93 * We dont use pointers to save space. 94 * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array 95 * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH] 96 * are 'pointers' to dep[] array 97 */ 98 struct sfq_head { 99 sfq_index next; 100 sfq_index prev; 101 }; 102 103 struct sfq_slot { 104 struct sk_buff *skblist_next; 105 struct sk_buff *skblist_prev; 106 sfq_index qlen; /* number of skbs in skblist */ 107 sfq_index next; /* next slot in sfq RR chain */ 108 struct sfq_head dep; /* anchor in dep[] chains */ 109 unsigned short hash; /* hash value (index in ht[]) */ 110 short allot; /* credit for this slot */ 111 112 unsigned int backlog; 113 struct red_vars vars; 114 }; 115 116 struct sfq_sched_data { 117 /* frequently used fields */ 118 int limit; /* limit of total number of packets in this qdisc */ 119 unsigned int divisor; /* number of slots in hash table */ 120 u8 headdrop; 121 u8 maxdepth; /* limit of packets per flow */ 122 123 u32 perturbation; 124 u8 cur_depth; /* depth of longest slot */ 125 u8 flags; 126 unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */ 127 struct tcf_proto __rcu *filter_list; 128 sfq_index *ht; /* Hash table ('divisor' slots) */ 129 struct sfq_slot *slots; /* Flows table ('maxflows' entries) */ 130 131 struct red_parms *red_parms; 132 struct tc_sfqred_stats stats; 133 struct sfq_slot *tail; /* current slot in round */ 134 135 struct sfq_head dep[SFQ_MAX_DEPTH + 1]; 136 /* Linked lists of slots, indexed by depth 137 * dep[0] : list of unused flows 138 * dep[1] : list of flows with 1 packet 139 * dep[X] : list of flows with X packets 140 */ 141 142 unsigned int maxflows; /* number of flows in flows array */ 143 int perturb_period; 144 unsigned int quantum; /* Allotment per round: MUST BE >= MTU */ 145 struct timer_list perturb_timer; 146 }; 147 148 /* 149 * sfq_head are either in a sfq_slot or in dep[] array 150 */ 151 static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val) 152 { 153 if (val < SFQ_MAX_FLOWS) 154 return &q->slots[val].dep; 155 return &q->dep[val - SFQ_MAX_FLOWS]; 156 } 157 158 static unsigned int sfq_hash(const struct sfq_sched_data *q, 159 const struct sk_buff *skb) 160 { 161 return skb_get_hash_perturb(skb, q->perturbation) & (q->divisor - 1); 162 } 163 164 static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch, 165 int *qerr) 166 { 167 struct sfq_sched_data *q = qdisc_priv(sch); 168 struct tcf_result res; 169 struct tcf_proto *fl; 170 int result; 171 172 if (TC_H_MAJ(skb->priority) == sch->handle && 173 TC_H_MIN(skb->priority) > 0 && 174 TC_H_MIN(skb->priority) <= q->divisor) 175 return TC_H_MIN(skb->priority); 176 177 fl = rcu_dereference_bh(q->filter_list); 178 if (!fl) 179 return sfq_hash(q, skb) + 1; 180 181 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 182 result = tc_classify(skb, fl, &res, false); 183 if (result >= 0) { 184 #ifdef CONFIG_NET_CLS_ACT 185 switch (result) { 186 case TC_ACT_STOLEN: 187 case TC_ACT_QUEUED: 188 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 189 case TC_ACT_SHOT: 190 return 0; 191 } 192 #endif 193 if (TC_H_MIN(res.classid) <= q->divisor) 194 return TC_H_MIN(res.classid); 195 } 196 return 0; 197 } 198 199 /* 200 * x : slot number [0 .. SFQ_MAX_FLOWS - 1] 201 */ 202 static inline void sfq_link(struct sfq_sched_data *q, sfq_index x) 203 { 204 sfq_index p, n; 205 struct sfq_slot *slot = &q->slots[x]; 206 int qlen = slot->qlen; 207 208 p = qlen + SFQ_MAX_FLOWS; 209 n = q->dep[qlen].next; 210 211 slot->dep.next = n; 212 slot->dep.prev = p; 213 214 q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */ 215 