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 42struct 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 50struct 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 70static 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 76static 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 fallthrough; 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 */ 116static 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) */ 126static 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 137static 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 184static 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 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 */ 255static 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 273static 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 281static 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 288begin: 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 329static 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 335static 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 q->memory_usage = 0; 351} 352 353static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = { 354 [TCA_FQ_CODEL_TARGET] = { .type = NLA_U32 }, 355 [TCA_FQ_CODEL_LIMIT] = { .type = NLA_U32 }, 356 [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 }, 357 [TCA_FQ_CODEL_ECN] = { .type = NLA_U32 }, 358 [TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 }, 359 [TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 }, 360 [TCA_FQ_CODEL_CE_THRESHOLD] = { .type = NLA_U32 }, 361 [TCA_FQ_CODEL_DROP_BATCH_SIZE] = { .type = NLA_U32 }, 362 [TCA_FQ_CODEL_MEMORY_LIMIT] = { .type = NLA_U32 }, 363}; 364 365static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt, 366 struct netlink_ext_ack *extack) 367{ 368 struct fq_codel_sched_data *q = qdisc_priv(sch); 369 struct nlattr *tb[TCA_FQ_CODEL_MAX + 1]; 370 u32 quantum = 0; 371 int err; 372 373 if (!opt) 374 return -EINVAL; 375 376 err = nla_parse_nested_deprecated(tb, TCA_FQ_CODEL_MAX, opt, 377 fq_codel_policy, NULL); 378 if (err < 0) 379 return err; 380 if (tb[TCA_FQ_CODEL_FLOWS]) { 381 if (q->flows) 382 return -EINVAL; 383 q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]); 384 if (!q->flows_cnt || 385 q->flows_cnt > 65536) 386 return -EINVAL; 387 } 388 if (tb[TCA_FQ_CODEL_QUANTUM]) { 389 quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM])); 390 if (quantum > FQ_CODEL_QUANTUM_MAX) { 391 NL_SET_ERR_MSG(extack, "Invalid quantum"); 392 return -EINVAL; 393 } 394 } 395 sch_tree_lock(sch); 396 397 if (tb[TCA_FQ_CODEL_TARGET]) { 398 u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]); 399 400 q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT; 401 } 402 403 if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) { 404 u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]); 405 406 q->cparams.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT; 407 } 408 409 if (tb[TCA_FQ_CODEL_INTERVAL]) { 410 u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]); 411 412 q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT; 413 } 414 415 if (tb[TCA_FQ_CODEL_LIMIT]) 416 sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]); 417 418 if (tb[TCA_FQ_CODEL_ECN]) 419 q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]); 420 421 if (quantum) 422 q->quantum = quantum; 423 424 if (tb[TCA_FQ_CODEL_DROP_BATCH_SIZE]) 425 q->drop_batch_size = max(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])); 426 427 if (tb[TCA_FQ_CODEL_MEMORY_LIMIT]) 428 q->memory_limit = min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT])); 429 430 while (sch->q.qlen > sch->limit || 431 q->memory_usage > q->memory_limit) { 432 struct sk_buff *skb = fq_codel_dequeue(sch); 433 434 q->cstats.drop_len += qdisc_pkt_len(skb); 435 rtnl_kfree_skbs(skb, skb); 436 q->cstats.drop_count++; 437 } 438 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, q->cstats.drop_len); 