net/sched/sch_fq.c

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