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, QDISC_DROP_OVERLIMIT); 397 } 398 399 if (q->drop_early && must_drop(sch, q, skb)) { 400 qdisc_drop_reason(skb, sch, to_free, QDISC_DROP_CONGESTED); 401 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 402 } 403 404 cb = dualpi2_skb_cb(skb); 405 cb->ts = ktime_get_ns(); 406 q->memory_used += skb->truesize; 407 if (q->memory_used > q->max_memory_used) 408 q->max_memory_used = q->memory_used; 409 410 if (qdisc_qlen(sch) > q->maxq) 411 q->maxq = qdisc_qlen(sch); 412 413 if (skb_in_l_queue(skb)) { 414 /* Apply step thresh if skb is L4S && L-queue len >= min_qlen */ 415 dualpi2_skb_cb(skb)->apply_step = skb_apply_step(skb, q); 416 417 /* Keep the overall qdisc stats consistent */ 418 ++sch->q.qlen; 419 qdisc_qstats_backlog_inc(sch, skb); 420 ++q->packets_in_l; 421 if (!q->l_head_ts) 422 q->l_head_ts = cb->ts; 423 return qdisc_enqueue_tail(skb, q->l_queue); 424 } 425 ++q->packets_in_c; 426 if (!q->c_head_ts) 427 q->c_head_ts = cb->ts; 428 return qdisc_enqueue_tail(skb, sch); 429 } 430 431 /* By default, dualpi2 will split GSO skbs into independent skbs and enqueue 432 * each of those individually. This yields the following benefits, at the 433 * expense of CPU usage: 434 * - Finer-grained AQM actions as the sub-packets of a burst no longer share the 435 * same fate (e.g., the random mark/drop probability is applied individually) 436 * - Improved precision of the starvation protection/WRR scheduler at dequeue, 437 * as the size of the dequeued packets will be smaller. 438 */ 439 static int dualpi2_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch, 440 struct sk_buff **to_free) 441 { 442 struct dualpi2_sched_data *q = qdisc_priv(sch); 443 int err; 444 445 err = dualpi2_skb_classify(q, skb); 446 if (err != NET_XMIT_SUCCESS) { 447 if (err & __NET_XMIT_BYPASS) 448 qdisc_qstats_drop(sch); 449 __qdisc_drop(skb, to_free); 450 return err; 451 } 452 453 if (q->split_gso && skb_is_gso(skb)) { 454 netdev_features_t features; 455 struct sk_buff *nskb, *next; 456 int cnt, byte_len, orig_len; 457 int err; 458 459 features = netif_skb_features(skb); 460 nskb = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK); 461 if (IS_ERR_OR_NULL(nskb)) 462 return qdisc_drop(skb, sch, to_free); 463 464 cnt = 1; 465 byte_len = 0; 466 orig_len = qdisc_pkt_len(skb); 467 skb_list_walk_safe(nskb, nskb, next) { 468 skb_mark_not_on_list(nskb); 469 470 /* Iterate through GSO fragments of an skb: 471 * (1) Set pkt_len from the single GSO fragments 472 * (2) Copy classified and ect values of an skb 473 * (3) Enqueue fragment & set ts in dualpi2_enqueue_skb 474 */ 475 qdisc_skb_cb(nskb)->pkt_len = nskb->len; 476 qdisc_skb_cb(nskb)->pkt_segs = 1; 477 dualpi2_skb_cb(nskb)->classified = 478 dualpi2_skb_cb(skb)->classified; 479 dualpi2_skb_cb(nskb)->ect = dualpi2_skb_cb(skb)->ect; 480 err = dualpi2_enqueue_skb(nskb, sch, to_free); 481 482 if (err == NET_XMIT_SUCCESS) { 483 /* Compute the backlog adjustment that needs 484 * to be propagated in the qdisc tree to reflect 485 * all new skbs successfully enqueued. 