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 <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
  56 /*
  57  * Per flow structure, dynamically allocated
  58  */
  59 struct fq_flow {
  60         struct sk_buff  *head;          /* list of skbs for this flow : first skb */
  61         union {
  62                 struct sk_buff *tail;   /* last skb in the list */
  63                 unsigned long  age;     /* jiffies when flow was emptied, for gc */
  64         };
  65         struct rb_node  fq_node;        /* anchor in fq_root[] trees */
  66         struct sock     *sk;
  67         int             qlen;           /* number of packets in flow queue */
  68         int             credit;
  69         u32             socket_hash;    /* sk_hash */
  70         struct fq_flow *next;           /* next pointer in RR lists, or &detached */
  71
  72         struct rb_node  rate_node;      /* anchor in q->delayed tree */
  73         u64             time_next_packet;
  74 };
  75
  76 struct fq_flow_head {
  77         struct fq_flow *first;
  78         struct fq_flow *last;
  79 };
  80
  81 struct fq_sched_data {
  82         struct fq_flow_head new_flows;
  83
  84         struct fq_flow_head old_flows;
  85
  86         struct rb_root  delayed;        /* for rate limited flows */
  87         u64             time_next_delayed_flow;
  88
  89         struct fq_flow  internal;       /* for non classified or high prio packets */
  90         u32             quantum;
  91         u32             initial_quantum;
  92         u32             flow_refill_delay;
  93         u32             flow_max_rate;  /* optional max rate per flow */
  94         u32             flow_plimit;    /* max packets per flow */
  95         struct rb_root  *fq_root;
  96         u8              rate_enable;
  97         u8              fq_trees_log;
  98
  99         u32             flows;
 100         u32             inactive_flows;
 101         u32             throttled_flows;
 102
 103         u64             stat_gc_flows;
 104         u64             stat_internal_packets;
 105         u64             stat_tcp_retrans;
 106         u64             stat_throttled;
 107         u64             stat_flows_plimit;
 108         u64             stat_pkts_too_long;
 109         u64             stat_allocation_errors;
 110         struct qdisc_watchdog watchdog;
 111 };
 112
 113 /* special value to mark a detached flow (not on old/new list) */
 114 static struct fq_flow detached, throttled;
 115
 116 static void fq_flow_set_detached(struct fq_flow *f)
 117 {
 118         f->next = &detached;
 119         f->age = jiffies;
 120 }
 121
 122 static bool fq_flow_is_detached(const struct fq_flow *f)
 123 {
 124         return f->next == &detached;
 125 }
 126
 127 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
 128 {
 129         struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
 130
 131         while (*p) {
 132                 struct fq_flow *aux;
 133
 134                 parent = *p;
 135                 aux = container_of(parent, struct fq_flow, rate_node);
 136                 if (f->time_next_packet >= aux->time_next_packet)
 137                         p = &parent->rb_right;
 138                 else
 139                         p = &parent->rb_left;
 140         }
 141         rb_link_node(&f->rate_node, parent, p);
 142         rb_insert_color(&f->rate_node, &q->delayed);
 143         q->throttled_flows++;
 144         q->stat_throttled++;
 145
 146         f->next = &throttled;
 147         if (q->time_next_delayed_flow > f->time_next_packet)
 148                 q->time_next_delayed_flow = f->time_next_packet;
 149 }
 150
 151
 152 static struct kmem_cache *fq_flow_cachep __read_mostly;
 153
 154 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
 155 {
 156         if (head->first)
 157                 head->last->next = flow;
 158         else
 159                 head->first = flow;
 160         head->last = flow;
 161         flow->next = NULL;
 162 }
 163
 164 /* limit number of collected flows per round */
 165 #define FQ_GC_MAX 8
 166 #define FQ_GC_AGE (3*HZ)
 167
 168 static bool fq_gc_candidate(const struct fq_flow *f)
 169 {
 170         return fq_flow_is_detached(f) &&
 171                time_after(jiffies, f->age + FQ_GC_AGE);
 172 }
 173
 174 static void fq_gc(struct fq_sched_data *q,
 175                   struct rb_root *root,
 176                   struct sock *sk)
 177 {
 178         struct fq_flow *f, *tofree[FQ_GC_MAX];
 179         struct rb_node **p, *parent;
 180         int fcnt = 0;
 181
 182         p = &root->rb_node;
