net/sched/sch_fq.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
   4  *
   5  *  Copyright (C) 2013-2015 Eric Dumazet <edumazet@google.com>
   6  *
   7  *  Meant to be mostly used for locally generated traffic :
   8  *  Fast classification depends on skb->sk being set before reaching us.
   9  *  If not, (router workload), we use rxhash as fallback, with 32 bits wide hash.
  10  *  All packets belonging to a socket are considered as a 'flow'.
  11  *
  12  *  Flows are dynamically allocated and stored in a hash table of RB trees
  13  *  They are also part of one Round Robin 'queues' (new or old flows)
  14  *
  15  *  Burst avoidance (aka pacing) capability :
  16  *
  17  *  Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a
  18  *  bunch of packets, and this packet scheduler adds delay between
  19  *  packets to respect rate limitation.
  20  *
  21  *  enqueue() :
  22  *   - lookup one RB tree (out of 1024 or more) to find the flow.
  23  *     If non existent flow, create it, add it to the tree.
  24  *     Add skb to the per flow list of skb (fifo).
  25  *   - Use a special fifo for high prio packets
  26  *
  27  *  dequeue() : serves flows in Round Robin
  28  *  Note : When a flow becomes empty, we do not immediately remove it from
  29  *  rb trees, for performance reasons (its expected to send additional packets,
  30  *  or SLAB cache will reuse socket for another flow)
  31  */
  32
  33 #include <linux/module.h>
  34 #include <linux/types.h>
  35 #include <linux/kernel.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/string.h>
  38 #include <linux/in.h>
  39 #include <linux/errno.h>
  40 #include <linux/init.h>
  41 #include <linux/skbuff.h>
  42 #include <linux/slab.h>
  43 #include <linux/rbtree.h>
  44 #include <linux/hash.h>
  45 #include <linux/prefetch.h>
  46 #include <linux/vmalloc.h>
  47 #include <net/netlink.h>
  48 #include <net/pkt_sched.h>
  49 #include <net/sock.h>
  50 #include <net/tcp_states.h>
  51 #include <net/tcp.h>
  52
  53 struct fq_skb_cb {
  54         u64             time_to_send;
  55 };
  56
  57 static inline struct fq_skb_cb *fq_skb_cb(struct sk_buff *skb)
  58 {
  59         qdisc_cb_private_validate(skb, sizeof(struct fq_skb_cb));
  60         return (struct fq_skb_cb *)qdisc_skb_cb(skb)->data;
  61 }
  62
  63 /*
  64  * Per flow structure, dynamically allocated.
  65  * If packets have monotically increasing time_to_send, they are placed in O(1)
  66  * in linear list (head,tail), otherwise are placed in a rbtree (t_root).
  67  */
  68 struct fq_flow {
  69         struct rb_root  t_root;
  70         struct sk_buff  *head;          /* list of skbs for this flow : first skb */
  71         union {
  72                 struct sk_buff *tail;   /* last skb in the list */
  73                 unsigned long  age;     /* jiffies when flow was emptied, for gc */
  74         };
  75         struct rb_node  fq_node;        /* anchor in fq_root[] trees */
  76         struct sock     *sk;
  77         int             qlen;           /* number of packets in flow queue */
  78         int             credit;
  79         u32             socket_hash;    /* sk_hash */
  80         struct fq_flow *next;           /* next pointer in RR lists, or &detached */
  81
  82         struct rb_node  rate_node;      /* anchor in q->delayed tree */
  83         u64             time_next_packet;
  84 };
  85
  86 struct fq_flow_head {
  87         struct fq_flow *first;
  88         struct fq_flow *last;
  89 };
  90
  91 struct fq_sched_data {
  92         struct fq_flow_head new_flows;
  93
  94         struct fq_flow_head old_flows;
  95
  96         struct rb_root  delayed;        /* for rate limited flows */
  97         u64             time_next_delayed_flow;
  98         unsigned long   unthrottle_latency_ns;
  99
 100         struct fq_flow  internal;       /* for non classified or high prio packets */
 101         u32             quantum;
 102         u32             initial_quantum;
 103         u32             flow_refill_delay;
 104         u32             flow_plimit;    /* max packets per flow */
 105         unsigned long   flow_max_rate;  /* optional max rate per flow */
 106         u64             ce_threshold;
 107         u32             orphan_mask;    /* mask for orphaned skb */
 108         u32             low_rate_threshold;
 109         struct rb_root  *fq_root;
 110         u8              rate_enable;
 111         u8              fq_trees_log;
 112
 113         u32             flows;
 114         u32             inactive_flows;
 115         u32             throttled_flows;
 116
 117         u64             stat_gc_flows;
 118         u64             stat_internal_packets;
 119         u64             stat_throttled;
 120         u64             stat_ce_mark;
 121         u64             stat_flows_plimit;
 122         u64             stat_pkts_too_long;
 123         u64             stat_allocation_errors;
 124         struct qdisc_watchdog watchdog;
 125 };
 126
