1 /* 2 * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing) 3 * 4 * Copyright (C) 2013-2015 Eric Dumazet <edumazet@google.com> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * Meant to be mostly used for locally generated traffic : 12 * Fast classification depends on skb->sk being set before reaching us. 13 * If not, (router workload), we use rxhash as fallback, with 32 bits wide hash. 14 * All packets belonging to a socket are considered as a 'flow'. 15 * 16 * Flows are dynamically allocated and stored in a hash table of RB trees 17 * They are also part of one Round Robin 'queues' (new or old flows) 18 * 19 * Burst avoidance (aka pacing) capability : 20 * 21 * Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a 22 * bunch of packets, and this packet scheduler adds delay between 23 * packets to respect rate limitation. 24 * 25 * enqueue() : 26 * - lookup one RB tree (out of 1024 or more) to find the flow. 27 * If non existent flow, create it, add it to the tree. 28 * Add skb to the per flow list of skb (fifo). 29 * - Use a special fifo for high prio packets 30 * 31 * dequeue() : serves flows in Round Robin 32 * Note : When a flow becomes empty, we do not immediately remove it from 33 * rb trees, for performance reasons (its expected to send additional packets, 34 * or SLAB cache will reuse socket for another flow) 35 */ 36 37 #include <linux/module.h> 38 #include <linux/types.h> 39 #include <linux/kernel.h> 40 #include <linux/jiffies.h> 41 #include <linux/string.h> 42 #include <linux/in.h> 43 #include <linux/errno.h> 44 #include <linux/init.h> 45 #include <linux/skbuff.h> 46 #include <linux/slab.h> 47 #include <linux/rbtree.h> 48 #include <linux/hash.h> 49 #include <linux/prefetch.h> 50 #include <linux/vmalloc.h> 51 #include <net/netlink.h> 52 #include <net/pkt_sched.h> 53 #include <net/sock.h> 54 #include <net/tcp_states.h> 55 #include <net/tcp.h> 56 57 /* 58 * Per flow structure, dynamically allocated 59 */ 60 struct fq_flow { 61 struct sk_buff *head; /* list of skbs for this flow : first skb */ 62 union { 63 struct sk_buff *tail; /* last skb in the list */ 64 unsigned long age; /* jiffies when flow was emptied, for gc */ 65 }; 66 struct rb_node fq_node; /* anchor in fq_root[] trees */ 67 struct sock *sk; 68 int qlen; /* number of packets in flow queue */ 69 int credit; 70 u32 socket_hash; /* sk_hash */ 71 struct fq_flow *next; /* next pointer in RR lists, or &detached */ 72 73 struct rb_node rate_node; /* anchor in q->delayed tree */ 74 u64 time_next_packet; 75 }; 76 77 struct fq_flow_head { 78 struct fq_flow *first; 79 struct fq_flow *last; 80 }; 81 82 struct fq_sched_data { 83 struct fq_flow_head new_flows; 84 85 struct fq_flow_head old_flows; 86 87 struct rb_root delayed; /* for rate limited flows */ 88 u64 time_next_delayed_flow; 89 unsigned long unthrottle_latency_ns; 90 91 struct fq_flow internal; /* for non classified or high prio packets */ 92 u32 quantum; 93 u32 initial_quantum; 94 u32 flow_refill_delay; 95 u32 flow_max_rate; /* optional max rate per flow */ 96 u32 flow_plimit; /* max packets per flow */ 97 u32 orphan_mask; /* mask for orphaned skb */ 98 u32 low_rate_threshold; 99 struct rb_root *fq_root; 100 u8 rate_enable; 101 u8 fq_trees_log; 102 103 u32 flows; 104 u32 inactive_flows; 105 u32 throttled_flows; 106 107 u64 stat_gc_flows; 108 u64 stat_internal_packets; 109 u64 stat_tcp_retrans; 110 u64 stat_throttled; 111 u64 stat_flows_plimit; 112 u64 stat_pkts_too_long; 113 u64 stat_allocation_errors; 114 struct qdisc_watchdog watchdog; 115 }; 