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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> | |
5a0e3ad6 | 12 | #include <linux/slab.h> |
13d2a1d2 PM |
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 | ||
c1a8f1f1 | 26 | struct gnet_stats_basic_packed bstats; |
13d2a1d2 | 27 | struct gnet_stats_queue qstats; |
45203a3b | 28 | struct gnet_stats_rate_est64 rate_est; |
13d2a1d2 PM |
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; | |
25d8c0d5 | 38 | struct tcf_proto __rcu *filter_list; |
13d2a1d2 PM |
39 | struct Qdisc_class_hash clhash; |
40 | }; | |
41 | ||
42 | static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid) | |
43 | { | |
44 | struct drr_sched *q = qdisc_priv(sch); | |
45 | struct Qdisc_class_common *clc; | |
46 | ||
47 | clc = qdisc_class_find(&q->clhash, classid); | |
48 | if (clc == NULL) | |
49 | return NULL; | |
50 | return container_of(clc, struct drr_class, common); | |
51 | } | |
52 | ||
53 | static void drr_purge_queue(struct drr_class *cl) | |
54 | { | |
55 | unsigned int len = cl->qdisc->q.qlen; | |
2ccccf5f | 56 | unsigned int backlog = cl->qdisc->qstats.backlog; |
13d2a1d2 PM |
57 | |
58 | qdisc_reset(cl->qdisc); | |
2ccccf5f | 59 | qdisc_tree_reduce_backlog(cl->qdisc, len, backlog); |
13d2a1d2 PM |
60 | } |
61 | ||
62 | static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = { | |
63 | [TCA_DRR_QUANTUM] = { .type = NLA_U32 }, | |
64 | }; | |
65 | ||
66 | static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid, | |
67 | struct nlattr **tca, unsigned long *arg) | |
68 | { | |
69 | struct drr_sched *q = qdisc_priv(sch); | |
70 | struct drr_class *cl = (struct drr_class *)*arg; | |
1844f747 | 71 | struct nlattr *opt = tca[TCA_OPTIONS]; |
13d2a1d2 PM |
72 | struct nlattr *tb[TCA_DRR_MAX + 1]; |
73 | u32 quantum; | |
74 | int err; | |
75 | ||
1844f747 JP |
76 | if (!opt) |
77 | return -EINVAL; | |
78 | ||
79 | err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy); | |
13d2a1d2 PM |
80 | if (err < 0) |
81 | return err; | |
82 | ||
83 | if (tb[TCA_DRR_QUANTUM]) { | |
84 | quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]); | |
85 | if (quantum == 0) | |
86 | return -EINVAL; | |
87 | } else | |
88 | quantum = psched_mtu(qdisc_dev(sch)); | |
89 | ||
90 | if (cl != NULL) { | |
71bcb09a | 91 | if (tca[TCA_RATE]) { |
22e0f8b9 JF |
92 | err = gen_replace_estimator(&cl->bstats, NULL, |
93 | &cl->rate_est, | |
71bcb09a SH |
94 | qdisc_root_sleeping_lock(sch), |
95 | tca[TCA_RATE]); | |
96 | if (err) | |
97 | return err; | |
98 | } | |
99 | ||
13d2a1d2 PM |
100 | sch_tree_lock(sch); |
101 | if (tb[TCA_DRR_QUANTUM]) | |
102 | cl->quantum = quantum; | |
103 | sch_tree_unlock(sch); | |
104 | ||
13d2a1d2 PM |
105 | return 0; |
106 | } | |
107 | ||
108 | cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL); | |
109 | if (cl == NULL) | |
110 | return -ENOBUFS; | |
111 | ||
112 | cl->refcnt = 1; | |
113 | cl->common.classid = classid; | |
114 | cl->quantum = quantum; | |
3511c913 | 115 | cl->qdisc = qdisc_create_dflt(sch->dev_queue, |
13d2a1d2 PM |
116 | &pfifo_qdisc_ops, classid); |
117 | if (cl->qdisc == NULL) | |
118 | cl->qdisc = &noop_qdisc; | |
119 | ||
71bcb09a | 120 | if (tca[TCA_RATE]) { |
22e0f8b9 | 121 | err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est, |
71bcb09a SH |
122 | qdisc_root_sleeping_lock(sch), |
123 | tca[TCA_RATE]); | |
124 | if (err) { | |
125 | qdisc_destroy(cl->qdisc); | |
126 | kfree(cl); | |
127 | return err; | |
128 | } | |
129 | } | |
13d2a1d2 PM |
130 | |
131 | sch_tree_lock(sch); | |
132 | qdisc_class_hash_insert(&q->clhash, &cl->common); | |
133 | sch_tree_unlock(sch); | |
134 | ||
