2 * net/sched/sch_drr.c Deficit Round Robin scheduler
4 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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.
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>
22 struct Qdisc_class_common common;
24 unsigned int filter_cnt;
26 struct gnet_stats_basic_packed bstats;
27 struct gnet_stats_queue qstats;
28 struct net_rate_estimator __rcu *rate_est;
29 struct list_head alist;
37 struct list_head active;
38 struct tcf_proto __rcu *filter_list;
39 struct tcf_block *block;
40 struct Qdisc_class_hash clhash;
43 static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid)
45 struct drr_sched *q = qdisc_priv(sch);
46 struct Qdisc_class_common *clc;
48 clc = qdisc_class_find(&q->clhash, classid);
51 return container_of(clc, struct drr_class, common);
54 static void drr_purge_queue(struct drr_class *cl)
56 unsigned int len = cl->qdisc->q.qlen;
57 unsigned int backlog = cl->qdisc->qstats.backlog;
59 qdisc_reset(cl->qdisc);
60 qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
63 static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
64 [TCA_DRR_QUANTUM] = { .type = NLA_U32 },
67 static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
68 struct nlattr **tca, unsigned long *arg)
70 struct drr_sched *q = qdisc_priv(sch);
71 struct drr_class *cl = (struct drr_class *)*arg;
72 struct nlattr *opt = tca[TCA_OPTIONS];
73 struct nlattr *tb[TCA_DRR_MAX + 1];
80 err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, NULL);
84 if (tb[TCA_DRR_QUANTUM]) {
85 quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
89 quantum = psched_mtu(qdisc_dev(sch));
93 err = gen_replace_estimator(&cl->bstats, NULL,
96 qdisc_root_sleeping_running(sch),
103 if (tb[TCA_DRR_QUANTUM])
104 cl->quantum = quantum;
105 sch_tree_unlock(sch);
110 cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
115 cl->common.classid = classid;
116 cl->quantum = quantum;
117 cl->qdisc = qdisc_create_dflt(sch->dev_queue,
118 &pfifo_qdisc_ops, classid);
119 if (cl->qdisc == NULL)
120 cl->qdisc = &noop_qdisc;
122 qdisc_hash_add(cl->qdisc, true);
125 err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est,
127 qdisc_root_sleeping_running(sch),
130 qdisc_destroy(cl->qdisc);
137 qdisc_class_hash_insert(&q->clhash, &cl->common);
138 sch_tree_unlock(sch);
140 qdisc_class_hash_grow(sch, &q->clhash);
142 *arg = (unsigned long)cl;
146 static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
148 gen_kill_estimator(&cl->rate_est);
149 qdisc_destroy(cl->qdisc);
153 static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
155 struct drr_sched *q = qdisc_priv(sch);
156 struct drr_class *cl = (struct drr_class *)arg;
158 if (cl->filter_cnt > 0)
164 qdisc_class_hash_remove(&q->clhash, &cl->common);
166 BUG_ON(--cl->refcnt == 0);
168 * This shouldn't happen: we "hold" one cops->get() when called
169 * from tc_ctl_tclass; the destroy method is done from cops->put().
172 sch_tree_unlock(sch);
176 static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
178 struct drr_class *cl = drr_find_class(sch, classid);
183 return (unsigned long)cl;
186 static void drr_put_class(struct Qdisc *sch, unsigned long arg)
188 struct drr_class *cl = (struct drr_class *)arg;
190 if (--cl->refcnt == 0)
191 drr_destroy_class(sch, cl);
194 static struct tcf_block *drr_tcf_block(struct Qdisc *sch, unsigned long cl)
196 struct drr_sched *q = qdisc_priv(sch);
204 static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
207 struct drr_class *cl = drr_find_class(sch, classid);
212 return (unsigned long)cl;
215 static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
217 struct drr_class *cl = (struct drr_class *)arg;
222 static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
223 struct Qdisc *new, struct Qdisc **old)
225 struct drr_class *cl = (struct drr_class *)arg;
228 new = qdisc_create_dflt(sch->dev_queue,
229 &pfifo_qdisc_ops, cl->common.classid);
234 *old = qdisc_replace(sch, new, &cl->qdisc);
238 static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
240 struct drr_class *cl = (struct drr_class *)arg;
245 static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
247 struct drr_class *cl = (struct drr_class *)arg;
249 if (cl->qdisc->q.qlen == 0)
250 list_del(&cl->alist);
253 static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
254 struct sk_buff *skb, struct tcmsg *tcm)
256 struct drr_class *cl = (struct drr_class *)arg;
259 tcm->tcm_parent = TC_H_ROOT;
260 tcm->tcm_handle = cl->common.classid;
261 tcm->tcm_info = cl->qdisc->handle;
263 nest = nla_nest_start(skb, TCA_OPTIONS);
265 goto nla_put_failure;
266 if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum))
267 goto nla_put_failure;
268 return nla_nest_end(skb, nest);
