1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Fair Queue CoDel discipline 4 * 5 * Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com> 6 */ 7 8 #include <linux/module.h> 9 #include <linux/types.h> 10 #include <linux/kernel.h> 11 #include <linux/jiffies.h> 12 #include <linux/string.h> 13 #include <linux/in.h> 14 #include <linux/errno.h> 15 #include <linux/init.h> 16 #include <linux/skbuff.h> 17 #include <linux/slab.h> 18 #include <linux/vmalloc.h> 19 #include <net/netlink.h> 20 #include <net/pkt_sched.h> 21 #include <net/pkt_cls.h> 22 #include <net/codel.h> 23 #include <net/codel_impl.h> 24 #include <net/codel_qdisc.h> 25 26 /* Fair Queue CoDel. 27 * 28 * Principles : 29 * Packets are classified (internal classifier or external) on flows. 30 * This is a Stochastic model (as we use a hash, several flows 31 * might be hashed on same slot) 32 * Each flow has a CoDel managed queue. 33 * Flows are linked onto two (Round Robin) lists, 34 * so that new flows have priority on old ones. 35 * 36 * For a given flow, packets are not reordered (CoDel uses a FIFO) 37 * head drops only. 38 * ECN capability is on by default. 39 * Low memory footprint (64 bytes per flow) 40 */ 41 42 struct fq_codel_flow { 43 struct sk_buff *head; 44 struct sk_buff *tail; 45 struct list_head flowchain; 46 int deficit; 47 struct codel_vars cvars; 48 }; /* please try to keep this structure <= 64 bytes */ 49 50 struct fq_codel_sched_data { 51 struct tcf_proto __rcu *filter_list; /* optional external classifier */ 52 struct tcf_block *block; 53 struct fq_codel_flow *flows; /* Flows table [flows_cnt] */ 54 u32 *backlogs; /* backlog table [flows_cnt] */ 55 u32 flows_cnt; /* number of flows */ 56 u32 quantum; /* psched_mtu(qdisc_dev(sch)); */ 57 u32 drop_batch_size; 58 u32 memory_limit; 59 struct codel_params cparams; 60 struct codel_stats cstats; 61 u32 memory_usage; 62 u32 drop_overmemory; 63 u32 drop_overlimit; 64 u32 new_flow_count; 65 66 struct list_head new_flows; /* list of new flows */ 67 struct list_head old_flows; /* list of old flows */ 68 }; 69 70 static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q, 71 struct sk_buff *skb) 72 { 73 return reciprocal_scale(skb_get_hash(skb), q->flows_cnt); 74 } 75 76 static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch, 77 int *qerr) 78 { 79 struct fq_codel_sched_data *q = qdisc_priv(sch); 80 struct tcf_proto *filter; 81 struct tcf_result res; 82 int result; 83 84 if (TC_H_MAJ(skb->priority) == sch->handle && 85 TC_H_MIN(skb->priority) > 0 && 86 TC_H_MIN(skb->priority) <= q->flows_cnt) 87 return TC_H_MIN(skb->priority); 88 89 filter = rcu_dereference_bh(q->filter_list); 90 if (!filter) 91 return fq_codel_hash(q, skb) + 1; 92 93 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 94 result = tcf_classify(skb, filter, &res, false); 95 if (result >= 0) { 96 #ifdef CONFIG_NET_CLS_ACT 97 switch (result) { 98 case TC_ACT_STOLEN: 99 case TC_ACT_QUEUED: 100 case TC_ACT_TRAP: 101 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 102 /* fall through */ 103 case TC_ACT_SHOT: 104 return 0; 105 } 106 #endif 107 if (TC_H_MIN(res.classid) <= q->flows_cnt) 108 return TC_H_MIN(res.classid); 109 } 110 return 0; 111 } 112 113 /* helper functions : might be changed when/if skb use a standard list_head */ 114 115 /* remove one skb from head of slot queue */ 116 static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow) 117 { 118 struct sk_buff *skb = flow->head; 119 120 flow->head = skb->next; 121 skb_mark_not_on_list(skb); 