135 | qdisc_class_hash_grow(sch, &q->clhash); | |
136 | ||
137 | *arg = (unsigned long)cl; | |
138 | return 0; | |
139 | } | |
140 | ||
141 | static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl) | |
142 | { | |
143 | gen_kill_estimator(&cl->bstats, &cl->rate_est); | |
144 | qdisc_destroy(cl->qdisc); | |
145 | kfree(cl); | |
146 | } | |
147 | ||
148 | static int drr_delete_class(struct Qdisc *sch, unsigned long arg) | |
149 | { | |
150 | struct drr_sched *q = qdisc_priv(sch); | |
151 | struct drr_class *cl = (struct drr_class *)arg; | |
152 | ||
153 | if (cl->filter_cnt > 0) | |
154 | return -EBUSY; | |
155 | ||
156 | sch_tree_lock(sch); | |
157 | ||
158 | drr_purge_queue(cl); | |
159 | qdisc_class_hash_remove(&q->clhash, &cl->common); | |
160 | ||
7cd0a638 JP |
161 | BUG_ON(--cl->refcnt == 0); |
162 | /* | |
163 | * This shouldn't happen: we "hold" one cops->get() when called | |
164 | * from tc_ctl_tclass; the destroy method is done from cops->put(). | |
165 | */ | |
13d2a1d2 PM |
166 | |
167 | sch_tree_unlock(sch); | |
168 | return 0; | |
169 | } | |
170 | ||
171 | static unsigned long drr_get_class(struct Qdisc *sch, u32 classid) | |
172 | { | |
173 | struct drr_class *cl = drr_find_class(sch, classid); | |
174 | ||
175 | if (cl != NULL) | |
176 | cl->refcnt++; | |
177 | ||
178 | return (unsigned long)cl; | |
179 | } | |
180 | ||
181 | static void drr_put_class(struct Qdisc *sch, unsigned long arg) | |
182 | { | |
183 | struct drr_class *cl = (struct drr_class *)arg; | |
184 | ||
185 | if (--cl->refcnt == 0) | |
186 | drr_destroy_class(sch, cl); | |
187 | } | |
188 | ||
25d8c0d5 JF |
189 | static struct tcf_proto __rcu **drr_tcf_chain(struct Qdisc *sch, |
190 | unsigned long cl) | |
13d2a1d2 PM |
191 | { |
192 | struct drr_sched *q = qdisc_priv(sch); | |
193 | ||
194 | if (cl) | |
195 | return NULL; | |
196 | ||
197 | return &q->filter_list; | |
198 | } | |
199 | ||
200 | static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent, | |
201 | u32 classid) | |
202 | { | |
203 | struct drr_class *cl = drr_find_class(sch, classid); | |
204 | ||
205 | if (cl != NULL) | |
206 | cl->filter_cnt++; | |
207 | ||
208 | return (unsigned long)cl; | |
209 | } | |
210 | ||
211 | static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg) | |
212 | { | |
213 | struct drr_class *cl = (struct drr_class *)arg; | |
214 | ||
215 | cl->filter_cnt--; | |
216 | } | |
217 | ||
218 | static int drr_graft_class(struct Qdisc *sch, unsigned long arg, | |
219 | struct Qdisc *new, struct Qdisc **old) | |
220 | { | |
221 | struct drr_class *cl = (struct drr_class *)arg; | |
222 | ||
223 | if (new == NULL) { | |
3511c913 | 224 | new = qdisc_create_dflt(sch->dev_queue, |
13d2a1d2 PM |
225 | &pfifo_qdisc_ops, cl->common.classid); |
226 | if (new == NULL) | |
227 | new = &noop_qdisc; | |
228 | } | |
229 | ||
86a7996c | 230 | *old = qdisc_replace(sch, new, &cl->qdisc); |
13d2a1d2 PM |
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; | |
1b34ec43 DM |
262 | if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum)) |
263 | goto nla_put_failure; | |
13d2a1d2 PM |
264 | return nla_nest_end(skb, nest); |
265 | ||
266 | nla_put_failure: | |
267 | nla_nest_cancel(skb, nest); | |
268 | return -EMSGSIZE; | |
269 | } | |
270 | ||
271 | static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg, | |
272 | struct gnet_dump *d) | |
273 | { | |
274 | struct drr_class *cl = (struct drr_class *)arg; | |
64015853 | 275 | __u32 qlen = cl->qdisc->q.qlen; |
13d2a1d2 PM |
276 | struct tc_drr_stats xstats; |
277 | ||
278 | memset(&xstats, 0, sizeof(xstats)); | |
64015853 | 279 | if (qlen) |
13d2a1d2 PM |
280 | xstats.deficit = cl->deficit; |
