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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 net_rate_estimator __rcu *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 __rcu *filter_list; | |
39 | struct tcf_block *block; | |
40 | struct Qdisc_class_hash clhash; | |
41 | }; | |
42 | ||
43 | static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid) | |
44 | { | |
45 | struct drr_sched *q = qdisc_priv(sch); | |
46 | struct Qdisc_class_common *clc; | |
47 | ||
48 | clc = qdisc_class_find(&q->clhash, classid); | |
49 | if (clc == NULL) | |
50 | return NULL; | |
51 | return container_of(clc, struct drr_class, common); | |
52 | } | |
53 | ||
54 | static void drr_purge_queue(struct drr_class *cl) | |
55 | { | |
56 | unsigned int len = cl->qdisc->q.qlen; | |
57 | unsigned int backlog = cl->qdisc->qstats.backlog; | |
58 | ||
59 | qdisc_reset(cl->qdisc); | |
60 | qdisc_tree_reduce_backlog(cl->qdisc, len, backlog); | |
61 | } | |
62 | ||
63 | static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = { | |
64 | [TCA_DRR_QUANTUM] = { .type = NLA_U32 }, | |
65 | }; | |
66 | ||
67 | static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid, | |
68 | struct nlattr **tca, unsigned long *arg) | |
69 | { | |
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]; | |
74 | u32 quantum; | |
75 | int err; | |
76 | ||
77 | if (!opt) | |
78 | return -EINVAL; | |
79 | ||
80 | err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, NULL); | |
81 | if (err < 0) | |
82 | return err; | |
83 | ||
84 | if (tb[TCA_DRR_QUANTUM]) { | |
85 | quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]); | |
86 | if (quantum == 0) | |
87 | return -EINVAL; | |
88 | } else | |
89 | quantum = psched_mtu(qdisc_dev(sch)); | |
90 | ||
91 | if (cl != NULL) { | |
92 | if (tca[TCA_RATE]) { | |
93 | err = gen_replace_estimator(&cl->bstats, NULL, | |
94 | &cl->rate_est, | |
95 | NULL, | |
96 | qdisc_root_sleeping_running(sch), | |
97 | tca[TCA_RATE]); | |
98 | if (err) | |
99 | return err; | |
100 | } | |
101 | ||
102 | sch_tree_lock(sch); | |
103 | if (tb[TCA_DRR_QUANTUM]) | |
104 | cl->quantum = quantum; | |
105 | sch_tree_unlock(sch); | |
106 | ||
107 | return 0; | |
108 | } | |
109 | ||
110 | cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL); | |
111 | if (cl == NULL) | |
112 | return -ENOBUFS; | |
113 | ||
114 | cl->refcnt = 1; | |
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; | |
121 | else | |
122 | qdisc_hash_add(cl->qdisc, true); | |
123 | ||
124 | if (tca[TCA_RATE]) { | |
125 | err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est, | |
126 | NULL, | |
127 | qdisc_root_sleeping_running(sch), | |
128 | tca[TCA_RATE]); | |
129 | if (err) { | |
130 | qdisc_destroy(cl->qdisc); | |
131 | kfree(cl); | |
132 | return err; | |
133 | } | |
134 | } | |
135 | ||
136 | sch_tree_lock(sch); | |
137 | qdisc_class_hash_insert(&q->clhash, &cl->common); | |
138 | sch_tree_unlock(sch); | |
139 | ||
140 | qdisc_class_hash_grow(sch, &q->clhash); | |
141 | ||
142 | *arg = (unsigned long)cl; | |
143 | return 0; | |
144 | } | |
145 | ||
146 | static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl) | |
147 | { | |
148 | gen_kill_estimator(&cl->rate_est); | |
149 | qdisc_destroy(cl->qdisc); | |
150 | kfree(cl); | |
151 | } | |
152 | ||