486 */ 487 ++cnt; 488 byte_len += nskb->len; 489 } 490 } 491 if (cnt > 1) { 492 /* The caller will add the original skb stats to its 493 * backlog, compensate this if any nskb is enqueued. 494 */ 495 --cnt; 496 byte_len -= orig_len; 497 } 498 qdisc_tree_reduce_backlog(sch, -cnt, -byte_len); 499 consume_skb(skb); 500 return err; 501 } 502 return dualpi2_enqueue_skb(skb, sch, to_free); 503 } 504 505 /* Select the queue from which the next packet can be dequeued, ensuring that 506 * neither queue can starve the other with a WRR scheduler. 507 * 508 * The sign of the WRR credit determines the next queue, while the size of 509 * the dequeued packet determines the magnitude of the WRR credit change. If 510 * either queue is empty, the WRR credit is kept unchanged. 511 * 512 * As the dequeued packet can be dropped later, the caller has to perform the 513 * qdisc_bstats_update() calls. 514 */ 515 static struct sk_buff *dequeue_packet(struct Qdisc *sch, 516 struct dualpi2_sched_data *q, 517 int *credit_change, 518 u64 now) 519 { 520 struct sk_buff *skb = NULL; 521 int c_len; 522 523 *credit_change = 0; 524 c_len = qdisc_qlen(sch) - qdisc_qlen(q->l_queue); 525 if (qdisc_qlen(q->l_queue) && (!c_len || q->c_protection_credit <= 0)) { 526 skb = __qdisc_dequeue_head(&q->l_queue->q); 527 WRITE_ONCE(q->l_head_ts, head_enqueue_time(q->l_queue)); 528 if (c_len) 529 *credit_change = q->c_protection_wc; 530 qdisc_qstats_backlog_dec(q->l_queue, skb); 531 532 /* Keep the global queue size consistent */ 533 --sch->q.qlen; 534 q->memory_used -= skb->truesize; 535 } else if (c_len) { 536 skb = __qdisc_dequeue_head(&sch->q); 537 WRITE_ONCE(q->c_head_ts, head_enqueue_time(sch)); 538 if (qdisc_qlen(q->l_queue)) 539 *credit_change = ~((s32)q->c_protection_wl) + 1; 540 q->memory_used -= skb->truesize; 541 } else { 542 dualpi2_reset_c_protection(q); 543 return NULL; 544 } 545 *credit_change *= qdisc_pkt_len(skb); 546 qdisc_qstats_backlog_dec(sch, skb); 547 return skb; 548 } 549 550 static int do_step_aqm(struct dualpi2_sched_data *q, struct sk_buff *skb, 551 u64 now) 552 { 553 u64 qdelay = 0; 554 555 if (q->step_in_packets) 556 qdelay = qdisc_qlen(q->l_queue); 557 else 558 qdelay = dualpi2_sojourn_time(skb, now); 559 560 if (dualpi2_skb_cb(skb)->apply_step && qdelay > q->step_thresh) { 561 if (!dualpi2_skb_cb(skb)->ect) { 562 /* Drop this non-ECT packet */ 563 return 1; 564 } 565 566 if (dualpi2_mark(q, skb)) 567 ++q->step_marks; 568 } 569 qdisc_bstats_update(q->l_queue, skb); 570 return 0; 571 } 572 573 static void drop_and_retry(struct dualpi2_sched_data *q, struct sk_buff *skb, 574 struct Qdisc *sch, enum qdisc_drop_reason reason) 575 { 576 ++q->deferred_drops_cnt; 577 q->deferred_drops_len += qdisc_pkt_len(skb); 578 qdisc_dequeue_drop(sch, skb, reason); 579 qdisc_qstats_drop(sch); 580 } 581 582 static struct sk_buff *dualpi2_qdisc_dequeue(struct Qdisc *sch) 583 { 584 struct dualpi2_sched_data *q = qdisc_priv(sch); 585 struct sk_buff *skb; 586 int credit_change; 587 u64 now; 588 589 now = ktime_get_ns(); 590 591 while ((skb = dequeue_packet(sch, q, &credit_change, now))) { 