122 return skb; 123 } 124 125 /* add skb to flow queue (tail add) */ 126 static inline void flow_queue_add(struct fq_codel_flow *flow, 127 struct sk_buff *skb) 128 { 129 if (flow->head == NULL) 130 flow->head = skb; 131 else 132 flow->tail->next = skb; 133 flow->tail = skb; 134 skb->next = NULL; 135 } 136 137 static unsigned int fq_codel_drop(struct Qdisc *sch, unsigned int max_packets, 138 struct sk_buff **to_free) 139 { 140 struct fq_codel_sched_data *q = qdisc_priv(sch); 141 struct sk_buff *skb; 142 unsigned int maxbacklog = 0, idx = 0, i, len; 143 struct fq_codel_flow *flow; 144 unsigned int threshold; 145 unsigned int mem = 0; 146 147 /* Queue is full! Find the fat flow and drop packet(s) from it. 148 * This might sound expensive, but with 1024 flows, we scan 149 * 4KB of memory, and we dont need to handle a complex tree 150 * in fast path (packet queue/enqueue) with many cache misses. 151 * In stress mode, we'll try to drop 64 packets from the flow, 152 * amortizing this linear lookup to one cache line per drop. 153 */ 154 for (i = 0; i < q->flows_cnt; i++) { 155 if (q->backlogs[i] > maxbacklog) { 156 maxbacklog = q->backlogs[i]; 157 idx = i; 158 } 159 } 160 161 /* Our goal is to drop half of this fat flow backlog */ 162 threshold = maxbacklog >> 1; 163 164 flow = &q->flows[idx]; 165 len = 0; 166 i = 0; 167 do { 168 skb = dequeue_head(flow); 169 len += qdisc_pkt_len(skb); 170 mem += get_codel_cb(skb)->mem_usage; 171 __qdisc_drop(skb, to_free); 172 } while (++i < max_packets && len < threshold); 173 174 /* Tell codel to increase its signal strength also */ 175 flow->cvars.count += i; 176 q->backlogs[idx] -= len; 177 q->memory_usage -= mem; 178 sch->qstats.drops += i; 179 sch->qstats.backlog -= len; 180 sch->q.qlen -= i; 181 return idx; 182 } 183 184 static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch, 185 struct sk_buff **to_free) 186 { 187 struct fq_codel_sched_data *q = qdisc_priv(sch); 188 unsigned int idx, prev_backlog, prev_qlen; 189 struct fq_codel_flow *flow; 190 int uninitialized_var(ret); 191 unsigned int pkt_len; 192 bool memory_limited; 193 194 idx = fq_codel_classify(skb, sch, &ret); 195 if (idx == 0) { 196 if (ret & __NET_XMIT_BYPASS) 197 qdisc_qstats_drop(sch); 198 __qdisc_drop(skb, to_free); 199 return ret; 200 } 201 idx--; 202 203 codel_set_enqueue_time(skb); 204 flow = &q->flows[idx]; 205 flow_queue_add(flow, skb); 206 q->backlogs[idx] += qdisc_pkt_len(skb); 207 qdisc_qstats_backlog_inc(sch, skb); 208 209 if (list_empty(&flow->flowchain)) { 210 list_add_tail(&flow->flowchain, &q->new_flows); 211 q->new_flow_count++; 212 flow->deficit = q->quantum; 213 } 214 get_codel_cb(skb)->mem_usage = skb->truesize; 215 q->memory_usage += get_codel_cb(skb)->mem_usage; 216 memory_limited = q->memory_usage > q->memory_limit; 217 if (++sch->q.qlen <= sch->limit && !memory_limited) 218 return NET_XMIT_SUCCESS; 219 220 prev_backlog = sch->qstats.backlog; 221 prev_qlen = sch->q.qlen; 222 223 /* save this packet length as it might be dropped by fq_codel_drop() */ 224 pkt_len = qdisc_pkt_len(skb); 225 /* fq_codel_drop() is quite expensive, as it performs a linear search 226 * in q->backlogs[] to find a fat flow. 227 * So instead of dropping a single packet, drop half of its backlog 228 * with a 64 packets limit to not add a too big cpu spike here. 229 */ 230 ret = fq_codel_drop(sch, q->drop_batch_size, to_free); 231 232 prev_qlen -= sch->q.qlen; 233 prev_backlog -= sch->qstats.backlog; 234 q->drop_overlimit += prev_qlen; 235 if (memory_limited) 236 q->drop_overmemory += prev_qlen; 237 238 /* As we dropped packet(s), better let upper stack know this. 239 * If we dropped a packet for this flow, return NET_XMIT_CN, 240 * but in this case, our parents wont increase their backlogs. 