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_plimit;    /* max packets per flow */
  96         unsigned long   flow_max_rate;  /* optional max rate per flow */
  97         u64             ce_threshold;
  98         u32             orphan_mask;    /* mask for orphaned skb */
  99         u32             low_rate_threshold;
 100         struct rb_root  *fq_root;
 101         u8              rate_enable;
 102         u8              fq_trees_log;
 103
 104         u32             flows;
 105         u32             inactive_flows;
 106         u32             throttled_flows;
 107
 108         u64             stat_gc_flows;
 109         u64             stat_internal_packets;
 110         u64             stat_throttled;
 111         u64             stat_ce_mark;
 112         u64             stat_flows_plimit;
 113         u64             stat_pkts_too_long;
 114         u64             stat_allocation_errors;
 115         struct qdisc_watchdog watchdog;
 116 };
 117
 118 /* special value to mark a detached flow (not on old/new list) */
 119 static struct fq_flow detached, throttled;
 120
 121 static void fq_flow_set_detached(struct fq_flow *f)
 122 {
 123         f->next = &detached;
 124         f->age = jiffies;
 125 }
 126
 127 static bool fq_flow_is_detached(const struct fq_flow *f)
 128 {
 129         return f->next == &detached;
 130 }
 131
 132 static bool fq_flow_is_throttled(const struct fq_flow *f)
 133 {
 134         return f->next == &throttled;
 135 }
 136
 137 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
 138 {
 139         if (head->first)
 140                 head->last->next = flow;
 141         else
 142                 head->first = flow;
 143         head->last = flow;
 144         flow->next = NULL;
 145 }
 146
 147 static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)
 148 {
 149         rb_erase(&f->rate_node, &q->delayed);
 150         q->throttled_flows--;
 151         fq_flow_add_tail(&q->old_flows, f);
 152 }
 153
 154 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
 155 {
 156         struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
 157
 158         while (*p) {
 159                 struct fq_flow *aux;
 160
 161                 parent = *p;
 162                 aux = rb_entry(parent, struct fq_flow, rate_node);
 163                 if (f->time_next_packet >= aux->time_next_packet)
 164                         p = &parent->rb_right;
 165                 else
 166                         p = &parent->rb_left;
 167         }
 168         rb_link_node(&f->rate_node, parent, p);
 169         rb_insert_color(&f->rate_node, &q->delayed);
 170         q->throttled_flows++;
 171         q->stat_throttled++;
 172
 173         f->next = &throttled;
 174         if (q->time_next_delayed_flow > f->time_next_packet)
 175                 q->time_next_delayed_flow = f->time_next_packet;
 176 }
 177
 178
 179 static struct kmem_cache *fq_flow_cachep __read_mostly;
 180
 181
 182 /* limit number of collected flows per round */
 183 #define FQ_GC_MAX 8
 184 #define FQ_GC_AGE (3*HZ)
 185
 186 static bool fq_gc_candidate(const struct fq_flow *f)
 187 {
 188         return fq_flow_is_detached(f) &&
 189                time_after(jiffies, f->age + FQ_GC_AGE);
 190 }
 191
 192 static void fq_gc(struct fq_sched_data *q,
 193                   struct rb_root *root,
 194                   struct sock *sk)
 195 {
 196         struct fq_flow *f, *tofree[FQ_GC_MAX];
 197         struct rb_node **p, *parent;
 198         int fcnt = 0;
 199
 200         p = &root->rb_node;
 201         parent = NULL;
 202         while (*p) {
 203                 parent = *p;
 204
 205                 f = rb_entry(parent, struct fq_flow, fq_node);
 206                 if (f->sk == sk)
 207                         break;
 208
 209                 if (fq_gc_candidate(f)) {
 210                         tofree[fcnt++] = f;
 211                         if (fcnt == FQ_GC_MAX)
 212                                 break;
 213                 }
 214
 215                 if (f->sk > sk)
 216                         p = &parent->rb_right;
 217                 else
 218                         p = &parent->rb_left;
 219         }
 220
 221         q->flows -= fcnt;
 222         q->inactive_flows -= fcnt;
 223         q->stat_gc_flows += fcnt;
 224         while (fcnt) {
 225                 struct fq_flow *f = tofree[--fcnt];
 226
 227                 rb_erase(&f->fq_node, root);
 228                 kmem_cache_free(fq_flow_cachep, f);
 229         }
 230 }
 231
 232 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 233 {
 234         struct rb_node **p, *parent;
 235         struct sock *sk = skb->sk;
 236         struct rb_root *root;
 237         struct fq_flow *f;
 238