592 if (!q->drop_early && must_drop(sch, q, skb)) { 593 drop_and_retry(q, skb, sch, QDISC_DROP_CONGESTED); 594 continue; 595 } 596 597 if (skb_in_l_queue(skb) && do_step_aqm(q, skb, now)) { 598 qdisc_qstats_drop(q->l_queue); 599 drop_and_retry(q, skb, sch, QDISC_DROP_L4S_STEP_NON_ECN); 600 continue; 601 } 602 603 q->c_protection_credit += credit_change; 604 qdisc_bstats_update(sch, skb); 605 break; 606 } 607 608 if (q->deferred_drops_cnt) { 609 qdisc_tree_reduce_backlog(sch, q->deferred_drops_cnt, 610 q->deferred_drops_len); 611 q->deferred_drops_cnt = 0; 612 q->deferred_drops_len = 0; 613 } 614 return skb; 615 } 616 617 static s64 __scale_delta(u64 diff) 618 { 619 do_div(diff, 1 << ALPHA_BETA_GRANULARITY); 620 return diff; 621 } 622 623 static void get_queue_delays(struct dualpi2_sched_data *q, u64 *qdelay_c, 624 u64 *qdelay_l) 625 { 626 u64 now, qc, ql; 627 628 now = ktime_get_ns(); 629 qc = READ_ONCE(q->c_head_ts); 630 ql = READ_ONCE(q->l_head_ts); 631 632 *qdelay_c = qc ? now - qc : 0; 633 *qdelay_l = ql ? now - ql : 0; 634 } 635 636 static u32 calculate_probability(struct Qdisc *sch) 637 { 638 struct dualpi2_sched_data *q = qdisc_priv(sch); 639 u32 new_prob; 640 u64 qdelay_c; 641 u64 qdelay_l; 642 u64 qdelay; 643 s64 delta; 644 645 get_queue_delays(q, &qdelay_c, &qdelay_l); 646 qdelay = max(qdelay_l, qdelay_c); 647 648 /* Alpha and beta take at most 32b, i.e, the delay difference would 649 * overflow for queuing delay differences > ~4.2sec. 650 */ 651 delta = ((s64)qdelay - (s64)q->pi2_target) * q->pi2_alpha; 652 delta += ((s64)qdelay - (s64)q->last_qdelay) * q->pi2_beta; 653 q->last_qdelay = qdelay; 654 655 /* Bound new_prob between 0 and MAX_PROB */ 656 if (delta > 0) { 657 new_prob = __scale_delta(delta) + q->pi2_prob; 658 if (new_prob < q->pi2_prob) 659 new_prob = MAX_PROB; 660 } else { 661 new_prob = q->pi2_prob - __scale_delta(~delta + 1); 662 if (new_prob > q->pi2_prob) 663 new_prob = 0; 664 } 665 666 /* If we do not drop on overload, ensure we cap the L4S probability to 667 * 100% to keep window fairness when overflowing. 668 */ 669 if (!q->drop_overload) 670 return min_t(u32, new_prob, MAX_PROB / q->coupling_factor); 671 return new_prob; 672 } 673 674 static u32 get_memory_limit(struct Qdisc *sch, u32 limit) 675 { 676 /* Apply rule of thumb, i.e., doubling the packet length, 677 * to further include per packet overhead in memory_limit. 678 */ 679 u64 memlim = mul_u32_u32(limit, 2 * psched_mtu(qdisc_dev(sch))); 680 681 if (upper_32_bits(memlim)) 682 return U32_MAX; 683 else 684 return lower_32_bits(memlim); 685 } 686 687 static u32 convert_us_to_nsec(u32 us) 688 { 689 u64 ns = mul_u32_u32(us, NSEC_PER_USEC); 690 691 if (upper_32_bits(ns)) 692 return U32_MAX; 693 694 return lower_32_bits(ns); 695 } 696 697 static u32 convert_ns_to_usec(u64 ns) 698 { 699 do_div(ns, NSEC_PER_USEC); 700 if (upper_32_bits(ns)) 701 return U32_MAX; 702 703 return lower_32_bits(ns); 704 } 705 706 static enum hrtimer_restart dualpi2_timer(struct hrtimer *timer) 707 { 708 struct dualpi2_sched_data *q = timer_container_of(q, timer, pi2_timer); 