 183         parent = NULL;
 184         while (*p) {
 185                 parent = *p;
 186
 187                 f = container_of(parent, struct fq_flow, fq_node);
 188                 if (f->sk == sk)
 189                         break;
 190
 191                 if (fq_gc_candidate(f)) {
 192                         tofree[fcnt++] = f;
 193                         if (fcnt == FQ_GC_MAX)
 194                                 break;
 195                 }
 196
 197                 if (f->sk > sk)
 198                         p = &parent->rb_right;
 199                 else
 200                         p = &parent->rb_left;
 201         }
 202
 203         q->flows -= fcnt;
 204         q->inactive_flows -= fcnt;
 205         q->stat_gc_flows += fcnt;
 206         while (fcnt) {
 207                 struct fq_flow *f = tofree[--fcnt];
 208
 209                 rb_erase(&f->fq_node, root);
 210                 kmem_cache_free(fq_flow_cachep, f);
 211         }
 212 }
 213
 214 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 215 {
 216         struct rb_node **p, *parent;
 217         struct sock *sk = skb->sk;
 218         struct rb_root *root;
 219         struct fq_flow *f;
 220
 221         /* warning: no starvation prevention... */
 222         if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
 223                 return &q->internal;
 224
 225         if (unlikely(!sk)) {
 226                 /* By forcing low order bit to 1, we make sure to not
 227                  * collide with a local flow (socket pointers are word aligned)
 228                  */
 229                 sk = (struct sock *)(skb_get_hash(skb) | 1L);
 230         }
 231
 232         root = &q->fq_root[hash_32((u32)(long)sk, q->fq_trees_log)];
 233
 234         if (q->flows >= (2U << q->fq_trees_log) &&
 235             q->inactive_flows > q->flows/2)
 236                 fq_gc(q, root, sk);
 237
 238         p = &root->rb_node;
 239         parent = NULL;
 240         while (*p) {
 241                 parent = *p;
 242
 243                 f = container_of(parent, struct fq_flow, fq_node);
 244                 if (f->sk == sk) {
 245                         /* socket might have been reallocated, so check
 246                          * if its sk_hash is the same.
 247                          * It not, we need to refill credit with
 248                          * initial quantum
 249                          */
 250                         if (unlikely(skb->sk &&
 251                                      f->socket_hash != sk->sk_hash)) {
 252                                 f->credit = q->initial_quantum;
 253                                 f->socket_hash = sk->sk_hash;
 254                                 f->time_next_packet = 0ULL;
 255                         }
 256                         return f;
 257                 }
 258                 if (f->sk > sk)
 259                         p = &parent->rb_right;
 260                 else
 261                         p = &parent->rb_left;
 262         }
 263
 264         f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
 265         if (unlikely(!f)) {
 266                 q->stat_allocation_errors++;
 267                 return &q->internal;
 268         }
 269         fq_flow_set_detached(f);
 270         f->sk = sk;
 271         if (skb->sk)
 272                 f->socket_hash = sk->sk_hash;
 273         f->credit = q->initial_quantum;
 274
 275         rb_link_node(&f->fq_node, parent, p);
 276         rb_insert_color(&f->fq_node, root);
 277
 278         q->flows++;
 279         q->inactive_flows++;
 280         return f;
 281 }
 282
 283
 284 /* remove one skb from head of flow queue */
 285 static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
 286 {
 287         struct sk_buff *skb = flow->head;
 288
 289         if (skb) {
 290                 flow->head = skb->next;
 291                 skb->next = NULL;
 292                 flow->qlen--;
 293                 qdisc_qstats_backlog_dec(sch, skb);
 294                 sch->q.qlen--;
 295         }
 296         return skb;
 297 }
 298
 299 /* We might add in the future detection of retransmits
 300  * For the time being, just return false
 301  */
 302 static bool skb_is_retransmit(struct sk_buff *skb)
 303 {
 304         return false;
 305 }
 306
 307 /* add skb to flow queue
 308  * flow queue is a linked list, kind of FIFO, except for TCP retransmits
 309  * We special case tcp retransmits to be transmitted before other packets.
 310  * We rely on fact that TCP retransmits are unlikely, so we do not waste
 311  * a separate queue or a pointer.