116 117 /* special value to mark a detached flow (not on old/new list) */ 118 static struct fq_flow detached, throttled; 119 120 static void fq_flow_set_detached(struct fq_flow *f) 121 { 122 f->next = &detached; 123 f->age = jiffies; 124 } 125 126 static bool fq_flow_is_detached(const struct fq_flow *f) 127 { 128 return f->next == &detached; 129 } 130 131 static bool fq_flow_is_throttled(const struct fq_flow *f) 132 { 133 return f->next == &throttled; 134 } 135 136 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow) 137 { 138 if (head->first) 139 head->last->next = flow; 140 else 141 head->first = flow; 142 head->last = flow; 143 flow->next = NULL; 144 } 145 146 static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f) 147 { 148 rb_erase(&f->rate_node, &q->delayed); 149 q->throttled_flows--; 150 fq_flow_add_tail(&q->old_flows, f); 151 } 152 153 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f) 154 { 155 struct rb_node **p = &q->delayed.rb_node, *parent = NULL; 156 157 while (*p) { 158 struct fq_flow *aux; 159 160 parent = *p; 161 aux = rb_entry(parent, struct fq_flow, rate_node); 162 if (f->time_next_packet >= aux->time_next_packet) 163 p = &parent->rb_right; 164 else 165 p = &parent->rb_left; 166 } 167 rb_link_node(&f->rate_node, parent, p); 168 rb_insert_color(&f->rate_node, &q->delayed); 169 q->throttled_flows++; 170 q->stat_throttled++; 171 172 f->next = &throttled; 173 if (q->time_next_delayed_flow > f->time_next_packet) 174 q->time_next_delayed_flow = f->time_next_packet; 175 } 176 177 178 static struct kmem_cache *fq_flow_cachep __read_mostly; 179 180 181 /* limit number of collected flows per round */ 182 #define FQ_GC_MAX 8 183 #define FQ_GC_AGE (3*HZ) 184 185 static bool fq_gc_candidate(const struct fq_flow *f) 186 { 187 return fq_flow_is_detached(f) && 188 time_after(jiffies, f->age + FQ_GC_AGE); 189 } 190 191 static void fq_gc(struct fq_sched_data *q, 192 struct rb_root *root, 193 struct sock *sk) 194 { 195 struct fq_flow *f, *tofree[FQ_GC_MAX]; 196 struct rb_node **p, *parent; 197 int fcnt = 0; 198 199 p = &root->rb_node; 200 parent = NULL; 201 while (*p) { 202 parent = *p; 203 204 f = rb_entry(parent, struct fq_flow, fq_node); 205 if (f->sk == sk) 206 break; 207 208 if (fq_gc_candidate(f)) { 209 tofree[fcnt++] = f; 210 if (fcnt == FQ_GC_MAX) 211 break; 212 } 213 214 if (f->sk > sk) 215 p = &parent->rb_right; 216 else 217 p = &parent->rb_left; 218 } 219 220 q->flows -= fcnt; 221 q->inactive_flows -= fcnt; 222 q->stat_gc_flows += fcnt; 223 while (fcnt) { 224 struct fq_flow *f = tofree[--fcnt]; 225 226 rb_erase(&f->fq_node, root); 227 kmem_cache_free(fq_flow_cachep, f); 228 } 229 } 230 231 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q) 232 { 233 struct rb_node **p, *parent; 234 struct sock *sk = skb->sk; 235 struct rb_root *root; 236 struct fq_flow *f; 237 238 /* warning: no starvation prevention... */ 239 if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL)) 240 return &q->internal; 241 242 /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket 243 * or a listener (SYNCOOKIE mode) 244 * 1) request sockets are not full blown, 245 * they do not contain sk_pacing_rate 246 * 2) They are not part of a 'flow' yet 247 * 3) We do not want to rate limit them (eg SYNFLOOD attack), 248 * especially if the listener set SO_MAX_PACING_RATE 249 * 4) We pretend they are orphaned 250 */ 251 if (!sk || sk_listener(sk)) { 252 unsigned long hash = skb_get_hash(skb) & q->orphan_mask; 253 254 /* By forcing low order bit to 1, we make sure to not 255 * collide with a local flow (socket pointers are word aligned) 256 */ 257 sk = (struct sock *)((hash << 1) | 1UL); 258 skb_orphan(skb); 259 } 260 261 root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)]; 262 263 if (q->flows >= (2U << q->fq_trees_log) && 264 q->inactive_flows > q->flows/2) 265 fq_gc(q, root, sk); 266 267 p = &root->rb_node; 268 parent = NULL; 269 while (*p) { 270 parent = *p; 271 272 f = rb_entry(parent, struct fq_flow, fq_node); 273 if (f->sk == sk) { 274 /* socket might have been reallocated, so check 275 * if its sk_hash is the same. 276 * It not, we need to refill credit with 277 * initial quantum 278 */ 279 if (unlikely(skb->sk && 280 f->socket_hash != sk->sk_hash)) { 281 f->credit = q->initial_quantum; 282 f->socket_hash = sk->sk_hash; 283 if (fq_flow_is_throttled(f)) 284 fq_flow_unset_throttled(q, f); 285 f->time_next_packet = 0ULL; 286 } 287 return f; 288 } 289 if (f->sk > sk) 290 p = &parent->rb_right; 291 else 292 p = &parent->rb_left; 293 } 294 295 f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN); 296 if (unlikely(!f)) { 297 q->stat_allocation_errors++; 298 return &q->internal; 299 } 300 fq_flow_set_detached(f); 301 f->sk = sk; 302 if (skb->sk) 303 f->socket_hash = sk->sk_hash; 304 f->credit = q->initial_quantum; 305 306 rb_link_node(&f->fq_node, parent, p); 307 rb_insert_color(&f->fq_node, root); 308 309 q->flows++; 310 q->inactive_flows++; 311 return f; 312 } 313 314 315 /* remove one skb from head of flow queue */ 316 static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow) 317 { 318 struct sk_buff *skb = flow->head; 319 320 if (skb) { 321 flow->head = skb->next; 322 skb->next = NULL; 323 flow->qlen--; 324 qdisc_qstats_backlog_dec(sch, skb); 325 sch->q.qlen--; 326 } 327 return skb; 328 } 329 330 /* We might add in the future detection of retransmits 331 * For the time being, just return false 332 */ 333 static bool skb_is_retransmit(struct sk_buff *skb) 334 { 335 return false; 336 } 337 338 /* add skb to flow queue 339 * flow queue is a linked list, kind of FIFO, except for TCP retransmits 340 * We special case tcp retransmits to be transmitted before other packets. 341 * We rely on fact that TCP retransmits are unlikely, so we do not waste 342 * a separate queue or a pointer. 343 * head-> [retrans pkt 1] 344 * [retrans pkt 2] 345 * [ normal pkt 1] 346 * [ normal pkt 2] 347 * [ normal pkt 3] 348 * tail-> [ normal pkt 4] 349 */ 350 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb) 351 { 352 struct sk_buff *prev, *head = flow->head; 353 354 skb->next = NULL; 355 if (!head) { 356 flow->head = skb; 357 flow->tail = skb; 358 return; 359 } 360 if (likely(!skb_is_retransmit(skb))) { 361 flow->tail->next = skb; 362 flow->tail = skb; 363 return; 364 } 365 366 /* This skb is a tcp retransmit, 367 * find the last retrans packet in the queue 368 */ 369 prev = NULL; 370 while (skb_is_retransmit(head)) { 371 prev = head; 372 head = head->next; 373 if (!head) 374 break; 375 } 376 if (!prev) { /* no rtx packet in queue, become the new head */ 377 skb->next = flow->head; 378 flow->head = skb; 379 } else { 380 if (prev == flow->tail) 381 flow->tail = skb; 382 else 383 skb->next = prev->next; 384 prev->next = skb; 385 } 386 } 387 388 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, 389 struct sk_buff **to_free) 390 { 391 struct fq_sched_data *q = qdisc_priv(sch); 392 struct fq_flow *f; 393 394 if (unlikely(sch->q.qlen >= sch->limit)) 395 return qdisc_drop(skb, sch, to_free); 396 397 f = fq_classify(skb, q); 398 