1 // SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause 2 /* Copyright (C) 2024 Nokia 3 * 4 * Author: Koen De Schepper <koen.de_schepper@nokia-bell-labs.com> 5 * Author: Olga Albisser <olga@albisser.org> 6 * Author: Henrik Steen <henrist@henrist.net> 7 * Author: Olivier Tilmans <olivier.tilmans@nokia.com> 8 * Author: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> 9 * 10 * DualPI Improved with a Square (dualpi2): 11 * - Supports congestion controls that comply with the Prague requirements 12 * in RFC9331 (e.g. TCP-Prague) 13 * - Supports coupled dual-queue with PI2 as defined in RFC9332 14 * - Supports ECN L4S-identifier (IP.ECN==0b*1) 15 * 16 * note: Although DCTCP and BBRv3 can use shallow-threshold ECN marks, 17 * they do not meet the 'Prague L4S Requirements' listed in RFC 9331 18 * Section 4, so they can only be used with DualPI2 in a datacenter 19 * context. 20 * 21 * References: 22 * - RFC9332: https://datatracker.ietf.org/doc/html/rfc9332 23 * - De Schepper, Koen, et al. "PI 2: A linearized AQM for both classic and 24 * scalable TCP." in proc. ACM CoNEXT'16, 2016. 25 */ 26 27 #include <linux/errno.h> 28 #include <linux/hrtimer.h> 29 #include <linux/if_vlan.h> 30 #include <linux/kernel.h> 31 #include <linux/limits.h> 32 #include <linux/module.h> 33 #include <linux/skbuff.h> 34 #include <linux/types.h> 35 36 #include <net/gso.h> 37 #include <net/inet_ecn.h> 38 #include <net/pkt_cls.h> 39 #include <net/pkt_sched.h> 40 41 /* 32b enable to support flows with windows up to ~8.6 * 1e9 packets 42 * i.e., twice the maximal snd_cwnd. 43 * MAX_PROB must be consistent with the RNG in dualpi2_roll(). 44 */ 45 #define MAX_PROB U32_MAX 46 47 /* alpha/beta values exchanged over netlink are in units of 256ns */ 48 #define ALPHA_BETA_SHIFT 8 49 50 /* Scaled values of alpha/beta must fit in 32b to avoid overflow in later 51 * computations. Consequently (see and dualpi2_scale_alpha_beta()), their 52 * netlink-provided values can use at most 31b, i.e. be at most (2^23)-1 53 * (~4MHz) as those are given in 1/256th. This enable to tune alpha/beta to 54 * control flows whose maximal RTTs can be in usec up to few secs. 55 */ 56 #define ALPHA_BETA_MAX ((1U << 31) - 1) 57 58 /* Internal alpha/beta are in units of 64ns. 59 * This enables to use all alpha/beta values in the allowed range without loss 60 * of precision due to rounding when scaling them internally, e.g., 61 * scale_alpha_beta(1) will not round down to 0. 62 */ 63 #define ALPHA_BETA_GRANULARITY 6 64 65 #define ALPHA_BETA_SCALING (ALPHA_BETA_SHIFT - ALPHA_BETA_GRANULARITY) 66 67 /* We express the weights (wc, wl) in %, i.e., wc + wl = 100 */ 68 #define MAX_WC 100 69 70 struct dualpi2_sched_data { 71 struct Qdisc *l_queue; /* The L4S Low latency queue (L-queue) */ 72 struct Qdisc *sch; /* The Classic queue (C-queue) */ 73 74 /* Registered tc filters */ 75 struct tcf_proto __rcu *tcf_filters; 76 struct tcf_block *tcf_block; 77 78 /* PI2 parameters */ 79 u64 pi2_target; /* Target delay in nanoseconds */ 80 u32 pi2_tupdate; /* Timer frequency in nanoseconds */ 81 u32 pi2_prob; /* Base PI probability */ 82 u32 pi2_alpha; /* Gain factor for the integral rate response */ 83 u32 pi2_beta; /* Gain factor for the proportional response */ 84 struct hrtimer pi2_timer; /* prob update timer */ 85 86 /* Step AQM (L-queue only) parameters */ 87 u32 step_thresh; /* Step threshold */ 88 bool step_in_packets; /* Step thresh in packets (1) or time (0) */ 89 90 /* C-queue starvation protection */ 91 s32 c_protection_credit; /* Credit (sign indicates which queue) */ 92 s32 c_protection_init; /* Reset value of the credit */ 93 u8 c_protection_wc; /* C-queue weight (between 0 and MAX_WC) */ 94 u8 c_protection_wl; /* L-queue weight (MAX_WC - wc) */ 95 96 /* General dualQ parameters */ 97 u32 memory_limit; /* Memory limit of both queues */ 98 u8 coupling_factor;/* Coupling factor (k) between both queues */ 99 u8 ecn_mask; /* Mask to match packets into L-queue */ 100 u32 min_qlen_step; /* Minimum queue length to apply step thresh */ 101 bool drop_early; /* Drop at enqueue (1) instead of dequeue (0) */ 102 bool drop_overload; /* Drop (1) on overload, or overflow (0) */ 103 bool split_gso; /* Split aggregated skb (1) or leave as is (0) */ 104 105 /* Statistics */ 106 u64 c_head_ts; /* Enqueue timestamp of the C-queue head */ 107 u64 l_head_ts; /* Enqueue timestamp of the L-queue head */ 108 u64 last_qdelay; /* Q delay val at the last probability update */ 109 u32 packets_in_c; /* Enqueue packet counter of the C-queue */ 110 u32 packets_in_l; /* Enqueue packet counter of the L-queue */ 111 u32 maxq; /* Maximum queue size of the C-queue */ 112 u32 