 127 /* special value to mark a detached flow (not on old/new list) */
 128 static struct fq_flow detached, throttled;
 129
 130 static void fq_flow_set_detached(struct fq_flow *f)
 131 {
 132         f->next = &detached;
 133         f->age = jiffies;
 134 }
 135
 136 static bool fq_flow_is_detached(const struct fq_flow *f)
 137 {
 138         return f->next == &detached;
 139 }
 140
 141 static bool fq_flow_is_throttled(const struct fq_flow *f)
 142 {
 143         return f->next == &throttled;
 144 }
 145
 146 static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow)
 147 {
 148         if (head->first)
 149                 head->last->next = flow;
 150         else
 151                 head->first = flow;
 152         head->last = flow;
 153         flow->next = NULL;
 154 }
 155
 156 static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)
 157 {
 158         rb_erase(&f->rate_node, &q->delayed);
 159         q->throttled_flows--;
 160         fq_flow_add_tail(&q->old_flows, f);
 161 }
 162
 163 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
 164 {
 165         struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
 166
 167         while (*p) {
 168                 struct fq_flow *aux;
 169
 170                 parent = *p;
 171                 aux = rb_entry(parent, struct fq_flow, rate_node);
 172                 if (f->time_next_packet >= aux->time_next_packet)
 173                         p = &parent->rb_right;
 174                 else
 175                         p = &parent->rb_left;
 176         }
 177         rb_link_node(&f->rate_node, parent, p);
 178         rb_insert_color(&f->rate_node, &q->delayed);
 179         q->throttled_flows++;
 180         q->stat_throttled++;
 181
 182         f->next = &throttled;
 183         if (q->time_next_delayed_flow > f->time_next_packet)
 184                 q->time_next_delayed_flow = f->time_next_packet;
 185 }
 186
 187
 188 static struct kmem_cache *fq_flow_cachep __read_mostly;
 189
 190
 191 /* limit number of collected flows per round */
 192 #define FQ_GC_MAX 8
 193 #define FQ_GC_AGE (3*HZ)
 194
 195 static bool fq_gc_candidate(const struct fq_flow *f)
 196 {
 197         return fq_flow_is_detached(f) &&
 198                time_after(jiffies, f->age + FQ_GC_AGE);
 199 }
 200
 201 static void fq_gc(struct fq_sched_data *q,
 202                   struct rb_root *root,
 203                   struct sock *sk)
 204 {
 205         struct fq_flow *f, *tofree[FQ_GC_MAX];
 206         struct rb_node **p, *parent;
 207         int fcnt = 0;
 208
 209         p = &root->rb_node;
 210         parent = NULL;
 211         while (*p) {
 212                 parent = *p;
 213
 214                 f = rb_entry(parent, struct fq_flow, fq_node);
 215                 if (f->sk == sk)
 216                         break;
 217
 218                 if (fq_gc_candidate(f)) {
 219                         tofree[fcnt++] = f;
 220                         if (fcnt == FQ_GC_MAX)
 221                                 break;
 222                 }
 223
 224                 if (f->sk > sk)
 225                         p = &parent->rb_right;
 226                 else
 227                         p = &parent->rb_left;
 228         }
 229
 230         q->flows -= fcnt;
 231         q->inactive_flows -= fcnt;
 232         q->stat_gc_flows += fcnt;
 233         while (fcnt) {
 234                 struct fq_flow *f = tofree[--fcnt];
 235
 236                 rb_erase(&f->fq_node, root);
 237                 kmem_cache_free(fq_flow_cachep, f);
 238         }
 239 }
 240
 241 static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q)
 242 {
 243         struct rb_node **p, *parent;
 244         struct sock *sk = skb->sk;
 245         struct rb_root *root;
 246         struct fq_flow *f;
 247
 248         /* warning: no starvation prevention... */
 249         if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
 250                 return &q->internal;
 251
 252         /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
 253          * or a listener (SYNCOOKIE mode)
 254          * 1) request sockets are not full blown,
 255          *    they do not contain sk_pacing_rate
 256          * 2) They are not part of a 'flow' yet
 257          * 3) We do not want to rate limit them (eg SYNFLOOD attack),
 258          *    especially if the listener set SO_MAX_PACING_RATE
 259          * 4) We pretend they are orphaned
 260          */
 261         if (!sk || sk_listener(sk)) {
 262                 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
 263
 264                 /* By forcing low order bit to 1, we make sure to not
 265                  * collide with a local flow (socket pointers are word aligned)
 266                  */
 267                 sk = (struct sock *)((hash << 1) | 1UL);
 268                 skb_orphan(skb);
 269         } else if (sk->sk_state == TCP_CLOSE) {
 270                 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
 271                 /*
 272                  * Sockets in TCP_CLOSE are non connected.