if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) { 399 q->stat_flows_plimit++; 400 return qdisc_drop(skb, sch, to_free); 401 } 402 403 f->qlen++; 404 if (skb_is_retransmit(skb)) 405 q->stat_tcp_retrans++; 406 qdisc_qstats_backlog_inc(sch, skb); 407 if (fq_flow_is_detached(f)) { 408 struct sock *sk = skb->sk; 409 410 fq_flow_add_tail(&q->new_flows, f); 411 if (time_after(jiffies, f->age + q->flow_refill_delay)) 412 f->credit = max_t(u32, f->credit, q->quantum); 413 if (sk && q->rate_enable) { 414 if (unlikely(smp_load_acquire(&sk->sk_pacing_status) != 415 SK_PACING_FQ)) 416 smp_store_release(&sk->sk_pacing_status, 417 SK_PACING_FQ); 418 } 419 q->inactive_flows--; 420 } 421 422 /* Note: this overwrites f->age */ 423 flow_queue_add(f, skb); 424 425 if (unlikely(f == &q->internal)) { 426 q->stat_internal_packets++; 427 } 428 sch->q.qlen++; 429 430 return NET_XMIT_SUCCESS; 431 } 432 433 static void fq_check_throttled(struct fq_sched_data *q, u64 now) 434 { 435 unsigned long sample; 436 struct rb_node *p; 437 438 if (q->time_next_delayed_flow > now) 439 return; 440 441 /* Update unthrottle latency EWMA. 442 * This is cheap and can help diagnosing timer/latency problems. 443 */ 444 sample = (unsigned long)(now - q->time_next_delayed_flow); 445 q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3; 446 q->unthrottle_latency_ns += sample >> 3; 447 448 q->time_next_delayed_flow = ~0ULL; 449 while ((p = rb_first(&q->delayed)) != NULL) { 450 struct fq_flow *f = rb_entry(p, struct fq_flow, rate_node); 451 452 if (f->time_next_packet > now) { 453 q->time_next_delayed_flow = f->time_next_packet; 454 break; 455 } 456 fq_flow_unset_throttled(q, f); 457 } 458 } 459 460 static struct sk_buff *fq_dequeue(struct Qdisc *sch) 461 { 462 struct fq_sched_data *q = qdisc_priv(sch); 463 u64 now = ktime_get_ns(); 464 struct fq_flow_head *head; 465 struct sk_buff *skb; 466 struct fq_flow *f; 467 u32 rate, plen; 468 469 skb = fq_dequeue_head(sch, &q->internal); 470 if (skb) 471 goto out; 472 fq_check_throttled(q, now); 473 begin: 474 head = &q->new_flows; 475 if (!head->first) { 476 head = &q->old_flows; 477 if (!head->first) { 478 if (q->time_next_delayed_flow != ~0ULL) 479 qdisc_watchdog_schedule_ns(&q->watchdog, 480 q->time_next_delayed_flow); 481 return NULL; 482 } 483 } 484 f = head->first; 485 486 if (f->credit <= 0) { 487 f->credit += q->quantum; 488 head->first = f->next; 489 fq_flow_add_tail(&q->old_flows, f); 490 goto begin; 491 } 492 493 skb = f->head; 494 if (unlikely(skb && now < f->time_next_packet && 495 !skb_is_tcp_pure_ack(skb))) { 496 head->first = f->next; 497 fq_flow_set_throttled(q, f); 498 goto begin; 499 } 500 501 skb = fq_dequeue_head(sch, f); 502 if (!skb) { 503 head->first = f->next; 504 /* force a pass through old_flows to prevent starvation */ 505 if ((head == &q->new_flows) && q->old_flows.first) { 506 fq_flow_add_tail(&q->old_flows, f); 507 } else { 508 fq_flow_set_detached(f); 509 q->inactive_flows++; 510 } 511 goto begin; 512 } 513 prefetch(&skb->end); 514 f->credit -= qdisc_pkt_len(skb); 515 516 if (!q->rate_enable) 517 goto out; 518 519 /* Do not pace locally generated ack packets */ 520 if (skb_is_tcp_pure_ack(skb)) 521 goto out; 522 523 rate = q->flow_max_rate; 524 if (skb->sk) 525 rate = min(skb->sk->sk_pacing_rate, rate); 526 527 if (rate <= q->low_rate_threshold) { 528 f->credit = 0; 529 plen = qdisc_pkt_len(skb); 530 } else { 531 plen = max(qdisc_pkt_len(skb), q->quantum); 532 if (f->credit > 0) 533 goto out; 534 } 535 if (rate != ~0U) { 536 u64 len = (u64)plen * NSEC_PER_SEC; 537 538 if (likely(rate)) 539 do_div(len, rate); 540 /* Since socket rate can change later, 541 * clamp the delay to 1 second. 