241 */ 242 if (ret == idx) { 243 qdisc_tree_reduce_backlog(sch, prev_qlen - 1, 244 prev_backlog - pkt_len); 245 return NET_XMIT_CN; 246 } 247 qdisc_tree_reduce_backlog(sch, prev_qlen, prev_backlog); 248 return NET_XMIT_SUCCESS; 249 } 250 251 /* This is the specific function called from codel_dequeue() 252 * to dequeue a packet from queue. Note: backlog is handled in 253 * codel, we dont need to reduce it here. 254 */ 255 static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx) 256 { 257 struct Qdisc *sch = ctx; 258 struct fq_codel_sched_data *q = qdisc_priv(sch); 259 struct fq_codel_flow *flow; 260 struct sk_buff *skb = NULL; 261 262 flow = container_of(vars, struct fq_codel_flow, cvars); 263 if (flow->head) { 264 skb = dequeue_head(flow); 265 q->backlogs[flow - q->flows] -= qdisc_pkt_len(skb); 266 q->memory_usage -= get_codel_cb(skb)->mem_usage; 267 sch->q.qlen--; 268 sch->qstats.backlog -= qdisc_pkt_len(skb); 269 } 270 return skb; 271 } 272 273 static void drop_func(struct sk_buff *skb, void *ctx) 274 { 275 struct Qdisc *sch = ctx; 276 277 kfree_skb(skb); 278 qdisc_qstats_drop(sch); 279 } 280 281 static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch) 282 { 283 struct fq_codel_sched_data *q = qdisc_priv(sch); 284 struct sk_buff *skb; 285 struct fq_codel_flow *flow; 286 struct list_head *head; 287 288 begin: 289 head = &q->new_flows; 290 if (list_empty(head)) { 291 head = &q->old_flows; 292 if (list_empty(head)) 293 return NULL; 294 } 295 flow = list_first_entry(head, struct fq_codel_flow, flowchain); 296 297 if (flow->deficit <= 0) { 298 flow->deficit += q->quantum; 299 list_move_tail(&flow->flowchain, &q->old_flows); 300 goto begin; 301 } 302 303 skb = codel_dequeue(sch, &sch->qstats.backlog, &q->cparams, 304 &flow->cvars, &q->cstats, qdisc_pkt_len, 305 codel_get_enqueue_time, drop_func, dequeue_func); 306 307 if (!skb) { 308 /* force a pass through old_flows to prevent starvation */ 309 if ((head == &q->new_flows) && !list_empty(&q->old_flows)) 310 list_move_tail(&flow->flowchain, &q->old_flows); 311 else 312 list_del_init(&flow->flowchain); 313 goto begin; 314 } 315 qdisc_bstats_update(sch, skb); 316 flow->deficit -= qdisc_pkt_len(skb); 317 /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0, 318 * or HTB crashes. Defer it for next round. 319 */ 320 if (q->cstats.drop_count && sch->q.qlen) { 321 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, 322 q->cstats.drop_len); 323 q->cstats.drop_count = 0; 324 q->cstats.drop_len = 0; 325 } 326 return skb; 327 } 328 329 static void fq_codel_flow_purge(struct fq_codel_flow *flow) 330 { 331 rtnl_kfree_skbs(flow->head, flow->tail); 332 flow->head = NULL; 333 } 334 335 static void fq_codel_reset(struct Qdisc *sch) 336 { 337 struct fq_codel_sched_data *q = qdisc_priv(sch); 338 int i; 339 340 INIT_LIST_HEAD(&q->new_flows); 341 INIT_LIST_HEAD(&q->old_flows); 342 for (i = 0; i < q->flows_cnt; i++) { 343 struct fq_codel_flow *flow = q->flows + i; 344 345 fq_codel_flow_purge(flow); 346 INIT_LIST_HEAD(&flow->flowchain); 347 codel_vars_init(&flow->cvars); 348 } 349 memset(q->backlogs, 0, q->flows_cnt * sizeof(u32)); 350 sch->q.qlen = 0; 351 sch->qstats.backlog = 0; 352 q->memory_usage = 0; 353 } 354 355 