ecn_mark; /* ECN mark pkt counter due to PI probability */ 113 u32 step_marks; /* ECN mark pkt counter due to step AQM */ 114 u32 memory_used; /* Memory used of both queues */ 115 u32 max_memory_used;/* Maximum used memory */ 116 117 /* Deferred drop statistics */ 118 u32 deferred_drops_cnt; /* Packets dropped */ 119 u32 deferred_drops_len; /* Bytes dropped */ 120 }; 121 122 struct dualpi2_skb_cb { 123 u64 ts; /* Timestamp at enqueue */ 124 u8 apply_step:1, /* Can we apply the step threshold */ 125 classified:2, /* Packet classification results */ 126 ect:2; /* Packet ECT codepoint */ 127 }; 128 129 enum dualpi2_classification_results { 130 DUALPI2_C_CLASSIC = 0, /* C-queue */ 131 DUALPI2_C_L4S = 1, /* L-queue (scale mark/classic drop) */ 132 DUALPI2_C_LLLL = 2, /* L-queue (no drops/marks) */ 133 __DUALPI2_C_MAX /* Keep last*/ 134 }; 135 136 static struct dualpi2_skb_cb *dualpi2_skb_cb(struct sk_buff *skb) 137 { 138 qdisc_cb_private_validate(skb, sizeof(struct dualpi2_skb_cb)); 139 return (struct dualpi2_skb_cb *)qdisc_skb_cb(skb)->data; 140 } 141 142 static u64 dualpi2_sojourn_time(struct sk_buff *skb, u64 reference) 143 { 144 return reference - dualpi2_skb_cb(skb)->ts; 145 } 146 147 static u64 head_enqueue_time(struct Qdisc *q) 148 { 149 struct sk_buff *skb = qdisc_peek_head(q); 150 151 return skb ? dualpi2_skb_cb(skb)->ts : 0; 152 } 153 154 static u32 dualpi2_scale_alpha_beta(u32 param) 155 { 156 u64 tmp = ((u64)param * MAX_PROB >> ALPHA_BETA_SCALING); 157 158 do_div(tmp, NSEC_PER_SEC); 159 return tmp; 160 } 161 162 static u32 dualpi2_unscale_alpha_beta(u32 param) 163 { 164 u64 tmp = ((u64)param * NSEC_PER_SEC << ALPHA_BETA_SCALING); 165 166 do_div(tmp, MAX_PROB); 167 return tmp; 168 } 169 170 static ktime_t next_pi2_timeout(struct dualpi2_sched_data *q) 171 { 172 return ktime_add_ns(ktime_get_ns(), q->pi2_tupdate); 173 } 174 175 static bool skb_is_l4s(struct sk_buff *skb) 176 { 177 return dualpi2_skb_cb(skb)->classified == DUALPI2_C_L4S; 178 } 179 180 static bool skb_in_l_queue(struct sk_buff *skb) 181 { 182 return dualpi2_skb_cb(skb)->classified != DUALPI2_C_CLASSIC; 183 } 184 185 static bool skb_apply_step(struct sk_buff *skb, struct dualpi2_sched_data *q) 186 { 187 return skb_is_l4s(skb) && qdisc_qlen(q->l_queue) >= q->min_qlen_step; 188 } 189 190 static bool dualpi2_mark(struct dualpi2_sched_data *q, struct sk_buff *skb) 191 { 192 if (INET_ECN_set_ce(skb)) { 193 q->ecn_mark++; 194 return true; 195 } 196 return false; 197 } 198 199 static void dualpi2_reset_c_protection(struct dualpi2_sched_data *q) 200 { 201 q->c_protection_credit = q->c_protection_init; 202 } 203 204 /* This computes the initial credit value and WRR weight for the L queue (wl) 205 * from the weight of the C queue (wc). 206 * If wl > wc, the scheduler will start with the L queue when reset. 207 */ 208 static void dualpi2_calculate_c_protection(struct Qdisc *sch, 209 struct dualpi2_sched_data *q, u32 wc) 210 { 211 q->c_protection_wc = wc; 212 q->c_protection_wl = MAX_WC - wc; 213 q->c_protection_init = (s32)psched_mtu(qdisc_dev(sch)) * 214 ((int)q->c_protection_wc - (int)q->c_protection_wl); 215 dualpi2_reset_c_protection(q); 216 } 217 218 static bool dualpi2_roll(u32 prob) 219 { 220 return get_random_u32() <= prob; 221 } 222 223 /* Packets in the C-queue are subject to a marking probability pC, which is the 224 * square of the internal PI probability (i.e., have an overall lower mark/drop 225 * probability). If the qdisc is overloaded, ignore ECT values and only drop. 226 * 227 * Note that this marking scheme is also applied to L4S packets during overload. 228 * Return true if packet dropping is required in C queue 229 */ 230 static bool dualpi2_classic_marking(struct dualpi2_sched_data *q, 231 struct sk_buff *skb, u32 prob, 232 bool overload) 233 { 234 if (dualpi2_roll(prob) && dualpi2_roll(prob)) { 235 if (overload || dualpi2_skb_cb(skb)->ect == INET_ECN_NOT_ECT) 236 return true; 237 dualpi2_mark(q, skb); 238 } 239 return false; 240 } 241 242 /* Packets in the L-queue are subject to a marking probability pL given by the 243 * internal PI probability scaled by the coupling factor. 244 * 245 * On overload (i.e., @local_l_prob is >= 100%): 246 * - if the qdisc is configured to trade losses to preserve latency (i.e., 247 * @q->drop_overload), apply classic drops first before marking. 248 * - otherwise, preserve the "no loss" property of ECN at the cost of queueing 249 * delay, eventually resulting in taildrop behavior once sch->limit is 250 * reached. 251 * Return true if packet dropping is required in L queue 252 */ 253 static bool dualpi2_scalable_marking(struct dualpi2_sched_data *q, 254 struct sk_buff *skb, 255 u64 local_l_prob, u32 prob, 256 bool overload) 257 { 258 if (overload) { 259 /* Apply classic drop */ 260 if (!q->drop_overload || 261 !