271 nla_nest_cancel(skb, nest);
275 static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
278 struct drr_class *cl = (struct drr_class *)arg;
279 __u32 qlen = cl->qdisc->q.qlen;
280 struct tc_drr_stats xstats;
282 memset(&xstats, 0, sizeof(xstats));
284 xstats.deficit = cl->deficit;
286 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
287 d, NULL, &cl->bstats) < 0 ||
288 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
289 gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 0)
292 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
295 static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
297 struct drr_sched *q = qdisc_priv(sch);
298 struct drr_class *cl;
304 for (i = 0; i < q->clhash.hashsize; i++) {
305 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
306 if (arg->count < arg->skip) {
310 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
319 static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
322 struct drr_sched *q = qdisc_priv(sch);
323 struct drr_class *cl;
324 struct tcf_result res;
325 struct tcf_proto *fl;
328 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
329 cl = drr_find_class(sch, skb->priority);
334 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
335 fl = rcu_dereference_bh(q->filter_list);
336 result = tcf_classify(skb, fl, &res, false);
338 #ifdef CONFIG_NET_CLS_ACT
343 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
348 cl = (struct drr_class *)res.class;
350 cl = drr_find_class(sch, res.classid);
356 static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch,
357 struct sk_buff **to_free)
359 struct drr_sched *q = qdisc_priv(sch);
360 struct drr_class *cl;
363 cl = drr_classify(skb, sch, &err);
365 if (err & __NET_XMIT_BYPASS)
366 qdisc_qstats_drop(sch);
367 __qdisc_drop(skb, to_free);
371 err = qdisc_enqueue(skb, cl->qdisc, to_free);
372 if (unlikely(err != NET_XMIT_SUCCESS)) {
373 if (net_xmit_drop_count(err)) {
375 qdisc_qstats_drop(sch);
380 if (cl->qdisc->q.qlen == 1) {
381 list_add_tail(&cl->alist, &q->active);
382 cl->deficit = cl->quantum;
385 qdisc_qstats_backlog_inc(sch, skb);
390 static struct sk_buff *drr_dequeue(struct Qdisc *sch)
392 struct drr_sched *q = qdisc_priv(sch);
393 struct drr_class *cl;
397 if (list_empty(&q->active))
400 cl = list_first_entry(&q->active, struct drr_class, alist);
401 skb = cl->qdisc->ops->peek(cl->qdisc);
403 qdisc_warn_nonwc(__func__, cl->qdisc);
407 len = qdisc_pkt_len(skb);
408 if (len <= cl->deficit) {
410 skb = qdisc_dequeue_peeked(cl->qdisc);
411 if (unlikely(skb == NULL))
413 if (cl->qdisc->q.qlen == 0)
414 list_del(&cl->alist);
416 bstats_update(&cl->bstats, skb);
417 qdisc_bstats_update(sch, skb);
418 qdisc_qstats_backlog_dec(sch, skb);
423 cl->deficit += cl->quantum;
424 list_move_tail(&cl->alist, &q->active);
430 static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
432 struct drr_sched *q = qdisc_priv(sch);
435 err = tcf_block_get(&q->block, &q->filter_list);
438 err = qdisc_class_hash_init(&q->clhash);
441 INIT_LIST_HEAD(&q->active);
445 static void drr_reset_qdisc(struct Qdisc *sch)
447 struct drr_sched *q = qdisc_priv(sch);
448 struct drr_class *cl;
451 for (i = 0; i < q->clhash.hashsize; i++) {
452 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
453 if (cl->qdisc->q.qlen)
454 list_del(&cl->alist);
455 qdisc_reset(cl->qdisc);
458 sch->qstats.backlog = 0;
462 static void drr_destroy_qdisc(struct Qdisc *sch)
464 struct drr_sched *q = qdisc_priv(sch);
465 struct drr_class *cl;
466 struct hlist_node *next;
469 tcf_block_put(q->block);
471 for (i = 0; i < q->clhash.hashsize; i++) {
472 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
474 drr_destroy_class(sch, cl);
476 qdisc_class_hash_destroy(&q->clhash);
479 static const struct Qdisc_class_ops drr_class_ops = {
480 .change = drr_change_class,
481 .delete = drr_delete_class,
482 .get = drr_get_class,
483 .put = drr_put_class,
484 .tcf_block = drr_tcf_block,
485 .bind_tcf = drr_bind_tcf,
486 .unbind_tcf = drr_unbind_tcf,
487 .graft = drr_graft_class,
488 .leaf = drr_class_leaf,
489 .qlen_notify = drr_qlen_notify,
490 .dump = drr_dump_class,
491 .dump_stats = drr_dump_class_stats,
495 static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
496 .cl_ops = &drr_class_ops,
498 .priv_size = sizeof(struct drr_sched),
499 .enqueue = drr_enqueue,
500 .dequeue = drr_dequeue,
501 .peek = qdisc_peek_dequeued,
502 .init = drr_init_qdisc,
503 .reset = drr_reset_qdisc,
504 .destroy = drr_destroy_qdisc,
505 .owner = THIS_MODULE,
508 static int __init drr_init(void)
510 return register_qdisc(&drr_qdisc_ops);
513 static void __exit drr_exit(void)
515 unregister_qdisc(&drr_qdisc_ops);
518 module_init(drr_init);
519 module_exit(drr_exit);
520 MODULE_LICENSE("GPL");