 239         /* warning: no starvation prevention... */
 240         if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
 241                 return &q->internal;
 242
 243         /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
 244          * or a listener (SYNCOOKIE mode)
 245          * 1) request sockets are not full blown,
 246          *    they do not contain sk_pacing_rate
 247          * 2) They are not part of a 'flow' yet
 248          * 3) We do not want to rate limit them (eg SYNFLOOD attack),
 249          *    especially if the listener set SO_MAX_PACING_RATE
 250          * 4) We pretend they are orphaned
 251          */
 252         if (!sk || sk_listener(sk)) {
 253                 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
 254
 255                 /* By forcing low order bit to 1, we make sure to not
 256                  * collide with a local flow (socket pointers are word aligned)
 257                  */
 258                 sk = (struct sock *)((hash << 1) | 1UL);
 259                 skb_orphan(skb);
 260         }
 261
 262         root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)];
 263
 264         if (q->flows >= (2U << q->fq_trees_log) &&
 265             q->inactive_flows > q->flows/2)
 266                 fq_gc(q, root, sk);
 267
 268         p = &root->rb_node;
 269         parent = NULL;
 270         while (*p) {
 271                 parent = *p;
 272
 273                 f = rb_entry(parent, struct fq_flow, fq_node);
 274                 if (f->sk == sk) {
 275                         /* socket might have been reallocated, so check
 276                          * if its sk_hash is the same.
 277                          * It not, we need to refill credit with
 278                          * initial quantum
 279                          */
 280                         if (unlikely(skb->sk &&
 281                                      f->socket_hash != sk->sk_hash)) {
 282                                 f->credit = q->initial_quantum;
 283                                 f->socket_hash = sk->sk_hash;
 284                                 if (fq_flow_is_throttled(f))
 285                                         fq_flow_unset_throttled(q, f);
 286                                 f->time_next_packet = 0ULL;
 287                         }
 288                         return f;
 289                 }
 290                 if (f->sk > sk)
 291                         p = &parent->rb_right;
 292                 else
 293                         p = &parent->rb_left;
 294         }
 295
 296         f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
 297         if (unlikely(!f)) {
 298                 q->stat_allocation_errors++;
 299                 return &q->internal;
 300         }
 301         fq_flow_set_detached(f);
 302         f->sk = sk;
 303         if (skb->sk)
 304                 f->socket_hash = sk->sk_hash;
 305         f->credit = q->initial_quantum;
 306
 307         rb_link_node(&f->fq_node, parent, p);
 308         rb_insert_color(&f->fq_node, root);
 309
 310         q->flows++;
 311         q->inactive_flows++;
 312         return f;
 313 }
 314
 315
 316 /* remove one skb from head of flow queue */
 317 static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
 318 {
 319         struct sk_buff *skb = flow->head;
 320
 321         if (skb) {
 322                 flow->head = skb->next;
 323                 skb_mark_not_on_list(skb);
 324                 flow->qlen--;
 325                 qdisc_qstats_backlog_dec(sch, skb);
 326                 sch->q.qlen--;
 327         }
 328         return skb;
 329 }
 330
 331 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
 332 {
 333         struct sk_buff *head = flow->head;
 334
 335         skb->next = NULL;
 336         if (!head)
 337                 flow->head = skb;
 338         else
 339                 flow->tail->next = skb;
 340
 341         flow->tail = skb;
 342 }
 343
 344 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 345                       struct sk_buff **to_free)
 346 {
 347         struct fq_sched_data *q = qdisc_priv(sch);
 348         struct fq_flow *f;
 349
 350         if (unlikely(sch->q.qlen >= sch->limit))
 351                 return qdisc_drop(skb, sch, to_free);
 352
 353         f = fq_classify(skb, q);
 354         if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
 355                 q->stat_flows_plimit++;
 356                 return qdisc_drop(skb, sch, to_free);
 357         }
 358
 359         f->qlen++;
 360         qdisc_qstats_backlog_inc(sch, skb);
 361         if (fq_flow_is_detached(f)) {
 362                 struct sock *sk = skb->sk;
 363
 364                 fq_flow_add_tail(&q->new_flows, f);