(dualpi2_roll(prob) && dualpi2_roll(prob))) 262 goto mark; 263 return true; 264 } 265 266 /* We can safely cut the upper 32b as overload==false */ 267 if (dualpi2_roll(local_l_prob)) { 268 /* Non-ECT packets could have classified as L4S by filters. */ 269 if (dualpi2_skb_cb(skb)->ect == INET_ECN_NOT_ECT) 270 return true; 271 mark: 272 dualpi2_mark(q, skb); 273 } 274 return false; 275 } 276 277 /* Decide whether a given packet must be dropped (or marked if ECT), according 278 * to the PI2 probability. 279 * 280 * Never mark/drop if we have a standing queue of less than 2 MTUs. 281 */ 282 static bool must_drop(struct Qdisc *sch, struct dualpi2_sched_data *q, 283 struct sk_buff *skb) 284 { 285 u64 local_l_prob; 286 bool overload; 287 u32 prob; 288 289 if (sch->qstats.backlog < 2 * psched_mtu(qdisc_dev(sch))) 290 return false; 291 292 prob = READ_ONCE(q->pi2_prob); 293 local_l_prob = (u64)prob * q->coupling_factor; 294 overload = local_l_prob > MAX_PROB; 295 296 switch (dualpi2_skb_cb(skb)->classified) { 297 case DUALPI2_C_CLASSIC: 298 return dualpi2_classic_marking(q, skb, prob, overload); 299 case DUALPI2_C_L4S: 300 return dualpi2_scalable_marking(q, skb, local_l_prob, prob, 301 overload); 302 default: /* DUALPI2_C_LLLL */ 303 return false; 304 } 305 } 306 307 static void dualpi2_read_ect(struct sk_buff *skb) 308 { 309 struct dualpi2_skb_cb *cb = dualpi2_skb_cb(skb); 310 int wlen = skb_network_offset(skb); 311 312 switch (skb_protocol(skb, true)) { 313 case htons(ETH_P_IP): 314 wlen += sizeof(struct iphdr); 315 if (!pskb_may_pull(skb, wlen) || 316 skb_try_make_writable(skb, wlen)) 317 goto not_ecn; 318 319 cb->ect = ipv4_get_dsfield(ip_hdr(skb)) & INET_ECN_MASK; 320 break; 321 case htons(ETH_P_IPV6): 322 wlen += sizeof(struct ipv6hdr); 323 if (!pskb_may_pull(skb, wlen) || 324 skb_try_make_writable(skb, wlen)) 325 goto not_ecn; 326 327 cb->ect = ipv6_get_dsfield(ipv6_hdr(skb)) & INET_ECN_MASK; 328 break; 329 default: 330 goto not_ecn; 331 } 332 return; 333 334 not_ecn: 335 /* Non pullable/writable packets can only be dropped hence are 336 * classified as not ECT. 337 */ 338 cb->ect = INET_ECN_NOT_ECT; 339 } 340 341 static int dualpi2_skb_classify(struct dualpi2_sched_data *q, 342 struct sk_buff *skb) 343 { 344 struct dualpi2_skb_cb *cb = dualpi2_skb_cb(skb); 345 struct tcf_result res; 346 struct tcf_proto *fl; 347 int result; 348 349 dualpi2_read_ect(skb); 350 if (cb->ect & q->ecn_mask) { 351 cb->classified = DUALPI2_C_L4S; 352 return NET_XMIT_SUCCESS; 353 } 354 355 if (TC_H_MAJ(skb->priority) == q->sch->handle && 356 TC_H_MIN(skb->priority) < __DUALPI2_C_MAX) { 357 cb->classified = TC_H_MIN(skb->priority); 358 return NET_XMIT_SUCCESS; 359 } 360 361 fl = rcu_dereference_bh(q->tcf_filters); 362 if (!fl) { 363 cb->classified = DUALPI2_C_CLASSIC; 364 return NET_XMIT_SUCCESS; 365 } 366 367 result = tcf_classify(skb, NULL, fl, &res, false); 368 if (result >= 0) { 369 #ifdef CONFIG_NET_CLS_ACT 370 switch (result) { 371 case TC_ACT_STOLEN: 372 case TC_ACT_QUEUED: 373 case TC_ACT_TRAP: 374 return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 375 case TC_ACT_SHOT: 376 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 377 } 378 #endif 379 cb->classified = TC_H_MIN(res.classid) < __DUALPI2_C_MAX ? 380 TC_H_MIN(res.classid) : DUALPI2_C_CLASSIC; 381 } 382 return NET_XMIT_SUCCESS; 383 } 384 385 static int dualpi2_enqueue_skb(struct sk_buff *skb, struct Qdisc *sch, 386 struct sk_buff **to_free) 387 { 388 struct dualpi2_sched_data *q = qdisc_priv(sch); 389 struct dualpi2_skb_cb *cb; 390 391 if (unlikely(qdisc_qlen(sch) >= sch->limit) || 392 unlikely((u64)q->memory_used + skb->truesize > q->memory_limit)) { 393 qdisc_qstats_overlimit(sch); 394 if (skb_in_l_queue(skb)) 395 qdisc_qstats_overlimit(q->l_queue); 396 return qdisc_drop_reason(skb, sch, to_free, 397 SKB_DROP_REASON_QDISC_OVERLIMIT); 398 } 399 400 if (q->drop_early && must_drop(sch, q, skb)) { 401 qdisc_drop_reason(skb, sch, to_free, 402 SKB_DROP_REASON_QDISC_CONGESTED); 403 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 404 } 405 406 cb = dualpi2_skb_cb(skb); 407 cb->ts = ktime_get_ns(); 408 q->memory_used += skb->truesize; 409 if (q->memory_used > q->max_memory_used) 410 q->max_memory_used = q->memory_used; 411 412 if (qdisc_qlen(sch) > q->maxq) 413 q->maxq = qdisc_qlen(sch); 414 415 if (skb_in_l_queue(skb)) { 416 /* Apply step thresh if skb is L4S && L-queue len >= min_qlen */ 417 dualpi2_skb_cb(skb)->apply_step = skb_apply_step(skb, q); 418 419 /* Keep the overall