1 /* 2 * net/sched/sch_drr.c Deficit Round Robin scheduler 3 * 4 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * version 2 as published by the Free Software Foundation. 9 */ 10 11 #include <linux/module.h> 12 #include <linux/slab.h> 13 #include <linux/init.h> 14 #include <linux/errno.h> 15 #include <linux/netdevice.h> 16 #include <linux/pkt_sched.h> 17 #include <net/sch_generic.h> 18 #include <net/pkt_sched.h> 19 #include <net/pkt_cls.h> 20 21 struct drr_class { 22 struct Qdisc_class_common common; 23 unsigned int refcnt; 24 unsigned int filter_cnt; 25 26 struct gnet_stats_basic_packed bstats; 27 struct gnet_stats_queue qstats; 28 struct gnet_stats_rate_est rate_est; 29 struct list_head alist; 30 struct Qdisc *qdisc; 31 32 u32 quantum; 33 u32 deficit; 34 }; 35 36 struct drr_sched { 37 struct list_head active; 38 struct tcf_proto *filter_list; 39 struct Qdisc_class_hash clhash; 40 }; 41 42 static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid) 43 { 44 struct drr_sched *q = qdisc_priv(sch); 45 struct Qdisc_class_common *clc; 46 47 clc = qdisc_class_find(&q->clhash, classid); 48 if (clc == NULL) 49 return NULL; 50 return container_of(clc, struct drr_class, common); 51 } 52 53 static void drr_purge_queue(struct drr_class *cl) 54 { 55 unsigned int len = cl->qdisc->q.qlen; 56 57 qdisc_reset(cl->qdisc); 58 qdisc_tree_decrease_qlen(cl->qdisc, len); 59 } 60 61 static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = { 62 [TCA_DRR_QUANTUM] = { .type = NLA_U32 }, 63 }; 64 65 static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid, 66 struct nlattr **tca, unsigned long *arg) 67 { 68 struct drr_sched *q = qdisc_priv(sch); 69 struct drr_class *cl = (struct drr_class *)*arg; 70 struct nlattr *opt = tca[TCA_OPTIONS]; 71 struct nlattr *tb[TCA_DRR_MAX + 1]; 72 u32 quantum; 73 int err; 74 75 if (!opt) 76 return -EINVAL; 77 78 err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy); 79 if (err < 0) 80 return err; 81 82 if (tb[TCA_DRR_QUANTUM]) { 83 quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]); 84 if (quantum == 0) 85 return -EINVAL; 86 } else 87 quantum = psched_mtu(qdisc_dev(sch)); 88 89 if (cl != NULL) { 90 if (tca[TCA_RATE]) { 91 err = gen_replace_estimator(&cl->bstats, &cl->rate_est, 92 qdisc_root_sleeping_lock(sch), 93 tca[TCA_RATE]); 94 if (err) 95 return err; 96 } 97 98 sch_tree_lock(sch); 99 if (tb[TCA_DRR_QUANTUM]) 100 cl->quantum = quantum; 101 sch_tree_unlock(sch); 102 103 return 0; 104 } 105 106 cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL); 107 if (cl == NULL) 108 return -ENOBUFS; 109 110 cl->refcnt = 1; 111 cl->common.classid = classid; 112 cl->quantum = quantum; 113 cl->qdisc = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue, 114 &pfifo_qdisc_ops, classid); 115 if (cl->qdisc == NULL) 116 cl->qdisc = &noop_qdisc; 117 118 if (tca[TCA_RATE]) { 119 err = gen_replace_estimator(&cl->bstats, &cl->rate_est, 120 qdisc_root_sleeping_lock(sch), 121 tca[TCA_RATE]); 122 if (err) { 123 qdisc_destroy(cl->qdisc); 124 kfree(cl); 125 return err; 126 } 127 } 128 129 sch_tree_lock(sch); 130 qdisc_class_hash_insert(&q->clhash, &cl->common); 131 sch_tree_unlock(sch); 132 133 qdisc_class_hash_grow(sch, &q->clhash); 