net/sched/sch_fq.c

   1 /*
   2  * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
   3  *
   4  *  Copyright (C) 2013 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 localy 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 <net/netlink.h>
  51 #include <net/pkt_sched.h>
  52 #include <net/sock.h>
  53 #include <net/tcp_states.h>
  54
  55 /*
  56  * Per flow structure, dynamically allocated
  57  */
  58 struct fq_flow {
  59         struct sk_buff  *head;          /* list of skbs for this flow : first skb */
  60         union {
  61                 struct sk_buff *tail;   /* last skb in the list */
  62                 unsigned long  age;     /* jiffies when flow was emptied, for gc */
  63         };
  64         struct rb_node  fq_node;        /* anchor in fq_root[] trees */
  65         struct sock     *sk;
  66         int             qlen;           /* number of packets in flow queue */
  67         int             credit;
  68         u32             socket_hash;    /* sk_hash */
  69         struct fq_flow *next;           /* next pointer in RR lists, or &detached */
  70
  71         struct rb_node  rate_node;      /* anchor in q->delayed tree */
  72         u64             time_next_packet;
  73 };
  74
  75 struct fq_flow_head {
  76         struct fq_flow *first;
  77         struct fq_flow *last;
  78 };
  79
  80 struct fq_sched_data {
  81         struct fq_flow_head new_flows;
  82
  83         struct fq_flow_head old_flows;
  84
  85         struct rb_root  delayed;        /* for rate limited flows */
  86         u64             time_next_delayed_flow;
  87
  88         struct fq_flow  internal;       /* for non classified or high prio packets */
  89         u32             quantum;
  90         u32             initial_quantum;
  91         u32             flow_default_rate;/* rate per flow : bytes per second */
  92         u32             flow_max_rate;  /* optional max rate per flow */
  93         u32             flow_plimit;    /* max packets per flow */
  94         struct rb_root  *fq_root;
  95         u8              rate_enable;
  96         u8              fq_trees_log;
  97
  98         u32             flows;
  99         u32             inactive_flows;
 100         u32             throttled_flows;
 101
 102         u64             stat_gc_flows;
 103         u64             stat_internal_packets;
 104         u64             stat_tcp_retrans;
 105         u64             stat_throttled;
 106         u64             stat_flows_plimit;
 107         u64             stat_pkts_too_long;
 108         u64             stat_allocation_errors;
 109         struct qdisc_watchdog watchdog;
 110 };
 111
 112 /* special value to mark a detached flow (not on old/new list) */
 113 static struct fq_flow detached, throttled;
 114
 115 static void fq_flow_set_detached(struct fq_flow *f)
 116 {
 117         f->next = &detached;
 118 }
 119
 120 static bool fq_flow_is_detached(const struct fq_flow *f)
 121 {
 122         return f->next == &detached;
 123 }
 124
 125 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
 126 {
 127         struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
 128
 129         while (*p) {
 130                 struct fq_flow *aux;
 131
 132                 parent = *p;
 133                 aux = container_of(parent, struct fq_flow, rate_node);
 134                 if (f->time_next_packet >= aux->time_next_packet)
 135                         p = &parent->rb_right;
 136                 else
 137                         p = &parent->rb_left;
 138         }
 139         rb_link_node(&f->rate_node, parent, p);
 140         rb_insert_color(&f->rate_node, &q->delayed);
 141         q->throttled_flows++;
 142         q->stat_throttled++;
 143
 144         f->next = &throttled;
 145         if (q->time_next_delayed_flow > f->time_next_packet)
 146                 q->time_next_delayed_flow = f->time_next_packet;
 147 }
 148
 149
 150 static struct kmem_cache *fq_flow_cachep __read_mostly;
 151
 152 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
 153 {
 154         if (head->first)
 155                 head->last->next = flow;
 156         else
 157                 head->first = flow;
 158         head->last = flow;
 159         flow->next = NULL;
 160 }
 161
 162 /* limit number of collected flows per round */
 163 #define FQ_GC_MAX 8
 164 #define FQ_GC_AGE (3*HZ)
 165
 166 static bool fq_gc_candidate(const struct fq_flow *f)
 167 {
 168         return fq_flow_is_detached(f) &&
 169                time_after(jiffies, f->age + FQ_GC_AGE);
 170 }
 171
 172 static void fq_gc(struct fq_sched_data *q,
 173                   struct rb_root *root,
 174                   struct sock *sk)
