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/flow_keys.h> 27 #include <net/red.h> 28 29 30 /* Stochastic Fairness Queuing algorithm. 31 ======================================= 32 33 Source: 34 Paul E. McKenney "Stochastic Fairness Queuing", 35 IEEE INFOCOMM'90 Proceedings, San Francisco, 1990. 36 37 Paul E. McKenney "Stochastic Fairness Queuing", 38 "Interworking: Research and Experience", v.2, 1991, p.113-131. 39 40 41 See also: 42 M. Shreedhar and George Varghese "Efficient Fair 43 Queuing using Deficit Round Robin", Proc. SIGCOMM 95. 44 45 46 This is not the thing that is usually called (W)FQ nowadays. 47 It does not use any timestamp mechanism, but instead 48 processes queues in round-robin order. 49 50 ADVANTAGE: 51 52 - It is very cheap. Both CPU and memory requirements are minimal. 53 54 DRAWBACKS: 55 56 - "Stochastic" -> It is not 100% fair. 57 When hash collisions occur, several flows are considered as one. 58 59 - "Round-robin" -> It introduces larger delays than virtual clock 60 based schemes, and should not be used for isolating interactive 61 traffic from non-interactive. It means, that this scheduler 62 should be used as leaf of CBQ or P3, which put interactive traffic 63 to higher priority band. 64 65 We still need true WFQ for top level CSZ, but using WFQ 66 for the best effort traffic is absolutely pointless: 67 SFQ is superior for this purpose. 68 69 IMPLEMENTATION: 70 This implementation limits : 71 - maximal queue length per flow to 127 packets. 72 - max mtu to 2^18-1; 73 - max 65408 flows, 74 - number of hash buckets to 65536. 75 76 It is easy to increase these values, but not in flight. */ 77 78 #define SFQ_MAX_DEPTH 127 /* max number of packets per flow */ 79 #define SFQ_DEFAULT_FLOWS 128 80 #define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */ 81 #define SFQ_EMPTY_SLOT 0xffff 82 #define SFQ_DEFAULT_HASH_DIVISOR 1024 83 84 /* We use 16 bits to store allot, and want to handle packets up to 64K 85 * Scale allot by 8 (1<<3) so that no overflow occurs. 86 */ 87 #define SFQ_ALLOT_SHIFT 3 88 #define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT) 89 90 /* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */ 91 typedef u16 sfq_index; 92 93 /* 94 * We dont use pointers to save space. 95 * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array 96 * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH] 97 * are 'pointers' to dep[] array 98 */ 99 struct sfq_head { 100 sfq_index next; 101 sfq_index prev; 102 }; 103 104 struct sfq_slot { 105 struct sk_buff *skblist_next; 106 struct sk_buff *skblist_prev; 107 sfq_index qlen; /* number of skbs in skblist */ 108 sfq_index next; /* next slot in sfq RR chain */ 109 struct sfq_head dep; /* anchor in dep[] chains */ 110 unsigned short hash; /* hash value (index in ht[]) */ 111 short allot; /* credit for this slot */ 112 113 unsigned int backlog; 114 struct red_vars vars; 115 }; 116 117 struct sfq_sched_data { 118 /* frequently used fields */ 119 int limit; /* limit of total number of packets in this qdisc */ 120 unsigned int divisor; /* number of slots in hash table */ 121 u8 headdrop; 122 u8 maxdepth; /* limit of packets per flow */ 123 124 u32 perturbation; 125 u8 cur_depth; /* depth of longest slot */ 126 u8 flags; 127 unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */ 128 struct tcf_proto *filter_list; 129 sfq_index *ht; /* Hash table ('divisor' slots) */ 130 struct sfq_slot *slots; /* Flows table ('maxflows' entries) */ 131 132 struct