qdisc stats consistent */ 420 ++sch->q.qlen; 421 qdisc_qstats_backlog_inc(sch, skb); 422 ++q->packets_in_l; 423 if (!q->l_head_ts) 424 q->l_head_ts = cb->ts; 425 return qdisc_enqueue_tail(skb, q->l_queue); 426 } 427 ++q->packets_in_c; 428 if (!q->c_head_ts) 429 q->c_head_ts = cb->ts; 430 return qdisc_enqueue_tail(skb, sch); 431 } 432 433 /* By default, dualpi2 will split GSO skbs into independent skbs and enqueue 434 * each of those individually. This yields the following benefits, at the 435 * expense of CPU usage: 436 * - Finer-grained AQM actions as the sub-packets of a burst no longer share the 437 * same fate (e.g., the random mark/drop probability is applied individually) 438 * - Improved precision of the starvation protection/WRR scheduler at dequeue, 439 * as the size of the dequeued packets will be smaller. 440 */ 441 static int dualpi2_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch, 442 struct sk_buff **to_free) 443 { 444 struct dualpi2_sched_data *q = qdisc_priv(sch); 445 int err; 446 447 err = dualpi2_skb_classify(q, skb); 448 if (err != NET_XMIT_SUCCESS) { 449 if (err & __NET_XMIT_BYPASS) 450 qdisc_qstats_drop(sch); 451 __qdisc_drop(skb, to_free); 452 return err; 453 } 454 455 if (q->split_gso && skb_is_gso(skb)) { 456 netdev_features_t features; 457 struct sk_buff *nskb, *next; 458 int cnt, byte_len, orig_len; 459 int err; 460 461 features = netif_skb_features(skb); 462 nskb = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); 463 if (IS_ERR_OR_NULL(nskb)) 464 return qdisc_drop(skb, sch, to_free); 465 466 cnt = 1; 467 byte_len = 0; 468 orig_len = qdisc_pkt_len(skb); 469 skb_list_walk_safe(nskb, nskb, next) { 470 skb_mark_not_on_list(nskb); 471 472 /* Iterate through GSO fragments of an skb: 473 * (1) Set pkt_len from the single GSO fragments 474 * (2) Copy classified and ect values of an skb 475 * (3) Enqueue fragment & set ts in dualpi2_enqueue_skb 476 */ 477 qdisc_skb_cb(nskb)->pkt_len = nskb->len; 478 dualpi2_skb_cb(nskb)->classified = 479 dualpi2_skb_cb(skb)->classified; 480 dualpi2_skb_cb(nskb)->ect = dualpi2_skb_cb(skb)->ect; 481 err = dualpi2_enqueue_skb(nskb, sch, to_free); 482 483 if (err == NET_XMIT_SUCCESS) { 484 /* Compute the backlog adjustment that needs 485 * to be propagated in the qdisc tree to reflect 486 * all new skbs successfully enqueued. 487 */ 488 ++cnt; 489 byte_len += nskb->len; 490 } 491 } 492 if (cnt > 1) { 493 /* The caller will add the original skb stats to its 494 * backlog, compensate this if any nskb is enqueued. 495 */ 496 --cnt; 497 byte_len -= orig_len; 498 } 499 qdisc_tree_reduce_backlog(sch, -cnt, -byte_len); 500 consume_skb(skb); 501 return err; 502 } 503 return dualpi2_enqueue_skb(skb, sch, to_free); 504 } 505 506 /* Select the queue from which the next packet can be dequeued, ensuring that 507 * neither queue can starve the other with a WRR scheduler. 508 * 509 * The sign of the WRR credit determines the next queue, while the size of 510 * the dequeued packet determines the magnitude of the WRR credit change. If 511 * either queue is empty, the WRR credit is kept unchanged. 512 * 513 * As the dequeued packet can be dropped later, the caller has to perform the 514 * qdisc_bstats_update() calls. 515 */ 516 static struct sk_buff *dequeue_packet(struct Qdisc *sch, 517 struct dualpi2_sched_data *q, 518 int *credit_change, 519 u64 now) 520 { 521 struct sk_buff *skb = NULL; 522 int c_len; 523 524 *credit_change = 0; 525 c_len = qdisc_qlen(sch) - qdisc_qlen(q->l_queue); 526 if (qdisc_qlen(q->l_queue) && (!c_len || q->c_protection_credit <= 0)) { 527 skb = __qdisc_dequeue_head(&q->l_queue->q); 528 WRITE_ONCE(q->l_head_ts, head_enqueue_time(q->l_queue)); 529 if (c_len) 530 *credit_change = q->c_protection_wc; 531 qdisc_qstats_backlog_dec(q->l_queue, skb); 532 533 /* Keep the global queue size consistent */ 534 --sch->q.qlen; 535 q->memory_used -= skb->truesize; 536 } else if (c_len) { 537 skb = __qdisc_dequeue_head(&sch->q); 538 WRITE_ONCE(q->c_head_ts, head_enqueue_time(sch)); 539 if (qdisc_qlen(q->l_queue)) 540 *credit_change = ~((s32)q->c_protection_wl) + 1; 541 q->memory_used -= skb->truesize; 542 } else { 543 dualpi2_reset_c_protection(q); 544 return NULL; 545 } 546 *credit_change *= qdisc_pkt_len(skb); 547 qdisc_qstats_backlog_dec(sch, skb); 548 return skb; 549 } 550 551 static int do_step_aqm(struct dualpi2_sched_data *q, struct sk_buff *skb, 552 u64 now) 553 { 554 u64 qdelay = 0; 555 556 if (q->step_in_packets) 557 qdelay = qdisc_qlen(q->l_queue); 558 else 559 qdelay = dualpi2_sojourn_time(skb, now); 560 561 if (dualpi2_skb_cb(skb)->apply_step && qdelay > q->step_thresh) { 562 if (!dualpi2_skb_cb(skb)->ect) { 