sfq_dep_head(q, n)->prev = x; 216 } 217 218 #define sfq_unlink(q, x, n, p) \ 219 do { \ 220 n = q->slots[x].dep.next; \ 221 p = q->slots[x].dep.prev; \ 222 sfq_dep_head(q, p)->next = n; \ 223 sfq_dep_head(q, n)->prev = p; \ 224 } while (0) 225 226 227 static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x) 228 { 229 sfq_index p, n; 230 int d; 231 232 sfq_unlink(q, x, n, p); 233 234 d = q->slots[x].qlen--; 235 if (n == p && q->cur_depth == d) 236 q->cur_depth--; 237 sfq_link(q, x); 238 } 239 240 static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x) 241 { 242 sfq_index p, n; 243 int d; 244 245 sfq_unlink(q, x, n, p); 246 247 d = ++q->slots[x].qlen; 248 if (q->cur_depth < d) 249 q->cur_depth = d; 250 sfq_link(q, x); 251 } 252 253 /* helper functions : might be changed when/if skb use a standard list_head */ 254 255 /* remove one skb from tail of slot queue */ 256 static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot) 257 { 258 struct sk_buff *skb = slot->skblist_prev; 259 260 slot->skblist_prev = skb->prev; 261 skb->prev->next = (struct sk_buff *)slot; 262 skb->next = skb->prev = NULL; 263 return skb; 264 } 265 266 /* remove one skb from head of slot queue */ 267 static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot) 268 { 269 struct sk_buff *skb = slot->skblist_next; 270 271 slot->skblist_next = skb->next; 272 skb->next->prev = (struct sk_buff *)slot; 273 skb->next = skb->prev = NULL; 274 return skb; 275 } 276 277 static inline void slot_queue_init(struct sfq_slot *slot) 278 { 279 memset(slot, 0, sizeof(*slot)); 280 slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot; 281 } 282 283 /* add skb to slot queue (tail add) */ 284 static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb) 285 { 286 skb->prev = slot->skblist_prev; 287 skb->next = (struct sk_buff *)slot; 288 slot->skblist_prev->next = skb; 289 slot->skblist_prev = skb; 290 } 291 292 static unsigned int sfq_drop(struct Qdisc *sch) 293 { 294 struct sfq_sched_data *q = qdisc_priv(sch); 295 sfq_index x, d = q->cur_depth; 296 struct sk_buff *skb; 297 unsigned int len; 298 struct sfq_slot *slot; 299 300 /* Queue is full! Find the longest slot and drop tail packet from it */ 301 if (d > 1) { 302 x = q->dep[d].next; 303 slot = &q->slots[x]; 304 drop: 305 skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot); 306 len = qdisc_pkt_len(skb); 307 slot->backlog -= len; 308 sfq_dec(q, x); 309 sch->q.qlen--; 310 qdisc_qstats_drop(sch); 311 qdisc_qstats_backlog_dec(sch, skb); 312 kfree_skb(skb); 313 return len; 314 } 315 316 if (d == 1) { 317 /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */ 318 x = q->tail->next; 319 slot = &q->slots[x]; 320 q->tail->next = slot->next; 321 q->ht[slot->hash] = SFQ_EMPTY_SLOT; 322 goto drop; 323 } 324 325 return 0; 326 } 327 328 /* Is ECN parameter configured */ 329 static int sfq_prob_mark(const struct sfq_sched_data *q) 330 { 331 return q->flags & TC_RED_ECN; 332 } 333 334 /* Should packets over max threshold just be marked */ 335 static int sfq_hard_mark(const struct sfq_sched_data *q) 336 { 337 return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN; 338 } 339 340 static int sfq_headdrop(const struct sfq_sched_data *q) 341 { 342 return q->headdrop; 343 } 344 345 static int 346 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) 347 { 348 struct sfq_sched_data *q = qdisc_priv(sch); 349 unsigned int hash, dropped; 350 sfq_index x, qlen; 351 struct sfq_slot *slot; 352 int uninitialized_var(ret); 353 struct sk_buff *head; 354 int delta; 355 356 hash = sfq_classify(skb, sch, &ret); 357 if (hash == 0) { 358 if (ret & __NET_XMIT_BYPASS) 359 qdisc_qstats_drop(sch); 360 kfree_skb(skb); 361 return ret; 362 } 363 hash--; 364 365 x = q->ht[hash]; 366 slot = &q->slots[x]; 367 if (x == SFQ_EMPTY_SLOT) { 368 x = q->dep[0].next; /* get a free slot */ 369 if (x >= SFQ_MAX_FLOWS) 370 return qdisc_drop(skb, sch); 371 q->ht[hash] = x; 372 slot = &q->slots[x]; 373 slot->hash = hash; 374 slot->backlog = 0; /* should already be 0 anyway... */ 375 red_set_vars(&slot->vars); 376 goto enqueue; 377 } 378 if (q->red_parms) { 379 slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms, 380 &slot->vars, 381 slot->backlog); 382 switch (red_action(q->red_parms, 383 &slot->vars, 384 slot->vars.qavg)) { 385 case RED_DONT_MARK: 386 break; 387 388 case RED_PROB_MARK: 389 qdisc_qstats_overlimit(sch); 390 if (sfq_prob_mark(q)) { 391 /* We know we have at least one packet in queue */ 392 if (sfq_headdrop(q) && 393 INET_ECN_set_ce(slot->skblist_next)) { 394 q->stats.prob_mark_head++; 395 break; 396 } 397 if (INET_ECN_set_ce(skb)) { 398 q->stats.prob_mark++; 399 break; 400 } 401 } 402 q->stats.prob_drop++; 403 goto congestion_drop; 404 405 case RED_HARD_MARK: 406 qdisc_qstats_overlimit(sch); 407 if (sfq_hard_mark(q)) { 408 /* We know we have at least one packet in queue */ 409 if (sfq_headdrop(q) && 410 INET_ECN_set_ce(slot->skblist_next)) { 411 q->stats.forced_mark_head++; 412 break; 413 } 414 if (INET_ECN_set_ce(skb)) { 415 q->stats.forced_mark++; 416 break; 417 } 418 } 419 q->stats.forced_drop++; 420 goto congestion_drop; 421 } 422 } 423 424 if (slot->qlen >= q->maxdepth) { 425 congestion_drop: 426 if (!sfq_headdrop(q)) 427 return qdisc_drop(skb, sch); 428 429 /* We know we have at least one packet in queue */ 430 head = slot_dequeue_head(slot); 431 delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb); 432 sch->qstats.backlog -= delta; 433 slot->backlog -= delta; 434 qdisc_drop(head, sch); 435 436 slot_queue_add(slot, skb); 437 return NET_XMIT_CN; 438 } 439 440 enqueue: 441 qdisc_qstats_backlog_inc(sch, skb); 442 slot->backlog += qdisc_pkt_len(skb); 443 slot_queue_add(slot, skb); 444 sfq_inc(q, x); 445 if (slot->qlen == 1) { /* The flow is new */ 446 if (q->tail == NULL) { /* It is the first flow */ 447 slot->next = x; 448 } else { 449 slot->next = q->tail->next; 450 q->tail->next = x; 451 } 452 /* We put this flow at the end of our flow list. 453 * This might sound unfair for a new flow to wait after old ones, 454 * but we could endup servicing new flows only, and freeze old ones. 455 */ 456 q->tail = slot; 457 /* We could use a bigger initial quantum for new flows */ 458 slot->allot = q->scaled_quantum; 459 } 460 if (++sch->q.qlen <= q->limit) 461 return NET_XMIT_SUCCESS; 462 463 qlen = slot->qlen; 464 dropped = sfq_drop(sch); 465 /* Return Congestion Notification only if we dropped a packet 466 * from this flow. 467 */ 468 if (qlen != slot->qlen) 469 return NET_XMIT_CN; 470 471 /* As we dropped a packet, better let upper stack know this */ 472 qdisc_tree_reduce_backlog(sch, 1, dropped); 473 return NET_XMIT_SUCCESS; 474 } 475 476 static struct sk_buff * 477 sfq_dequeue(struct Qdisc *sch) 478 { 479 struct sfq_sched_data *q = qdisc_priv(sch); 480 struct sk_buff *skb; 481 sfq_index a, next_a; 482 struct sfq_slot *slot; 483 484 /* No active slots */ 485 if (q->tail == NULL) 486 return NULL; 487 488 next_slot: 489 a = q->tail->next; 490 slot = &q->slots[a]; 491 if (slot->allot <= 0) { 492 q->tail = slot; 493 slot->allot += q->scaled_quantum; 494 goto next_slot; 495 } 496 skb = slot_dequeue_head(slot); 497 sfq_dec(q, a); 498 qdisc_bstats_update(sch, skb); 499 