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13d2a1d2 PM |
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; | |
1844f747 | 69 | struct nlattr *opt = tca[TCA_OPTIONS]; |
13d2a1d2 PM |
70 | struct nlattr *tb[TCA_DRR_MAX + 1]; |
71 | u32 quantum; | |
72 | int err; | |
73 | ||
1844f747 JP |
74 | if (!opt) |
75 | return -EINVAL; | |
76 | ||
77 | err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy); | |
13d2a1d2 PM |
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) { | |
71bcb09a SH |
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 | ||
13d2a1d2 PM |
97 | sch_tree_lock(sch); |
98 | if (tb[TCA_DRR_QUANTUM]) | |
99 | cl->quantum = quantum; | |
100 | sch_tree_unlock(sch); | |
101 | ||
13d2a1d2 PM |
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 | ||
71bcb09a SH |
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 | } | |
13d2a1d2 PM |
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 | ||
7cd0a638 JP |
158 | 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 | */ | |
13d2a1d2 PM |
163 | |
164 | sch_tree_unlock(sch); | |
165 | return 0; | |
166 | } | |
167 | ||
168 | static 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 | ||
178 | static 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 | ||
186 | static 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 | ||
196 | static 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 | ||
207 | static 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 | ||
214 | static 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); | |
b94c8afc PM |
228 | *old = cl->qdisc; |
229 | cl->qdisc = new; | |
13d2a1d2 PM |
230 | sch_tree_unlock(sch); |
231 | return 0; | |
232 | } | |
233 | ||
234 | static 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 | ||
241 | static 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 | ||
249 | static 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 | ||
265 | nla_put_failure: | |
266 | nla_nest_cancel(skb, nest); | |
267 | return -EMSGSIZE; | |
268 | } | |
269 | ||
270 | static 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 | ||
288 | static 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 | ||
313 | static 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 | ||
347 | static 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 | ||
386 | static 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 | ||
3f0947c3 PM |
393 | if (list_empty(&q->active)) |
394 | goto out; | |
395 | while (1) { | |
13d2a1d2 PM |
396 | cl = list_first_entry(&q->active, struct drr_class, alist); |
397 | skb = cl->qdisc->ops->peek(cl->qdisc); | |
398 | if (skb == NULL) | |
3f0947c3 | 399 | goto out; |
13d2a1d2 PM |
400 | |
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; | |
13d2a1d2 PM |
412 | list_move_tail(&cl->alist, &q->active); |
413 | } | |
3f0947c3 | 414 | out: |
13d2a1d2 PM |
415 | return NULL; |
416 | } | |
417 | ||
418 | static 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) { | |
98aa9c80 | 428 | sch->q.qlen--; |
13d2a1d2 PM |
429 | if (cl->qdisc->q.qlen == 0) |
430 | list_del(&cl->alist); | |
431 | return len; | |
432 | } | |
433 | } | |
434 | } | |
435 | return 0; | |
436 | } | |
437 | ||
438 | static 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 | ||
450 | static 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 | ||
467 | static 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 | ||
484 | static 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 | ||
500 | static 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 | ||
514 | static int __init drr_init(void) | |
515 | { | |
516 | return register_qdisc(&drr_qdisc_ops); | |
517 | } | |
518 | ||
519 | static void __exit drr_exit(void) | |
520 | { | |
521 | unregister_qdisc(&drr_qdisc_ops); | |
522 | } | |
523 | ||
524 | module_init(drr_init); | |
525 | module_exit(drr_exit); | |
526 | MODULE_LICENSE("GPL"); |