red_parms *red_parms; 133 struct tc_sfqred_stats stats; 134 struct sfq_slot *tail; /* current slot in round */ 135 136 struct sfq_head dep[SFQ_MAX_DEPTH + 1]; 137 /* Linked lists of slots, indexed by depth 138 * dep[0] : list of unused flows 139 * dep[1] : list of flows with 1 packet 140 * dep[X] : list of flows with X packets 141 */ 142 143 unsigned int maxflows; /* number of flows in flows array */ 144 int perturb_period; 145 unsigned int quantum; /* Allotment per round: MUST BE >= MTU */ 146 struct timer_list perturb_timer; 147 }; 148 149 /* 150 * sfq_head are either in a sfq_slot or in dep[] array 151 */ 152 static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val) 153 { 154 if (val < SFQ_MAX_FLOWS) 155 return &q->slots[val].dep; 156 return &q->dep[val - SFQ_MAX_FLOWS]; 157 } 158 159 /* 160 * In order to be able to quickly rehash our queue when timer changes 161 * q->perturbation, we store flow_keys in skb->cb[] 162 */ 163 struct sfq_skb_cb { 164 struct flow_keys keys; 165 }; 166 167 static inline struct sfq_skb_cb *sfq_skb_cb(const struct sk_buff *skb) 168 { 169 qdisc_cb_private_validate(skb, sizeof(struct sfq_skb_cb)); 170 return (struct sfq_skb_cb *)qdisc_skb_cb(skb)->data; 171 } 172 173 static unsigned int sfq_hash(const struct sfq_sched_data *q, 174 const struct sk_buff *skb) 175 { 176 const struct flow_keys *keys = &sfq_skb_cb(skb)->keys; 177 unsigned int hash; 178 179 hash = jhash_3words((__force u32)keys->dst, 180 (__force u32)keys->src ^ keys->ip_proto, 181 (__force u32)keys->ports, q->perturbation); 182 return hash & (q->divisor - 1); 183 } 184 185 static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch, 186 int *qerr) 187 { 188 struct sfq_sched_data *q = qdisc_priv(sch); 189 struct tcf_result res; 190 int result; 191 192 if (TC_H_MAJ(skb->priority) == sch->handle && 193 TC_H_MIN(skb->priority) > 0 && 194 TC_H_MIN(skb->priority) <= q->divisor) 195 return TC_H_MIN(skb->priority); 196 197 if (!q->filter_list) { 198 skb_flow_dissect(skb, &sfq_skb_cb(skb)->keys); 199 return sfq_hash(q, skb) + 1; 200 } 201 202 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 203 result = tc_classify(skb, q->filter_list, &res); 204 if (result >= 0) { 205 #ifdef CONFIG_NET_CLS_ACT 206 switch (result) { 207 case TC_ACT_STOLEN: 208 case TC_ACT_QUEUED: 209 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 210 case TC_ACT_SHOT: 211 return 0; 212 } 213 #endif 214 if (TC_H_MIN(res.classid) <= q->divisor) 215 return TC_H_MIN(res.classid); 216 } 217 return 0; 218 } 219 220 /* 221 * x : slot number [0 .. SFQ_MAX_FLOWS - 1] 222 */ 223 static inline void sfq_link(struct sfq_sched_data *q, sfq_index x) 224 { 225 sfq_index p, n; 226 struct sfq_slot *slot = &q->slots[x]; 227 int qlen = slot->qlen; 228 229 p = qlen + SFQ_MAX_FLOWS; 230 n = q->dep[qlen].next; 231 232 slot->dep.next = n; 233 slot->dep.prev = p; 234 235 q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */ 236 sfq_dep_head(q, n)->prev = x; 237 } 238 239 #define sfq_unlink(q, x, n, p) \ 240 n = q->slots[x].dep.next; \ 241 p = q->slots[x].dep.prev; \ 242 sfq_dep_head(q, p)->next = n; \ 243 sfq_dep_head(q, n)->prev = p 244 245 246 static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x) 247 { 248 sfq_index p, n; 249 int d; 250 251 sfq_unlink(q, x, n, p); 252 253 d = q->slots[x].qlen--; 254 if (n == p && q->cur_depth == d) 255 q->cur_depth--; 256 sfq_link(q, x); 257 } 258 259 static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x) 260 { 261 sfq_index p, n; 