709 struct Qdisc *sch = q->sch; 710 spinlock_t *root_lock; /* to lock qdisc for probability calculations */ 711 712 rcu_read_lock(); 713 root_lock = qdisc_lock(qdisc_root_sleeping(sch)); 714 spin_lock(root_lock); 715 716 WRITE_ONCE(q->pi2_prob, calculate_probability(sch)); 717 hrtimer_set_expires(&q->pi2_timer, next_pi2_timeout(q)); 718 719 spin_unlock(root_lock); 720 rcu_read_unlock(); 721 return HRTIMER_RESTART; 722 } 723 724 static struct netlink_range_validation dualpi2_alpha_beta_range = { 725 .min = 1, 726 .max = ALPHA_BETA_MAX, 727 }; 728 729 static const struct nla_policy dualpi2_policy[TCA_DUALPI2_MAX + 1] = { 730 [TCA_DUALPI2_LIMIT] = NLA_POLICY_MIN(NLA_U32, 1), 731 [TCA_DUALPI2_MEMORY_LIMIT] = NLA_POLICY_MIN(NLA_U32, 1), 732 [TCA_DUALPI2_TARGET] = { .type = NLA_U32 }, 733 [TCA_DUALPI2_TUPDATE] = NLA_POLICY_MIN(NLA_U32, 1), 734 [TCA_DUALPI2_ALPHA] = 735 NLA_POLICY_FULL_RANGE(NLA_U32, &dualpi2_alpha_beta_range), 736 [TCA_DUALPI2_BETA] = 737 NLA_POLICY_FULL_RANGE(NLA_U32, &dualpi2_alpha_beta_range), 738 [TCA_DUALPI2_STEP_THRESH_PKTS] = { .type = NLA_U32 }, 739 [TCA_DUALPI2_STEP_THRESH_US] = { .type = NLA_U32 }, 740 [TCA_DUALPI2_MIN_QLEN_STEP] = { .type = NLA_U32 }, 741 [TCA_DUALPI2_COUPLING] = NLA_POLICY_MIN(NLA_U8, 1), 742 [TCA_DUALPI2_DROP_OVERLOAD] = 743 NLA_POLICY_MAX(NLA_U8, TCA_DUALPI2_DROP_OVERLOAD_MAX), 744 [TCA_DUALPI2_DROP_EARLY] = 745 NLA_POLICY_MAX(NLA_U8, TCA_DUALPI2_DROP_EARLY_MAX), 746 [TCA_DUALPI2_C_PROTECTION] = 747 NLA_POLICY_RANGE(NLA_U8, 0, MAX_WC), 748 [TCA_DUALPI2_ECN_MASK] = 749 NLA_POLICY_RANGE(NLA_U8, TC_DUALPI2_ECN_MASK_L4S_ECT, 750 TCA_DUALPI2_ECN_MASK_MAX), 751 [TCA_DUALPI2_SPLIT_GSO] = 752 NLA_POLICY_MAX(NLA_U8, TCA_DUALPI2_SPLIT_GSO_MAX), 753 }; 754 755 static int dualpi2_change(struct Qdisc *sch, struct nlattr *opt, 756 struct netlink_ext_ack *extack) 757 { 758 struct nlattr *tb[TCA_DUALPI2_MAX + 1]; 759 struct dualpi2_sched_data *q; 760 int old_backlog; 761 int old_qlen; 762 int err; 763 764 if (!opt || !nla_len(opt)) { 765 NL_SET_ERR_MSG_MOD(extack, "Dualpi2 options are required"); 766 return -EINVAL; 767 } 768 err = nla_parse_nested(tb, TCA_DUALPI2_MAX, opt, dualpi2_policy, 769 extack); 770 if (err < 0) 771 return err; 772 if (tb[TCA_DUALPI2_STEP_THRESH_PKTS] && tb[TCA_DUALPI2_STEP_THRESH_US]) { 773 NL_SET_ERR_MSG_MOD(extack, "multiple step thresh attributes"); 774 return -EINVAL; 775 } 776 777 q = qdisc_priv(sch); 778 sch_tree_lock(sch); 779 780 if (tb[TCA_DUALPI2_LIMIT]) { 781 u32 limit = nla_get_u32(tb[TCA_DUALPI2_LIMIT]); 782 783 WRITE_ONCE(sch->limit, limit); 784 WRITE_ONCE(q->memory_limit, get_memory_limit(sch, limit)); 785 } 786 787 if (tb[TCA_DUALPI2_MEMORY_LIMIT]) 788 WRITE_ONCE(q->memory_limit, 789 nla_get_u32(tb[TCA_DUALPI2_MEMORY_LIMIT])); 790 791 if (tb[TCA_DUALPI2_TARGET]) { 792 u64 target = nla_get_u32(tb[TCA_DUALPI2_TARGET]); 793 794 WRITE_ONCE(q->pi2_target, target * NSEC_PER_USEC); 795 } 796 797 if (tb[TCA_DUALPI2_TUPDATE]) { 798 u64 tupdate = nla_get_u32(tb[TCA_DUALPI2_TUPDATE]); 799 800 WRITE_ONCE(q->pi2_tupdate, convert_us_to_nsec(tupdate)); 801 } 802 803 if (tb[TCA_DUALPI2_ALPHA]) { 