sch->q.qlen--; 500 qdisc_qstats_backlog_dec(sch, skb); 501 slot->backlog -= qdisc_pkt_len(skb); 502 /* Is the slot empty? */ 503 if (slot->qlen == 0) { 504 q->ht[slot->hash] = SFQ_EMPTY_SLOT; 505 next_a = slot->next; 506 if (a == next_a) { 507 q->tail = NULL; /* no more active slots */ 508 return skb; 509 } 510 q->tail->next = next_a; 511 } else { 512 slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb)); 513 } 514 return skb; 515 } 516 517 static void 518 sfq_reset(struct Qdisc *sch) 519 { 520 struct sk_buff *skb; 521 522 while ((skb = sfq_dequeue(sch)) != NULL) 523 kfree_skb(skb); 524 } 525 526 /* 527 * When q->perturbation is changed, we rehash all queued skbs 528 * to avoid OOO (Out Of Order) effects. 529 * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change 530 * counters. 531 */ 532 static void sfq_rehash(struct Qdisc *sch) 533 { 534 struct sfq_sched_data *q = qdisc_priv(sch); 535 struct sk_buff *skb; 536 int i; 537 struct sfq_slot *slot; 538 struct sk_buff_head list; 539 int dropped = 0; 540 unsigned int drop_len = 0; 541 542 __skb_queue_head_init(&list); 543 544 for (i = 0; i < q->maxflows; i++) { 545 slot = &q->slots[i]; 546 if (!slot->qlen) 547 continue; 548 while (slot->qlen) { 549 skb = slot_dequeue_head(slot); 550 sfq_dec(q, i); 551 __skb_queue_tail(&list, skb); 552 } 553 slot->backlog = 0; 554 red_set_vars(&slot->vars); 555 q->ht[slot->hash] = SFQ_EMPTY_SLOT; 556 } 557 q->tail = NULL; 558 559 while ((skb = __skb_dequeue(&list)) != NULL) { 560 unsigned int hash = sfq_hash(q, skb); 561 sfq_index x = q->ht[hash]; 562 563 slot = &q->slots[x]; 564 if (x == SFQ_EMPTY_SLOT) { 565 x = q->dep[0].next; /* get a free slot */ 566 if (x >= SFQ_MAX_FLOWS) { 567 drop: 568 qdisc_qstats_backlog_dec(sch, skb); 569 drop_len += qdisc_pkt_len(skb); 570 kfree_skb(skb); 571 dropped++; 572 continue; 573 } 574 q->ht[hash] = x; 575 slot = &q->slots[x]; 576 slot->hash = hash; 577 } 578 if (slot->qlen >= q->maxdepth) 579 goto drop; 580 slot_queue_add(slot, skb); 581 if (q->red_parms) 582 slot->vars.qavg = red_calc_qavg(q->red_parms, 583 &slot->vars, 584 slot->backlog); 585 slot->backlog += qdisc_pkt_len(skb); 586 sfq_inc(q, x); 587 if (slot->qlen == 1) { /* The flow is new */ 588 if (q->tail == NULL) { /* It is the first flow */ 589 slot->next = x; 590 } else { 591 slot->next = q->tail->next; 592 q->tail->next = x; 593 } 594 q->tail = slot; 595 slot->allot = q->scaled_quantum; 596 } 597 } 598 sch->q.qlen -= dropped; 599 qdisc_tree_reduce_backlog(sch, dropped, drop_len); 600 } 601 602 static void sfq_perturbation(unsigned long arg) 603 { 604 struct Qdisc *sch = (struct Qdisc *)arg; 605 struct sfq_sched_data *q = qdisc_priv(sch); 606 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); 607 608 spin_lock(root_lock); 609 q->perturbation = prandom_u32(); 610 if (!q->filter_list && q->tail) 611 sfq_rehash(sch); 612 spin_unlock(root_lock); 613 614 if (q->perturb_period) 615 mod_timer(&q->perturb_timer, jiffies + q->perturb_period); 616 } 617 618 static int sfq_change(struct Qdisc *sch, struct nlattr *opt) 619 { 620 struct sfq_sched_data *q = qdisc_priv(sch); 621 struct tc_sfq_qopt *ctl = nla_data(opt); 622 struct tc_sfq_qopt_v1 *ctl_v1 = NULL; 623 unsigned int qlen, dropped = 0; 624 struct red_parms *p = NULL; 625 626 if (opt->nla_len < nla_attr_size(sizeof(*ctl))) 627 return -EINVAL; 628 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1))) 629 ctl_v1 = nla_data(opt); 630 if (ctl->divisor && 631 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536)) 632 return -EINVAL; 633 if (ctl_v1 && ctl_v1->qth_min) { 634 p = kmalloc(sizeof(*p), GFP_KERNEL); 