blob: 7597fe14686600e6fa2584544b69ebdfb1144edf [file] [log] [blame]
Patrick McHardy13d2a1d2008-11-20 04:10:00 -08001/*
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
20struct 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
35struct drr_sched {
36 struct list_head active;
37 struct tcf_proto *filter_list;
38 struct Qdisc_class_hash clhash;
39};
40
41static 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
52static 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
60static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
61 [TCA_DRR_QUANTUM] = { .type = NLA_U32 },
62};
63
64static 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;
Jarek Poplawski1844f742009-02-27 02:42:38 -080069 struct nlattr *opt = tca[TCA_OPTIONS];
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080070 struct nlattr *tb[TCA_DRR_MAX + 1];
71 u32 quantum;
72 int err;
73
Jarek Poplawski1844f742009-02-27 02:42:38 -080074 if (!opt)
75 return -EINVAL;
76
77 err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy);
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080078 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) {
Stephen Hemminger71bcb092008-11-25 21:13:31 -080089 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
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080097 sch_tree_lock(sch);
98 if (tb[TCA_DRR_QUANTUM])
99 cl->quantum = quantum;
100 sch_tree_unlock(sch);
101
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800102 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
Stephen Hemminger71bcb092008-11-25 21:13:31 -0800117 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 }
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800127
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
138static 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
145static 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
Jarek Poplawski7cd0a632009-03-15 20:00:19 -0700158 BUG_ON(--cl->refcnt == 0);
159 /*
160 * This shouldn't happen: we "hold" one cops->get() when called
161 * from tc_ctl_tclass; the destroy method is done from cops->put().
162 */
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800163
164 sch_tree_unlock(sch);
165 return 0;
166}
167
168static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
169{
170 struct drr_class *cl = drr_find_class(sch, classid);
171
172 if (cl != NULL)
173 cl->refcnt++;
174
175 return (unsigned long)cl;
176}
177
178static void drr_put_class(struct Qdisc *sch, unsigned long arg)
179{
180 struct drr_class *cl = (struct drr_class *)arg;
181
182 if (--cl->refcnt == 0)
183 drr_destroy_class(sch, cl);
184}
185
186static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl)
187{
188 struct drr_sched *q = qdisc_priv(sch);
189
190 if (cl)
191 return NULL;
192
193 return &q->filter_list;
194}
195
196static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
197 u32 classid)
198{
199 struct drr_class *cl = drr_find_class(sch, classid);
200
201 if (cl != NULL)
202 cl->filter_cnt++;
203
204 return (unsigned long)cl;
205}
206
207static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
208{
209 struct drr_class *cl = (struct drr_class *)arg;
210
211 cl->filter_cnt--;
212}
213
214static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
215 struct Qdisc *new, struct Qdisc **old)
216{
217 struct drr_class *cl = (struct drr_class *)arg;
218
219 if (new == NULL) {
220 new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
221 &pfifo_qdisc_ops, cl->common.classid);
222 if (new == NULL)
223 new = &noop_qdisc;
224 }
225
226 sch_tree_lock(sch);
227 drr_purge_queue(cl);
Patrick McHardyb94c8af2008-11-20 04:11:36 -0800228 *old = cl->qdisc;
229 cl->qdisc = new;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800230 sch_tree_unlock(sch);
231 return 0;
232}
233