 365                 if (time_after(jiffies, f->age + q->flow_refill_delay))
 366                         f->credit = max_t(u32, f->credit, q->quantum);
 367                 if (sk && q->rate_enable) {
 368                         if (unlikely(smp_load_acquire(&sk->sk_pacing_status) !=
 369                                      SK_PACING_FQ))
 370                                 smp_store_release(&sk->sk_pacing_status,
 371                                                   SK_PACING_FQ);
 372                 }
 373                 q->inactive_flows--;
 374         }
 375
 376         /* Note: this overwrites f->age */
 377         flow_queue_add(f, skb);
 378
 379         if (unlikely(f == &q->internal)) {
 380                 q->stat_internal_packets++;
 381         }
 382         sch->q.qlen++;
 383
 384         return NET_XMIT_SUCCESS;
 385 }
 386
 387 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
 388 {
 389         unsigned long sample;
 390         struct rb_node *p;
 391
 392         if (q->time_next_delayed_flow > now)
 393                 return;
 394
 395         /* Update unthrottle latency EWMA.
 396          * This is cheap and can help diagnosing timer/latency problems.
 397          */
 398         sample = (unsigned long)(now - q->time_next_delayed_flow);
 399         q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
 400         q->unthrottle_latency_ns += sample >> 3;
 401
 402         q->time_next_delayed_flow = ~0ULL;
 403         while ((p = rb_first(&q->delayed)) != NULL) {
 404                 struct fq_flow *f = rb_entry(p, struct fq_flow, rate_node);
 405
 406                 if (f->time_next_packet > now) {
 407                         q->time_next_delayed_flow = f->time_next_packet;
 408                         break;
 409                 }
 410                 fq_flow_unset_throttled(q, 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         struct fq_flow_head *head;
 418         struct sk_buff *skb;
 419         struct fq_flow *f;
 420         unsigned long rate;
 421         u32 plen;
 422         u64 now;
 423
 424         if (!sch->q.qlen)
 425                 return NULL;
 426
 427         skb = fq_dequeue_head(sch, &q->internal);
 428         if (skb)
 429                 goto out;
 430
 431         now = ktime_get_ns();
 432         fq_check_throttled(q, now);
 433 begin:
 434         head = &q->new_flows;
 435         if (!head->first) {
 436                 head = &q->old_flows;
 437                 if (!head->first) {
 438                         if (q->time_next_delayed_flow != ~0ULL)
 439                                 qdisc_watchdog_schedule_ns(&q->watchdog,
 440                                                            q->time_next_delayed_flow);
 441                         return NULL;
 442                 }
 443         }
 444         f = head->first;
 445
 446         if (f->credit <= 0) {
 447                 f->credit += q->quantum;
 448                 head->first = f->next;
 449                 fq_flow_add_tail(&q->old_flows, f);
 450                 goto begin;
 451         }
 452
 453         skb = f->head;
 454         if (skb) {
 455                 u64 time_next_packet = max_t(u64, ktime_to_ns(skb->tstamp),
 456                                              f->time_next_packet);
 457
 458                 if (now < time_next_packet) {
 459                         head->first = f->next;
 460                         f->time_next_packet = time_next_packet;
 461                         fq_flow_set_throttled(q, f);
 462                         goto begin;
 463                 }
 464                 if (time_next_packet &&
 465                     (s64)(now - time_next_packet - q->ce_threshold) > 0) {
 466                         INET_ECN_set_ce(skb);
 467                         q->stat_ce_mark++;
 468                 }
 469         }
 470
 471         skb = fq_dequeue_head(sch, f);
 472         if (!skb) {
 473                 head->first = f->next;
 474                 /* force a pass through old_flows to prevent starvation */
 475                 if ((head == &q->new_flows) && q->old_flows.first) {
 476                         fq_flow_add_tail(&q->old_flows, f);
 477                 } else {
 478                         fq_flow_set_detached(f);
 479                         q->inactive_flows++;
 480                 }
 481                 goto begin;
 482         }
 483         prefetch(&skb->end);
 484         plen = qdisc_pkt_len(skb);
 485         f->credit -= plen;
 486
 487         if (!q->rate_enable)
 488                 goto out;
 489
 490         rate = q->flow_max_rate;
 491
 492         /* If EDT time was provided for this skb, we need to
 493          * update f->time_next_packet only if this qdisc enforces
 494          * a flow max rate.