563 /* Drop this non-ECT packet */ 564 return 1; 565 } 566 567 if (dualpi2_mark(q, skb)) 568 ++q->step_marks; 569 } 570 qdisc_bstats_update(q->l_queue, skb); 571 return 0; 572 } 573 574 static void drop_and_retry(struct dualpi2_sched_data *q, struct sk_buff *skb, 575 struct Qdisc *sch, enum skb_drop_reason reason) 576 { 577 ++q->deferred_drops_cnt; 578 q->deferred_drops_len += qdisc_pkt_len(skb); 579 kfree_skb_reason(skb, reason); 580 qdisc_qstats_drop(sch); 581 } 582 583 static struct sk_buff *dualpi2_qdisc_dequeue(struct Qdisc *sch) 584 { 585 struct dualpi2_sched_data *q = qdisc_priv(sch); 586 struct sk_buff *skb; 587 int credit_change; 588 u64 now; 589 590 now = ktime_get_ns(); 591 592 while ((skb = dequeue_packet(sch, q, &credit_change, now))) { 593 if (!q->drop_early && must_drop(sch, q, skb)) { 594 drop_and_retry(q, skb, sch, 595 SKB_DROP_REASON_QDISC_CONGESTED); 596 continue; 597 } 598 599 if (skb_in_l_queue(skb) && do_step_aqm(q, skb, now)) { 600 qdisc_qstats_drop(q->l_queue); 601 drop_and_retry(q, skb, sch, 602 SKB_DROP_REASON_DUALPI2_STEP_DROP); 603 continue; 604 } 605 606 q->c_protection_credit += credit_change; 607 qdisc_bstats_update(sch, skb); 608 break; 609 } 610 611 if (q->deferred_drops_cnt) { 612 qdisc_tree_reduce_backlog(sch, q->deferred_drops_cnt, 613 q->deferred_drops_len); 614 q->deferred_drops_cnt = 0; 615 q->deferred_drops_len = 0; 616 } 617 return skb; 618 } 619 620 static s64 __scale_delta(u64 diff) 621 { 622 do_div(diff, 1 << ALPHA_BETA_GRANULARITY); 623 return diff; 624 } 625 626 static void get_queue_delays(struct dualpi2_sched_data *q, u64 *qdelay_c, 627 u64 *qdelay_l) 628 { 629 u64 now, qc, ql; 630 631 now = ktime_get_ns(); 632 qc = READ_ONCE(q->c_head_ts); 633 ql = READ_ONCE(q->l_head_ts); 634 635 *qdelay_c = qc ? now - qc : 0; 636 *qdelay_l = ql ? now - ql : 0; 637 } 638 639 static u32 calculate_probability(struct Qdisc *sch) 640 { 641 struct dualpi2_sched_data *q = qdisc_priv(sch); 642 u32 new_prob; 643 u64 qdelay_c; 644 u64 qdelay_l; 645 u64 qdelay; 646 s64 delta; 647 648 get_queue_delays(q, &qdelay_c, &qdelay_l); 649 qdelay = max(qdelay_l, qdelay_c); 650 651 /* Alpha and beta take at most 32b, i.e, the delay difference would 652 * overflow for queuing delay differences > ~4.2sec. 653 */ 654 delta = ((s64)qdelay - (s64)q->pi2_target) * q->pi2_alpha; 655 delta += ((s64)qdelay - (s64)q->last_qdelay) * q->pi2_beta; 656 q->last_qdelay = qdelay; 657 658 /* Bound new_prob between 0 and MAX_PROB */ 659 if (delta > 0) { 660 new_prob = __scale_delta(delta) + q->pi2_prob; 661 if (new_prob < q->pi2_prob) 662 new_prob = MAX_PROB; 663 } else { 664 new_prob = q->pi2_prob - __scale_delta(~delta + 1); 665 if (new_prob > q->pi2_prob) 666 new_prob = 0; 667 } 668 669 /* If we do not drop on overload, ensure we cap the L4S probability to 670 * 100% to keep window fairness when overflowing. 671 */ 672 if (!q->drop_overload) 673 return min_t(u32, new_prob, MAX_PROB / q->coupling_factor); 674 return new_prob; 675 } 676 677 static u32 get_memory_limit(struct Qdisc *sch, u32 limit) 678 { 679 /* Apply rule of thumb, i.e., doubling the packet length, 680 * to further include per packet overhead in memory_limit. 681 */ 682 u64 memlim = mul_u32_u32(limit, 2 * psched_mtu(qdisc_dev(sch))); 683 684 if (upper_32_bits(memlim)) 685 return U32_MAX; 686 else 687 return lower_32_bits(memlim); 688 } 689 690 static u32 convert_us_to_nsec(u32 us) 691 { 692 u64 ns = mul_u32_u32(us, NSEC_PER_USEC); 693 694 if (upper_32_bits(ns)) 695 return U32_MAX; 696 697 return lower_32_bits(ns); 698 } 699 700 static u32 convert_ns_to_usec(u64 ns) 701 { 702 do_div(ns, NSEC_PER_USEC); 703 if (upper_32_bits(ns)) 704 return U32_MAX; 705 706 return lower_32_bits(ns); 707 } 708 709 static enum hrtimer_restart dualpi2_timer(struct hrtimer *timer) 710 { 711 struct dualpi2_sched_data *q = timer_container_of(q, timer, pi2_timer); 712 struct Qdisc *sch = q->sch; 713 spinlock_t *root_lock; /* to lock qdisc for probability calculations */ 714 715 rcu_read_lock(); 716 root_lock = qdisc_lock(qdisc_root_sleeping(sch)); 717 spin_lock(root_lock); 718 719 WRITE_ONCE(q->pi2_prob, calculate_probability(sch)); 720 hrtimer_set_expires(&q->pi2_timer, next_pi2_timeout(q)); 721 722 spin_unlock(root_lock); 723 rcu_read_unlock(); 724 return HRTIMER_RESTART; 725 } 726 727 static struct netlink_range_validation dualpi2_alpha_beta_range = { 728 .min = 1, 729 .max = ALPHA_BETA_MAX, 730 }; 731 732 static const struct nla_policy dualpi2_policy[TCA_DUALPI2_MAX + 1] = { 733 [TCA_DUALPI2_LIMIT] = NLA_POLICY_MIN(NLA_U32, 1), 734 [TCA_DUALPI2_MEMORY_LIMIT] = NLA_POLICY_MIN(NLA_U32, 1), 735 [TCA_DUALPI2_TARGET] = { .type = NLA_U32 }, 