262 int d; 263 264 sfq_unlink(q, x, n, p); 265 266 d = ++q->slots[x].qlen; 267 if (q->cur_depth < d) 268 q->cur_depth = d; 269 sfq_link(q, x); 270 } 271 272 /* helper functions : might be changed when/if skb use a standard list_head */ 273 274 /* remove one skb from tail of slot queue */ 275 static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot) 276 { 277 struct sk_buff *skb = slot->skblist_prev; 278 279 slot->skblist_prev = skb->prev; 280 skb->prev->next = (struct sk_buff *)slot; 281 skb->next = skb->prev = NULL; 282 return skb; 283 } 284 285 /* remove one skb from head of slot queue */ 286 static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot) 287 { 288 struct sk_buff *skb = slot->skblist_next; 289 290 slot->skblist_next = skb->next; 291 skb->next->prev = (struct sk_buff *)slot; 292 skb->next = skb->prev = NULL; 293 return skb; 294 } 295 296 static inline void slot_queue_init(struct sfq_slot *slot) 297 { 298 memset(slot, 0, sizeof(*slot)); 299 slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot; 300 } 301 302 /* add skb to slot queue (tail add) */ 303 static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb) 304 { 305 skb->prev = slot->skblist_prev; 306 skb->next = (struct sk_buff *)slot; 307 slot->skblist_prev->next = skb; 308 slot->skblist_prev = skb; 309 } 310 311 #define slot_queue_walk(slot, skb) \ 312 for (skb = slot->skblist_next; \ 313 skb != (struct sk_buff *)slot; \ 314 skb = skb->next) 315 316 static unsigned int sfq_drop(struct Qdisc *sch) 317 { 318 struct sfq_sched_data *q = qdisc_priv(sch); 319 sfq_index x, d = q->cur_depth; 320 struct sk_buff *skb; 321 unsigned int len; 322 struct sfq_slot *slot; 323 324 /* Queue is full! Find the longest slot and drop tail packet from it */ 325 if (d > 1) { 326 x = q->dep[d].next; 327 slot = &q->slots[x]; 328 drop: 329 skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot); 330 len = qdisc_pkt_len(skb); 331 slot->backlog -= len; 332 sfq_dec(q, x); 333 kfree_skb(skb); 334 sch->q.qlen--; 335 sch->qstats.drops++; 336 sch->qstats.backlog -= len; 337 return len; 338 } 339 340 if (d == 1) { 341 /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */ 342 x = q->tail->next; 343 slot = &q->slots[x]; 344 q->tail->next = slot->next; 345 q->ht[slot->hash] = SFQ_EMPTY_SLOT; 346 goto drop; 347 } 348 349 return 0; 350 } 351 352 /* Is ECN parameter configured */ 353 static int sfq_prob_mark(const struct sfq_sched_data *q) 354 { 355 return q->flags & TC_RED_ECN; 356 } 357 358 /* Should packets over max threshold just be marked */ 359 static int sfq_hard_mark(const struct sfq_sched_data *q) 360 { 361 return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN; 362 } 363 364 static int sfq_headdrop(const struct sfq_sched_data *q) 365 { 366 return q->headdrop; 367 } 368 369 static int 370 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) 371 { 372 struct sfq_sched_data *q = qdisc_priv(sch); 373 unsigned int hash; 374 sfq_index x, qlen; 375 struct sfq_slot *slot; 376 int uninitialized_var(ret); 377 struct sk_buff *head; 378 int delta; 379 380 hash = sfq_classify(skb, sch, &ret); 381 if (hash == 0) { 382 if (ret & __NET_XMIT_BYPASS) 383 sch->qstats.drops++; 384 kfree_skb(skb); 385 return ret; 386 } 387 hash--; 388 389 x = q->ht[hash]; 390 slot = &q->slots[x]; 391 if (x == SFQ_EMPTY_SLOT) { 392 x = q->dep[0].next; /* get a free slot */ 393 if (x >= SFQ_MAX_FLOWS) 394 return qdisc_drop(skb, sch); 395 q->ht[hash] = x; 396 slot = &q->slots[x]; 397 slot->hash = hash; 