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