804 u32 alpha = nla_get_u32(tb[TCA_DUALPI2_ALPHA]); 805 806 WRITE_ONCE(q->pi2_alpha, dualpi2_scale_alpha_beta(alpha)); 807 } 808 809 if (tb[TCA_DUALPI2_BETA]) { 810 u32 beta = nla_get_u32(tb[TCA_DUALPI2_BETA]); 811 812 WRITE_ONCE(q->pi2_beta, dualpi2_scale_alpha_beta(beta)); 813 } 814 815 if (tb[TCA_DUALPI2_STEP_THRESH_PKTS]) { 816 u32 step_th = nla_get_u32(tb[TCA_DUALPI2_STEP_THRESH_PKTS]); 817 818 WRITE_ONCE(q->step_in_packets, true); 819 WRITE_ONCE(q->step_thresh, step_th); 820 } else if (tb[TCA_DUALPI2_STEP_THRESH_US]) { 821 u32 step_th = nla_get_u32(tb[TCA_DUALPI2_STEP_THRESH_US]); 822 823 WRITE_ONCE(q->step_in_packets, false); 824 WRITE_ONCE(q->step_thresh, convert_us_to_nsec(step_th)); 825 } 826 827 if (tb[TCA_DUALPI2_MIN_QLEN_STEP]) 828 WRITE_ONCE(q->min_qlen_step, 829 nla_get_u32(tb[TCA_DUALPI2_MIN_QLEN_STEP])); 830 831 if (tb[TCA_DUALPI2_COUPLING]) { 832 u8 coupling = nla_get_u8(tb[TCA_DUALPI2_COUPLING]); 833 834 WRITE_ONCE(q->coupling_factor, coupling); 835 } 836 837 if (tb[TCA_DUALPI2_DROP_OVERLOAD]) { 838 u8 drop_overload = nla_get_u8(tb[TCA_DUALPI2_DROP_OVERLOAD]); 839 840 WRITE_ONCE(q->drop_overload, (bool)drop_overload); 841 } 842 843 if (tb[TCA_DUALPI2_DROP_EARLY]) { 844 u8 drop_early = nla_get_u8(tb[TCA_DUALPI2_DROP_EARLY]); 845 846 WRITE_ONCE(q->drop_early, (bool)drop_early); 847 } 848 849 if (tb[TCA_DUALPI2_C_PROTECTION]) { 850 u8 wc = nla_get_u8(tb[TCA_DUALPI2_C_PROTECTION]); 851 852 dualpi2_calculate_c_protection(sch, q, wc); 853 } 854 855 if (tb[TCA_DUALPI2_ECN_MASK]) { 856 u8 ecn_mask = nla_get_u8(tb[TCA_DUALPI2_ECN_MASK]); 857 858 WRITE_ONCE(q->ecn_mask, ecn_mask); 859 } 860 861 if (tb[TCA_DUALPI2_SPLIT_GSO]) { 862 u8 split_gso = nla_get_u8(tb[TCA_DUALPI2_SPLIT_GSO]); 863 864 WRITE_ONCE(q->split_gso, (bool)split_gso); 865 } 866 867 old_qlen = qdisc_qlen(sch); 868 old_backlog = sch->qstats.backlog; 869 while (qdisc_qlen(sch) > sch->limit || 870 q->memory_used > q->memory_limit) { 871 struct sk_buff *skb = NULL; 872 873 if (qdisc_qlen(sch) > qdisc_qlen(q->l_queue)) { 874 skb = qdisc_dequeue_internal(sch, true); 875 if (unlikely(!skb)) { 876 WARN_ON_ONCE(1); 877 break; 878 } 879 q->memory_used -= skb->truesize; 880 rtnl_qdisc_drop(skb, sch); 881 } else if (qdisc_qlen(q->l_queue)) { 882 skb = qdisc_dequeue_internal(q->l_queue, true); 883 if (unlikely(!skb)) { 884 WARN_ON_ONCE(1); 885 break; 886 } 887 /* L-queue packets are counted in both sch and 888 * l_queue on enqueue; qdisc_dequeue_internal() 889 * handled l_queue, so we further account for sch. 890 */ 891 --sch->q.qlen; 892 qdisc_qstats_backlog_dec(sch, skb); 893 q->memory_used -= skb->truesize; 894 rtnl_qdisc_drop(skb, q->l_queue); 895 qdisc_qstats_drop(sch); 896 } else { 897 WARN_ON_ONCE(1); 898 break; 899 } 900 } 901 qdisc_tree_reduce_backlog(sch, old_qlen - qdisc_qlen(sch), 902 old_backlog - sch->qstats.backlog); 903 904 sch_tree_unlock(sch); 905 return 0; 906 } 907 908 /* Default alpha/beta values give a 10dB stability margin with max_rtt=100ms. */ 909 static void dualpi2_reset_default(struct Qdisc *sch) 910 { 911 struct dualpi2_sched_data *q = qdisc_priv(sch); 912 913 q->sch->limit = 10000; /* Max 125ms at 1Gbps */ 914 q->memory_limit = get_memory_limit(sch, q->sch->limit); 915 916 q->pi2_target = 15 * NSEC_PER_MSEC; 917 q->pi2_tupdate = 16 * NSEC_PER_MSEC; 918 q->pi2_alpha = dualpi2_scale_alpha_beta(41); /* ~0.16 Hz * 256 */ 919 q->pi2_beta = dualpi2_scale_alpha_beta(819); /* ~3.20 Hz * 256 */ 920 921 q->step_thresh = 1 * NSEC_PER_MSEC; 922 q->step_in_packets = false; 923 924 dualpi2_calculate_c_protection(q->sch, q, 10); /* wc=10%, wl=90% */ 925 926 q->ecn_mask = TC_DUALPI2_ECN_MASK_L4S_ECT; /* INET_ECN_ECT_1 */ 927 q->min_qlen_step = 0; /* Always apply step mark in L-queue */ 928 q->coupling_factor = 2; /* window fairness for equal RTTs */ 929 q->drop_overload = TC_DUALPI2_DROP_OVERLOAD_DROP; /* Drop overload */ 930 q->drop_early = TC_DUALPI2_DROP_EARLY_DROP_DEQUEUE; /* Drop dequeue */ 931 q->split_gso = TC_DUALPI2_SPLIT_GSO_SPLIT_GSO; /* Split GSO */ 932 } 933 934 static int dualpi2_init(struct Qdisc *sch, struct nlattr *opt, 935 struct netlink_ext_ack *extack) 936 { 937 struct dualpi2_sched_data *q = qdisc_priv(sch); 938 int err; 939 940 sch->flags |= TCQ_F_DEQUEUE_DROPS; 941 942 q->l_queue = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, 943 TC_H_MAKE(sch->handle, 1), extack); 944 if (!q->l_queue) 945 return -ENOMEM; 946 947 err = tcf_block_get(&q->tcf_block, &q->tcf_filters, sch, extack); 948 if (err) 949 return err; 950 951 q->sch = sch; 952 dualpi2_reset_default(sch); 953 hrtimer_setup(&q->pi2_timer, dualpi2_timer, CLOCK_MONOTONIC, 954 HRTIMER_MODE_ABS_PINNED_SOFT); 955 956 if (opt && nla_len(opt)) { 957 err = dualpi2_change(sch, opt, extack); 958 959 if (err) 960 return err; 961 } 962 963 hrtimer_start(&q->pi2_timer, next_pi2_timeout(q), 964 HRTIMER_MODE_ABS_PINNED_SOFT); 965 return 0; 966 } 967 968 static int dualpi2_dump(struct Qdisc *sch, struct sk_buff *skb) 969 { 970 struct dualpi2_sched_data *q = qdisc_priv(sch); 971 struct nlattr *opts; 972 bool step_in_pkts; 973 u32 step_th; 974 975 step_in_pkts = READ_ONCE(q->step_in_packets); 976 step_th = READ_ONCE(q->step_thresh); 977 978 opts = nla_nest_start_noflag(skb, TCA_OPTIONS); 979 if (!opts) 980 goto nla_put_failure; 981 982 if (step_in_pkts && 983 (nla_put_u32(skb, TCA_DUALPI2_LIMIT, READ_ONCE(sch->limit)) || 984 nla_put_u32(skb, TCA_DUALPI2_MEMORY_LIMIT, 985 READ_ONCE(q->memory_limit)) || 986 nla_put_u32(skb, TCA_DUALPI2_TARGET, 987 convert_ns_to_usec(READ_ONCE(q->pi2_target))) || 988 nla_put_u32(skb, TCA_DUALPI2_TUPDATE, 989 convert_ns_to_usec(READ_ONCE(q->pi2_tupdate))) || 990 nla_put_u32(skb, TCA_DUALPI2_ALPHA, 991 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_alpha))) || 992 nla_put_u32(skb, TCA_DUALPI2_BETA, 993 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_beta))) || 994 nla_put_u32(skb, TCA_DUALPI2_STEP_THRESH_PKTS, step_th) || 995 nla_put_u32(skb, TCA_DUALPI2_MIN_QLEN_STEP, 996 READ_ONCE(q->min_qlen_step)) || 997 nla_put_u8(skb, TCA_DUALPI2_COUPLING, 998 READ_ONCE(q->coupling_factor)) || 999 nla_put_u8(skb, TCA_DUALPI2_DROP_OVERLOAD, 1000 READ_ONCE(q->drop_overload)) || 1001 