635 if (!p) 636 return -ENOMEM; 637 } 638 sch_tree_lock(sch); 639 if (ctl->quantum) { 640 q->quantum = ctl->quantum; 641 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); 642 } 643 q->perturb_period = ctl->perturb_period * HZ; 644 if (ctl->flows) 645 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS); 646 if (ctl->divisor) { 647 q->divisor = ctl->divisor; 648 q->maxflows = min_t(u32, q->maxflows, q->divisor); 649 } 650 if (ctl_v1) { 651 if (ctl_v1->depth) 652 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH); 653 if (p) { 654 swap(q->red_parms, p); 655 red_set_parms(q->red_parms, 656 ctl_v1->qth_min, ctl_v1->qth_max, 657 ctl_v1->Wlog, 658 ctl_v1->Plog, ctl_v1->Scell_log, 659 NULL, 660 ctl_v1->max_P); 661 } 662 q->flags = ctl_v1->flags; 663 q->headdrop = ctl_v1->headdrop; 664 } 665 if (ctl->limit) { 666 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows); 667 q->maxflows = min_t(u32, q->maxflows, q->limit); 668 } 669 670 qlen = sch->q.qlen; 671 while (sch->q.qlen > q->limit) 672 dropped += sfq_drop(sch); 673 qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped); 674 675 del_timer(&q->perturb_timer); 676 if (q->perturb_period) { 677 mod_timer(&q->perturb_timer, jiffies + q->perturb_period); 678 q->perturbation = prandom_u32(); 679 } 680 sch_tree_unlock(sch); 681 kfree(p); 682 return 0; 683 } 684 685 static void *sfq_alloc(size_t sz) 686 { 687 void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN); 688 689 if (!ptr) 690 ptr = vmalloc(sz); 691 return ptr; 692 } 693 694 static void sfq_free(void *addr) 695 { 696 kvfree(addr); 697 } 698 699 static void sfq_destroy(struct Qdisc *sch) 700 { 701 struct sfq_sched_data *q = qdisc_priv(sch); 702 703 tcf_destroy_chain(&q->filter_list); 704 q->perturb_period = 0; 705 del_timer_sync(&q->perturb_timer); 706 sfq_free(q->ht); 707 sfq_free(q->slots); 708 kfree(q->red_parms); 709 } 710 711 static int sfq_init(struct Qdisc *sch, struct nlattr *opt) 712 { 713 struct sfq_sched_data *q = qdisc_priv(sch); 714 int i; 715 716 q->perturb_timer.function = sfq_perturbation; 717 q->perturb_timer.data = (unsigned long)sch; 718 init_timer_deferrable(&q->perturb_timer); 719 720 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) { 721 q->dep[i].next = i + SFQ_MAX_FLOWS; 722 q->dep[i].prev = i + SFQ_MAX_FLOWS; 723 } 724 725 q->limit = SFQ_MAX_DEPTH; 726 q->maxdepth = SFQ_MAX_DEPTH; 727 q->cur_depth = 0; 728 q->tail = NULL; 729 q->divisor = SFQ_DEFAULT_HASH_DIVISOR; 730 q->maxflows = SFQ_DEFAULT_FLOWS; 731 q->quantum = psched_mtu(qdisc_dev(sch)); 732 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); 733 q->perturb_period = 0; 734 q->perturbation = prandom_u32(); 735 736 if (opt) { 737 int err = sfq_change(sch, opt); 738 if (err) 739 return err; 740 } 741 742 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor); 743 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows); 744 if (!q->ht || !q->slots) { 745 sfq_destroy(sch); 746 return -ENOMEM; 747 } 748 for (i = 0; i < q->divisor; i++) 749 q->ht[i] = SFQ_EMPTY_SLOT; 750 751 for (i = 0; i < q->maxflows; i++) { 752 slot_queue_init(&q->slots[i]); 753 sfq_link(q, i); 754 } 755 if (q->limit >= 1) 756 sch->flags |= TCQ_F_CAN_BYPASS; 757 else 758 sch->flags &= ~TCQ_F_CAN_BYPASS; 759 return 0; 760 } 761 762 static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb) 763 { 764 struct sfq_sched_data *q = qdisc_priv(sch); 765 unsigned char *b = skb_tail_pointer(skb); 766 struct tc_sfq_qopt_v1 opt; 767 struct red_parms *p = q->red_parms; 768 769 memset(&opt, 0, sizeof(opt)); 770 opt.v0.quantum = q->quantum; 771 