153 | static int drr_delete_class(struct Qdisc *sch, unsigned long arg) | |
154 | { | |
155 | struct drr_sched *q = qdisc_priv(sch); | |
156 | struct drr_class *cl = (struct drr_class *)arg; | |
157 | ||
158 | if (cl->filter_cnt > 0) | |
159 | return -EBUSY; | |
160 | ||
161 | sch_tree_lock(sch); | |
162 | ||
163 | drr_purge_queue(cl); | |
164 | qdisc_class_hash_remove(&q->clhash, &cl->common); | |
165 | ||
166 | BUG_ON(--cl->refcnt == 0); | |
167 | /* | |
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(). | |
170 | */ | |
171 | ||
172 | sch_tree_unlock(sch); | |
173 | return 0; | |
174 | } | |
175 | ||
176 | static unsigned long drr_get_class(struct Qdisc *sch, u32 classid) | |
177 | { | |
178 | struct drr_class *cl = drr_find_class(sch, classid); | |
179 | ||
180 | if (cl != NULL) | |
181 | cl->refcnt++; | |
182 | ||
183 | return (unsigned long)cl; | |
184 | } | |
185 | ||
186 | static void drr_put_class(struct Qdisc *sch, unsigned long arg) | |
187 | { | |
188 | struct drr_class *cl = (struct drr_class *)arg; | |
189 | ||
190 | if (--cl->refcnt == 0) | |
191 | drr_destroy_class(sch, cl); | |
192 | } | |
193 | ||
194 | static struct tcf_block *drr_tcf_block(struct Qdisc *sch, unsigned long cl) | |
195 | { | |
196 | struct drr_sched *q = qdisc_priv(sch); | |
197 | ||
198 | if (cl) | |
199 | return NULL; | |
200 | ||
201 | return q->block; | |
202 | } | |
203 | ||
204 | static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent, | |
205 | u32 classid) | |
206 | { | |
207 | struct drr_class *cl = drr_find_class(sch, classid); | |
208 | ||
209 | if (cl != NULL) | |
210 | cl->filter_cnt++; | |
211 | ||
212 | return (unsigned long)cl; | |
213 | } | |
214 | ||
215 | static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg) | |
216 | { | |
217 | struct drr_class *cl = (struct drr_class *)arg; | |
218 | ||
219 | cl->filter_cnt--; | |
220 | } | |
221 | ||
222 | static int drr_graft_class(struct Qdisc *sch, unsigned long arg, | |
223 | struct Qdisc *new, struct Qdisc **old) | |
224 | { | |
225 | struct drr_class *cl = (struct drr_class *)arg; | |
226 | ||
227 | if (new == NULL) { | |
228 | new = qdisc_create_dflt(sch->dev_queue, | |
229 | &pfifo_qdisc_ops, cl->common.classid); | |
230 | if (new == NULL) | |
231 | new = &noop_qdisc; | |
232 | } | |
233 | ||
234 | *old = qdisc_replace(sch, new, &cl->qdisc); | |
235 | return 0; | |
236 | } | |
237 | ||
238 | static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg) | |
239 | { | |
240 | struct drr_class *cl = (struct drr_class *)arg; | |
241 | ||
242 | return cl->qdisc; | |
243 | } | |
244 | ||
245 | static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg) | |
246 | { | |
247 | struct drr_class *cl = (struct drr_class *)arg; | |
248 | ||
249 | if (cl->qdisc->q.qlen == 0) | |
250 | list_del(&cl->alist); | |
251 | } | |
252 | ||
253 | static int drr_dump_class(struct Qdisc *sch, unsigned long arg, | |
254 | struct sk_buff *skb, struct tcmsg *tcm) | |
255 | { | |
256 | struct drr_class *cl = (struct drr_class *)arg; | |
257 | struct nlattr *nest; | |
258 | ||
259 | tcm->tcm_parent = TC_H_ROOT; | |
260 | tcm->tcm_handle = cl->common.classid; | |
261 | tcm->tcm_info = cl->qdisc->handle; | |
262 | ||
263 | nest = nla_nest_start(skb, TCA_OPTIONS); | |
264 | if (nest == NULL) | |