 312  * head->  [retrans pkt 1]
 313  *         [retrans pkt 2]
 314  *         [ normal pkt 1]
 315  *         [ normal pkt 2]
 316  *         [ normal pkt 3]
 317  * tail->  [ normal pkt 4]
 318  */
 319 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
 320 {
 321         struct sk_buff *prev, *head = flow->head;
 322
 323         skb->next = NULL;
 324         if (!head) {
 325                 flow->head = skb;
 326                 flow->tail = skb;
 327                 return;
 328         }
 329         if (likely(!skb_is_retransmit(skb))) {
 330                 flow->tail->next = skb;
 331                 flow->tail = skb;
 332                 return;
 333         }
 334
 335         /* This skb is a tcp retransmit,
 336          * find the last retrans packet in the queue
 337          */
 338         prev = NULL;
 339         while (skb_is_retransmit(head)) {
 340                 prev = head;
 341                 head = head->next;
 342                 if (!head)
 343                         break;
 344         }
 345         if (!prev) { /* no rtx packet in queue, become the new head */
 346                 skb->next = flow->head;
 347                 flow->head = skb;
 348         } else {
 349                 if (prev == flow->tail)
 350                         flow->tail = skb;
 351                 else
 352                         skb->next = prev->next;
 353                 prev->next = skb;
 354         }
 355 }
 356
 357 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 358 {
 359         struct fq_sched_data *q = qdisc_priv(sch);
 360         struct fq_flow *f;
 361
 362         if (unlikely(sch->q.qlen >= sch->limit))
 363                 return qdisc_drop(skb, sch);
 364
 365         f = fq_classify(skb, q);
 366         if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
 367                 q->stat_flows_plimit++;
 368                 return qdisc_drop(skb, sch);
 369         }
 370
 371         f->qlen++;
 372         if (skb_is_retransmit(skb))
 373                 q->stat_tcp_retrans++;
 374         qdisc_qstats_backlog_inc(sch, skb);
 375         if (fq_flow_is_detached(f)) {
 376                 fq_flow_add_tail(&q->new_flows, f);
 377                 if (time_after(jiffies, f->age + q->flow_refill_delay))
 378                         f->credit = max_t(u32, f->credit, q->quantum);
 379                 q->inactive_flows--;
 380         }
 381
 382         /* Note: this overwrites f->age */
 383         flow_queue_add(f, skb);
 384
 385         if (unlikely(f == &q->internal)) {
 386                 q->stat_internal_packets++;
 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_get_ns();
 418         struct fq_flow_head *head;
 419         struct sk_buff *skb;
 420         struct fq_flow *f;
 421         u32 rate;
 422
 423         skb = fq_dequeue_head(sch, &q->internal);
 424         if (skb)
 425                 goto out;
 426         fq_check_throttled(q, now);
 427 begin:
 428         head = &q->new_flows;
 429         if (!head->first) {
 430                 head = &q->old_flows;
 431                 if (!head->first) {
 432                         if (q->time_next_delayed_flow != ~0ULL)
 433                                 qdisc_watchdog_schedule_ns(&q->watchdog,
 434                                                            q->time_next_delayed_flow,
 435                                                            false);
 436                         return NULL;
 437                 }
 438         }
 439         f = head->first;
 440
 441         if (f->credit <= 0) {
 442                 f->credit += q->quantum;
 443                 head->first = f->next;
 444                 fq_flow_add_tail(&q->old_flows, f);
 445                 goto begin;
 446         }
 447
 448         if (unlikely(f->head && now < f->time_next_packet)) {
 449                 head->first = f->next;
 450                 fq_flow_set_throttled(q, f);
 451                 goto begin;
 452         }
 453
 454         skb = fq_dequeue_head(sch, f);
 455         if (!skb) {
 456                 head->first = f->next;
 457                 /* force a pass through old_flows to prevent starvation */
 458                 if ((head == &q->new_flows) && q->old_flows.first) {
 459                         fq_flow_add_tail(&q->old_flows, f);
 460                 } else {
 461                         fq_flow_set_detached(f);
 462                         q->inactive_flows++;
 463                 }
 464                 goto begin;
 465         }
 466         prefetch(&skb->end);
 467         f->time_next_packet = now;
 468         f->credit -= qdisc_pkt_len(skb);
 469
 470         if (f->credit > 0 || !q->rate_enable)
 471                 goto out;
 472
 473         rate = q->flow_max_rate;
 474         if (skb->sk && skb->sk->sk_state != TCP_TIME_WAIT)
 475                 rate = min(skb->sk->sk_pacing_rate, rate);
 476
 477         if (rate != ~0U) {
 478                 u32 plen = max(qdisc_pkt_len(skb), q->quantum);
 479                 u64 len = (u64)plen * NSEC_PER_SEC;
 480
 481                 if (likely(rate))
 482                         do_div(len, rate);
 483                 /* Since socket rate can change later,
 484                  * clamp the delay to 1 second.