736 [TCA_DUALPI2_TUPDATE] = NLA_POLICY_MIN(NLA_U32, 1), 737 [TCA_DUALPI2_ALPHA] = 738 NLA_POLICY_FULL_RANGE(NLA_U32, &dualpi2_alpha_beta_range), 739 [TCA_DUALPI2_BETA] = 740 NLA_POLICY_FULL_RANGE(NLA_U32, &dualpi2_alpha_beta_range), 741 [TCA_DUALPI2_STEP_THRESH_PKTS] = { .type = NLA_U32 }, 742 [TCA_DUALPI2_STEP_THRESH_US] = { .type = NLA_U32 }, 743 [TCA_DUALPI2_MIN_QLEN_STEP] = { .type = NLA_U32 }, 744 [TCA_DUALPI2_COUPLING] = NLA_POLICY_MIN(NLA_U8, 1), 745 [TCA_DUALPI2_DROP_OVERLOAD] = 746 NLA_POLICY_MAX(NLA_U8, TCA_DUALPI2_DROP_OVERLOAD_MAX), 747 [TCA_DUALPI2_DROP_EARLY] = 748 NLA_POLICY_MAX(NLA_U8, TCA_DUALPI2_DROP_EARLY_MAX), 749 [TCA_DUALPI2_C_PROTECTION] = 750 NLA_POLICY_RANGE(NLA_U8, 0, MAX_WC), 751 [TCA_DUALPI2_ECN_MASK] = 752 NLA_POLICY_RANGE(NLA_U8, TC_DUALPI2_ECN_MASK_L4S_ECT, 753 TCA_DUALPI2_ECN_MASK_MAX), 754 [TCA_DUALPI2_SPLIT_GSO] = 755 NLA_POLICY_MAX(NLA_U8, TCA_DUALPI2_SPLIT_GSO_MAX), 756 }; 757 758 static int dualpi2_change(struct Qdisc *sch, struct nlattr *opt, 759 struct netlink_ext_ack *extack) 760 { 761 struct nlattr *tb[TCA_DUALPI2_MAX + 1]; 762 struct dualpi2_sched_data *q; 763 int old_backlog; 764 int old_qlen; 765 int err; 766 767 if (!opt || !nla_len(opt)) { 768 NL_SET_ERR_MSG_MOD(extack, "Dualpi2 options are required"); 769 return -EINVAL; 770 } 771 err = nla_parse_nested(tb, TCA_DUALPI2_MAX, opt, dualpi2_policy, 772 extack); 773 if (err < 0) 774 return err; 775 if (tb[TCA_DUALPI2_STEP_THRESH_PKTS] && tb[TCA_DUALPI2_STEP_THRESH_US]) { 776 NL_SET_ERR_MSG_MOD(extack, "multiple step thresh attributes"); 777 return -EINVAL; 778 } 779 780 q = qdisc_priv(sch); 781 sch_tree_lock(sch); 782 783 if (tb[TCA_DUALPI2_LIMIT]) { 784 u32 limit = nla_get_u32(tb[TCA_DUALPI2_LIMIT]); 785 786 WRITE_ONCE(sch->limit, limit); 787 WRITE_ONCE(q->memory_limit, get_memory_limit(sch, limit)); 788 } 789 790 if (tb[TCA_DUALPI2_MEMORY_LIMIT]) 791 WRITE_ONCE(q->memory_limit, 792 nla_get_u32(tb[TCA_DUALPI2_MEMORY_LIMIT])); 793 794 if (tb[TCA_DUALPI2_TARGET]) { 795 u64 target = nla_get_u32(tb[TCA_DUALPI2_TARGET]); 796 797 WRITE_ONCE(q->pi2_target, target * NSEC_PER_USEC); 798 } 799 800 if (tb[TCA_DUALPI2_TUPDATE]) { 801 u64 tupdate = nla_get_u32(tb[TCA_DUALPI2_TUPDATE]); 802 803 WRITE_ONCE(q->pi2_tupdate, convert_us_to_nsec(tupdate)); 804 } 805 806 if (tb[TCA_DUALPI2_ALPHA]) { 807 u32 alpha = nla_get_u32(tb[TCA_DUALPI2_ALPHA]); 808 809 WRITE_ONCE(q->pi2_alpha, dualpi2_scale_alpha_beta(alpha)); 810 } 811 812 if (tb[TCA_DUALPI2_BETA]) { 813 u32 beta = nla_get_u32(tb[TCA_DUALPI2_BETA]); 814 815 WRITE_ONCE(q->pi2_beta, dualpi2_scale_alpha_beta(beta)); 816 } 817 818 if (tb[TCA_DUALPI2_STEP_THRESH_PKTS]) { 819 u32 step_th = nla_get_u32(tb[TCA_DUALPI2_STEP_THRESH_PKTS]); 820 821 WRITE_ONCE(q->step_in_packets, true); 822 WRITE_ONCE(q->step_thresh, step_th); 823 } else if (tb[TCA_DUALPI2_STEP_THRESH_US]) { 824 u32 step_th = nla_get_u32(tb[TCA_DUALPI2_STEP_THRESH_US]); 825 826 WRITE_ONCE(q->step_in_packets, false); 827 WRITE_ONCE(q->step_thresh, convert_us_to_nsec(step_th)); 828 } 829 830 if (tb[TCA_DUALPI2_MIN_QLEN_STEP]) 831 WRITE_ONCE(q->min_qlen_step, 832 nla_get_u32(tb[TCA_DUALPI2_MIN_QLEN_STEP])); 833 834 if (tb[TCA_DUALPI2_COUPLING]) { 835 u8 coupling = nla_get_u8(tb[TCA_DUALPI2_COUPLING]); 836 837 WRITE_ONCE(q->coupling_factor, coupling); 838 } 839 840 if (tb[TCA_DUALPI2_DROP_OVERLOAD]) { 841 u8 drop_overload = nla_get_u8(tb[TCA_DUALPI2_DROP_OVERLOAD]); 842 843 WRITE_ONCE(q->drop_overload, (bool)drop_overload); 844 } 845 846 if (tb[TCA_DUALPI2_DROP_EARLY]) { 847 u8 drop_early = nla_get_u8(tb[TCA_DUALPI2_DROP_EARLY]); 848 849 WRITE_ONCE(q->drop_early, (bool)drop_early); 850 } 851 852 if (tb[TCA_DUALPI2_C_PROTECTION]) { 853 u8 wc = nla_get_u8(tb[TCA_DUALPI2_C_PROTECTION]); 854 855 dualpi2_calculate_c_protection(sch, q, wc); 856 } 857 858 if (tb[TCA_DUALPI2_ECN_MASK]) { 859 u8 ecn_mask = nla_get_u8(tb[TCA_DUALPI2_ECN_MASK]); 860 861 WRITE_ONCE(q->ecn_mask, ecn_mask); 862 } 863 864 if (tb[TCA_DUALPI2_SPLIT_GSO]) { 865 u8 split_gso = nla_get_u8(tb[TCA_DUALPI2_SPLIT_GSO]); 866 867 WRITE_ONCE(q->split_gso, (bool)split_gso); 868 } 869 870 old_qlen = qdisc_qlen(sch); 871 old_backlog = sch->qstats.backlog; 872 while (qdisc_qlen(sch) > sch->limit || 873 q->memory_used > q->memory_limit) { 874 struct sk_buff *skb = qdisc_dequeue_internal(sch, true); 875 876 q->memory_used -= skb->truesize; 877 qdisc_qstats_backlog_dec(sch, skb); 878 rtnl_qdisc_drop(skb, sch); 879 } 880 qdisc_tree_reduce_backlog(sch, old_qlen - qdisc_qlen(sch), 881 old_backlog - sch->qstats.backlog); 882 883 sch_tree_unlock(sch); 884 return 0; 885 } 886 887 /* Default alpha/beta values give a 10dB stability margin with