 273                  * Typical use case is UDP sockets, they can send packets
 274                  * with sendto() to many different destinations.
 275                  * We probably could use a generic bit advertising
 276                  * non connected sockets, instead of sk_state == TCP_CLOSE,
 277                  * if we care enough.
 278                  */
 279                 sk = (struct sock *)((hash << 1) | 1UL);
 280         }
 281
 282         root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)];
 283
 284         if (q->flows >= (2U << q->fq_trees_log) &&
 285             q->inactive_flows > q->flows/2)
 286                 fq_gc(q, root, sk);
 287
 288         p = &root->rb_node;
 289         parent = NULL;
 290         while (*p) {
 291                 parent = *p;
 292
 293                 f = rb_entry(parent, struct fq_flow, fq_node);
 294                 if (f->sk == sk) {
 295                         /* socket might have been reallocated, so check
 296                          * if its sk_hash is the same.
 297                          * It not, we need to refill credit with
 298                          * initial quantum
 299                          */
 300                         if (unlikely(skb->sk == sk &&
 301                                      f->socket_hash != sk->sk_hash)) {
 302                                 f->credit = q->initial_quantum;
 303                                 f->socket_hash = sk->sk_hash;
 304                                 if (fq_flow_is_throttled(f))
 305                                         fq_flow_unset_throttled(q, f);
 306                                 f->time_next_packet = 0ULL;
 307                         }
 308                         return f;
 309                 }
 310                 if (f->sk > sk)
 311                         p = &parent->rb_right;
 312                 else
 313                         p = &parent->rb_left;
 314         }
 315
 316         f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
 317         if (unlikely(!f)) {
 318                 q->stat_allocation_errors++;
 319                 return &q->internal;
 320         }
 321         /* f->t_root is already zeroed after kmem_cache_zalloc() */
 322
 323         fq_flow_set_detached(f);
 324         f->sk = sk;
 325         if (skb->sk == sk)
 326                 f->socket_hash = sk->sk_hash;
 327         f->credit = q->initial_quantum;
 328
 329         rb_link_node(&f->fq_node, parent, p);
 330         rb_insert_color(&f->fq_node, root);
 331
 332         q->flows++;
 333         q->inactive_flows++;
 334         return f;
 335 }
 336
 337 static struct sk_buff *fq_peek(struct fq_flow *flow)
 338 {
 339         struct sk_buff *skb = skb_rb_first(&flow->t_root);
 340         struct sk_buff *head = flow->head;
 341
 342         if (!skb)
 343                 return head;
 344
 345         if (!head)
 346                 return skb;
 347
 348         if (fq_skb_cb(skb)->time_to_send < fq_skb_cb(head)->time_to_send)
 349                 return skb;
 350         return head;
 351 }
 352
 353 static void fq_erase_head(struct Qdisc *sch, struct fq_flow *flow,
 354                           struct sk_buff *skb)
 355 {
 356         if (skb == flow->head) {
 357                 flow->head = skb->next;
 358         } else {
 359                 rb_erase(&skb->rbnode, &flow->t_root);
 360                 skb->dev = qdisc_dev(sch);
 361         }
 362 }
 363
 364 /* remove one skb from head of flow queue */
 365 static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
 366 {
 367         struct sk_buff *skb = fq_peek(flow);
 368
 369         if (skb) {
 370                 fq_erase_head(sch, flow, skb);
 371                 skb_mark_not_on_list(skb);
 372                 flow->qlen--;
 373                 qdisc_qstats_backlog_dec(sch, skb);
 374                 sch->q.qlen--;
 375         }
 376         return skb;
 377 }
 378
 379 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
 380 {