134 135 *arg = (unsigned long)cl; 136 return 0; 137 } 138 139 static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl) 140 { 141 gen_kill_estimator(&cl->bstats, &cl->rate_est); 142 qdisc_destroy(cl->qdisc); 143 kfree(cl); 144 } 145 146 static int drr_delete_class(struct Qdisc *sch, unsigned long arg) 147 { 148 struct drr_sched *q = qdisc_priv(sch); 149 struct drr_class *cl = (struct drr_class *)arg; 150 151 if (cl->filter_cnt > 0) 152 return -EBUSY; 153 154 sch_tree_lock(sch); 155 156 drr_purge_queue(cl); 157 qdisc_class_hash_remove(&q->clhash, &cl->common); 158 159 BUG_ON(--cl->refcnt == 0); 160 /* 161 * This shouldn't happen: we "hold" one cops->get() when called 162 * from tc_ctl_tclass; the destroy method is done from cops->put(). 163 */ 164 165 sch_tree_unlock(sch); 166 return 0; 167 } 168 169 static unsigned long drr_get_class(struct Qdisc *sch, u32 classid) 170 { 171 struct drr_class *cl = drr_find_class(sch, classid); 172 173 if (cl != NULL) 174 cl->refcnt++; 175 176 return (unsigned long)cl; 177 } 178 179 static void drr_put_class(struct Qdisc *sch, unsigned long arg) 180 { 181 struct drr_class *cl = (struct drr_class *)arg; 182 183 if (--cl->refcnt == 0) 184 drr_destroy_class(sch, cl); 185 } 186 187 static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl) 188 { 189 struct drr_sched *q = qdisc_priv(sch); 190 191 if (cl) 192 return NULL; 193 194 return &q->filter_list; 195 } 196 197 static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent, 198 u32 classid) 199 { 200 struct drr_class *cl = drr_find_class(sch, classid); 201 202 if (cl != NULL) 203 cl->filter_cnt++; 204 205 return (unsigned long)cl; 206 } 207 208 static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg) 209 { 210 struct drr_class *cl = (struct drr_class *)arg; 211 212 cl->filter_cnt--; 213 } 214 215 static int drr_graft_class(struct Qdisc *sch, unsigned long arg, 216 struct Qdisc *new, struct Qdisc **old) 217 { 218 struct drr_class *cl = (struct drr_class *)arg; 219 220 if (new == NULL) { 221 new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue, 222 &pfifo_qdisc_ops, cl->common.classid); 223 if (new == NULL) 224 new = &noop_qdisc; 225 } 226 227 sch_tree_lock(sch); 228 drr_purge_queue(cl); 229 *old = cl->qdisc; 230 cl->qdisc = new; 231 sch_tree_unlock(sch); 232 return 0; 233 } 234 235 static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg) 236 { 237 struct drr_class *cl = (struct drr_class *)arg; 238 239 return cl->qdisc; 240 } 241 242 static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg) 243 { 244 struct drr_class *cl = (struct drr_class *)arg; 245 246 if (cl->qdisc->q.qlen == 0) 247 list_del(&cl->alist); 248 } 249 250 static int drr_dump_class(struct Qdisc *sch, unsigned long arg, 251 struct sk_buff *skb, struct tcmsg *tcm) 252 { 253 struct drr_class *cl = (struct drr_class *)arg; 254 struct nlattr *nest; 255 256 tcm->tcm_parent = TC_H_ROOT; 257 tcm->tcm_handle = cl->common.classid; 258 tcm->tcm_info = cl->qdisc->handle; 259 260 nest = nla_nest_start(skb, TCA_OPTIONS); 261 if (nest == NULL) 262 goto nla_put_failure; 263 NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum); 264 return nla_nest_end(skb, nest); 