max_rtt=100ms. */ 888 static void dualpi2_reset_default(struct Qdisc *sch) 889 { 890 struct dualpi2_sched_data *q = qdisc_priv(sch); 891 892 q->sch->limit = 10000; /* Max 125ms at 1Gbps */ 893 q->memory_limit = get_memory_limit(sch, q->sch->limit); 894 895 q->pi2_target = 15 * NSEC_PER_MSEC; 896 q->pi2_tupdate = 16 * NSEC_PER_MSEC; 897 q->pi2_alpha = dualpi2_scale_alpha_beta(41); /* ~0.16 Hz * 256 */ 898 q->pi2_beta = dualpi2_scale_alpha_beta(819); /* ~3.20 Hz * 256 */ 899 900 q->step_thresh = 1 * NSEC_PER_MSEC; 901 q->step_in_packets = false; 902 903 dualpi2_calculate_c_protection(q->sch, q, 10); /* wc=10%, wl=90% */ 904 905 q->ecn_mask = TC_DUALPI2_ECN_MASK_L4S_ECT; /* INET_ECN_ECT_1 */ 906 q->min_qlen_step = 0; /* Always apply step mark in L-queue */ 907 q->coupling_factor = 2; /* window fairness for equal RTTs */ 908 q->drop_overload = TC_DUALPI2_DROP_OVERLOAD_DROP; /* Drop overload */ 909 q->drop_early = TC_DUALPI2_DROP_EARLY_DROP_DEQUEUE; /* Drop dequeue */ 910 q->split_gso = TC_DUALPI2_SPLIT_GSO_SPLIT_GSO; /* Split GSO */ 911 } 912 913 static int dualpi2_init(struct Qdisc *sch, struct nlattr *opt, 914 struct netlink_ext_ack *extack) 915 { 916 struct dualpi2_sched_data *q = qdisc_priv(sch); 917 int err; 918 919 q->l_queue = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, 920 TC_H_MAKE(sch->handle, 1), extack); 921 if (!q->l_queue) 922 return -ENOMEM; 923 924 err = tcf_block_get(&q->tcf_block, &q->tcf_filters, sch, extack); 925 if (err) 926 return err; 927 928 q->sch = sch; 929 dualpi2_reset_default(sch); 930 hrtimer_setup(&q->pi2_timer, dualpi2_timer, CLOCK_MONOTONIC, 931 HRTIMER_MODE_ABS_PINNED_SOFT); 932 933 if (opt && nla_len(opt)) { 934 err = dualpi2_change(sch, opt, extack); 935 936 if (err) 937 return err; 938 } 939 940 hrtimer_start(&q->pi2_timer, next_pi2_timeout(q), 941 HRTIMER_MODE_ABS_PINNED_SOFT); 942 return 0; 943 } 944 945 static int dualpi2_dump(struct Qdisc *sch, struct sk_buff *skb) 946 { 947 struct dualpi2_sched_data *q = qdisc_priv(sch); 948 struct nlattr *opts; 949 bool step_in_pkts; 950 u32 step_th; 951 952 step_in_pkts = READ_ONCE(q->step_in_packets); 953 step_th = READ_ONCE(q->step_thresh); 954 955 opts = nla_nest_start_noflag(skb, TCA_OPTIONS); 956 if (!opts) 957 goto nla_put_failure; 958 959 if (step_in_pkts && 960 (nla_put_u32(skb, TCA_DUALPI2_LIMIT, READ_ONCE(sch->limit)) || 961 nla_put_u32(skb, TCA_DUALPI2_MEMORY_LIMIT, 962 READ_ONCE(q->memory_limit)) || 963 nla_put_u32(skb, TCA_DUALPI2_TARGET, 964 convert_ns_to_usec(READ_ONCE(q->pi2_target))) || 965 nla_put_u32(skb, TCA_DUALPI2_TUPDATE, 966 convert_ns_to_usec(READ_ONCE(q->pi2_tupdate))) || 967 nla_put_u32(skb, TCA_DUALPI2_ALPHA, 968 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_alpha))) || 969 nla_put_u32(skb, TCA_DUALPI2_BETA, 970 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_beta))) || 971 nla_put_u32(skb, TCA_DUALPI2_STEP_THRESH_PKTS, step_th) || 972 nla_put_u32(skb, TCA_DUALPI2_MIN_QLEN_STEP, 973 READ_ONCE(q->min_qlen_step)) || 974 nla_put_u8(skb, TCA_DUALPI2_COUPLING, 975 READ_ONCE(q->coupling_factor)) || 976 nla_put_u8(skb, TCA_DUALPI2_DROP_OVERLOAD, 977 READ_ONCE(q->drop_overload)) || 978 nla_put_u8(skb, TCA_DUALPI2_DROP_EARLY, 979 READ_ONCE(q->drop_early)) || 980 nla_put_u8(skb, TCA_DUALPI2_C_PROTECTION, 981 READ_ONCE(q->c_protection_wc)) || 982 nla_put_u8(skb, TCA_DUALPI2_ECN_MASK, READ_ONCE(q->ecn_mask)) || 983 nla_put_u8(skb, TCA_DUALPI2_SPLIT_GSO, READ_ONCE(q->split_gso)))) 984 goto nla_put_failure; 985 986 if (!step_in_pkts && 987 (nla_put_u32(skb, TCA_DUALPI2_LIMIT, READ_ONCE(sch->limit)) || 988 nla_put_u32(skb, TCA_DUALPI2_MEMORY_LIMIT, 989 READ_ONCE(q->memory_limit)) || 990 nla_put_u32(skb, TCA_DUALPI2_TARGET, 991 convert_ns_to_usec(READ_ONCE(q->pi2_target))) || 992 nla_put_u32(skb, TCA_DUALPI2_TUPDATE, 993 convert_ns_to_usec(READ_ONCE(q->pi2_tupdate))) || 994 nla_put_u32(skb, TCA_DUALPI2_ALPHA, 995 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_alpha))) || 996 nla_put_u32(skb, TCA_DUALPI2_BETA, 997 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_beta))) || 998 nla_put_u32(skb, TCA_DUALPI2_STEP_THRESH_US, 999 convert_ns_to_usec(step_th)) || 1000 nla_put_u32(skb, TCA_DUALPI2_MIN_QLEN_STEP, 1001 READ_ONCE(q->min_qlen_step)) || 1002 nla_put_u8(skb, TCA_DUALPI2_COUPLING, 1003 READ_ONCE(q->coupling_factor)) || 1004 nla_put_u8(skb, TCA_DUALPI2_DROP_OVERLOAD, 1005 READ_ONCE(q->drop_overload)) || 1006 nla_put_u8(skb, TCA_DUALPI2_DROP_EARLY, 1007 READ_ONCE(q->drop_early)) || 1008 nla_put_u8(skb, TCA_DUALPI2_C_PROTECTION, 1009 READ_ONCE(q->c_protection_wc)) || 1010 nla_put_u8(skb, TCA_DUALPI2_ECN_MASK, READ_ONCE(q->ecn_mask)) || 1011 