 175 {
 176         struct fq_flow *f, *tofree[FQ_GC_MAX];
 177         struct rb_node **p, *parent;
 178         int fcnt = 0;
 179
 180         p = &root->rb_node;
 181         parent = NULL;
 182         while (*p) {
 183                 parent = *p;
 184
 185                 f = container_of(parent, struct fq_flow, fq_node);
 186                 if (f->sk == sk)
 187                         break;
 188
 189                 if (fq_gc_candidate(f)) {
 190                         tofree[fcnt++] = f;
 191                         if (fcnt == FQ_GC_MAX)
 192                                 break;
 193                 }
 194
 195                 if (f->sk > sk)
 196                         p = &parent->rb_right;
 197                 else
 198                         p = &parent->rb_left;
 199         }
 200
 201         q->flows -= fcnt;
 202         q->inactive_flows -= fcnt;
 203         q->stat_gc_flows += fcnt;
 204         while (fcnt) {
 205                 struct fq_flow *f = tofree[--fcnt];
 206
 207                 rb_erase(&f->fq_node, root);
 208                 kmem_cache_free(fq_flow_cachep, f);
 209         }
 210 }
 211
 212 static const u8 prio2band[TC_PRIO_MAX + 1] = {
 213         1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
 214 };
 215
 216 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 217 {
 218         struct rb_node **p, *parent;
 219         struct sock *sk = skb->sk;
 220         struct rb_root *root;
 221         struct fq_flow *f;
 222         int band;
 223
 224         /* warning: no starvation prevention... */
 225         band = prio2band[skb->priority & TC_PRIO_MAX];
 226         if (unlikely(band == 0))
 227                 return &q->internal;
 228
 229         if (unlikely(!sk)) {
 230                 /* By forcing low order bit to 1, we make sure to not
 231                  * collide with a local flow (socket pointers are word aligned)
 232                  */
 233                 sk = (struct sock *)(skb_get_rxhash(skb) | 1L);
 234         }
 235
 236         root = &q->fq_root[hash_32((u32)(long)sk, q->fq_trees_log)];
 237
 238         if (q->flows >= (2U << q->fq_trees_log) &&
 239             q->inactive_flows > q->flows/2)
 240                 fq_gc(q, root, sk);
 241
 242         p = &root->rb_node;
 243         parent = NULL;
 244         while (*p) {
 245                 parent = *p;
 246
 247                 f = container_of(parent, struct fq_flow, fq_node);
 248                 if (f->sk == sk) {
 249                         /* socket might have been reallocated, so check
 250                          * if its sk_hash is the same.
 251                          * It not, we need to refill credit with
 252                          * initial quantum
 253                          */
 254                         if (unlikely(skb->sk &&
 255                                      f->socket_hash != sk->sk_hash)) {
 256                                 f->credit = q->initial_quantum;
 257                                 f->socket_hash = sk->sk_hash;
 258                         }
 259                         return f;
 260                 }
 261                 if (f->sk > sk)
 262                         p = &parent->rb_right;
 263                 else
 264                         p = &parent->rb_left;
 265         }
 266
 267         f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
 268         if (unlikely(!f)) {
 269                 q->stat_allocation_errors++;
 270                 return &q->internal;
 271         }
 272         fq_flow_set_detached(f);
 273         f->sk = sk;
 274         if (skb->sk)
 275                 f->socket_hash = sk->sk_hash;
 276         f->credit = q->initial_quantum;
 277
 278         rb_link_node(&f->fq_node, parent, p);
 279         rb_insert_color(&f->fq_node, root);
 280
 281         q->flows++;
 282         q->inactive_flows++;
 283         return f;
 284 }
 285
 286
 287 /* remove one skb from head of flow queue */
 288 static struct sk_buff *fq_dequeue_head(struct fq_flow *flow)
 289 {
 290         struct sk_buff *skb = flow->head;
 291
 292         if (skb) {
 293                 flow->head = skb->next;
 294                 skb->next = NULL;
 295                 flow->qlen--;
 296         }
 297         return skb;
 298 }
 299
 300 /* We might add in the future detection of retransmits
 301  * For the time being, just return false
 302  */
 303 static bool skb_is_retransmit(struct sk_buff *skb)
 304 {
 305         return false;
 306 }
 307
 308 /* add skb to flow queue
 309  * flow queue is a linked list, kind of FIFO, except for TCP retransmits
 310  * We special case tcp retransmits to be transmitted before other packets.