 381         struct rb_node **p, *parent;
 382         struct sk_buff *head, *aux;
 383
 384         fq_skb_cb(skb)->time_to_send = skb->tstamp ?: ktime_get_ns();
 385
 386         head = flow->head;
 387         if (!head ||
 388             fq_skb_cb(skb)->time_to_send >= fq_skb_cb(flow->tail)->time_to_send) {
 389                 if (!head)
 390                         flow->head = skb;
 391                 else
 392                         flow->tail->next = skb;
 393                 flow->tail = skb;
 394                 skb->next = NULL;
 395                 return;
 396         }
 397
 398         p = &flow->t_root.rb_node;
 399         parent = NULL;
 400
 401         while (*p) {
 402                 parent = *p;
 403                 aux = rb_to_skb(parent);
 404                 if (fq_skb_cb(skb)->time_to_send >= fq_skb_cb(aux)->time_to_send)
 405                         p = &parent->rb_right;
 406                 else
 407                         p = &parent->rb_left;
 408         }
 409         rb_link_node(&skb->rbnode, parent, p);
 410         rb_insert_color(&skb->rbnode, &flow->t_root);
 411 }
 412
 413 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 414                       struct sk_buff **to_free)
 415 {
 416         struct fq_sched_data *q = qdisc_priv(sch);
 417         struct fq_flow *f;
 418
 419         if (unlikely(sch->q.qlen >= sch->limit))
 420                 return qdisc_drop(skb, sch, to_free);
 421
 422         f = fq_classify(skb, q);
 423         if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
 424                 q->stat_flows_plimit++;
 425                 return qdisc_drop(skb, sch, to_free);
 426         }
 427
 428         f->qlen++;
 429         qdisc_qstats_backlog_inc(sch, skb);
 430         if (fq_flow_is_detached(f)) {
 431                 struct sock *sk = skb->sk;
 432
 433                 fq_flow_add_tail(&q->new_flows, f);
 434                 if (time_after(jiffies, f->age + q->flow_refill_delay))
 435                         f->credit = max_t(u32, f->credit, q->quantum);
 436                 if (sk && q->rate_enable) {
 437                         if (unlikely(smp_load_acquire(&sk->sk_pacing_status) !=
 438                                      SK_PACING_FQ))
 439                                 smp_store_release(&sk->sk_pacing_status,
 440                                                   SK_PACING_FQ);
 441                 }
 442                 q->inactive_flows--;
 443         }
 444
 445         /* Note: this overwrites f->age */
 446         flow_queue_add(f, skb);
 447
 448         if (unlikely(f == &q->internal)) {
 449                 q->stat_internal_packets++;
 450         }
 451         sch->q.qlen++;
 452
 453         return NET_XMIT_SUCCESS;
 454 }
 455
 456 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
 457 {
 458         unsigned long sample;
 459         struct rb_node *p;
 460
 461         if (q->time_next_delayed_flow > now)
 462                 return;
 463
 464         /* Update unthrottle latency EWMA.
 465          * This is cheap and can help diagnosing timer/latency problems.
 466          */
 467         sample = (unsigned long)(now - q->time_next_delayed_flow);
 468         q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
 469         q->unthrottle_latency_ns += sample >> 3;
 470
 471         q->time_next_delayed_flow = ~0ULL;
 472         while ((p = rb_first(&q->delayed)) != NULL) {
 473                 struct fq_flow *f = rb_entry(p, struct fq_flow, rate_node);
 474
 475                 if (f->time_next_packet > now) {
 476                         q->time_next_delayed_flow = f->time_next_packet;
 477                         break;
 478                 }
 479                 fq_flow_unset_throttled(q, f);
 480         }
 481 }
 482
 483 static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 484 {
 485         struct fq_sched_data *q = qdisc_priv(sch);
 486         struct fq_flow_head *head;
 487         struct sk_buff *skb;
 488         struct fq_flow *f;
 489         unsigned long rate;