542 * Really, providers of too big packets should be fixed ! 543 */ 544 if (unlikely(len > NSEC_PER_SEC)) { 545 len = NSEC_PER_SEC; 546 q->stat_pkts_too_long++; 547 } 548 /* Account for schedule/timers drifts. 549 * f->time_next_packet was set when prior packet was sent, 550 * and current time (@now) can be too late by tens of us. 551 */ 552 if (f->time_next_packet) 553 len -= min(len/2, now - f->time_next_packet); 554 f->time_next_packet = now + len; 555 } 556 out: 557 qdisc_bstats_update(sch, skb); 558 return skb; 559 } 560 561 static void fq_flow_purge(struct fq_flow *flow) 562 { 563 rtnl_kfree_skbs(flow->head, flow->tail); 564 flow->head = NULL; 565 flow->qlen = 0; 566 } 567 568 static void fq_reset(struct Qdisc *sch) 569 { 570 struct fq_sched_data *q = qdisc_priv(sch); 571 struct rb_root *root; 572 struct rb_node *p; 573 struct fq_flow *f; 574 unsigned int idx; 575 576 sch->q.qlen = 0; 577 sch->qstats.backlog = 0; 578 579 fq_flow_purge(&q->internal); 580 581 if (!q->fq_root) 582 return; 583 584 for (idx = 0; idx < (1U << q->fq_trees_log); idx++) { 585 root = &q->fq_root[idx]; 586 while ((p = rb_first(root)) != NULL) { 587 f = rb_entry(p, struct fq_flow, fq_node); 588 rb_erase(p, root); 589 590 fq_flow_purge(f); 591 592 kmem_cache_free(fq_flow_cachep, f); 593 } 594 } 595 q->new_flows.first = NULL; 596 q->old_flows.first = NULL; 597 q->delayed = RB_ROOT; 598 q->flows = 0; 599 q->inactive_flows = 0; 600 q->throttled_flows = 0; 601 } 602 603 static void fq_rehash(struct fq_sched_data *q, 604 struct rb_root *old_array, u32 old_log, 605 struct rb_root *new_array, u32 new_log) 606 { 607 struct rb_node *op, **np, *parent; 608 struct rb_root *oroot, *nroot; 609 struct fq_flow *of, *nf; 610 int fcnt = 0; 611 u32 idx; 612 613 for (idx = 0; idx < (1U << old_log); idx++) { 614 oroot = &old_array[idx]; 615 while ((op = rb_first(oroot)) != NULL) { 616 rb_erase(op, oroot); 617 of = rb_entry(op, struct fq_flow, fq_node); 618 if (fq_gc_candidate(of)) { 619 fcnt++; 620 kmem_cache_free(fq_flow_cachep, of); 621 continue; 622 } 623 nroot = &new_array[hash_ptr(of->sk, new_log)]; 624 625 np = &nroot->rb_node; 626 parent = NULL; 627 while (*np) { 628 parent = *np; 629 630 nf = rb_entry(parent, struct fq_flow, fq_node); 631 BUG_ON(nf->sk == of->sk); 632 633 if (nf->sk > of->sk) 634 np = &parent->rb_right; 635 else 636 np = &parent->rb_left; 637 } 638 639 rb_link_node(&of->fq_node, parent, np); 640 rb_insert_color(&of->fq_node, nroot); 641 } 642 } 643 q->flows -= fcnt; 644 q->inactive_flows -= fcnt; 645 q->stat_gc_flows += fcnt; 646 } 647 648 static void fq_free(void *addr) 649 { 650 kvfree(addr); 651 } 652 653 static int fq_resize(struct Qdisc *sch, u32 log) 654 { 655 struct fq_sched_data *q = qdisc_priv(sch); 656 struct rb_root *array; 657 void *old_fq_root; 658 u32 idx; 659 660 if (q->fq_root && log == q->fq_trees_log) 661 return 0; 662 663 /* If XPS was setup, we can allocate memory on right NUMA node */ 664 array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL, 665 netdev_queue_numa_node_read(sch->dev_queue)); 666 if (!array) 667 return -ENOMEM; 668 669 for (idx = 0; idx < (1U << log); idx++) 670 array[idx] = RB_ROOT; 671 672 sch_tree_lock(sch); 673 674 old_fq_root = q->fq_root; 675 if (old_fq_root) 676 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log); 677 678 q->fq_root = array; 679 q->fq_trees_log = log; 680 681 sch_tree_unlock(sch); 682 683 