398 slot->backlog = 0; /* should already be 0 anyway... */ 399 red_set_vars(&slot->vars); 400 goto enqueue; 401 } 402 if (q->red_parms) { 403 slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms, 404 &slot->vars, 405 slot->backlog); 406 switch (red_action(q->red_parms, 407 &slot->vars, 408 slot->vars.qavg)) { 409 case RED_DONT_MARK: 410 break; 411 412 case RED_PROB_MARK: 413 sch->qstats.overlimits++; 414 if (sfq_prob_mark(q)) { 415 /* We know we have at least one packet in queue */ 416 if (sfq_headdrop(q) && 417 INET_ECN_set_ce(slot->skblist_next)) { 418 q->stats.prob_mark_head++; 419 break; 420 } 421 if (INET_ECN_set_ce(skb)) { 422 q->stats.prob_mark++; 423 break; 424 } 425 } 426 q->stats.prob_drop++; 427 goto congestion_drop; 428 429 case RED_HARD_MARK: 430 sch->qstats.overlimits++; 431 if (sfq_hard_mark(q)) { 432 /* We know we have at least one packet in queue */ 433 if (sfq_headdrop(q) && 434 INET_ECN_set_ce(slot->skblist_next)) { 435 q->stats.forced_mark_head++; 436 break; 437 } 438 if (INET_ECN_set_ce(skb)) { 439 q->stats.forced_mark++; 440 break; 441 } 442 } 443 q->stats.forced_drop++; 444 goto congestion_drop; 445 } 446 } 447 448 if (slot->qlen >= q->maxdepth) { 449 congestion_drop: 450 if (!sfq_headdrop(q)) 451 return qdisc_drop(skb, sch); 452 453 /* We know we have at least one packet in queue */ 454 head = slot_dequeue_head(slot); 455 delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb); 456 sch->qstats.backlog -= delta; 457 slot->backlog -= delta; 458 qdisc_drop(head, sch); 459 460 slot_queue_add(slot, skb); 461 return NET_XMIT_CN; 462 } 463 464 enqueue: 465 sch->qstats.backlog += qdisc_pkt_len(skb); 466 slot->backlog += qdisc_pkt_len(skb); 467 slot_queue_add(slot, skb); 468 sfq_inc(q, x); 469 if (slot->qlen == 1) { /* The flow is new */ 470 if (q->tail == NULL) { /* It is the first flow */ 471 slot->next = x; 472 } else { 473 slot->next = q->tail->next; 474 q->tail->next = x; 475 } 476 /* We put this flow at the end of our flow list. 477 * This might sound unfair for a new flow to wait after old ones, 478 * but we could endup servicing new flows only, and freeze old ones. 479 */ 480 q->tail = slot; 481 /* We could use a bigger initial quantum for new flows */ 482 slot->allot = q->scaled_quantum; 483 } 484 if (++sch->q.qlen <= q->limit) 485 return NET_XMIT_SUCCESS; 486 487 qlen = slot->qlen; 488 sfq_drop(sch); 489 /* Return Congestion Notification only if we dropped a packet 490 * from this flow. 491 */ 492 if (qlen != slot->qlen) 493 return NET_XMIT_CN; 494 495 /* As we dropped a packet, better let upper stack know this */ 496 qdisc_tree_decrease_qlen(sch, 1); 497 return NET_XMIT_SUCCESS; 498 } 499 500 static struct sk_buff * 501 sfq_dequeue(struct Qdisc *sch) 502 { 503 struct sfq_sched_data *q = qdisc_priv(sch); 504 struct sk_buff *skb; 505 sfq_index a, next_a; 506 struct sfq_slot *slot; 507 508 /* No active slots */ 509 if (q->tail == NULL) 510 return NULL; 511 512 next_slot: 513 a = q->tail->next; 514 slot = &q->slots[a]; 515 if (slot->allot <= 0) { 516 q->tail = slot; 517 slot->allot += q->scaled_quantum; 518 goto next_slot; 519 } 520 skb = slot_dequeue_head(slot); 521 sfq_dec(q, a); 522 qdisc_bstats_update(sch, skb); 523 sch->q.qlen--; 524 sch->qstats.backlog -= qdisc_pkt_len(skb); 525 slot->backlog -= qdisc_pkt_len(skb); 526 /* Is the slot empty? */ 527 if (slot->qlen == 0) { 528 q->ht[slot->hash] = SFQ_EMPTY_SLOT; 529 next_a = slot->next; 530 if (a == next_a) { 531 q->tail = NULL; /* no more active slots */ 532 return skb; 533 } 534 q->tail->next = next_a; 535 } else { 536 slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb)); 537 } 538 return skb; 539 } 540 541 static void 542 sfq_reset(struct Qdisc *sch) 543 { 544 struct sk_buff *skb; 545 546 while ((skb = sfq_dequeue(sch)) != NULL) 547 kfree_skb(skb); 548 } 549 550 /* 551 * When q->perturbation is changed, we rehash all queued skbs 552 * to avoid OOO (Out Of Order) effects. 