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); | |
269 | ||
270 | nla_put_failure: | |
271 | nla_nest_cancel(skb, nest); | |
272 | return -EMSGSIZE; | |
273 | } | |
274 | ||
275 | static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg, | |
276 | struct gnet_dump *d) | |
277 | { | |
278 | struct drr_class *cl = (struct drr_class *)arg; | |
279 | __u32 qlen = cl->qdisc->q.qlen; | |
280 | struct tc_drr_stats xstats; | |
281 | ||
282 | memset(&xstats, 0, sizeof(xstats)); | |
283 | if (qlen) | |
284 | xstats.deficit = cl->deficit; | |
285 | ||
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) | |
290 | return -1; | |
291 | ||
292 | return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); | |
293 | } | |
294 | ||
295 | static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg) | |
296 | { | |
297 | struct drr_sched *q = qdisc_priv(sch); | |
298 | struct drr_class *cl; | |
299 | unsigned int i; | |
300 | ||
301 | if (arg->stop) | |
302 | return; | |
303 | ||
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) { | |
307 | arg->count++; | |
308 | continue; | |
309 | } | |
310 | if (arg->fn(sch, (unsigned long)cl, arg) < 0) { | |
311 | arg->stop = 1; | |
312 | return; | |
313 | } | |
314 | arg->count++; | |
315 | } | |
316 | } | |
317 | } | |
318 | ||
319 | static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch, | |
320 | int *qerr) | |
321 | { | |
322 | struct drr_sched *q = qdisc_priv(sch); | |
323 | struct drr_class *cl; | |
324 | struct tcf_result res; | |
325 | struct tcf_proto *fl; | |
326 | int result; | |
327 | ||
328 | if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { | |
329 | cl = drr_find_class(sch, skb->priority); | |
330 | if (cl != NULL) | |
331 | return cl; | |
332 | } | |
333 | ||
334 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; | |
335 | fl = rcu_dereference_bh(q->filter_list); | |
336 | result = tcf_classify(skb, fl, &res, false); | |
337 | if (result >= 0) { | |
338 | #ifdef CONFIG_NET_CLS_ACT | |
339 | switch (result) { | |
340 | case TC_ACT_QUEUED: | |
341 | case TC_ACT_STOLEN: | |
342 | case TC_ACT_TRAP: | |
343 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; | |
344 | case TC_ACT_SHOT: | |
345 | return NULL; | |
346 | } | |
347 | #endif | |
348 | cl = (struct drr_class *)res.class; | |
349 | if (cl == NULL) | |
350 | cl = drr_find_class(sch, res.classid); | |
351 | return cl; | |
352 | } | |
353 | return NULL; | |
354 | } | |
355 | ||
356 | static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, | |
357 | struct sk_buff **to_free) | |
358 | { | |
359 | struct drr_sched *q = qdisc_priv(sch); | |
360 | struct drr_class *cl; | |
361 | int err = 0; | |
362 | ||
363 | cl = drr_classify(skb, sch, &err); | |
364 | if (cl == NULL) { | |
365 | if (err & __NET_XMIT_BYPASS) | |
366 | qdisc_qstats_drop(sch); | |
367 | __qdisc_drop(skb, to_free); | |
368 | return err; | |
369 | } | |
370 | ||
371 | err = qdisc_enqueue(skb, cl->qdisc, to_free); | |
372 | if (unlikely(err != NET_XMIT_SUCCESS)) { | |
373 | if (net_xmit_drop_count(err)) { | |
374 | cl->qstats.drops++; | |
375 | qdisc_qstats_drop(sch); | |
376 | } | |
377 | return err; | |
378 | } | |
379 | ||
380 | if (cl->qdisc->q.qlen == 1) { | |
381 | list_add_tail(&cl->alist, &q->active); | |
382 | cl->deficit = cl->quantum; | |