 490         u32 plen;
 491         u64 now;
 492
 493         if (!sch->q.qlen)
 494                 return NULL;
 495
 496         skb = fq_dequeue_head(sch, &q->internal);
 497         if (skb)
 498                 goto out;
 499
 500         now = ktime_get_ns();
 501         fq_check_throttled(q, now);
 502 begin:
 503         head = &q->new_flows;
 504         if (!head->first) {
 505                 head = &q->old_flows;
 506                 if (!head->first) {
 507                         if (q->time_next_delayed_flow != ~0ULL)
 508                                 qdisc_watchdog_schedule_ns(&q->watchdog,
 509                                                            q->time_next_delayed_flow);
 510                         return NULL;
 511                 }
 512         }
 513         f = head->first;
 514
 515         if (f->credit <= 0) {
 516                 f->credit += q->quantum;
 517                 head->first = f->next;
 518                 fq_flow_add_tail(&q->old_flows, f);
 519                 goto begin;
 520         }
 521
 522         skb = fq_peek(f);
 523         if (skb) {
 524                 u64 time_next_packet = max_t(u64, fq_skb_cb(skb)->time_to_send,
 525                                              f->time_next_packet);
 526
 527                 if (now < time_next_packet) {
 528                         head->first = f->next;
 529                         f->time_next_packet = time_next_packet;
 530                         fq_flow_set_throttled(q, f);
 531                         goto begin;
 532                 }
 533                 if ((s64)(now - time_next_packet - q->ce_threshold) > 0) {
 534                         INET_ECN_set_ce(skb);
 535                         q->stat_ce_mark++;
 536                 }
 537         }
 538
 539         skb = fq_dequeue_head(sch, f);
 540         if (!skb) {
 541                 head->first = f->next;
 542                 /* force a pass through old_flows to prevent starvation */
 543                 if ((head == &q->new_flows) && q->old_flows.first) {
 544                         fq_flow_add_tail(&q->old_flows, f);
 545                 } else {
 546                         fq_flow_set_detached(f);
 547                         q->inactive_flows++;
 548                 }
 549                 goto begin;
 550         }
 551         prefetch(&skb->end);
 552         plen = qdisc_pkt_len(skb);
 553         f->credit -= plen;
 554
 555         if (!q->rate_enable)
 556                 goto out;
 557
 558         rate = q->flow_max_rate;
 559
 560         /* If EDT time was provided for this skb, we need to
 561          * update f->time_next_packet only if this qdisc enforces
 562          * a flow max rate.
 563          */
 564         if (!skb->tstamp) {
 565                 if (skb->sk)
 566                         rate = min(skb->sk->sk_pacing_rate, rate);
 567
 568                 if (rate <= q->low_rate_threshold) {
 569                         f->credit = 0;
 570                 } else {
 571                         plen = max(plen, q->quantum);
 572                         if (f->credit > 0)
 573                                 goto out;
 574                 }
 575         }
 576         if (rate != ~0UL) {
 577                 u64 len = (u64)plen * NSEC_PER_SEC;
 578
 579                 if (likely(rate))
 580                         len = div64_ul(len, rate);
 581                 /* Since socket rate can change later,
 582                  * clamp the delay to 1 second.
 583                  * Really, providers of too big packets should be fixed !
 584                  */
 585                 if (unlikely(len > NSEC_PER_SEC)) {
 586                         len = NSEC_PER_SEC;
 587                         q->stat_pkts_too_long++;
 588                 }
 589                 /* Account for schedule/timers drifts.
 590                  * f->time_next_packet was set when prior packet was sent,
 591                  * and current time (@now) can be too late by tens of us.