 495          */
 496         if (!skb->tstamp) {
 497                 if (skb->sk)
 498                         rate = min(skb->sk->sk_pacing_rate, rate);
 499
 500                 if (rate <= q->low_rate_threshold) {
 501                         f->credit = 0;
 502                 } else {
 503                         plen = max(plen, q->quantum);
 504                         if (f->credit > 0)
 505                                 goto out;
 506                 }
 507         }
 508         if (rate != ~0UL) {
 509                 u64 len = (u64)plen * NSEC_PER_SEC;
 510
 511                 if (likely(rate))
 512                         len = div64_ul(len, rate);
 513                 /* Since socket rate can change later,
 514                  * clamp the delay to 1 second.
 515                  * Really, providers of too big packets should be fixed !
 516                  */
 517                 if (unlikely(len > NSEC_PER_SEC)) {
 518                         len = NSEC_PER_SEC;
 519                         q->stat_pkts_too_long++;
 520                 }
 521                 /* Account for schedule/timers drifts.
 522                  * f->time_next_packet was set when prior packet was sent,
 523                  * and current time (@now) can be too late by tens of us.
 524                  */
 525                 if (f->time_next_packet)
 526                         len -= min(len/2, now - f->time_next_packet);
 527                 f->time_next_packet = now + len;
 528         }
 529 out:
 530         qdisc_bstats_update(sch, skb);
 531         return skb;
 532 }
 533
 534 static void fq_flow_purge(struct fq_flow *flow)
 535 {
 536         rtnl_kfree_skbs(flow->head, flow->tail);
 537         flow->head = NULL;
 538         flow->qlen = 0;
 539 }
 540
 541 static void fq_reset(struct Qdisc *sch)
 542 {
 543         struct fq_sched_data *q = qdisc_priv(sch);
 544         struct rb_root *root;
 545         struct rb_node *p;
 546         struct fq_flow *f;
 547         unsigned int idx;
 548
 549         sch->q.qlen = 0;
 550         sch->qstats.backlog = 0;
 551
 552         fq_flow_purge(&q->internal);
 553
 554         if (!q->fq_root)
 555                 return;
 556
 557         for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
 558                 root = &q->fq_root[idx];
 559                 while ((p = rb_first(root)) != NULL) {
 560                         f = rb_entry(p, struct fq_flow, fq_node);
 561                         rb_erase(p, root);
 562
 563                         fq_flow_purge(f);
 564
 565                         kmem_cache_free(fq_flow_cachep, f);
 566                 }
 567         }
 568         q->new_flows.first      = NULL;
 569         q->old_flows.first      = NULL;
 570         q->delayed              = RB_ROOT;
 571         q->flows                = 0;
 572         q->inactive_flows       = 0;
 573         q->throttled_flows      = 0;
 574 }
 575
 576 static void fq_rehash(struct fq_sched_data *q,
 577                       struct rb_root *old_array, u32 old_log,
 578                       struct rb_root *new_array, u32 new_log)
 579 {
 580         struct rb_node *op, **np, *parent;
 581         struct rb_root *oroot, *nroot;
 582         struct fq_flow *of, *nf;
 583         int fcnt = 0;
 584         u32 idx;
 585
 586         for (idx = 0; idx < (1U << old_log); idx++) {
 587                 oroot = &old_array[idx];
 588                 while ((op = rb_first(oroot)) != NULL) {
 589                         rb_erase(op, oroot);
 590                         of = rb_entry(op, struct fq_flow, fq_node);
 591                         if (fq_gc_candidate(of)) {
 592                                 fcnt++;
 593                                 kmem_cache_free(fq_flow_cachep, of);
 594                                 continue;
 595                         }
 596                         nroot = &new_array[hash_ptr(of->sk, new_log)];
 597
 598                         np = &nroot->rb_node;
 599                         parent = NULL;
 600                         while (*np) {
 601                                 parent = *np;