234static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
235{
236 struct drr_class *cl = (struct drr_class *)arg;
237
238 return cl->qdisc;
239}
240
241static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
242{
243 struct drr_class *cl = (struct drr_class *)arg;
244
245 if (cl->qdisc->q.qlen == 0)
246 list_del(&cl->alist);
247}
248
249static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
250 struct sk_buff *skb, struct tcmsg *tcm)
251{
252 struct drr_class *cl = (struct drr_class *)arg;
253 struct nlattr *nest;
254
255 tcm->tcm_parent = TC_H_ROOT;
256 tcm->tcm_handle = cl->common.classid;
257 tcm->tcm_info = cl->qdisc->handle;
258
259 nest = nla_nest_start(skb, TCA_OPTIONS);
260 if (nest == NULL)
261 goto nla_put_failure;
262 NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
263 return nla_nest_end(skb, nest);
264
265nla_put_failure:
266 nla_nest_cancel(skb, nest);
267 return -EMSGSIZE;
268}
269
270static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
271 struct gnet_dump *d)
272{
273 struct drr_class *cl = (struct drr_class *)arg;
274 struct tc_drr_stats xstats;
275
276 memset(&xstats, 0, sizeof(xstats));
277 if (cl->qdisc->q.qlen)
278 xstats.deficit = cl->deficit;
279
280 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
281 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
282 gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
283 return -1;
284
285 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
286}
287
288static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
289{
290 struct drr_sched *q = qdisc_priv(sch);
291 struct drr_class *cl;
292 struct hlist_node *n;
293 unsigned int i;
294
295 if (arg->stop)
296 return;
297
298 for (i = 0; i < q->clhash.hashsize; i++) {
299 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
300 if (arg->count < arg->skip) {
301 arg->count++;
302 continue;
303 }
304 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
305 arg->stop = 1;
306 return;
307 }
308 arg->count++;
309 }
310 }
311}
312
313static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
314 int *qerr)
315{
316 struct drr_sched *q = qdisc_priv(sch);
317 struct drr_class *cl;
318 struct tcf_result res;
319 int result;
320
321 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
322 cl = drr_find_class(sch, skb->priority);
323 if (cl != NULL)
324 return cl;
325 }
326
327 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
328 result = tc_classify(skb, q->filter_list, &res);
329 if (result >= 0) {
330#ifdef CONFIG_NET_CLS_ACT
331 switch (result) {
332 case TC_ACT_QUEUED:
333 case TC_ACT_STOLEN:
334 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
335 case TC_ACT_SHOT:
336 return NULL;
337 }
338#endif
339 cl = (struct drr_class *)res.class;
340 if (cl == NULL)
341 cl = drr_find_class(sch, res.classid);
342 return cl;
343 }
344 return NULL;
345}
346
347static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
348{
349 struct drr_sched *q = qdisc_priv(sch);
350 struct drr_class *cl;
351 unsigned int len;
352 int err;
353
354 cl = drr_classify(skb, sch, &err);
355 if (cl == NULL) {
356 if (err & __NET_XMIT_BYPASS)
357 sch->qstats.drops++;
358 kfree_skb(skb);
359 return err;
360 }
361
362 len = qdisc_pkt_len(skb);
363 err = qdisc_enqueue(skb, cl->qdisc);
364 if (unlikely(err != NET_XMIT_SUCCESS)) {
365 if (net_xmit_drop_count(err)) {
366 cl->qstats.drops++;
367 sch->qstats.drops++;
368 }
369 return err;
370 }
371
372 if (cl->qdisc->q.qlen == 1) {
373 list_add_tail(&cl->alist, &q->active);
374 cl->deficit = cl->quantum;
375 }
376
377 cl->bstats.packets++;
378 cl->bstats.bytes += len;
379 sch->bstats.packets++;
380 sch->bstats.bytes += len;
381
382 sch->q.qlen++;
383 return err;
384}
385
386static struct sk_buff *drr_dequeue(struct Qdisc *sch)
387{