 485                  * Really, providers of too big packets should be fixed !
 486                  */
 487                 if (unlikely(len > NSEC_PER_SEC)) {
 488                         len = NSEC_PER_SEC;
 489                         q->stat_pkts_too_long++;
 490                 }
 491
 492                 f->time_next_packet = now + len;
 493         }
 494 out:
 495         qdisc_bstats_update(sch, skb);
 496         return skb;
 497 }
 498
 499 static void fq_reset(struct Qdisc *sch)
 500 {
 501         struct fq_sched_data *q = qdisc_priv(sch);
 502         struct rb_root *root;
 503         struct sk_buff *skb;
 504         struct rb_node *p;
 505         struct fq_flow *f;
 506         unsigned int idx;
 507
 508         while ((skb = fq_dequeue_head(sch, &q->internal)) != NULL)
 509                 kfree_skb(skb);
 510
 511         if (!q->fq_root)
 512                 return;
 513
 514         for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
 515                 root = &q->fq_root[idx];
 516                 while ((p = rb_first(root)) != NULL) {
 517                         f = container_of(p, struct fq_flow, fq_node);
 518                         rb_erase(p, root);
 519
 520                         while ((skb = fq_dequeue_head(sch, f)) != NULL)
 521                                 kfree_skb(skb);
 522
 523                         kmem_cache_free(fq_flow_cachep, f);
 524                 }
 525         }
 526         q->new_flows.first      = NULL;
 527         q->old_flows.first      = NULL;
 528         q->delayed              = RB_ROOT;
 529         q->flows                = 0;
 530         q->inactive_flows       = 0;
 531         q->throttled_flows      = 0;
 532 }
 533
 534 static void fq_rehash(struct fq_sched_data *q,
 535                       struct rb_root *old_array, u32 old_log,
 536                       struct rb_root *new_array, u32 new_log)
 537 {
 538         struct rb_node *op, **np, *parent;
 539         struct rb_root *oroot, *nroot;
 540         struct fq_flow *of, *nf;
 541         int fcnt = 0;
 542         u32 idx;
 543
 544         for (idx = 0; idx < (1U << old_log); idx++) {
 545                 oroot = &old_array[idx];
 546                 while ((op = rb_first(oroot)) != NULL) {
 547                         rb_erase(op, oroot);
 548                         of = container_of(op, struct fq_flow, fq_node);
 549                         if (fq_gc_candidate(of)) {
 550                                 fcnt++;
 551                                 kmem_cache_free(fq_flow_cachep, of);
 552                                 continue;
 553                         }
 554                         nroot = &new_array[hash_32((u32)(long)of->sk, new_log)];
 555
 556                         np = &nroot->rb_node;
 557                         parent = NULL;
 558                         while (*np) {
 559                                 parent = *np;
 560
 561                                 nf = container_of(parent, struct fq_flow, fq_node);
 562                                 BUG_ON(nf->sk == of->sk);
 563
 564                                 if (nf->sk > of->sk)
 565                                         np = &parent->rb_right;
 566                                 else
 567                                         np = &parent->rb_left;
 568                         }
 569
 570                         rb_link_node(&of->fq_node, parent, np);
 571                         rb_insert_color(&of->fq_node, nroot);
 572                 }
 573         }
 574         q->flows -= fcnt;
 575         q->inactive_flows -= fcnt;
 576         q->stat_gc_flows += fcnt;
 577 }
 578
 579 static void *fq_alloc_node(size_t sz, int node)
 580 {
 581         void *ptr;
 582
 583         ptr = kmalloc_node(sz, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN, node);
 584         if (!ptr)
 585                 ptr = vmalloc_node(sz, node);
 586         return ptr;
 587 }
 588
 589 static void fq_free(void *addr)
 590 {
 591         kvfree(addr);
 592 }
 593
 594 static int fq_resize(struct Qdisc *sch, u32 log)
 595 {
 596         struct fq_sched_data *q = qdisc_priv(sch);
 597         struct rb_root *array;
 598         void *old_fq_root;
 599         u32 idx;
 600
 601         if (q->fq_root && log == q->fq_trees_log)
 602                 return 0;
 603
 604         /* If XPS was setup, we can allocate memory on right NUMA node */
 605         array = fq_alloc_node(sizeof(struct rb_root) << log,
 606                               netdev_queue_numa_node_read(sch->dev_queue));
 607         if (!array)