nla_put_u8(skb, TCA_DUALPI2_DROP_EARLY, 1002 READ_ONCE(q->drop_early)) || 1003 nla_put_u8(skb, TCA_DUALPI2_C_PROTECTION, 1004 READ_ONCE(q->c_protection_wc)) || 1005 nla_put_u8(skb, TCA_DUALPI2_ECN_MASK, READ_ONCE(q->ecn_mask)) || 1006 nla_put_u8(skb, TCA_DUALPI2_SPLIT_GSO, READ_ONCE(q->split_gso)))) 1007 goto nla_put_failure; 1008 1009 if (!step_in_pkts && 1010 (nla_put_u32(skb, TCA_DUALPI2_LIMIT, READ_ONCE(sch->limit)) || 1011 nla_put_u32(skb, TCA_DUALPI2_MEMORY_LIMIT, 1012 READ_ONCE(q->memory_limit)) || 1013 nla_put_u32(skb, TCA_DUALPI2_TARGET, 1014 convert_ns_to_usec(READ_ONCE(q->pi2_target))) || 1015 nla_put_u32(skb, TCA_DUALPI2_TUPDATE, 1016 convert_ns_to_usec(READ_ONCE(q->pi2_tupdate))) || 1017 nla_put_u32(skb, TCA_DUALPI2_ALPHA, 1018 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_alpha))) || 1019 nla_put_u32(skb, TCA_DUALPI2_BETA, 1020 dualpi2_unscale_alpha_beta(READ_ONCE(q->pi2_beta))) || 1021 nla_put_u32(skb, TCA_DUALPI2_STEP_THRESH_US, 1022 convert_ns_to_usec(step_th)) || 1023 nla_put_u32(skb, TCA_DUALPI2_MIN_QLEN_STEP, 1024 READ_ONCE(q->min_qlen_step)) || 1025 nla_put_u8(skb, TCA_DUALPI2_COUPLING, 1026 READ_ONCE(q->coupling_factor)) || 1027 nla_put_u8(skb, TCA_DUALPI2_DROP_OVERLOAD, 1028 READ_ONCE(q->drop_overload)) || 1029 nla_put_u8(skb, TCA_DUALPI2_DROP_EARLY, 1030 READ_ONCE(q->drop_early)) || 1031 nla_put_u8(skb, TCA_DUALPI2_C_PROTECTION, 1032 READ_ONCE(q->c_protection_wc)) || 1033 nla_put_u8(skb, TCA_DUALPI2_ECN_MASK, READ_ONCE(q->ecn_mask)) || 1034 nla_put_u8(skb, TCA_DUALPI2_SPLIT_GSO, READ_ONCE(q->split_gso)))) 1035 goto nla_put_failure; 1036 1037 return nla_nest_end(skb, opts); 1038 1039 nla_put_failure: 1040 nla_nest_cancel(skb, opts); 1041 return -1; 1042 } 1043 1044 static int dualpi2_dump_stats(struct Qdisc *sch, struct gnet_dump *d) 1045 { 1046 struct dualpi2_sched_data *q = qdisc_priv(sch); 1047 struct tc_dualpi2_xstats st = { 1048 .prob = READ_ONCE(q->pi2_prob), 1049 .packets_in_c = q->packets_in_c, 1050 .packets_in_l = q->packets_in_l, 1051 .maxq = q->maxq, 1052 .ecn_mark = q->ecn_mark, 1053 .credit = q->c_protection_credit, 1054 .step_marks = q->step_marks, 1055 .memory_used = q->memory_used, 1056 .max_memory_used = q->max_memory_used, 1057 .memory_limit = q->memory_limit, 1058 }; 1059 u64 qc, ql; 1060 1061 get_queue_delays(q, &qc, &ql); 1062 st.delay_l = convert_ns_to_usec(ql); 1063 st.delay_c = convert_ns_to_usec(qc); 1064 return gnet_stats_copy_app(d, &st, sizeof(st)); 1065 } 1066 1067 /* Reset both L-queue and C-queue, internal packet counters, PI probability, 1068 * C-queue protection credit, and timestamps, while preserving current 1069 * configuration of DUALPI2. 