static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = { 356 [TCA_FQ_CODEL_TARGET] = { .type = NLA_U32 }, 357 [TCA_FQ_CODEL_LIMIT] = { .type = NLA_U32 }, 358 [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 }, 359 [TCA_FQ_CODEL_ECN] = { .type = NLA_U32 }, 360 [TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 }, 361 [TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 }, 362 [TCA_FQ_CODEL_CE_THRESHOLD] = { .type = NLA_U32 }, 363 [TCA_FQ_CODEL_DROP_BATCH_SIZE] = { .type = NLA_U32 }, 364 [TCA_FQ_CODEL_MEMORY_LIMIT] = { .type = NLA_U32 }, 365 }; 366 367 static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt, 368 struct netlink_ext_ack *extack) 369 { 370 struct fq_codel_sched_data *q = qdisc_priv(sch); 371 struct nlattr *tb[TCA_FQ_CODEL_MAX + 1]; 372 int err; 373 374 if (!opt) 375 return -EINVAL; 376 377 err = nla_parse_nested_deprecated(tb, TCA_FQ_CODEL_MAX, opt, 378 fq_codel_policy, NULL); 379 if (err < 0) 380 return err; 381 if (tb[TCA_FQ_CODEL_FLOWS]) { 382 if (q->flows) 383 return -EINVAL; 384 q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]); 385 if (!q->flows_cnt || 386 q->flows_cnt > 65536) 387 return -EINVAL; 388 } 389 sch_tree_lock(sch); 390 391 if (tb[TCA_FQ_CODEL_TARGET]) { 392 u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]); 393 394 q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT; 395 } 396 397 if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) { 398 u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]); 399 400 q->cparams.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT; 401 } 402 403 if (tb[TCA_FQ_CODEL_INTERVAL]) { 404 u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]); 405 406 q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT; 407 } 408 409 if (tb[TCA_FQ_CODEL_LIMIT]) 410 sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]); 411 412 if (tb[TCA_FQ_CODEL_ECN]) 413 q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]); 414 415 if (tb[TCA_FQ_CODEL_QUANTUM]) 416 q->quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM])); 417 418 if (tb[TCA_FQ_CODEL_DROP_BATCH_SIZE]) 419 q->drop_batch_size = max(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])); 420 421 if (tb[TCA_FQ_CODEL_MEMORY_LIMIT]) 422 q->memory_limit = min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT])); 423 424 while (sch->q.qlen > sch->limit || 425 q->memory_usage > q->memory_limit) { 426 struct sk_buff *skb = fq_codel_dequeue(sch); 427 428 q->cstats.drop_len += qdisc_pkt_len(skb); 429 rtnl_kfree_skbs(skb, skb); 430 q->cstats.drop_count++; 431 } 432 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, q->cstats.drop_len); 433 q->cstats.drop_count = 0; 434 q->cstats.drop_len = 0; 435 436 sch_tree_unlock(sch); 437 return 0; 438 } 439 440 static void fq_codel_destroy(struct Qdisc *sch) 441 { 442 struct fq_codel_sched_data *q = qdisc_priv(sch); 443 444 tcf_block_put(q->block); 445 kvfree(q->backlogs); 446 kvfree(q->flows); 447 } 448 449 static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt, 450 struct netlink_ext_ack *extack) 451 { 452 struct fq_codel_sched_data *q = qdisc_priv(sch); 453 int i; 454 int err; 455 456 sch->limit = 10*1024; 457 q->flows_cnt = 1024; 458 q->memory_limit = 32 << 20; /* 32 MBytes */ 459 q->drop_batch_size = 64; 460 q->quantum = psched_mtu(qdisc_dev(sch)); 461 INIT_LIST_HEAD(&q->new_flows); 462 INIT_LIST_HEAD(&q->old_flows); 463 codel_params_init(&q->cparams); 464 codel_stats_init(&q->cstats); 465 q->cparams.ecn = true; 466 q->cparams.mtu = psched_mtu(qdisc_dev(sch)); 467 468 if (opt) { 469 err = fq_codel_change(sch, opt, extack); 470 if (err) 471 goto init_failure; 472 } 473 474 err = tcf_block_get(&q->block, &q->filter_list, sch, extack); 475 if (err) 476 goto init_failure; 477 478 if (!q->flows) { 479 q->flows = kvcalloc(q->flows_cnt, 480 sizeof(struct fq_codel_flow), 481 GFP_KERNEL); 482 if (!q->flows) { 483 err = -ENOMEM; 484 goto init_failure; 485 } 486 q->backlogs = kvcalloc(q->flows_cnt, sizeof(u32), GFP_KERNEL); 487 if (!q->backlogs) { 488 err = -ENOMEM; 489 goto alloc_failure; 490 } 491 for (i = 0; i < q->flows_cnt; i++) { 492 struct fq_codel_flow *flow = q->flows + i; 493 494 INIT_LIST_HEAD(&flow->flowchain); 495 codel_vars_init(&flow->cvars); 496 } 497 } 498 if (sch->limit >= 1) 499 sch->flags |= TCQ_F_CAN_BYPASS; 500 else 501 sch->flags &= ~TCQ_F_CAN_BYPASS; 502 return 0; 503 504 alloc_failure: 505 kvfree(q->flows); 506 q->flows = NULL; 507 init_failure: 508 q->flows_cnt = 0; 509 return err; 510 } 511 512 static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb) 513 { 514 struct fq_codel_sched_data *q = qdisc_priv(sch); 515 struct nlattr *opts; 516 517 opts = nla_nest_start_noflag(skb, TCA_OPTIONS); 518 if (opts == NULL) 519 goto nla_put_failure; 520 521 if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET, 522 codel_time_to_us(q->cparams.target)) || 523 nla_put_u32(skb, TCA_FQ_CODEL_LIMIT, 524 sch->limit) || 525 nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL, 526 codel_time_to_us(q->cparams.interval)) || 527 nla_put_u32(skb, TCA_FQ_CODEL_ECN, 528 q->cparams.ecn) || 529 nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM, 530 q->quantum) || 531 nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE, 532 q->drop_batch_size) || 533 nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT, 534 q->memory_limit) || 535 nla_put_u32(skb, TCA_FQ_CODEL_FLOWS, 536 q->flows_cnt)) 537 goto nla_put_failure; 538 539 if (q->cparams.ce_threshold != CODEL_DISABLED_THRESHOLD && 540 nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD, 541 codel_time_to_us(q->cparams.ce_threshold))) 542 goto nla_put_failure; 543 544 return nla_nest_end(skb, opts); 545 546 nla_put_failure: 547 return -1; 548 } 549 550 static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d) 551 { 552 struct fq_codel_sched_data *q = qdisc_priv(sch); 553 struct tc_fq_codel_xstats st = { 554 .type = TCA_FQ_CODEL_XSTATS_QDISC, 555 }; 556 struct list_head *pos; 557 558 st.qdisc_stats.maxpacket = q->cstats.maxpacket; 559 st.qdisc_stats.drop_overlimit = q->drop_overlimit; 560 st.qdisc_stats.ecn_mark = q->cstats.ecn_mark; 561 st.qdisc_stats.new_flow_count = q->new_flow_count; 562 st.qdisc_stats.ce_mark = q->cstats.ce_mark; 563 st.qdisc_stats.memory_usage = q->memory_usage; 564 st.qdisc_stats.drop_overmemory = q->drop_overmemory; 565 566 sch_tree_lock(sch); 567 list_for_each(pos, &q->new_flows) 568 st.qdisc_stats.new_flows_len++; 569 570 list_for_each(pos, &q->old_flows) 571 st.qdisc_stats.old_flows_len++; 572 sch_tree_unlock(sch); 573 574 return gnet_stats_copy_app(d, &st, sizeof(st)); 575 } 576 577 static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg) 578 { 579 return NULL; 580 } 581 582 static unsigned long fq_codel_find(struct Qdisc *sch, u32 classid) 583 { 584 return 0; 585 } 586 587 static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent, 588 u32 classid) 589 { 590 return 0; 591 } 592 593 static void fq_codel_unbind(struct Qdisc *q, unsigned long cl) 594 { 595 } 596 