fq_free(old_fq_root); 684 685 return 0; 686 } 687 688 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = { 689 [TCA_FQ_PLIMIT] = { .type = NLA_U32 }, 690 [TCA_FQ_FLOW_PLIMIT] = { .type = NLA_U32 }, 691 [TCA_FQ_QUANTUM] = { .type = NLA_U32 }, 692 [TCA_FQ_INITIAL_QUANTUM] = { .type = NLA_U32 }, 693 [TCA_FQ_RATE_ENABLE] = { .type = NLA_U32 }, 694 [TCA_FQ_FLOW_DEFAULT_RATE] = { .type = NLA_U32 }, 695 [TCA_FQ_FLOW_MAX_RATE] = { .type = NLA_U32 }, 696 [TCA_FQ_BUCKETS_LOG] = { .type = NLA_U32 }, 697 [TCA_FQ_FLOW_REFILL_DELAY] = { .type = NLA_U32 }, 698 [TCA_FQ_LOW_RATE_THRESHOLD] = { .type = NLA_U32 }, 699 }; 700 701 static int fq_change(struct Qdisc *sch, struct nlattr *opt, 702 struct netlink_ext_ack *extack) 703 { 704 struct fq_sched_data *q = qdisc_priv(sch); 705 struct nlattr *tb[TCA_FQ_MAX + 1]; 706 int err, drop_count = 0; 707 unsigned drop_len = 0; 708 u32 fq_log; 709 710 if (!opt) 711 return -EINVAL; 712 713 err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy, NULL); 714 if (err < 0) 715 return err; 716 717 sch_tree_lock(sch); 718 719 fq_log = q->fq_trees_log; 720 721 if (tb[TCA_FQ_BUCKETS_LOG]) { 722 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]); 723 724 if (nval >= 1 && nval <= ilog2(256*1024)) 725 fq_log = nval; 726 else 727 err = -EINVAL; 728 } 729 if (tb[TCA_FQ_PLIMIT]) 730 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]); 731 732 if (tb[TCA_FQ_FLOW_PLIMIT]) 733 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]); 734 735 if (tb[TCA_FQ_QUANTUM]) { 736 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]); 737 738 if (quantum > 0) 739 q->quantum = quantum; 740 else 741 err = -EINVAL; 742 } 743 744 if (tb[TCA_FQ_INITIAL_QUANTUM]) 745 q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]); 746 747 if (tb[TCA_FQ_FLOW_DEFAULT_RATE]) 748 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n", 749 nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE])); 750 751 if (tb[TCA_FQ_FLOW_MAX_RATE]) 752 q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]); 753 754 if (tb[TCA_FQ_LOW_RATE_THRESHOLD]) 755 q->low_rate_threshold = 756 nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]); 757 758 if (tb[TCA_FQ_RATE_ENABLE]) { 759 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]); 760 761 if (enable <= 1) 762 q->rate_enable = enable; 763 else 764 err = -EINVAL; 765 } 766 767 if (tb[TCA_FQ_FLOW_REFILL_DELAY]) { 768 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ; 769 770 q->flow_refill_delay = usecs_to_jiffies(usecs_delay); 771 } 772 773 if (tb[TCA_FQ_ORPHAN_MASK]) 774 q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]); 775 776 if (!err) { 777 sch_tree_unlock(sch); 778 err = fq_resize(sch, fq_log); 779 sch_tree_lock(sch); 780 } 781 while (sch->q.qlen > sch->limit) { 782 struct sk_buff *skb = fq_dequeue(sch); 783 784 if (!skb) 785 break; 786 drop_len += qdisc_pkt_len(skb); 787 rtnl_kfree_skbs(skb, skb); 788 drop_count++; 789 } 790 qdisc_tree_reduce_backlog(sch, drop_count, drop_len); 791 792 sch_tree_unlock(sch); 793 return err; 794 } 795 796 static void fq_destroy(struct Qdisc *sch) 797 { 798 struct fq_sched_data *q = qdisc_priv(sch); 799 800 fq_reset(sch); 801 fq_free(q->fq_root); 802 qdisc_watchdog_cancel(&q->watchdog); 803 } 804 805 static int fq_init(struct Qdisc *sch, struct nlattr *opt, 806 struct netlink_ext_ack *extack) 807 { 808 struct fq_sched_data *q = qdisc_priv(sch); 809 int err; 810 811 sch->limit = 10000; 812 q->flow_plimit = 100; 813 q->quantum = 2 * psched_mtu(qdisc_dev(sch)); 814 q->initial_quantum = 10 * psched_mtu(qdisc_dev(sch)); 815 q->flow_refill_delay = msecs_to_jiffies(40); 816 q->flow_max_rate = ~0U; 817 q->time_next_delayed_flow = ~0ULL; 818 q->rate_enable = 1; 819 q->new_flows.first = NULL; 820 q->old_flows.first = NULL; 821 q->delayed = RB_ROOT; 822 q->fq_root = NULL; 823 q->fq_trees_log = ilog2(1024); 824 q->orphan_mask = 1024 - 1; 825 q->low_rate_threshold = 550000 / 8; 826 qdisc_watchdog_init(&q->watchdog, sch); 827 828 if (opt) 829 err = fq_change(sch, opt, extack); 830 else 831 err = fq_resize(sch, q->fq_trees_log); 832 833 return err; 834 } 835 836 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb) 837 { 838 struct fq_sched_data *q = qdisc_priv(sch); 839 struct nlattr *opts; 840 841 opts = nla_nest_start(skb, TCA_OPTIONS); 842 if (opts == NULL) 843 goto nla_put_failure; 844 845 /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */ 846 847 if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) || 848 nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) || 849 nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) || 850 nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) || 851 nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) || 852 nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) || 853 nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY, 854 jiffies_to_usecs(q->flow_refill_delay)) || 855 nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) || 856 nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD, 857 q->low_rate_threshold) || 858 nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log)) 859 goto nla_put_failure; 860 861 return nla_nest_end(skb, opts); 862 863 nla_put_failure: 864 return -1; 865 } 866 867 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d) 868 { 869 struct fq_sched_data *q = qdisc_priv(sch); 870 struct tc_fq_qd_stats st; 871 872 sch_tree_lock(sch); 873 874 st.gc_flows = q->stat_gc_flows; 875 st.highprio_packets = q->stat_internal_packets; 876 st.tcp_retrans = q->stat_tcp_retrans; 877 st.throttled = q->stat_throttled; 878 st.flows_plimit = q->stat_flows_plimit; 879 st.pkts_too_long = q->stat_pkts_too_long; 880 st.allocation_errors = q->stat_allocation_errors; 881 st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns(); 882 st.flows = q->flows; 883 st.inactive_flows = q->inactive_flows; 884 st.throttled_flows = q->throttled_flows; 885 st.unthrottle_latency_ns = min_t(unsigned long, 886 q->unthrottle_latency_ns, ~0U); 887 sch_tree_unlock(sch); 888 889 return gnet_stats_copy_app(d, &st, sizeof(st)); 890 } 891 892 static struct Qdisc_ops fq_qdisc_ops __read_mostly = { 893 .id = "fq", 894 .priv_size = sizeof(struct fq_sched_data), 895 896 .enqueue = fq_enqueue, 897 .dequeue = fq_dequeue, 898 .peek = qdisc_peek_dequeued, 899 .init = fq_init, 900 .reset = fq_reset, 901 .destroy = fq_destroy, 902 .change = fq_change, 903 .dump = fq_dump, 904 .dump_stats = fq_dump_stats, 905 .owner = THIS_MODULE, 906 }; 907 908 static int __init fq_module_init(void) 909 { 910 int ret; 911 912 fq_flow_cachep = kmem_cache_create("fq_flow_cache", 913 sizeof(struct fq_flow), 914 0, 0, NULL); 915 if (!fq_flow_cachep) 916 return -ENOMEM; 917 918 ret = register_qdisc(&fq_qdisc_ops); 919 if (ret) 920 kmem_cache_destroy(fq_flow_cachep); 921 return ret; 922 } 923 924 static void __exit fq_module_exit(void) 925 { 926 unregister_qdisc(&fq_qdisc_ops); 927 kmem_cache_destroy(fq_flow_cachep); 928 } 929 930 module_init(fq_module_init) 931 module_exit(fq_module_exit) 932 MODULE_AUTHOR("Eric Dumazet"); 933 MODULE_LICENSE("GPL"); 934