 602
 603                                 nf = rb_entry(parent, struct fq_flow, fq_node);
 604                                 BUG_ON(nf->sk == of->sk);
 605
 606                                 if (nf->sk > of->sk)
 607                                         np = &parent->rb_right;
 608                                 else
 609                                         np = &parent->rb_left;
 610                         }
 611
 612                         rb_link_node(&of->fq_node, parent, np);
 613                         rb_insert_color(&of->fq_node, nroot);
 614                 }
 615         }
 616         q->flows -= fcnt;
 617         q->inactive_flows -= fcnt;
 618         q->stat_gc_flows += fcnt;
 619 }
 620
 621 static void fq_free(void *addr)
 622 {
 623         kvfree(addr);
 624 }
 625
 626 static int fq_resize(struct Qdisc *sch, u32 log)
 627 {
 628         struct fq_sched_data *q = qdisc_priv(sch);
 629         struct rb_root *array;
 630         void *old_fq_root;
 631         u32 idx;
 632
 633         if (q->fq_root && log == q->fq_trees_log)
 634                 return 0;
 635
 636         /* If XPS was setup, we can allocate memory on right NUMA node */
 637         array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL,
 638                               netdev_queue_numa_node_read(sch->dev_queue));
 639         if (!array)
 640                 return -ENOMEM;
 641
 642         for (idx = 0; idx < (1U << log); idx++)
 643                 array[idx] = RB_ROOT;
 644
 645         sch_tree_lock(sch);
 646
 647         old_fq_root = q->fq_root;
 648         if (old_fq_root)
 649                 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
 650
 651         q->fq_root = array;
 652         q->fq_trees_log = log;
 653
 654         sch_tree_unlock(sch);
 655
 656         fq_free(old_fq_root);
 657
 658         return 0;
 659 }
 660
 661 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 662         [TCA_FQ_PLIMIT]                 = { .type = NLA_U32 },
 663         [TCA_FQ_FLOW_PLIMIT]            = { .type = NLA_U32 },
 664         [TCA_FQ_QUANTUM]                = { .type = NLA_U32 },
 665         [TCA_FQ_INITIAL_QUANTUM]        = { .type = NLA_U32 },
 666         [TCA_FQ_RATE_ENABLE]            = { .type = NLA_U32 },
 667         [TCA_FQ_FLOW_DEFAULT_RATE]      = { .type = NLA_U32 },
 668         [TCA_FQ_FLOW_MAX_RATE]          = { .type = NLA_U32 },
 669         [TCA_FQ_BUCKETS_LOG]            = { .type = NLA_U32 },
 670         [TCA_FQ_FLOW_REFILL_DELAY]      = { .type = NLA_U32 },
 671         [TCA_FQ_LOW_RATE_THRESHOLD]     = { .type = NLA_U32 },
 672         [TCA_FQ_CE_THRESHOLD]           = { .type = NLA_U32 },
 673 };
 674
 675 static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 676                      struct netlink_ext_ack *extack)
 677 {
 678         struct fq_sched_data *q = qdisc_priv(sch);
 679         struct nlattr *tb[TCA_FQ_MAX + 1];
 680         int err, drop_count = 0;
 681         unsigned drop_len = 0;
 682         u32 fq_log;
 683
 684         if (!opt)
 685                 return -EINVAL;
 686
 687         err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy, NULL);
 688         if (err < 0)
 689                 return err;
 690
 691         sch_tree_lock(sch);
 692
 693         fq_log = q->fq_trees_log;
 694
 695         if (tb[TCA_FQ_BUCKETS_LOG]) {
 696                 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
 697
 698                 if (nval >= 1 && nval <= ilog2(256*1024))
 699                         fq_log = nval;
 700                 else
 701                         err = -EINVAL;
 702         }
 703         if (tb[TCA_FQ_PLIMIT])
 704                 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
 705
 706         if (tb[TCA_FQ_FLOW_PLIMIT])
 707                 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
 708
 709         if (tb[TCA_FQ_QUANTUM]) {
 710                 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 711
 712                 if (quantum > 0)
 713                         q->quantum = quantum;
 714                 else