 592                  */
 593                 if (f->time_next_packet)
 594                         len -= min(len/2, now - f->time_next_packet);
 595                 f->time_next_packet = now + len;
 596         }
 597 out:
 598         qdisc_bstats_update(sch, skb);
 599         return skb;
 600 }
 601
 602 static void fq_flow_purge(struct fq_flow *flow)
 603 {
 604         struct rb_node *p = rb_first(&flow->t_root);
 605
 606         while (p) {
 607                 struct sk_buff *skb = rb_to_skb(p);
 608
 609                 p = rb_next(p);
 610                 rb_erase(&skb->rbnode, &flow->t_root);
 611                 rtnl_kfree_skbs(skb, skb);
 612         }
 613         rtnl_kfree_skbs(flow->head, flow->tail);
 614         flow->head = NULL;
 615         flow->qlen = 0;
 616 }
 617
 618 static void fq_reset(struct Qdisc *sch)
 619 {
 620         struct fq_sched_data *q = qdisc_priv(sch);
 621         struct rb_root *root;
 622         struct rb_node *p;
 623         struct fq_flow *f;
 624         unsigned int idx;
 625
 626         sch->q.qlen = 0;
 627         sch->qstats.backlog = 0;
 628
 629         fq_flow_purge(&q->internal);
 630
 631         if (!q->fq_root)
 632                 return;
 633
 634         for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
 635                 root = &q->fq_root[idx];
 636                 while ((p = rb_first(root)) != NULL) {
 637                         f = rb_entry(p, struct fq_flow, fq_node);
 638                         rb_erase(p, root);
 639
 640                         fq_flow_purge(f);
 641
 642                         kmem_cache_free(fq_flow_cachep, f);
 643                 }
 644         }
 645         q->new_flows.first      = NULL;
 646         q->old_flows.first      = NULL;
 647         q->delayed              = RB_ROOT;
 648         q->flows                = 0;
 649         q->inactive_flows       = 0;
 650         q->throttled_flows      = 0;
 651 }
 652
 653 static void fq_rehash(struct fq_sched_data *q,
 654                       struct rb_root *old_array, u32 old_log,
 655                       struct rb_root *new_array, u32 new_log)
 656 {
 657         struct rb_node *op, **np, *parent;
 658         struct rb_root *oroot, *nroot;
 659         struct fq_flow *of, *nf;
 660         int fcnt = 0;
 661         u32 idx;
 662
 663         for (idx = 0; idx < (1U << old_log); idx++) {
 664                 oroot = &old_array[idx];
 665                 while ((op = rb_first(oroot)) != NULL) {
 666                         rb_erase(op, oroot);
 667                         of = rb_entry(op, struct fq_flow, fq_node);
 668                         if (fq_gc_candidate(of)) {
 669                                 fcnt++;
 670                                 kmem_cache_free(fq_flow_cachep, of);
 671                                 continue;
 672                         }
 673                         nroot = &new_array[hash_ptr(of->sk, new_log)];
 674
 675                         np = &nroot->rb_node;
 676                         parent = NULL;
 677                         while (*np) {
 678                                 parent = *np;
 679
 680                                 nf = rb_entry(parent, struct fq_flow, fq_node);
 681                                 BUG_ON(nf->sk == of->sk);
 682
 683                                 if (nf->sk > of->sk)
 684                                         np = &parent->rb_right;
 685                                 else
 686                                         np = &parent->rb_left;
 687                         }
 688
 689                         rb_link_node(&of->fq_node, parent, np);
 690                         rb_insert_color(&of->fq_node, nroot);
 691                 }
 692         }
 693         q->flows -= fcnt;
 694         q->inactive_flows -= fcnt;
 695         q->stat_gc_flows += fcnt;
 696 }
 697
 698 static void fq_free(void *addr)
 699 {
 700         kvfree(addr);
 701 }
 702
 703 static int fq_resize(struct Qdisc *sch, u32 log)
 704 {
 705         struct fq_sched_data *q = qdisc_priv(sch);
 706         struct rb_root *array;
 707         void *old_fq_root;
 708         u32 idx;
 709
 710         if (q->fq_root && log == q->fq_trees_log)
 711                 return 0;
 712
 713         /* If XPS was setup, we can allocate memory on right NUMA node */
 714         array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL,
 715                               netdev_queue_numa_node_read(sch->dev_queue));
 716         if (!array)
 717                 return -ENOMEM;
 718
 719         for (idx = 0; idx < (1U << log); idx++)
 720                 array[idx] = RB_ROOT;
 721
 722         sch_tree_lock(sch);
 723
 724         old_fq_root = q->fq_root;
 725         if (old_fq_root)
 726                 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
 727
 728         q->fq_root = array;
 729         q->fq_trees_log = log;
 730
 731         sch_tree_unlock(sch);
 732
 733         fq_free(old_fq_root);
 734
 735         return 0;
 736 }
 737
 738 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 739         [TCA_FQ_PLIMIT]                 = { .type = NLA_U32 },
 740         [TCA_FQ_FLOW_PLIMIT]            = { .type = NLA_U32 },