439 q->cstats.drop_count = 0; 440 q->cstats.drop_len = 0; 441 442 sch_tree_unlock(sch); 443 return 0; 444} 445 446static void fq_codel_destroy(struct Qdisc *sch) 447{ 448 struct fq_codel_sched_data *q = qdisc_priv(sch); 449 450 tcf_block_put(q->block); 451 kvfree(q->backlogs); 452 kvfree(q->flows); 453} 454 455static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt, 456 struct netlink_ext_ack *extack) 457{ 458 struct fq_codel_sched_data *q = qdisc_priv(sch); 459 int i; 460 int err; 461 462 sch->limit = 10*1024; 463 q->flows_cnt = 1024; 464 q->memory_limit = 32 << 20; /* 32 MBytes */ 465 q->drop_batch_size = 64; 466 q->quantum = psched_mtu(qdisc_dev(sch)); 467 INIT_LIST_HEAD(&q->new_flows); 468 INIT_LIST_HEAD(&q->old_flows); 469 codel_params_init(&q->cparams); 470 codel_stats_init(&q->cstats); 471 q->cparams.ecn = true; 472 q->cparams.mtu = psched_mtu(qdisc_dev(sch)); 473 474 if (opt) { 475 err = fq_codel_change(sch, opt, extack); 476 if (err) 477 goto init_failure; 478 } 479 480 err = tcf_block_get(&q->block, &q->filter_list, sch, extack); 481 if (err) 482 goto init_failure; 483 484 if (!q->flows) { 485 q->flows = kvcalloc(q->flows_cnt, 486 sizeof(struct fq_codel_flow), 487 GFP_KERNEL); 488 if (!q->flows) { 489 err = -ENOMEM; 490 goto init_failure; 491 } 492 q->backlogs = kvcalloc(q->flows_cnt, sizeof(u32), GFP_KERNEL); 493 if (!q->backlogs) { 494 err = -ENOMEM; 495 goto alloc_failure; 496 } 497 for (i = 0; i < q->flows_cnt; i++) { 498 struct fq_codel_flow *flow = q->flows + i; 499 500 INIT_LIST_HEAD(&flow->flowchain); 501 codel_vars_init(&flow->cvars); 502 } 503 } 504 if (sch->limit >= 1) 505 sch->flags |= TCQ_F_CAN_BYPASS; 506 else 507 sch->flags &= ~TCQ_F_CAN_BYPASS; 508 return 0; 509 510alloc_failure: 511 kvfree(q->flows); 512 q->flows = NULL; 513init_failure: 514 q->flows_cnt = 0; 515 return err; 516} 517 518static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb) 519{ 520 struct fq_codel_sched_data *q = qdisc_priv(sch); 521 struct nlattr *opts; 522 523 opts = nla_nest_start_noflag(skb, TCA_OPTIONS); 524 if (opts == NULL) 525 goto nla_put_failure; 526 527 if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET, 528 codel_time_to_us(q->cparams.target)) || 529 nla_put_u32(skb, TCA_FQ_CODEL_LIMIT, 530 sch->limit) || 531 nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL, 532 codel_time_to_us(q->cparams.interval)) || 533 nla_put_u32(skb, TCA_FQ_CODEL_ECN, 534 q->cparams.ecn) || 535 nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM, 536 q->quantum) || 537 nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE, 538 q->drop_batch_size) || 539 nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT, 540 q->memory_limit) || 541 nla_put_u32(skb, TCA_FQ_CODEL_FLOWS, 542 q->flows_cnt)) 543 goto nla_put_failure; 544 545 if (q->cparams.ce_threshold != CODEL_DISABLED_THRESHOLD && 546 nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD, 547 codel_time_to_us(q->cparams.ce_threshold))) 548 goto nla_put_failure; 549 550 return nla_nest_end(skb, opts); 551 552nla_put_failure: 553 return -1; 554} 555 556static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d) 557{ 558 struct fq_codel_sched_data *q = qdisc_priv(sch); 559 struct tc_fq_codel_xstats st = { 560 .type = TCA_FQ_CODEL_XSTATS_QDISC, 561 }; 562 struct list_head *pos; 563 564 st.qdisc_stats.maxpacket = q->cstats.maxpacket; 565 st.qdisc_stats.drop_overlimit = q->drop_overlimit; 566 st.qdisc_stats.ecn_mark = q->cstats.ecn_mark; 567 st.qdisc_stats.new_flow_count = q->new_flow_count; 568 st.qdisc_stats.ce_mark = q->cstats.ce_mark; 569 st.qdisc_stats.memory_usage = q->memory_usage; 570 st.qdisc_stats.drop_overmemory = q->drop_overmemory; 571 572 sch_tree_lock(sch); 573 list_for_each(pos, &q->new_flows) 574 st.qdisc_stats.new_flows_len++; 575 576 list_for_each(pos, &q->old_flows) 577 st.qdisc_stats.old_flows_len++; 578 sch_tree_unlock(sch); 579 580 