 715                         err = -EINVAL;
 716         }
 717
 718         if (tb[TCA_FQ_INITIAL_QUANTUM])
 719                 q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
 720
 721         if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 722                 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
 723                                     nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
 724
 725         if (tb[TCA_FQ_FLOW_MAX_RATE]) {
 726                 u32 rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 727
 728                 q->flow_max_rate = (rate == ~0U) ? ~0UL : rate;
 729         }
 730         if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
 731                 q->low_rate_threshold =
 732                         nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
 733
 734         if (tb[TCA_FQ_RATE_ENABLE]) {
 735                 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 736
 737                 if (enable <= 1)
 738                         q->rate_enable = enable;
 739                 else
 740                         err = -EINVAL;
 741         }
 742
 743         if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
 744                 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
 745
 746                 q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
 747         }
 748
 749         if (tb[TCA_FQ_ORPHAN_MASK])
 750                 q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
 751
 752         if (tb[TCA_FQ_CE_THRESHOLD])
 753                 q->ce_threshold = (u64)NSEC_PER_USEC *
 754                                   nla_get_u32(tb[TCA_FQ_CE_THRESHOLD]);
 755
 756         if (!err) {
 757                 sch_tree_unlock(sch);
 758                 err = fq_resize(sch, fq_log);
 759                 sch_tree_lock(sch);
 760         }
 761         while (sch->q.qlen > sch->limit) {
 762                 struct sk_buff *skb = fq_dequeue(sch);
 763
 764                 if (!skb)
 765                         break;
 766                 drop_len += qdisc_pkt_len(skb);
 767                 rtnl_kfree_skbs(skb, skb);
 768                 drop_count++;
 769         }
 770         qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
 771
 772         sch_tree_unlock(sch);
 773         return err;
 774 }
 775
 776 static void fq_destroy(struct Qdisc *sch)
 777 {
 778         struct fq_sched_data *q = qdisc_priv(sch);
 779
 780         fq_reset(sch);
 781         fq_free(q->fq_root);
 782         qdisc_watchdog_cancel(&q->watchdog);
 783 }
 784
 785 static int fq_init(struct Qdisc *sch, struct nlattr *opt,
 786                    struct netlink_ext_ack *extack)
 787 {
 788         struct fq_sched_data *q = qdisc_priv(sch);
 789         int err;
 790
 791         sch->limit              = 10000;
 792         q->flow_plimit          = 100;
 793         q->quantum              = 2 * psched_mtu(qdisc_dev(sch));
 794         q->initial_quantum      = 10 * psched_mtu(qdisc_dev(sch));
 795         q->flow_refill_delay    = msecs_to_jiffies(40);
 796         q->flow_max_rate        = ~0UL;
 797         q->time_next_delayed_flow = ~0ULL;
 798         q->rate_enable          = 1;
 799         q->new_flows.first      = NULL;
 800         q->old_flows.first      = NULL;
 801         q->delayed              = RB_ROOT;
 802         q->fq_root              = NULL;
 803         q->fq_trees_log         = ilog2(1024);
 804         q->orphan_mask          = 1024 - 1;
 805         q->low_rate_threshold   = 550000 / 8;
 806
 807         /* Default ce_threshold of 4294 seconds */
 808         q->ce_threshold         = (u64)NSEC_PER_USEC * ~0U;
 809
 810         qdisc_watchdog_init_clockid(&q->watchdog, sch, CLOCK_MONOTONIC);
 811
 812         if (opt)
 813                 err = fq_change(sch, opt, extack);
 814         else
 815                 err = fq_resize(sch, q->fq_trees_log);
 816
 817         return err;
 818 }
 819
 820 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 821 {
 822         struct fq_sched_data *q = qdisc_priv(sch);
 823         u64 ce_threshold = q->ce_threshold;