 741         [TCA_FQ_QUANTUM]                = { .type = NLA_U32 },
 742         [TCA_FQ_INITIAL_QUANTUM]        = { .type = NLA_U32 },
 743         [TCA_FQ_RATE_ENABLE]            = { .type = NLA_U32 },
 744         [TCA_FQ_FLOW_DEFAULT_RATE]      = { .type = NLA_U32 },
 745         [TCA_FQ_FLOW_MAX_RATE]          = { .type = NLA_U32 },
 746         [TCA_FQ_BUCKETS_LOG]            = { .type = NLA_U32 },
 747         [TCA_FQ_FLOW_REFILL_DELAY]      = { .type = NLA_U32 },
 748         [TCA_FQ_LOW_RATE_THRESHOLD]     = { .type = NLA_U32 },
 749         [TCA_FQ_CE_THRESHOLD]           = { .type = NLA_U32 },
 750 };
 751
 752 static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 753                      struct netlink_ext_ack *extack)
 754 {
 755         struct fq_sched_data *q = qdisc_priv(sch);
 756         struct nlattr *tb[TCA_FQ_MAX + 1];
 757         int err, drop_count = 0;
 758         unsigned drop_len = 0;
 759         u32 fq_log;
 760
 761         if (!opt)
 762                 return -EINVAL;
 763
 764         err = nla_parse_nested_deprecated(tb, TCA_FQ_MAX, opt, fq_policy,
 765                                           NULL);
 766         if (err < 0)
 767                 return err;
 768
 769         sch_tree_lock(sch);
 770
 771         fq_log = q->fq_trees_log;
 772
 773         if (tb[TCA_FQ_BUCKETS_LOG]) {
 774                 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
 775
 776                 if (nval >= 1 && nval <= ilog2(256*1024))
 777                         fq_log = nval;
 778                 else
 779                         err = -EINVAL;
 780         }
 781         if (tb[TCA_FQ_PLIMIT])
 782                 sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
 783
 784         if (tb[TCA_FQ_FLOW_PLIMIT])
 785                 q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
 786
 787         if (tb[TCA_FQ_QUANTUM]) {
 788                 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 789
 790                 if (quantum > 0)
 791                         q->quantum = quantum;
 792                 else
 793                         err = -EINVAL;
 794         }
 795
 796         if (tb[TCA_FQ_INITIAL_QUANTUM])
 797                 q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
 798
 799         if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 800                 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
 801                                     nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
 802
 803         if (tb[TCA_FQ_FLOW_MAX_RATE]) {
 804                 u32 rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 805
 806                 q->flow_max_rate = (rate == ~0U) ? ~0UL : rate;
 807         }
 808         if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
 809                 q->low_rate_threshold =
 810                         nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
 811
 812         if (tb[TCA_FQ_RATE_ENABLE]) {
 813                 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 814
 815                 if (enable <= 1)
 816                         q->rate_enable = enable;
 817                 else
 818                         err = -EINVAL;
 819         }
 820
 821         if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
 822                 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
 823
 824                 q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
 825         }
 826
 827         if (tb[TCA_FQ_ORPHAN_MASK])
 828                 q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
 829
 830         if (tb[TCA_FQ_CE_THRESHOLD])
 831                 q->ce_threshold = (u64)NSEC_PER_USEC *
 832                                   nla_get_u32(tb[TCA_FQ_CE_THRESHOLD]);
 833
 834         if (!err) {
 835                 sch_tree_unlock(sch);
 836                 err = fq_resize(sch, fq_log);
 837                 sch_tree_lock(sch);
 838         }
 839         while (sch->q.qlen > sch->limit) {
 840                 struct sk_buff *skb = fq_dequeue(sch);
 841
 842                 if (!skb)
 843                         break;
 844                 drop_len += qdisc_pkt_len(skb);
 845                 rtnl_kfree_skbs(skb, skb);
 846                 drop_count++;
 847         }
 848         qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
 849
 850         sch_tree_unlock(sch);
 851         return err;
 852 }
 853
 854 static void fq_destroy(struct Qdisc *sch)
 855 {
 856         struct fq_sched_data *q = qdisc_priv(sch);
 857
 858         fq_reset(sch);
 859         fq_free(q->fq_root);
 860         qdisc_watchdog_cancel(&q->watchdog);
 861 }
 862
 863 static int fq_init(struct Qdisc *sch, struct nlattr *opt,
 864                    struct netlink_ext_ack *extack)
 865 {
 866         struct fq_sched_data *q = qdisc_priv(sch);
 867         int err;
 868
 869         sch->limit              = 10000;
 870         q->flow_plimit          = 100;
 871         q->quantum              = 2 * psched_mtu(qdisc_dev(sch));
 872         q->initial_quantum      = 10 * psched_mtu(qdisc_dev(sch));
 873         q->flow_refill_delay    = msecs_to_jiffies(40);