return gnet_stats_copy_app(d, &st, sizeof(st)); 581} 582 583static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg) 584{ 585 return NULL; 586} 587 588static unsigned long fq_codel_find(struct Qdisc *sch, u32 classid) 589{ 590 return 0; 591} 592 593static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent, 594 u32 classid) 595{ 596 return 0; 597} 598 599static void fq_codel_unbind(struct Qdisc *q, unsigned long cl) 600{ 601} 602 603static struct tcf_block *fq_codel_tcf_block(struct Qdisc *sch, unsigned long cl, 604 struct netlink_ext_ack *extack) 605{ 606 struct fq_codel_sched_data *q = qdisc_priv(sch); 607 608 if (cl) 609 return NULL; 610 return q->block; 611} 612 613static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl, 614 struct sk_buff *skb, struct tcmsg *tcm) 615{ 616 tcm->tcm_handle |= TC_H_MIN(cl); 617 return 0; 618} 619 620static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl, 621 struct gnet_dump *d) 622{ 623 struct fq_codel_sched_data *q = qdisc_priv(sch); 624 u32 idx = cl - 1; 625 struct gnet_stats_queue qs = { 0 }; 626 struct tc_fq_codel_xstats xstats; 627 628 if (idx < q->flows_cnt) { 629 const struct fq_codel_flow *flow = &q->flows[idx]; 630 const struct sk_buff *skb; 631 632 memset(&xstats, 0, sizeof(xstats)); 633 xstats.type = TCA_FQ_CODEL_XSTATS_CLASS; 634 xstats.class_stats.deficit = flow->deficit; 635 xstats.class_stats.ldelay = 636 codel_time_to_us(flow->cvars.ldelay); 637 xstats.class_stats.count = flow->cvars.count; 638 xstats.class_stats.lastcount = flow->cvars.lastcount; 639 xstats.class_stats.dropping = flow->cvars.dropping; 640 if (flow->cvars.dropping) { 641 codel_tdiff_t delta = flow->cvars.drop_next - 642 codel_get_time(); 643 644 xstats.class_stats.drop_next = (delta >= 0) ? 645 codel_time_to_us(delta) : 646 -codel_time_to_us(-delta); 647 } 648 if (flow->head) { 649 sch_tree_lock(sch); 650 skb = flow->head; 651 while (skb) { 652 qs.qlen++; 653 skb = skb->next; 654 } 655 sch_tree_unlock(sch); 656 } 657 qs.backlog = q->backlogs[idx]; 658 qs.drops = 0; 659 } 660 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0) 661 return -1; 662 if (idx < q->flows_cnt) 663 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 664 return 0; 665} 666 667static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg) 668{ 669 struct fq_codel_sched_data *q = qdisc_priv(sch); 670 unsigned int i; 671 672 if (arg->stop) 673 return; 674 675 for (i = 0; i < q->flows_cnt; i++) { 676 if (list_empty(&q->flows[i].flowchain) || 677 arg->count < arg->skip) { 678 arg->count++; 679 continue; 680 } 681 if (arg->fn(sch, i + 1, arg) < 0) { 682 arg->stop = 1; 683 break; 684 } 685 arg->count++; 686 } 687} 688 689static const struct Qdisc_class_ops fq_codel_class_ops = { 690 .leaf = fq_codel_leaf, 691 .find = fq_codel_find, 692 .tcf_block = fq_codel_tcf_block, 693 .bind_tcf = fq_codel_bind, 694 .unbind_tcf = fq_codel_unbind, 695 .dump = fq_codel_dump_class, 696 .dump_stats = fq_codel_dump_class_stats, 697 .walk = fq_codel_walk, 698}; 699 700static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = { 701 .cl_ops = &fq_codel_class_ops, 702 .id = "fq_codel", 703 .priv_size = sizeof(struct fq_codel_sched_data), 704 .enqueue = fq_codel_enqueue, 705 .dequeue = fq_codel_dequeue, 706 .peek = qdisc_peek_dequeued, 707 .init = fq_codel_init, 708 .reset = fq_codel_reset, 709 .destroy = fq_codel_destroy, 710 .change = fq_codel_change, 711 .dump = fq_codel_dump, 712 .dump_stats = fq_codel_dump_stats, 713 .owner = THIS_MODULE, 714}; 715 716static int __init fq_codel_module_init(void) 717{ 718 return register_qdisc(&fq_codel_qdisc_ops); 719} 720 721static void __exit fq_codel_module_exit(void) 722{ 723 unregister_qdisc(&fq_codel_qdisc_ops); 724} 725 726module_init(fq_codel_module_init) 727module_exit(fq_codel_module_exit) 728MODULE_AUTHOR("Eric Dumazet"); 729MODULE_LICENSE("GPL"); 730MODULE_DESCRIPTION("Fair Queue CoDel discipline"); 731