1070 */ 1071 static void dualpi2_reset(struct Qdisc *sch) 1072 { 1073 struct dualpi2_sched_data *q = qdisc_priv(sch); 1074 1075 qdisc_reset_queue(sch); 1076 qdisc_reset_queue(q->l_queue); 1077 q->c_head_ts = 0; 1078 q->l_head_ts = 0; 1079 q->pi2_prob = 0; 1080 q->packets_in_c = 0; 1081 q->packets_in_l = 0; 1082 q->maxq = 0; 1083 q->ecn_mark = 0; 1084 q->step_marks = 0; 1085 q->memory_used = 0; 1086 q->max_memory_used = 0; 1087 dualpi2_reset_c_protection(q); 1088 } 1089 1090 static void dualpi2_destroy(struct Qdisc *sch) 1091 { 1092 struct dualpi2_sched_data *q = qdisc_priv(sch); 1093 1094 q->pi2_tupdate = 0; 1095 hrtimer_cancel(&q->pi2_timer); 1096 if (q->l_queue) 1097 qdisc_put(q->l_queue); 1098 tcf_block_put(q->tcf_block); 1099 } 1100 1101 static struct Qdisc *dualpi2_leaf(struct Qdisc *sch, unsigned long arg) 1102 { 1103 return NULL; 1104 } 1105 1106 static unsigned long dualpi2_find(struct Qdisc *sch, u32 classid) 1107 { 1108 return 0; 1109 } 1110 1111 static unsigned long dualpi2_bind(struct Qdisc *sch, unsigned long parent, 1112 u32 classid) 1113 { 1114 return 0; 1115 } 1116 1117 static void dualpi2_unbind(struct Qdisc *q, unsigned long cl) 1118 { 1119 } 1120 1121 static struct tcf_block *dualpi2_tcf_block(struct Qdisc *sch, unsigned long cl, 1122 struct netlink_ext_ack *extack) 1123 { 1124 struct dualpi2_sched_data *q = qdisc_priv(sch); 1125 1126 if (cl) 1127 return NULL; 1128 return q->tcf_block; 1129 } 1130 1131 static void dualpi2_walk(struct Qdisc *sch, struct qdisc_walker *arg) 1132 { 1133 unsigned int i; 1134 1135 if (arg->stop) 1136 return; 1137 1138 /* We statically define only 2 queues */ 1139 for (i = 0; i < 2; i++) { 1140 if (arg->count < arg->skip) { 1141 arg->count++; 1142 continue; 1143 } 1144 if (arg->fn(sch, i + 1, arg) < 0) { 1145 arg->stop = 1; 1146 break; 1147 } 1148 arg->count++; 1149 } 1150 } 1151 1152 /* Minimal class support to handle tc filters */ 1153 static const struct Qdisc_class_ops dualpi2_class_ops = { 1154 .leaf = dualpi2_leaf, 1155 .find = dualpi2_find, 1156 .tcf_block = dualpi2_tcf_block, 1157 .bind_tcf = dualpi2_bind, 1158 .unbind_tcf = dualpi2_unbind, 1159 .walk = dualpi2_walk, 1160 }; 1161 1162 static struct Qdisc_ops dualpi2_qdisc_ops __read_mostly = { 1163 .id = "dualpi2", 1164 .cl_ops = &dualpi2_class_ops, 1165 .priv_size = sizeof(struct dualpi2_sched_data), 1166 .enqueue = dualpi2_qdisc_enqueue, 1167 .dequeue = dualpi2_qdisc_dequeue, 1168 .peek = qdisc_peek_dequeued, 1169 .init = dualpi2_init, 1170 .destroy = dualpi2_destroy, 1171 .reset = dualpi2_reset, 1172 .change = dualpi2_change, 1173 .dump = dualpi2_dump, 1174 .dump_stats = dualpi2_dump_stats, 1175 .owner = THIS_MODULE, 1176 }; 1177 1178 static int __init dualpi2_module_init(void) 1179 { 1180 return register_qdisc(&dualpi2_qdisc_ops); 1181 } 1182 1183 static void __exit dualpi2_module_exit(void) 1184 { 1185 unregister_qdisc(&dualpi2_qdisc_ops); 1186 } 1187 1188 module_init(dualpi2_module_init); 1189 module_exit(dualpi2_module_exit); 1190 1191 MODULE_DESCRIPTION("Dual Queue with Proportional Integral controller Improved with a Square (dualpi2) scheduler"); 1192 MODULE_AUTHOR("Koen De Schepper <koen.de_schepper@nokia-bell-labs.com>"); 1193 MODULE_AUTHOR("Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>"); 1194 MODULE_AUTHOR("Olga Albisser <olga@albisser.org>"); 1195 MODULE_AUTHOR("Henrik Steen <henrist@henrist.net>"); 1196 MODULE_AUTHOR("Olivier Tilmans <olivier.tilmans@nokia.com>"); 1197 1198 MODULE_LICENSE("Dual BSD/GPL"); 1199 MODULE_VERSION("1.0"); 1200