553 * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change 554 * counters. 555 */ 556 static void sfq_rehash(struct Qdisc *sch) 557 { 558 struct sfq_sched_data *q = qdisc_priv(sch); 559 struct sk_buff *skb; 560 int i; 561 struct sfq_slot *slot; 562 struct sk_buff_head list; 563 int dropped = 0; 564 565 __skb_queue_head_init(&list); 566 567 for (i = 0; i < q->maxflows; i++) { 568 slot = &q->slots[i]; 569 if (!slot->qlen) 570 continue; 571 while (slot->qlen) { 572 skb = slot_dequeue_head(slot); 573 sfq_dec(q, i); 574 __skb_queue_tail(&list, skb); 575 } 576 slot->backlog = 0; 577 red_set_vars(&slot->vars); 578 q->ht[slot->hash] = SFQ_EMPTY_SLOT; 579 } 580 q->tail = NULL; 581 582 while ((skb = __skb_dequeue(&list)) != NULL) { 583 unsigned int hash = sfq_hash(q, skb); 584 sfq_index x = q->ht[hash]; 585 586 slot = &q->slots[x]; 587 if (x == SFQ_EMPTY_SLOT) { 588 x = q->dep[0].next; /* get a free slot */ 589 if (x >= SFQ_MAX_FLOWS) { 590 drop: sch->qstats.backlog -= qdisc_pkt_len(skb); 591 kfree_skb(skb); 592 dropped++; 593 continue; 594 } 595 q->ht[hash] = x; 596 slot = &q->slots[x]; 597 slot->hash = hash; 598 } 599 if (slot->qlen >= q->maxdepth) 600 goto drop; 601 slot_queue_add(slot, skb); 602 if (q->red_parms) 603 slot->vars.qavg = red_calc_qavg(q->red_parms, 604 &slot->vars, 605 slot->backlog); 606 slot->backlog += qdisc_pkt_len(skb); 607 sfq_inc(q, x); 608 if (slot->qlen == 1) { /* The flow is new */ 609 if (q->tail == NULL) { /* It is the first flow */ 610 slot->next = x; 611 } else { 612 slot->next = q->tail->next; 613 q->tail->next = x; 614 } 615 q->tail = slot; 616 slot->allot = q->scaled_quantum; 617 } 618 } 619 sch->q.qlen -= dropped; 620 qdisc_tree_decrease_qlen(sch, dropped); 621 } 622 623 static void sfq_perturbation(unsigned long arg) 624 { 625 struct Qdisc *sch = (struct Qdisc *)arg; 626 struct sfq_sched_data *q = qdisc_priv(sch); 627 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); 628 629 spin_lock(root_lock); 630 q->perturbation = net_random(); 631 if (!q->filter_list && q->tail) 632 sfq_rehash(sch); 633 spin_unlock(root_lock); 634 635 if (q->perturb_period) 636 mod_timer(&q->perturb_timer, jiffies + q->perturb_period); 637 } 638 639 static int sfq_change(struct Qdisc *sch, struct nlattr *opt) 640 { 641 struct sfq_sched_data *q = qdisc_priv(sch); 642 struct tc_sfq_qopt *ctl = nla_data(opt); 643 struct tc_sfq_qopt_v1 *ctl_v1 = NULL; 644 unsigned int qlen; 645 struct red_parms *p = NULL; 646 647 if (opt->nla_len < nla_attr_size(sizeof(*ctl))) 648 return -EINVAL; 649 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1))) 650 ctl_v1 = nla_data(opt); 651 if (ctl->divisor && 652 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536)) 653 return -EINVAL; 654 if (ctl_v1 && ctl_v1->qth_min) { 655 p = kmalloc(sizeof(*p), GFP_KERNEL); 656 if (!p) 657 return -ENOMEM; 658 } 659 sch_tree_lock(sch); 660 if (ctl->quantum) { 661 q->quantum = ctl->quantum; 662 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); 663 } 664 q->perturb_period = ctl->perturb_period * HZ; 665 if (ctl->flows) 666 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS); 667 if (ctl->divisor) { 668 q->divisor = ctl->divisor; 669 q->maxflows = min_t(u32, q->maxflows, q->divisor); 670 } 671 if (ctl_v1) { 672 if (ctl_v1->depth) 673 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH); 674 if (p) { 675 swap(q->red_parms, p); 676 red_set_parms(q->red_parms, 677 ctl_v1->qth_min, ctl_v1->qth_max, 678 ctl_v1->Wlog, 679 ctl_v1->Plog, ctl_v1->Scell_log, 680 NULL, 681 ctl_v1->max_P); 682 } 683 q->flags = ctl_v1->flags; 684 q->headdrop = ctl_v1->headdrop; 685 } 686 if (ctl->limit) { 687 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows); 688 q->maxflows = min_t(u32, q->maxflows, q->limit); 689 } 690 691 qlen = sch->q.qlen; 692 while (sch->q.qlen > q->limit) 693 sfq_drop(sch); 694 qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen); 695 696 del_timer(&q->perturb_timer); 697 if (q->perturb_period) { 698 mod_timer(&q->perturb_timer, jiffies + q->perturb_period); 699 q->perturbation = net_random(); 700 } 701 sch_tree_unlock(sch); 702 kfree(p); 703 return 0; 704 } 705 706 static void *sfq_alloc(size_t sz) 707 { 708 void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN); 709 710 if (!ptr) 711 ptr = vmalloc(sz); 712 return ptr; 713 } 714 715 static void sfq_free(void *addr) 716 { 717 if (addr) { 718 if (is_vmalloc_addr(addr)) 719 vfree(addr); 720 else 721 kfree(addr); 722 } 723 } 724 725 static void sfq_destroy(struct Qdisc *sch) 726 { 727 struct sfq_sched_data *q = qdisc_priv(sch); 728 729 tcf_destroy_chain(&q->filter_list); 730 q->perturb_period = 0; 731 del_timer_sync(&q->perturb_timer); 732 sfq_free(q->ht); 733 sfq_free(q->slots); 734 kfree(q->red_parms); 735 } 736 737 static int sfq_init(struct Qdisc *sch, struct nlattr *opt) 738 { 739 struct sfq_sched_data *q = qdisc_priv(sch); 740 int i; 741 742 q->perturb_timer.function = sfq_perturbation; 743 q->perturb_timer.data = (unsigned long)sch; 744 init_timer_deferrable(&q->perturb_timer); 745 746 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) { 747 q->dep[i].next = i + SFQ_MAX_FLOWS; 748 q->dep[i].prev = i + SFQ_MAX_FLOWS; 749 } 750 751 q->limit = SFQ_MAX_DEPTH; 752 q->maxdepth = SFQ_MAX_DEPTH; 753 q->cur_depth = 0; 754 q->tail = NULL; 755 q->divisor = SFQ_DEFAULT_HASH_DIVISOR; 756 q->maxflows = SFQ_DEFAULT_FLOWS; 757 q->quantum = psched_mtu(qdisc_dev(sch)); 758 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); 759 q->perturb_period = 0; 760 q->perturbation = net_random(); 761 762 if (opt) { 763 int err = sfq_change(sch, opt); 764 if (err) 765 return err; 766 } 767 768 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor); 769 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows); 770 if (!q->ht || !q->slots) { 771 sfq_destroy(sch); 772 return -ENOMEM; 773 } 774 for (i = 0; i < q->divisor; i++) 775 q->ht[i] = SFQ_EMPTY_SLOT; 776 777 for (i = 0; i < q->maxflows; i++) { 778 slot_queue_init(&q->slots[i]); 779 sfq_link(q, i); 780 } 781 if (q->limit >= 1) 782 sch->flags |= TCQ_F_CAN_BYPASS; 783 else 784 sch->flags &= ~TCQ_F_CAN_BYPASS; 785 return 0; 786 } 787 788 static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb) 789 { 790 struct sfq_sched_data *q = qdisc_priv(sch); 791 unsigned char *b = skb_tail_pointer(skb); 792 struct tc_sfq_qopt_v1 opt; 793 struct red_parms *p = q->red_parms; 794 795 memset(&opt, 0, sizeof(opt)); 796 opt.v0.quantum = q->quantum; 797 opt.v0.perturb_period = q->perturb_period / HZ; 798 opt.v0.limit = q->limit; 799 opt.v0.divisor = q->divisor; 800 opt.v0.flows = q->maxflows; 801 opt.depth = q->maxdepth; 802 opt.headdrop = q->headdrop; 803 804 if (p) { 805 opt.qth_min = p->qth_min >> p->Wlog; 806 opt.qth_max = p->qth_max >> p->Wlog; 807 opt.Wlog = p->Wlog; 808 opt.Plog = p->Plog; 809 opt.Scell_log = p->Scell_log; 810 opt.max_P = p->max_P; 811 } 812 memcpy(&opt.stats, &q->stats, sizeof(opt.stats)); 813 opt.flags = q->flags; 814 815 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 816 goto nla_put_failure; 817 818 return skb->len; 819 820 nla_put_failure: 821 nlmsg_trim(skb, b); 822 return -1; 823 } 824 825 static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg) 826 { 827 return NULL; 828 } 829 830 static unsigned long sfq_get(struct Qdisc *sch, u32 classid) 831 { 832 return 0; 833 } 834 835 static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent, 836 u32 classid) 837 { 838 /* we cannot bypass queue discipline anymore */ 839 sch->flags &= ~TCQ_F_CAN_BYPASS; 840 return 0; 841 } 842 843 static void sfq_put(struct Qdisc *q, unsigned long cl) 844 { 845 } 846 847 static struct tcf_proto **sfq_find_tcf(struct Qdisc *sch, unsigned long cl) 848 { 849 struct sfq_sched_data *q = qdisc_priv(sch); 850 851 if (cl) 852 return NULL; 853 return &q->filter_list; 854 } 855 856 static int sfq_dump_class(struct Qdisc *sch, unsigned long cl, 857 struct sk_buff *skb, struct tcmsg *tcm) 858 { 859 tcm->tcm_handle |= TC_H_MIN(cl); 860 return 0; 861 } 862 863 static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl, 864 struct gnet_dump *d) 865 { 866 struct sfq_sched_data *q = qdisc_priv(sch); 867 sfq_index idx = q->ht[cl - 1]; 868 struct gnet_stats_queue qs = { 0 }; 869 struct tc_sfq_xstats xstats = { 0 }; 870 871 if (idx != SFQ_EMPTY_SLOT) { 872 const struct sfq_slot *slot = &q->slots[idx]; 873 874 xstats.allot = slot->allot << SFQ_ALLOT_SHIFT; 875 qs.qlen = slot->qlen; 876 qs.backlog = slot->backlog; 877 } 878 if (gnet_stats_copy_queue(d, &qs) < 0) 879 return -1; 880 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 881 } 882 883 static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg) 884 { 885 struct sfq_sched_data *q = qdisc_priv(sch); 886 unsigned int i; 887 888 if (arg->stop) 889 return; 890 891 for (i = 0; i < q->divisor; i++) { 892 if (q->ht[i] == SFQ_EMPTY_SLOT || 893 arg->count < arg->skip) { 894 arg->count++; 895 continue; 896 } 897 if (arg->fn(sch, i + 1, arg) < 0) { 898 arg->stop = 1; 899 break; 900 } 901 arg->count++; 902 } 903 } 904 905 static const struct Qdisc_class_ops sfq_class_ops = { 906 .leaf = sfq_leaf, 907 .get = sfq_get, 908 .put = sfq_put, 909 .tcf_chain = sfq_find_tcf, 910 .bind_tcf = sfq_bind, 911 .unbind_tcf = sfq_put, 912 .dump = sfq_dump_class, 913 .dump_stats = sfq_dump_class_stats, 914 .walk = sfq_walk, 915 }; 916 917 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = { 918 .cl_ops = &sfq_class_ops, 919 .id = "sfq", 920 .priv_size = sizeof(struct sfq_sched_data), 921 .enqueue = sfq_enqueue, 922 .dequeue = sfq_dequeue, 923 .peek = qdisc_peek_dequeued, 924 .drop = sfq_drop, 925 .init = sfq_init, 926 .reset = sfq_reset, 927 .destroy = sfq_destroy, 928 .change = NULL, 929 .dump = sfq_dump, 930 .owner = THIS_MODULE, 931 }; 932 933 static int __init sfq_module_init(void) 934 { 935 return register_qdisc(&sfq_qdisc_ops); 936 } 937 static void __exit sfq_module_exit(void) 938 { 939 unregister_qdisc(&sfq_qdisc_ops); 940 } 941 module_init(sfq_module_init) 942 module_exit(sfq_module_exit) 943 MODULE_LICENSE("GPL"); 944