265 266 nla_put_failure: 267 nla_nest_cancel(skb, nest); 268 return -EMSGSIZE; 269 } 270 271 static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg, 272 struct gnet_dump *d) 273 { 274 struct drr_class *cl = (struct drr_class *)arg; 275 struct tc_drr_stats xstats; 276 277 memset(&xstats, 0, sizeof(xstats)); 278 if (cl->qdisc->q.qlen) { 279 xstats.deficit = cl->deficit; 280 cl->qdisc->qstats.qlen = cl->qdisc->q.qlen; 281 } 282 283 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 || 284 gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || 285 gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0) 286 return -1; 287 288 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 289 } 290 291 static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg) 292 { 293 struct drr_sched *q = qdisc_priv(sch); 294 struct drr_class *cl; 295 struct hlist_node *n; 296 unsigned int i; 297 298 if (arg->stop) 299 return; 300 301 for (i = 0; i < q->clhash.hashsize; i++) { 302 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) { 303 if (arg->count < arg->skip) { 304 arg->count++; 305 continue; 306 } 307 if (arg->fn(sch, (unsigned long)cl, arg) < 0) { 308 arg->stop = 1; 309 return; 310 } 311 arg->count++; 312 } 313 } 314 } 315 316 static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch, 317 int *qerr) 318 { 319 struct drr_sched *q = qdisc_priv(sch); 320 struct drr_class *cl; 321 struct tcf_result res; 322 int result; 323 324 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { 325 cl = drr_find_class(sch, skb->priority); 326 if (cl != NULL) 327 return cl; 328 } 329 330 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 331 result = tc_classify(skb, q->filter_list, &res); 332 if (result >= 0) { 333 #ifdef CONFIG_NET_CLS_ACT 334 switch (result) { 335 case TC_ACT_QUEUED: 336 case TC_ACT_STOLEN: 337 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 338 case TC_ACT_SHOT: 339 return NULL; 340 } 341 #endif 342 cl = (struct drr_class *)res.class; 343 if (cl == NULL) 344 cl = drr_find_class(sch, res.classid); 345 return cl; 346 } 347 return NULL; 348 } 349 350 static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch) 351 { 352 struct drr_sched *q = qdisc_priv(sch); 353 struct drr_class *cl; 354 unsigned int len; 355 int err; 356 357 cl = drr_classify(skb, sch, &err); 358 if (cl == NULL) { 359 if (err & __NET_XMIT_BYPASS) 360 sch->qstats.drops++; 361 kfree_skb(skb); 362 return err; 363 } 364 365 len = qdisc_pkt_len(skb); 366 err = qdisc_enqueue(skb, cl->qdisc); 367 if (unlikely(err != NET_XMIT_SUCCESS)) { 368 if (net_xmit_drop_count(err)) { 369 cl->qstats.drops++; 370 sch->qstats.drops++; 371 } 372 return err; 373 } 374 375 if (cl->qdisc->q.qlen == 1) { 376 list_add_tail(&cl->alist, &q->active); 377 cl->deficit = cl->quantum; 378 } 379 380 cl->bstats.packets++; 381 cl->bstats.bytes += len; 382 sch->bstats.packets++; 383 sch->bstats.bytes += len; 384 385 sch->q.qlen++; 386 return err; 387 } 388 389 static struct sk_buff *drr_dequeue(struct Qdisc *sch) 390 { 391 struct drr_sched *q = qdisc_priv(sch); 392 struct drr_class *cl; 393 struct sk_buff *skb; 394 unsigned int len; 395 396 if (list_empty(&q->active)) 397 goto out; 