opt.v0.perturb_period = q->perturb_period / HZ; 772 opt.v0.limit = q->limit; 773 opt.v0.divisor = q->divisor; 774 opt.v0.flows = q->maxflows; 775 opt.depth = q->maxdepth; 776 opt.headdrop = q->headdrop; 777 778 if (p) { 779 opt.qth_min = p->qth_min >> p->Wlog; 780 opt.qth_max = p->qth_max >> p->Wlog; 781 opt.Wlog = p->Wlog; 782 opt.Plog = p->Plog; 783 opt.Scell_log = p->Scell_log; 784 opt.max_P = p->max_P; 785 } 786 memcpy(&opt.stats, &q->stats, sizeof(opt.stats)); 787 opt.flags = q->flags; 788 789 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 790 goto nla_put_failure; 791 792 return skb->len; 793 794 nla_put_failure: 795 nlmsg_trim(skb, b); 796 return -1; 797 } 798 799 static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg) 800 { 801 return NULL; 802 } 803 804 static unsigned long sfq_get(struct Qdisc *sch, u32 classid) 805 { 806 return 0; 807 } 808 809 static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent, 810 u32 classid) 811 { 812 /* we cannot bypass queue discipline anymore */ 813 sch->flags &= ~TCQ_F_CAN_BYPASS; 814 return 0; 815 } 816 817 static void sfq_put(struct Qdisc *q, unsigned long cl) 818 { 819 } 820 821 static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch, 822 unsigned long cl) 823 { 824 struct sfq_sched_data *q = qdisc_priv(sch); 825 826 if (cl) 827 return NULL; 828 return &q->filter_list; 829 } 830 831 static int sfq_dump_class(struct Qdisc *sch, unsigned long cl, 832 struct sk_buff *skb, struct tcmsg *tcm) 833 { 834 tcm->tcm_handle |= TC_H_MIN(cl); 835 return 0; 836 } 837 838 static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl, 839 struct gnet_dump *d) 840 { 841 struct sfq_sched_data *q = qdisc_priv(sch); 842 sfq_index idx = q->ht[cl - 1]; 843 struct gnet_stats_queue qs = { 0 }; 844 struct tc_sfq_xstats xstats = { 0 }; 845 846 if (idx != SFQ_EMPTY_SLOT) { 847 const struct sfq_slot *slot = &q->slots[idx]; 848 849 xstats.allot = slot->allot << SFQ_ALLOT_SHIFT; 850 qs.qlen = slot->qlen; 851 qs.backlog = slot->backlog; 852 } 853 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0) 854 return -1; 855 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 856 } 857 858 static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 859 { 860 struct sfq_sched_data *q = qdisc_priv(sch); 861 unsigned int i; 862 863 if (arg->stop) 864 return; 865 866 for (i = 0; i < q->divisor; i++) { 867 if (q->ht[i] == SFQ_EMPTY_SLOT || 868 arg->count < arg->skip) { 869 arg->count++; 870 continue; 871 } 872 if (arg->fn(sch, i + 1, arg) < 0) { 873 arg->stop = 1; 874 break; 875 } 876 arg->count++; 877 } 878 } 879 880 static const struct Qdisc_class_ops sfq_class_ops = { 881 .leaf = sfq_leaf, 882 .get = sfq_get, 883 .put = sfq_put, 884 .tcf_chain = sfq_find_tcf, 885 .bind_tcf = sfq_bind, 886 .unbind_tcf = sfq_put, 887 .dump = sfq_dump_class, 888 .dump_stats = sfq_dump_class_stats, 889 .walk = sfq_walk, 890 }; 891 892 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = { 893 .cl_ops = &sfq_class_ops, 894 .id = "sfq", 895 .priv_size = sizeof(struct sfq_sched_data), 896 .enqueue = sfq_enqueue, 897 .dequeue = sfq_dequeue, 898 .peek = qdisc_peek_dequeued, 899 .drop = sfq_drop, 900 .init = sfq_init, 901 .reset = sfq_reset, 902 .destroy = sfq_destroy, 903 .change = NULL, 904 .dump = sfq_dump, 905 .owner = THIS_MODULE, 906 }; 907 908 static int __init sfq_module_init(void) 909 { 910 return register_qdisc(&sfq_qdisc_ops); 911 } 912 static void __exit sfq_module_exit(void) 913 { 914 unregister_qdisc(&sfq_qdisc_ops); 915 } 916 module_init(sfq_module_init) 917 module_exit(sfq_module_exit) 918 MODULE_LICENSE("GPL"); 919