 311  * We rely on fact that TCP retransmits are unlikely, so we do not waste
 312  * a separate queue or a pointer.
 313  * head->  [retrans pkt 1]
 314  *         [retrans pkt 2]
 315  *         [ normal pkt 1]
 316  *         [ normal pkt 2]
 317  *         [ normal pkt 3]
 318  * tail->  [ normal pkt 4]
 319  */
 320 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
 321 {
 322         struct sk_buff *prev, *head = flow->head;
 323
 324         skb->next = NULL;
 325         if (!head) {
 326                 flow->head = skb;
 327                 flow->tail = skb;
 328                 return;
 329         }
 330         if (likely(!skb_is_retransmit(skb))) {
 331                 flow->tail->next = skb;
 332                 flow->tail = skb;
 333                 return;
 334         }
 335
 336         /* This skb is a tcp retransmit,
 337          * find the last retrans packet in the queue
 338          */
 339         prev = NULL;
 340         while (skb_is_retransmit(head)) {
 341                 prev = head;
 342                 head = head->next;
 343                 if (!head)
 344                         break;
 345         }
 346         if (!prev) { /* no rtx packet in queue, become the new head */
 347                 skb->next = flow->head;
 348                 flow->head = skb;
 349         } else {
 350                 if (prev == flow->tail)
 351                         flow->tail = skb;
 352                 else
 353                         skb->next = prev->next;
 354                 prev->next = skb;
 355         }
 356 }
 357
 358 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 359 {
 360         struct fq_sched_data *q = qdisc_priv(sch);
 361         struct fq_flow *f;
 362
 363         if (unlikely(sch->q.qlen >= sch->limit))
 364                 return qdisc_drop(skb, sch);
 365
 366         f = fq_classify(skb, q);
 367         if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
 368                 q->stat_flows_plimit++;
 369                 return qdisc_drop(skb, sch);
 370         }
 371
 372         f->qlen++;
 373         flow_queue_add(f, skb);
 374         if (skb_is_retransmit(skb))
 375                 q->stat_tcp_retrans++;
 376         sch->qstats.backlog += qdisc_pkt_len(skb);
 377         if (fq_flow_is_detached(f)) {
 378                 fq_flow_add_tail(&q->new_flows, f);
 379                 if (q->quantum > f->credit)
 380                         f->credit = q->quantum;
 381                 q->inactive_flows--;
 382                 qdisc_unthrottled(sch);
 383         }
 384         if (unlikely(f == &q->internal)) {
 385                 q->stat_internal_packets++;
 386                 qdisc_unthrottled(sch);
 387         }
 388         sch->q.qlen++;
 389
 390         return NET_XMIT_SUCCESS;
 391 }
 392
 393 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
 394 {
 395         struct rb_node *p;
 396
 397         if (q->time_next_delayed_flow > now)
 398                 return;
 399
 400         q->time_next_delayed_flow = ~0ULL;
 401         while ((p = rb_first(&q->delayed)) != NULL) {
 402                 struct fq_flow *f = container_of(p, struct fq_flow, rate_node);
 403
 404                 if (f->time_next_packet > now) {
 405                         q->time_next_delayed_flow = f->time_next_packet;
 406                         break;
 407                 }
 408                 rb_erase(p, &q->delayed);
 409                 q->throttled_flows--;
 410                 fq_flow_add_tail(&q->old_flows, f);
 411         }
 412 }
 413
 414 static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 415 {
 416         struct fq_sched_data *q = qdisc_priv(sch);
 417         u64 now = ktime_to_ns(ktime_get());
 418         struct fq_flow_head *head;
 419         struct sk_buff *skb;
 420         struct fq_flow *f;
 421
 422         skb = fq_dequeue_head(&q->internal);
 423         if (skb)
 424                 goto out;
 425         fq_check_throttled(q, now);
 426 begin:
 427         head = &q->new_flows;
 428         if (!head->first) {
 429                 head = &q->old_flows;
 430                 if (!head->first) {
 431                         if (q->time_next_delayed_flow != ~0ULL)
 432                                 qdisc_watchdog_schedule_ns(&q->watchdog,
 433                                                            q->time_next_delayed_flow);
 434                         return NULL;
 435                 }
 436         }
 437         f = head->first;
 438
 439         if (f->credit <= 0) {