nla_put_u8(skb, TCA_DUALPI2_SPLIT_GSO, READ_ONCE(q->split_gso)))) 1012 goto nla_put_failure; 1013 1014 return nla_nest_end(skb, opts); 1015 1016 nla_put_failure: 1017 nla_nest_cancel(skb, opts); 1018 return -1; 1019 } 1020 1021 static int dualpi2_dump_stats(struct Qdisc *sch, struct gnet_dump *d) 1022 { 1023 struct dualpi2_sched_data *q = qdisc_priv(sch); 1024 struct tc_dualpi2_xstats st = { 1025 .prob = READ_ONCE(q->pi2_prob), 1026 .packets_in_c = q->packets_in_c, 1027 .packets_in_l = q->packets_in_l, 1028 .maxq = q->maxq, 1029 .ecn_mark = q->ecn_mark, 1030 .credit = q->c_protection_credit, 1031 .step_marks = q->step_marks, 1032 .memory_used = q->memory_used, 1033 .max_memory_used = q->max_memory_used, 1034 .memory_limit = q->memory_limit, 1035 }; 1036 u64 qc, ql; 1037 1038 get_queue_delays(q, &qc, &ql); 1039 st.delay_l = convert_ns_to_usec(ql); 1040 st.delay_c = convert_ns_to_usec(qc); 1041 return gnet_stats_copy_app(d, &st, sizeof(st)); 1042 } 1043 1044 /* Reset both L-queue and C-queue, internal packet counters, PI probability, 1045 * C-queue protection credit, and timestamps, while preserving current 1046 * configuration of DUALPI2. 1047 */ 1048 static void dualpi2_reset(struct Qdisc *sch) 1049 { 1050 struct dualpi2_sched_data *q = qdisc_priv(sch); 1051 1052 qdisc_reset_queue(sch); 1053 qdisc_reset_queue(q->l_queue); 1054 q->c_head_ts = 0; 1055 q->l_head_ts = 0; 1056 q->pi2_prob = 0; 1057 q->packets_in_c = 0; 1058 q->packets_in_l = 0; 1059 q->maxq = 0; 1060 q->ecn_mark = 0; 1061 q->step_marks = 0; 1062 q->memory_used = 0; 1063 q->max_memory_used = 0; 1064 dualpi2_reset_c_protection(q); 1065 } 1066 1067 static void dualpi2_destroy(struct Qdisc *sch) 1068 { 1069 struct dualpi2_sched_data *q = qdisc_priv(sch); 1070 1071 q->pi2_tupdate = 0; 1072 hrtimer_cancel(&q->pi2_timer); 1073 if (q->l_queue) 1074 qdisc_put(q->l_queue); 1075 tcf_block_put(q->tcf_block); 1076 } 1077 1078 static struct Qdisc *dualpi2_leaf(struct Qdisc *sch, unsigned long arg) 1079 { 1080 return NULL; 1081 } 1082 1083 static unsigned long dualpi2_find(struct Qdisc *sch, u32 classid) 1084 { 1085 return 0; 1086 } 1087 1088 static unsigned long dualpi2_bind(struct Qdisc *sch, unsigned long parent, 1089 u32 classid) 1090 { 1091 return 0; 1092 } 1093 1094 static void dualpi2_unbind(struct Qdisc *q, unsigned long cl) 1095 { 1096 } 1097 1098 static struct tcf_block *dualpi2_tcf_block(struct Qdisc *sch, unsigned long cl, 1099 struct netlink_ext_ack *extack) 1100 { 1101 struct dualpi2_sched_data *q = qdisc_priv(sch); 1102 1103 if (cl) 1104 return NULL; 1105 return q->tcf_block; 1106 } 1107 1108 static void dualpi2_walk(struct Qdisc *sch, struct qdisc_walker *arg) 1109 { 1110 unsigned int i; 1111 1112 if (arg->stop) 1113 return; 1114 1115 /* We statically define only 2 queues */ 1116 for (i = 0; i < 2; i++) { 1117 if (arg->count < arg->skip) { 1118 arg->count++; 1119 continue; 1120 } 1121 if (arg->fn(sch, i + 1, arg) < 0) { 1122 arg->stop = 1; 1123 break; 1124 } 1125 arg->count++; 1126 } 1127 } 1128 1129 /* Minimal class support to handle tc filters */ 1130 static const struct Qdisc_class_ops dualpi2_class_ops = { 1131 .leaf = dualpi2_leaf, 1132 .find = dualpi2_find, 1133 .tcf_block = dualpi2_tcf_block, 1134 .bind_tcf = dualpi2_bind, 1135 .unbind_tcf = dualpi2_unbind, 1136 .walk = dualpi2_walk, 1137 }; 1138 1139 static struct Qdisc_ops dualpi2_qdisc_ops __read_mostly = { 1140 .id = "dualpi2", 1141 .cl_ops = &dualpi2_class_ops, 1142 .priv_size = sizeof(struct dualpi2_sched_data), 1143 .enqueue = dualpi2_qdisc_enqueue, 1144 .dequeue = dualpi2_qdisc_dequeue, 1145 .peek = qdisc_peek_dequeued, 1146 .init = dualpi2_init, 1147 .destroy = dualpi2_destroy, 1148 .reset = dualpi2_reset, 1149 .change = dualpi2_change, 1150 .dump = dualpi2_dump, 1151 .dump_stats = dualpi2_dump_stats, 1152 .owner = THIS_MODULE, 1153 }; 1154 1155 static int __init dualpi2_module_init(void) 1156 { 1157 return register_qdisc(&dualpi2_qdisc_ops); 1158 } 1159 1160 static void __exit dualpi2_module_exit(void) 1161 { 1162 unregister_qdisc(&dualpi2_qdisc_ops); 1163 } 1164 1165 module_init(dualpi2_module_init); 1166 module_exit(dualpi2_module_exit); 1167 1168 MODULE_DESCRIPTION("Dual Queue with Proportional Integral controller Improved with a Square (dualpi2) scheduler"); 1169 MODULE_AUTHOR("Koen De Schepper <koen.de_schepper@nokia-bell-labs.com>"); 1170 MODULE_AUTHOR("Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>"); 1171 MODULE_AUTHOR("Olga Albisser <olga@albisser.org>"); 1172 MODULE_AUTHOR("Henrik Steen <henrist@henrist.net>"); 1173 MODULE_AUTHOR("Olivier Tilmans <olivier.tilmans@nokia.com>"); 1174 1175 MODULE_LICENSE("Dual BSD/GPL"); 1176 MODULE_VERSION("1.0"); 1177