 608                 return -ENOMEM;
 609
 610         for (idx = 0; idx < (1U << log); idx++)
 611                 array[idx] = RB_ROOT;
 612
 613         sch_tree_lock(sch);
 614
 615         old_fq_root = q->fq_root;
 616         if (old_fq_root)
 617                 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
 618
 619         q->fq_root = array;
 620         q->fq_trees_log = log;
 621
 622         sch_tree_unlock(sch);
 623
 624         fq_free(old_fq_root);
 625
 626         return 0;
 627 }
 628
 629 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 630         [TCA_FQ_PLIMIT]                 = { .type = NLA_U32 },
 631         [TCA_FQ_FLOW_PLIMIT]            = { .type = NLA_U32 },
 632         [TCA_FQ_QUANTUM]                = { .type = NLA_U32 },
 633         [TCA_FQ_INITIAL_QUANTUM]        = { .type = NLA_U32 },
 634         [TCA_FQ_RATE_ENABLE]            = { .type = NLA_U32 },
 635         [TCA_FQ_FLOW_DEFAULT_RATE]      = { .type = NLA_U32 },
 636         [TCA_FQ_FLOW_MAX_RATE]          = { .type = NLA_U32 },
 637         [TCA_FQ_BUCKETS_LOG]            = { .type = NLA_U32 },
 638         [TCA_FQ_FLOW_REFILL_DELAY]      = { .type = NLA_U32 },
 639 };
 640
 641 static int fq_change(struct Qdisc *sch, struct nlattr *opt)
 642 {
 643         struct fq_sched_data *q = qdisc_priv(sch);
 644         struct nlattr *tb[TCA_FQ_MAX + 1];
 645         int err, drop_count = 0;
 646         u32 fq_log;
 647
 648         if (!opt)
 649                 return -EINVAL;
 650
 651         err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy);
 652         if (err < 0)
 653                 return err;
 654
 655         sch_tree_lock(sch);
 656
 657         fq_log = q->fq_trees_log;
 658
 659         if (tb[TCA_FQ_BUCKETS_LOG]) {
 660                 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
 661
 662                 if (nval >= 1 && nval <= ilog2(256*1024))
 663                         fq_log = nval;
 664                 else
 665                         err = -EINVAL;
 666         }
 667         if (tb[TCA_FQ_PLIMIT])
 668                 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
 669
 670         if (tb[TCA_FQ_FLOW_PLIMIT])
 671                 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
 672
 673         if (tb[TCA_FQ_QUANTUM]) {
 674                 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 675
 676                 if (quantum > 0)
 677                         q->quantum = quantum;
 678                 else
 679                         err = -EINVAL;
 680         }
 681
 682         if (tb[TCA_FQ_INITIAL_QUANTUM])
 683                 q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
 684
 685         if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 686                 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
 687                                     nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
 688
 689         if (tb[TCA_FQ_FLOW_MAX_RATE])
 690                 q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 691
 692         if (tb[TCA_FQ_RATE_ENABLE]) {
 693                 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 694
 695                 if (enable <= 1)
 696                         q->rate_enable = enable;
 697                 else
 698                         err = -EINVAL;
 699         }
 700
 701         if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
 702                 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
 703
 704                 q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
 705         }
 706
 707         if (!err) {
 708                 sch_tree_unlock(sch);
 709                 err = fq_resize(sch, fq_log);
 710                 sch_tree_lock(sch);
 711         }
 712         while (sch->q.qlen > sch->limit) {
 713                 struct sk_buff *skb = fq_dequeue(sch);
 714
 715                 if (!skb)
 716                         break;
 717                 kfree_skb(skb);
 718                 drop_count++;
 719         }
 720         qdisc_tree_decrease_qlen(sch, drop_count);
 721
 722         sch_tree_unlock(sch);
 723         return err;
 724 }
 725
 726 static void fq_destroy(struct Qdisc *sch)
 727 {
 728         struct fq_sched_data *q = qdisc_priv(sch);
 729
 730         fq_reset(sch);
 731         fq_free(q->fq_root);
 732         qdisc_watchdog_cancel(&q->watchdog);
 733 }
 734
 735 static int fq_init(struct Qdisc *sch, struct nlattr *opt)
 736 {
 737         struct fq_sched_data *q = qdisc_priv(sch);
 738         int err;