 440                 f->credit += q->quantum;
 441                 head->first = f->next;
 442                 fq_flow_add_tail(&q->old_flows, f);
 443                 goto begin;
 444         }
 445
 446         if (unlikely(f->head && now < f->time_next_packet)) {
 447                 head->first = f->next;
 448                 fq_flow_set_throttled(q, f);
 449                 goto begin;
 450         }
 451
 452         skb = fq_dequeue_head(f);
 453         if (!skb) {
 454                 head->first = f->next;
 455                 /* force a pass through old_flows to prevent starvation */
 456                 if ((head == &q->new_flows) && q->old_flows.first) {
 457                         fq_flow_add_tail(&q->old_flows, f);
 458                 } else {
 459                         fq_flow_set_detached(f);
 460                         f->age = jiffies;
 461                         q->inactive_flows++;
 462                 }
 463                 goto begin;
 464         }
 465         prefetch(&skb->end);
 466         f->time_next_packet = now;
 467         f->credit -= qdisc_pkt_len(skb);
 468
 469         if (f->credit <= 0 &&
 470             q->rate_enable &&
 471             skb->sk && skb->sk->sk_state != TCP_TIME_WAIT) {
 472                 u32 rate = skb->sk->sk_pacing_rate ?: q->flow_default_rate;
 473
 474                 rate = min(rate, q->flow_max_rate);
 475                 if (rate) {
 476                         u64 len = (u64)qdisc_pkt_len(skb) * NSEC_PER_SEC;
 477
 478                         do_div(len, rate);
 479                         /* Since socket rate can change later,
 480                          * clamp the delay to 125 ms.
 481                          * TODO: maybe segment the too big skb, as in commit
 482                          * e43ac79a4bc ("sch_tbf: segment too big GSO packets")
 483                          */
 484                         if (unlikely(len > 125 * NSEC_PER_MSEC)) {
 485                                 len = 125 * NSEC_PER_MSEC;
 486                                 q->stat_pkts_too_long++;
 487                         }
 488
 489                         f->time_next_packet = now + len;
 490                 }
 491         }
 492 out:
 493         sch->qstats.backlog -= qdisc_pkt_len(skb);
 494         qdisc_bstats_update(sch, skb);
 495         sch->q.qlen--;
 496         qdisc_unthrottled(sch);
 497         return skb;
 498 }
 499
 500 static void fq_reset(struct Qdisc *sch)
 501 {
 502         struct sk_buff *skb;
 503
 504         while ((skb = fq_dequeue(sch)) != NULL)
 505                 kfree_skb(skb);
 506 }
 507
 508 static void fq_rehash(struct fq_sched_data *q,
 509                       struct rb_root *old_array, u32 old_log,
 510                       struct rb_root *new_array, u32 new_log)
 511 {
 512         struct rb_node *op, **np, *parent;
 513         struct rb_root *oroot, *nroot;
 514         struct fq_flow *of, *nf;
 515         int fcnt = 0;
 516         u32 idx;
 517
 518         for (idx = 0; idx < (1U << old_log); idx++) {
 519                 oroot = &old_array[idx];
 520                 while ((op = rb_first(oroot)) != NULL) {
 521                         rb_erase(op, oroot);
 522                         of = container_of(op, struct fq_flow, fq_node);
 523                         if (fq_gc_candidate(of)) {
 524                                 fcnt++;
 525                                 kmem_cache_free(fq_flow_cachep, of);
 526                                 continue;
 527                         }
 528                         nroot = &new_array[hash_32((u32)(long)of->sk, new_log)];
 529
 530                         np = &nroot->rb_node;
 531                         parent = NULL;
 532                         while (*np) {
 533                                 parent = *np;
 534
 535                                 nf = container_of(parent, struct fq_flow, fq_node);
 536                                 BUG_ON(nf->sk == of->sk);
 537
 538                                 if (nf->sk > of->sk)
 539                                         np = &parent->rb_right;
 540                                 else
 541                                         np = &parent->rb_left;
 542                         }
 543
 544                         rb_link_node(&of->fq_node, parent, np);
 545                         rb_insert_color(&of->fq_node, nroot);
 546                 }
 547         }
 548         q->flows -= fcnt;
 549         q->inactive_flows -= fcnt;
 550         q->stat_gc_flows += fcnt;
 551 }
 552