398 while (1) { 399 cl = list_first_entry(&q->active, struct drr_class, alist); 400 skb = cl->qdisc->ops->peek(cl->qdisc); 401 if (skb == NULL) 402 goto out; 403 404 len = qdisc_pkt_len(skb); 405 if (len <= cl->deficit) { 406 cl->deficit -= len; 407 skb = qdisc_dequeue_peeked(cl->qdisc); 408 if (cl->qdisc->q.qlen == 0) 409 list_del(&cl->alist); 410 sch->q.qlen--; 411 return skb; 412 } 413 414 cl->deficit += cl->quantum; 415 list_move_tail(&cl->alist, &q->active); 416 } 417 out: 418 return NULL; 419 } 420 421 static unsigned int drr_drop(struct Qdisc *sch) 422 { 423 struct drr_sched *q = qdisc_priv(sch); 424 struct drr_class *cl; 425 unsigned int len; 426 427 list_for_each_entry(cl, &q->active, alist) { 428 if (cl->qdisc->ops->drop) { 429 len = cl->qdisc->ops->drop(cl->qdisc); 430 if (len > 0) { 431 sch->q.qlen--; 432 if (cl->qdisc->q.qlen == 0) 433 list_del(&cl->alist); 434 return len; 435 } 436 } 437 } 438 return 0; 439 } 440 441 static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt) 442 { 443 struct drr_sched *q = qdisc_priv(sch); 444 int err; 445 446 err = qdisc_class_hash_init(&q->clhash); 447 if (err < 0) 448 return err; 449 INIT_LIST_HEAD(&q->active); 450 return 0; 451 } 452 453 static void drr_reset_qdisc(struct Qdisc *sch) 454 { 455 struct drr_sched *q = qdisc_priv(sch); 456 struct drr_class *cl; 457 struct hlist_node *n; 458 unsigned int i; 459 460 for (i = 0; i < q->clhash.hashsize; i++) { 461 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) { 462 if (cl->qdisc->q.qlen) 463 list_del(&cl->alist); 464 qdisc_reset(cl->qdisc); 465 } 466 } 467 sch->q.qlen = 0; 468 } 469 470 static void drr_destroy_qdisc(struct Qdisc *sch) 471 { 472 struct drr_sched *q = qdisc_priv(sch); 473 struct drr_class *cl; 474 struct hlist_node *n, *next; 475 unsigned int i; 476 477 tcf_destroy_chain(&q->filter_list); 478 479 for (i = 0; i < q->clhash.hashsize; i++) { 480 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i], 481 common.hnode) 482 drr_destroy_class(sch, cl); 483 } 484 qdisc_class_hash_destroy(&q->clhash); 485 } 486 487 static const struct Qdisc_class_ops drr_class_ops = { 488 .change = drr_change_class, 489 .delete = drr_delete_class, 490 .get = drr_get_class, 491 .put = drr_put_class, 492 .tcf_chain = drr_tcf_chain, 493 .bind_tcf = drr_bind_tcf, 494 .unbind_tcf = drr_unbind_tcf, 495 .graft = drr_graft_class, 496 .leaf = drr_class_leaf, 497 .qlen_notify = drr_qlen_notify, 498 .dump = drr_dump_class, 499 .dump_stats = drr_dump_class_stats, 500 .walk = drr_walk, 501 }; 502 503 static struct Qdisc_ops drr_qdisc_ops __read_mostly = { 504 .cl_ops = &drr_class_ops, 505 .id = "drr", 506 .priv_size = sizeof(struct drr_sched), 507 .enqueue = drr_enqueue, 508 .dequeue = drr_dequeue, 509 .peek = qdisc_peek_dequeued, 510 .drop = drr_drop, 511 .init = drr_init_qdisc, 512 .reset = drr_reset_qdisc, 513 .destroy = drr_destroy_qdisc, 514 .owner = THIS_MODULE, 515 }; 516 517 static int __init drr_init(void) 518 { 519 return register_qdisc(&drr_qdisc_ops); 520 } 521 522 static void __exit drr_exit(void) 523 { 524 unregister_qdisc(&drr_qdisc_ops); 525 } 526 527 module_init(drr_init); 528 module_exit(drr_exit); 529 MODULE_LICENSE("GPL"); 530