 824         struct nlattr *opts;
 825
 826         opts = nla_nest_start(skb, TCA_OPTIONS);
 827         if (opts == NULL)
 828                 goto nla_put_failure;
 829
 830         /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
 831
 832         do_div(ce_threshold, NSEC_PER_USEC);
 833
 834         if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
 835             nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
 836             nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
 837             nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
 838             nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
 839             nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE,
 840                         min_t(unsigned long, q->flow_max_rate, ~0U)) ||
 841             nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
 842                         jiffies_to_usecs(q->flow_refill_delay)) ||
 843             nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
 844             nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
 845                         q->low_rate_threshold) ||
 846             nla_put_u32(skb, TCA_FQ_CE_THRESHOLD, (u32)ce_threshold) ||
 847             nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 848                 goto nla_put_failure;
 849
 850         return nla_nest_end(skb, opts);
 851
 852 nla_put_failure:
 853         return -1;
 854 }
 855
 856 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 857 {
 858         struct fq_sched_data *q = qdisc_priv(sch);
 859         struct tc_fq_qd_stats st;
 860
 861         sch_tree_lock(sch);
 862
 863         st.gc_flows               = q->stat_gc_flows;
 864         st.highprio_packets       = q->stat_internal_packets;
 865         st.tcp_retrans            = 0;
 866         st.throttled              = q->stat_throttled;
 867         st.flows_plimit           = q->stat_flows_plimit;
 868         st.pkts_too_long          = q->stat_pkts_too_long;
 869         st.allocation_errors      = q->stat_allocation_errors;
 870         st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
 871         st.flows                  = q->flows;
 872         st.inactive_flows         = q->inactive_flows;
 873         st.throttled_flows        = q->throttled_flows;
 874         st.unthrottle_latency_ns  = min_t(unsigned long,
 875                                           q->unthrottle_latency_ns, ~0U);
 876         st.ce_mark                = q->stat_ce_mark;
 877         sch_tree_unlock(sch);
 878
 879         return gnet_stats_copy_app(d, &st, sizeof(st));
 880 }
 881
 882 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
 883         .id             =       "fq",
 884         .priv_size      =       sizeof(struct fq_sched_data),
 885
 886         .enqueue        =       fq_enqueue,
 887         .dequeue        =       fq_dequeue,
 888         .peek           =       qdisc_peek_dequeued,
 889         .init           =       fq_init,
 890         .reset          =       fq_reset,
 891         .destroy        =       fq_destroy,
 892         .change         =       fq_change,
 893         .dump           =       fq_dump,
 894         .dump_stats     =       fq_dump_stats,
 895         .owner          =       THIS_MODULE,
 896 };
 897
 898 static int __init fq_module_init(void)
 899 {
 900         int ret;
 901
 902         fq_flow_cachep = kmem_cache_create("fq_flow_cache",
 903                                            sizeof(struct fq_flow),
 904                                            0, 0, NULL);
 905         if (!fq_flow_cachep)
 906                 return -ENOMEM;
 907
 908         ret = register_qdisc(&fq_qdisc_ops);
 909         if (ret)
 910                 kmem_cache_destroy(fq_flow_cachep);
 911         return ret;
 912 }
 913
 914 static void __exit fq_module_exit(void)
 915 {
 916         unregister_qdisc(&fq_qdisc_ops);
 917         kmem_cache_destroy(fq_flow_cachep);
 918 }
 919
 920 module_init(fq_module_init)
 921 module_exit(fq_module_exit)
 922 MODULE_AUTHOR("Eric Dumazet");
 923 MODULE_LICENSE("GPL");