597 static struct tcf_block *fq_codel_tcf_block(struct Qdisc *sch, unsigned long cl, 598 struct netlink_ext_ack *extack) 599 { 600 struct fq_codel_sched_data *q = qdisc_priv(sch); 601 602 if (cl) 603 return NULL; 604 return q->block; 605 } 606 607 static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl, 608 struct sk_buff *skb, struct tcmsg *tcm) 609 { 610 tcm->tcm_handle |= TC_H_MIN(cl); 611 return 0; 612 } 613 614 static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl, 615 struct gnet_dump *d) 616 { 617 struct fq_codel_sched_data *q = qdisc_priv(sch); 618 u32 idx = cl - 1; 619 struct gnet_stats_queue qs = { 0 }; 620 struct tc_fq_codel_xstats xstats; 621 622 if (idx < q->flows_cnt) { 623 const struct fq_codel_flow *flow = &q->flows[idx]; 624 const struct sk_buff *skb; 625 626 memset(&xstats, 0, sizeof(xstats)); 627 xstats.type = TCA_FQ_CODEL_XSTATS_CLASS; 628 xstats.class_stats.deficit = flow->deficit; 629 xstats.class_stats.ldelay = 630 codel_time_to_us(flow->cvars.ldelay); 631 xstats.class_stats.count = flow->cvars.count; 632 xstats.class_stats.lastcount = flow->cvars.lastcount; 633 xstats.class_stats.dropping = flow->cvars.dropping; 634 if (flow->cvars.dropping) { 635 codel_tdiff_t delta = flow->cvars.drop_next - 636 codel_get_time(); 637 638 xstats.class_stats.drop_next = (delta >= 0) ? 639 codel_time_to_us(delta) : 640 -codel_time_to_us(-delta); 641 } 642 if (flow->head) { 643 sch_tree_lock(sch); 644 skb = flow->head; 645 while (skb) { 646 qs.qlen++; 647 skb = skb->next; 648 } 649 sch_tree_unlock(sch); 650 } 651 qs.backlog = q->backlogs[idx]; 652 qs.drops = 0; 653 } 654 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0) 655 return -1; 656 if (idx < q->flows_cnt) 657 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 658 return 0; 659 } 660 661 static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg) 662 { 663 struct fq_codel_sched_data *q = qdisc_priv(sch); 664 unsigned int i; 665 666 if (arg->stop) 667 return; 668 669 for (i = 0; i < q->flows_cnt; i++) { 670 if (list_empty(&q->flows[i].flowchain) || 671 arg->count < arg->skip) { 672 arg->count++; 673 continue; 674 } 675 if (arg->fn(sch, i + 1, arg) < 0) { 676 arg->stop = 1; 677 break; 678 } 679 arg->count++; 680 } 681 } 682 683 static const struct Qdisc_class_ops fq_codel_class_ops = { 684 .leaf = fq_codel_leaf, 685 .find = fq_codel_find, 686 .tcf_block = fq_codel_tcf_block, 687 .bind_tcf = fq_codel_bind, 688 .unbind_tcf = fq_codel_unbind, 689 .dump = fq_codel_dump_class, 690 .dump_stats = fq_codel_dump_class_stats, 691 .walk = fq_codel_walk, 692 }; 693 694 static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = { 695 .cl_ops = &fq_codel_class_ops, 696 .id = "fq_codel", 697 .priv_size = sizeof(struct fq_codel_sched_data), 698 .enqueue = fq_codel_enqueue, 699 .dequeue = fq_codel_dequeue, 700 .peek = qdisc_peek_dequeued, 701 .init = fq_codel_init, 702 .reset = fq_codel_reset, 703 .destroy = fq_codel_destroy, 704 .change = fq_codel_change, 705 .dump = fq_codel_dump, 706 .dump_stats = fq_codel_dump_stats, 707 .owner = THIS_MODULE, 708 }; 709 710 static int __init fq_codel_module_init(void) 711 { 712 return register_qdisc(&fq_codel_qdisc_ops); 713 } 714 715 static void __exit fq_codel_module_exit(void) 716 { 717 unregister_qdisc(&fq_codel_qdisc_ops); 718 } 719 720 module_init(fq_codel_module_init) 721 module_exit(fq_codel_module_exit) 722 MODULE_AUTHOR("Eric Dumazet"); 723 MODULE_LICENSE("GPL"); 724 MODULE_DESCRIPTION("Fair Queue CoDel discipline"); 725