388 struct drr_sched *q = qdisc_priv(sch);
389 struct drr_class *cl;
390 struct sk_buff *skb;
391 unsigned int len;
392
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800393 if (list_empty(&q->active))
394 goto out;
395 while (1) {
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800396 cl = list_first_entry(&q->active, struct drr_class, alist);
397 skb = cl->qdisc->ops->peek(cl->qdisc);
398 if (skb == NULL)
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800399 goto out;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800400
401 len = qdisc_pkt_len(skb);
402 if (len <= cl->deficit) {
403 cl->deficit -= len;
404 skb = qdisc_dequeue_peeked(cl->qdisc);
405 if (cl->qdisc->q.qlen == 0)
406 list_del(&cl->alist);
407 sch->q.qlen--;
408 return skb;
409 }
410
411 cl->deficit += cl->quantum;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800412 list_move_tail(&cl->alist, &q->active);
413 }
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800414out:
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800415 return NULL;
416}
417
418static unsigned int drr_drop(struct Qdisc *sch)
419{
420 struct drr_sched *q = qdisc_priv(sch);
421 struct drr_class *cl;
422 unsigned int len;
423
424 list_for_each_entry(cl, &q->active, alist) {
425 if (cl->qdisc->ops->drop) {
426 len = cl->qdisc->ops->drop(cl->qdisc);
427 if (len > 0) {
Jarek Poplawski98aa9c82008-11-21 04:37:27 -0800428 sch->q.qlen--;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800429 if (cl->qdisc->q.qlen == 0)
430 list_del(&cl->alist);
431 return len;
432 }
433 }
434 }
435 return 0;
436}
437
438static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
439{
440 struct drr_sched *q = qdisc_priv(sch);
441 int err;
442
443 err = qdisc_class_hash_init(&q->clhash);
444 if (err < 0)
445 return err;
446 INIT_LIST_HEAD(&q->active);
447 return 0;
448}
449
450static void drr_reset_qdisc(struct Qdisc *sch)
451{
452 struct drr_sched *q = qdisc_priv(sch);
453 struct drr_class *cl;
454 struct hlist_node *n;
455 unsigned int i;
456
457 for (i = 0; i < q->clhash.hashsize; i++) {
458 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
459 if (cl->qdisc->q.qlen)
460 list_del(&cl->alist);
461 qdisc_reset(cl->qdisc);
462 }
463 }
464 sch->q.qlen = 0;
465}
466
467static void drr_destroy_qdisc(struct Qdisc *sch)
468{
469 struct drr_sched *q = qdisc_priv(sch);
470 struct drr_class *cl;
471 struct hlist_node *n, *next;
472 unsigned int i;
473
474 tcf_destroy_chain(&q->filter_list);
475
476 for (i = 0; i < q->clhash.hashsize; i++) {
477 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
478 common.hnode)
479 drr_destroy_class(sch, cl);
480 }
481 qdisc_class_hash_destroy(&q->clhash);
482}
483
484static const struct Qdisc_class_ops drr_class_ops = {
485 .change = drr_change_class,
486 .delete = drr_delete_class,
487 .get = drr_get_class,
488 .put = drr_put_class,
489 .tcf_chain = drr_tcf_chain,
490 .bind_tcf = drr_bind_tcf,
491 .unbind_tcf = drr_unbind_tcf,
492 .graft = drr_graft_class,
493 .leaf = drr_class_leaf,
494 .qlen_notify = drr_qlen_notify,
495 .dump = drr_dump_class,
496 .dump_stats = drr_dump_class_stats,
497 .walk = drr_walk,
498};
499
500static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
501 .cl_ops = &drr_class_ops,
502 .id = "drr",
503 .priv_size = sizeof(struct drr_sched),
504 .enqueue = drr_enqueue,
505 .dequeue = drr_dequeue,
506 .peek = qdisc_peek_dequeued,
507 .drop = drr_drop,
508 .init = drr_init_qdisc,
509 .reset = drr_reset_qdisc,
510 .destroy = drr_destroy_qdisc,
511 .owner = THIS_MODULE,
512};
513
514static int __init drr_init(void)
515{
516 return register_qdisc(&drr_qdisc_ops);
517}
518
519static void __exit drr_exit(void)
520{
521 unregister_qdisc(&drr_qdisc_ops);
522}
523
524module_init(drr_init);
525module_exit(drr_exit);
526MODULE_LICENSE("GPL");