383 | } | |
384 | ||
385 | qdisc_qstats_backlog_inc(sch, skb); | |
386 | sch->q.qlen++; | |
387 | return err; | |
388 | } | |
389 | ||
390 | static struct sk_buff *drr_dequeue(struct Qdisc *sch) | |
391 | { | |
392 | struct drr_sched *q = qdisc_priv(sch); | |
393 | struct drr_class *cl; | |
394 | struct sk_buff *skb; | |
395 | unsigned int len; | |
396 | ||
397 | if (list_empty(&q->active)) | |
398 | goto out; | |
399 | while (1) { | |
400 | cl = list_first_entry(&q->active, struct drr_class, alist); | |
401 | skb = cl->qdisc->ops->peek(cl->qdisc); | |
402 | if (skb == NULL) { | |
403 | qdisc_warn_nonwc(__func__, cl->qdisc); | |
404 | goto out; | |
405 | } | |
406 | ||
407 | len = qdisc_pkt_len(skb); | |
408 | if (len <= cl->deficit) { | |
409 | cl->deficit -= len; | |
410 | skb = qdisc_dequeue_peeked(cl->qdisc); | |
411 | if (unlikely(skb == NULL)) | |
412 | goto out; | |
413 | if (cl->qdisc->q.qlen == 0) | |
414 | list_del(&cl->alist); | |
415 | ||
416 | bstats_update(&cl->bstats, skb); | |
417 | qdisc_bstats_update(sch, skb); | |
418 | qdisc_qstats_backlog_dec(sch, skb); | |
419 | sch->q.qlen--; | |
420 | return skb; | |
421 | } | |
422 | ||
423 | cl->deficit += cl->quantum; | |
424 | list_move_tail(&cl->alist, &q->active); | |
425 | } | |
426 | out: | |
427 | return NULL; | |
428 | } | |
429 | ||
430 | static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt) | |
431 | { | |
432 | struct drr_sched *q = qdisc_priv(sch); | |
433 | int err; | |
434 | ||
435 | err = tcf_block_get(&q->block, &q->filter_list); | |
436 | if (err) | |
437 | return err; | |
438 | err = qdisc_class_hash_init(&q->clhash); | |
439 | if (err < 0) | |
440 | return err; | |
441 | INIT_LIST_HEAD(&q->active); | |
442 | return 0; | |
443 | } | |
444 | ||
445 | static void drr_reset_qdisc(struct Qdisc *sch) | |
446 | { | |
447 | struct drr_sched *q = qdisc_priv(sch); | |
448 | struct drr_class *cl; | |
449 | unsigned int i; | |
450 | ||
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); | |
456 | } | |
457 | } | |
458 | sch->qstats.backlog = 0; | |
459 | sch->q.qlen = 0; | |
460 | } | |
461 | ||
462 | static void drr_destroy_qdisc(struct Qdisc *sch) | |
463 | { | |
464 | struct drr_sched *q = qdisc_priv(sch); | |
465 | struct drr_class *cl; | |
466 | struct hlist_node *next; | |
467 | unsigned int i; | |
468 | ||
469 | tcf_block_put(q->block); | |
470 | ||
471 | for (i = 0; i < q->clhash.hashsize; i++) { | |
472 | hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i], | |
473 | common.hnode) | |
474 | drr_destroy_class(sch, cl); | |
475 | } | |
476 | qdisc_class_hash_destroy(&q->clhash); | |
477 | } | |
478 | ||
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, | |
492 | .walk = drr_walk, | |
493 | }; | |
494 | ||
495 | static struct Qdisc_ops drr_qdisc_ops __read_mostly = { | |
496 | .cl_ops = &drr_class_ops, | |
497 | .id = "drr", | |
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, | |
506 | }; | |
507 | ||
508 | static int __init drr_init(void) | |
509 | { | |
510 | return register_qdisc(&drr_qdisc_ops); | |
511 | } | |
512 | ||
513 | static void __exit drr_exit(void) | |
514 | { | |
515 | unregister_qdisc(&drr_qdisc_ops); | |
516 | } | |
517 | ||
518 | module_init(drr_init); | |
519 | module_exit(drr_exit); | |
520 | MODULE_LICENSE("GPL"); |