 739
 740         sch->limit              = 10000;
 741         q->flow_plimit          = 100;
 742         q->quantum              = 2 * psched_mtu(qdisc_dev(sch));
 743         q->initial_quantum      = 10 * psched_mtu(qdisc_dev(sch));
 744         q->flow_refill_delay    = msecs_to_jiffies(40);
 745         q->flow_max_rate        = ~0U;
 746         q->rate_enable          = 1;
 747         q->new_flows.first      = NULL;
 748         q->old_flows.first      = NULL;
 749         q->delayed              = RB_ROOT;
 750         q->fq_root              = NULL;
 751         q->fq_trees_log         = ilog2(1024);
 752         qdisc_watchdog_init(&q->watchdog, sch);
 753
 754         if (opt)
 755                 err = fq_change(sch, opt);
 756         else
 757                 err = fq_resize(sch, q->fq_trees_log);
 758
 759         return err;
 760 }
 761
 762 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 763 {
 764         struct fq_sched_data *q = qdisc_priv(sch);
 765         struct nlattr *opts;
 766
 767         opts = nla_nest_start(skb, TCA_OPTIONS);
 768         if (opts == NULL)
 769                 goto nla_put_failure;
 770
 771         /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
 772
 773         if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
 774             nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
 775             nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
 776             nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
 777             nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
 778             nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) ||
 779             nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
 780                         jiffies_to_usecs(q->flow_refill_delay)) ||
 781             nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 782                 goto nla_put_failure;
 783
 784         return nla_nest_end(skb, opts);
 785
 786 nla_put_failure:
 787         return -1;
 788 }
 789
 790 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 791 {
 792         struct fq_sched_data *q = qdisc_priv(sch);
 793         u64 now = ktime_get_ns();
 794         struct tc_fq_qd_stats st = {
 795                 .gc_flows               = q->stat_gc_flows,
 796                 .highprio_packets       = q->stat_internal_packets,
 797                 .tcp_retrans            = q->stat_tcp_retrans,
 798                 .throttled              = q->stat_throttled,
 799                 .flows_plimit           = q->stat_flows_plimit,
 800                 .pkts_too_long          = q->stat_pkts_too_long,
 801                 .allocation_errors      = q->stat_allocation_errors,
 802                 .flows                  = q->flows,
 803                 .inactive_flows         = q->inactive_flows,
 804                 .throttled_flows        = q->throttled_flows,
 805                 .time_next_delayed_flow = q->time_next_delayed_flow - now,
 806         };
 807
 808         return gnet_stats_copy_app(d, &st, sizeof(st));
 809 }
 810
 811 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
 812         .id             =       "fq",
 813         .priv_size      =       sizeof(struct fq_sched_data),
 814
 815         .enqueue        =       fq_enqueue,
 816         .dequeue        =       fq_dequeue,
 817         .peek           =       qdisc_peek_dequeued,
 818         .init           =       fq_init,
 819         .reset          =       fq_reset,
 820         .destroy        =       fq_destroy,
 821         .change         =       fq_change,
 822         .dump           =       fq_dump,
 823         .dump_stats     =       fq_dump_stats,
 824         .owner          =       THIS_MODULE,
 825 };
 826
 827 static int __init fq_module_init(void)
 828 {
 829         int ret;
 830
 831         fq_flow_cachep = kmem_cache_create("fq_flow_cache",
 832                                            sizeof(struct fq_flow),
 833                                            0, 0, NULL);
 834         if (!fq_flow_cachep)
 835                 return -ENOMEM;
 836
 837         ret = register_qdisc(&fq_qdisc_ops);
 838         if (ret)
 839                 kmem_cache_destroy(fq_flow_cachep);
 840         return ret;
 841 }
 842
 843 static void __exit fq_module_exit(void)
 844 {
 845         unregister_qdisc(&fq_qdisc_ops);
 846         kmem_cache_destroy(fq_flow_cachep);
 847 }
 848
 849 module_init(fq_module_init)
 850 module_exit(fq_module_exit)
 851 MODULE_AUTHOR("Eric Dumazet");
 852 MODULE_LICENSE("GPL");