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