 874         q->flow_max_rate        = ~0UL;
 875         q->time_next_delayed_flow = ~0ULL;
 876         q->rate_enable          = 1;
 877         q->new_flows.first      = NULL;
 878         q->old_flows.first      = NULL;
 879         q->delayed              = RB_ROOT;
 880         q->fq_root              = NULL;
 881         q->fq_trees_log         = ilog2(1024);
 882         q->orphan_mask          = 1024 - 1;
 883         q->low_rate_threshold   = 550000 / 8;
 884
 885         /* Default ce_threshold of 4294 seconds */
 886         q->ce_threshold         = (u64)NSEC_PER_USEC * ~0U;
 887
 888         qdisc_watchdog_init_clockid(&q->watchdog, sch, CLOCK_MONOTONIC);
 889
 890         if (opt)
 891                 err = fq_change(sch, opt, extack);
 892         else
 893                 err = fq_resize(sch, q->fq_trees_log);
 894
 895         return err;
 896 }
 897
 898 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 899 {
 900         struct fq_sched_data *q = qdisc_priv(sch);
 901         u64 ce_threshold = q->ce_threshold;
 902         struct nlattr *opts;
 903
 904         opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
 905         if (opts == NULL)
 906                 goto nla_put_failure;
 907
 908         /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
 909
 910         do_div(ce_threshold, NSEC_PER_USEC);
 911
 912         if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
 913             nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
 914             nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
 915             nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
 916             nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
 917             nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE,
 918                         min_t(unsigned long, q->flow_max_rate, ~0U)) ||
 919             nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
 920                         jiffies_to_usecs(q->flow_refill_delay)) ||
 921             nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
 922             nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
 923                         q->low_rate_threshold) ||
 924             nla_put_u32(skb, TCA_FQ_CE_THRESHOLD, (u32)ce_threshold) ||
 925             nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
 926                 goto nla_put_failure;
 927
 928         return nla_nest_end(skb, opts);
 929
 930 nla_put_failure:
 931         return -1;
 932 }
 933
 934 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 935 {
 936         struct fq_sched_data *q = qdisc_priv(sch);
 937         struct tc_fq_qd_stats st;
 938
 939         sch_tree_lock(sch);
 940
 941         st.gc_flows               = q->stat_gc_flows;
 942         st.highprio_packets       = q->stat_internal_packets;
 943         st.tcp_retrans            = 0;
 944         st.throttled              = q->stat_throttled;
 945         st.flows_plimit           = q->stat_flows_plimit;
 946         st.pkts_too_long          = q->stat_pkts_too_long;
 947         st.allocation_errors      = q->stat_allocation_errors;
 948         st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
 949         st.flows                  = q->flows;
 950         st.inactive_flows         = q->inactive_flows;
 951         st.throttled_flows        = q->throttled_flows;
 952         st.unthrottle_latency_ns  = min_t(unsigned long,
 953                                           q->unthrottle_latency_ns, ~0U);
 954         st.ce_mark                = q->stat_ce_mark;
 955         sch_tree_unlock(sch);
 956
 957         return gnet_stats_copy_app(d, &st, sizeof(st));
 958 }
 959
 960 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
 961         .id             =       "fq",
 962         .priv_size      =       sizeof(struct fq_sched_data),
 963
 964         .enqueue        =       fq_enqueue,
 965         .dequeue        =       fq_dequeue,
 966         .peek           =       qdisc_peek_dequeued,
 967         .init           =       fq_init,
 968         .reset          =       fq_reset,
 969         .destroy        =       fq_destroy,
 970         .change         =       fq_change,
 971         .dump           =       fq_dump,
 972         .dump_stats     =       fq_dump_stats,
 973         .owner          =       THIS_MODULE,
 974 };
 975
 976 static int __init fq_module_init(void)
 977 {
 978         int ret;
 979
 980         fq_flow_cachep = kmem_cache_create("fq_flow_cache",
 981                                            sizeof(struct fq_flow),
 982                                            0, 0, NULL);
 983         if (!fq_flow_cachep)
 984                 return -ENOMEM;
 985
 986         ret = register_qdisc(&fq_qdisc_ops);
 987         if (ret)
 988                 kmem_cache_destroy(fq_flow_cachep);
 989         return ret;
 990 }
 991
 992 static void __exit fq_module_exit(void)
 993 {
 994         unregister_qdisc(&fq_qdisc_ops);
 995         kmem_cache_destroy(fq_flow_cachep);
 996 }
 997
 998 module_init(fq_module_init)
 999 module_exit(fq_module_exit)
1000 MODULE_AUTHOR("Eric Dumazet");
1001 MODULE_LICENSE("GPL");