 553 static int fq_resize(struct fq_sched_data *q, u32 log)
 554 {
 555         struct rb_root *array;
 556         u32 idx;
 557
 558         if (q->fq_root && log == q->fq_trees_log)
 559                 return 0;
 560
 561         array = kmalloc(sizeof(struct rb_root) << log, GFP_KERNEL);
 562         if (!array)
 563                 return -ENOMEM;
 564
 565         for (idx = 0; idx < (1U << log); idx++)
 566                 array[idx] = RB_ROOT;
 567
 568         if (q->fq_root) {
 569                 fq_rehash(q, q->fq_root, q->fq_trees_log, array, log);
 570                 kfree(q->fq_root);
 571         }
 572         q->fq_root = array;
 573         q->fq_trees_log = log;
 574
 575         return 0;
 576 }
 577
 578 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 579         [TCA_FQ_PLIMIT]                 = { .type = NLA_U32 },
 580         [TCA_FQ_FLOW_PLIMIT]            = { .type = NLA_U32 },
 581         [TCA_FQ_QUANTUM]                = { .type = NLA_U32 },
 582         [TCA_FQ_INITIAL_QUANTUM]        = { .type = NLA_U32 },
 583         [TCA_FQ_RATE_ENABLE]            = { .type = NLA_U32 },
 584         [TCA_FQ_FLOW_DEFAULT_RATE]      = { .type = NLA_U32 },
 585         [TCA_FQ_FLOW_MAX_RATE]          = { .type = NLA_U32 },
 586         [TCA_FQ_BUCKETS_LOG]            = { .type = NLA_U32 },
 587 };
 588
 589 static int fq_change(struct Qdisc *sch, struct nlattr *opt)
 590 {
 591         struct fq_sched_data *q = qdisc_priv(sch);
 592         struct nlattr *tb[TCA_FQ_MAX + 1];
 593         int err, drop_count = 0;
 594         u32 fq_log;
 595
 596         if (!opt)
 597                 return -EINVAL;
 598
 599         err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy);
 600         if (err < 0)
 601                 return err;
 602
 603         sch_tree_lock(sch);
 604
 605         fq_log = q->fq_trees_log;
 606
 607         if (tb[TCA_FQ_BUCKETS_LOG]) {
 608                 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
 609
 610                 if (nval >= 1 && nval <= ilog2(256*1024))
 611                         fq_log = nval;
 612                 else
 613                         err = -EINVAL;
 614         }
 615         if (tb[TCA_FQ_PLIMIT])
 616                 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
 617
 618         if (tb[TCA_FQ_FLOW_PLIMIT])
 619                 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
 620
 621         if (tb[TCA_FQ_QUANTUM])
 622                 q->quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 623
 624         if (tb[TCA_FQ_INITIAL_QUANTUM])
 625                 q->quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
 626
 627         if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 628                 q->flow_default_rate = nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]);
 629
 630         if (tb[TCA_FQ_FLOW_MAX_RATE])
 631                 q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 632
 633         if (tb[TCA_FQ_RATE_ENABLE]) {
 634                 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 635
 636                 if (enable <= 1)
 637                         q->rate_enable = enable;
 638                 else
 639                         err = -EINVAL;
 640         }
 641
 642         if (!err)
 643                 err = fq_resize(q, fq_log);
 644
 645         while (sch->q.qlen > sch->limit) {
 646                 struct sk_buff *skb = fq_dequeue(sch);
 647
 648                 kfree_skb(skb);
 649                 drop_count++;
 650         }
 651         qdisc_tree_decrease_qlen(sch, drop_count);
 652
 653         sch_tree_unlock(sch);
 654         return err;
 655 }
 656
 657 static void fq_destroy(struct Qdisc *sch)
 658 {
 659         struct fq_sched_data *q = qdisc_priv(sch);
 660         struct rb_root *root;
 661         struct rb_node *p;
 662         unsigned int idx;
 663
 664         if (q->fq_root) {
 665                 for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
 666                         root = &q->fq_root[idx];
 667                         while ((p = rb_first(root)) != NULL) {
 668                                 rb_erase(p, root);
 669                                 kmem_cache_free(fq_flow_cachep,
 670                                                 container_of(p, struct fq_flow, fq_node));
 671                         }
 672                 }
 673                 kfree(q->fq_root);
 674         }
 675         qdisc_watchdog_cancel(&q->watchdog);
 676 }
 677
 678 static int fq_init(struct Qdisc *sch, struct nlattr *opt)
 679 {
 680         struct fq_sched_data *q = qdisc_priv(sch);
 681         int err;
 682
 683         sch->limit              = 10000;
 684         q->flow_plimit          = 100;
 685         q->quantum              = 2 * psched_mtu(qdisc_dev(sch));
 686         q->initial_quantum      = 10 * psched_mtu(qdisc_dev(sch));
 687         q->flow_default_rate    = 0;
 688         q->flow_max_rate        = ~0U;
 689         q->rate_enable          = 1;
 690         q->new_flows.first      = NULL;
 691         q->old_flows.first      = NULL;
 692         q->delayed              = RB_ROOT;
 693         q->fq_root              = NULL;
 694         q->fq_trees_log         = ilog2(1024);
 695         qdisc_watchdog_init(&q->watchdog, sch);
 696
 697         if (opt)
 698                 err = fq_change(sch, opt);
 699         else
 700                 err = fq_resize(q, q->fq_trees_log);
 701
 702         return err;
 703 }
 704
 705 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 706 {
 707         struct fq_sched_data *q = qdisc_priv(sch);
 708         struct nlattr *opts;
 709
 710         opts = nla_nest_start(skb, TCA_OPTIONS);
 711         if (opts == NULL)
 712                 goto nla_put_failure;
 713
 714         if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
 715             nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
 716             nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
 717             nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
 718             nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
 719             nla_put_u32(skb, TCA_FQ_FLOW_DEFAULT_RATE, q->flow_default_rate) ||
 720             nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) ||
 721             nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 722                 goto nla_put_failure;
 723
 724         nla_nest_end(skb, opts);
 725         return skb->len;
 726
 727 nla_put_failure:
 728         return -1;
 729 }
 730
 731 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 732 {
 733         struct fq_sched_data *q = qdisc_priv(sch);
 734         u64 now = ktime_to_ns(ktime_get());
 735         struct tc_fq_qd_stats st = {
 736                 .gc_flows               = q->stat_gc_flows,
 737                 .highprio_packets       = q->stat_internal_packets,
 738                 .tcp_retrans            = q->stat_tcp_retrans,
 739                 .throttled              = q->stat_throttled,
 740                 .flows_plimit           = q->stat_flows_plimit,
 741                 .pkts_too_long          = q->stat_pkts_too_long,
 742                 .allocation_errors      = q->stat_allocation_errors,
 743                 .flows                  = q->flows,
 744                 .inactive_flows         = q->inactive_flows,
 745                 .throttled_flows        = q->throttled_flows,
 746                 .time_next_delayed_flow = q->time_next_delayed_flow - now,
 747         };
 748
 749         return gnet_stats_copy_app(d, &st, sizeof(st));
 750 }
 751
 752 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
 753         .id             =       "fq",
 754         .priv_size      =       sizeof(struct fq_sched_data),
 755
 756         .enqueue        =       fq_enqueue,
 757         .dequeue        =       fq_dequeue,
 758         .peek           =       qdisc_peek_dequeued,
 759         .init           =       fq_init,
 760         .reset          =       fq_reset,
 761         .destroy        =       fq_destroy,
 762         .change         =       fq_change,
 763         .dump           =       fq_dump,
 764         .dump_stats     =       fq_dump_stats,
 765         .owner          =       THIS_MODULE,
 766 };
 767
 768 static int __init fq_module_init(void)
 769 {
 770         int ret;
 771
 772         fq_flow_cachep = kmem_cache_create("fq_flow_cache",
 773                                            sizeof(struct fq_flow),
 774                                            0, 0, NULL);
 775         if (!fq_flow_cachep)
 776                 return -ENOMEM;
 777
 778         ret = register_qdisc(&fq_qdisc_ops);
 779         if (ret)
 780                 kmem_cache_destroy(fq_flow_cachep);
 781         return ret;
 782 }
 783
 784 static void __exit fq_module_exit(void)
 785 {
 786         unregister_qdisc(&fq_qdisc_ops);
 787         kmem_cache_destroy(fq_flow_cachep);
 788 }
 789
 790 module_init(fq_module_init)
 791 module_exit(fq_module_exit)
 792 MODULE_AUTHOR("Eric Dumazet");
 793 MODULE_LICENSE("GPL");