281 | ||
22e0f8b9 | 282 | if (gnet_stats_copy_basic(d, NULL, &cl->bstats) < 0 || |
d250a5f9 | 283 | gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || |
b0ab6f92 | 284 | gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 0) |
13d2a1d2 PM |
285 | return -1; |
286 | ||
287 | return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); | |
288 | } | |
289 | ||
290 | static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg) | |
291 | { | |
292 | struct drr_sched *q = qdisc_priv(sch); | |
293 | struct drr_class *cl; | |
13d2a1d2 PM |
294 | unsigned int i; |
295 | ||
296 | if (arg->stop) | |
297 | return; | |
298 | ||
299 | for (i = 0; i < q->clhash.hashsize; i++) { | |
b67bfe0d | 300 | hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { |
13d2a1d2 PM |
301 | if (arg->count < arg->skip) { |
302 | arg->count++; | |
303 | continue; | |
304 | } | |
305 | if (arg->fn(sch, (unsigned long)cl, arg) < 0) { | |
306 | arg->stop = 1; | |
307 | return; | |
308 | } | |
309 | arg->count++; | |
310 | } | |
311 | } | |
312 | } | |
313 | ||
314 | static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch, | |
315 | int *qerr) | |
316 | { | |
317 | struct drr_sched *q = qdisc_priv(sch); | |
318 | struct drr_class *cl; | |
319 | struct tcf_result res; | |
25d8c0d5 | 320 | struct tcf_proto *fl; |
13d2a1d2 PM |
321 | int result; |
322 | ||
323 | if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { | |
324 | cl = drr_find_class(sch, skb->priority); | |
325 | if (cl != NULL) | |
326 | return cl; | |
327 | } | |
328 | ||
329 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; | |
25d8c0d5 | 330 | fl = rcu_dereference_bh(q->filter_list); |
3b3ae880 | 331 | result = tc_classify(skb, fl, &res, false); |
13d2a1d2 PM |
332 | if (result >= 0) { |
333 | #ifdef CONFIG_NET_CLS_ACT | |
334 | switch (result) { | |
335 | case TC_ACT_QUEUED: | |
336 | case TC_ACT_STOLEN: | |
337 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; | |
338 | case TC_ACT_SHOT: | |
339 | return NULL; | |
340 | } | |
341 | #endif | |
342 | cl = (struct drr_class *)res.class; | |
343 | if (cl == NULL) | |
344 | cl = drr_find_class(sch, res.classid); | |
345 | return cl; | |
346 | } | |
347 | return NULL; | |
348 | } | |
349 | ||
350 | static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch) | |
351 | { | |
352 | struct drr_sched *q = qdisc_priv(sch); | |
353 | struct drr_class *cl; | |
f54ba779 | 354 | int err = 0; |
13d2a1d2 PM |
355 | |
356 | cl = drr_classify(skb, sch, &err); | |
357 | if (cl == NULL) { | |
358 | if (err & __NET_XMIT_BYPASS) | |
25331d6c | 359 | qdisc_qstats_drop(sch); |
13d2a1d2 PM |
360 | kfree_skb(skb); |
361 | return err; | |
362 | } | |
363 | ||
13d2a1d2 PM |
364 | err = qdisc_enqueue(skb, cl->qdisc); |
365 | if (unlikely(err != NET_XMIT_SUCCESS)) { | |
366 | if (net_xmit_drop_count(err)) { | |
367 | cl->qstats.drops++; | |
25331d6c | 368 | qdisc_qstats_drop(sch); |
13d2a1d2 PM |
369 | } |
370 | return err; | |
371 | } | |
372 | ||
373 | if (cl->qdisc->q.qlen == 1) { | |
374 | list_add_tail(&cl->alist, &q->active); | |
375 | cl->deficit = cl->quantum; | |
376 | } | |
377 | ||
13d2a1d2 PM |
378 | sch->q.qlen++; |
379 | return err; | |
380 | } | |
381 | ||
382 | static struct sk_buff *drr_dequeue(struct Qdisc *sch) | |
383 | { | |
384 | struct drr_sched *q = qdisc_priv(sch); | |
385 | struct drr_class *cl; | |
386 | struct sk_buff *skb; | |
387 | unsigned int len; | |
388 | ||
3f0947c3 PM |
389 | if (list_empty(&q->active)) |
390 | goto out; | |
391 | while (1) { | |
13d2a1d2 PM |
392 | cl = list_first_entry(&q->active, struct drr_class, alist); |
393 | skb = cl->qdisc->ops->peek(cl->qdisc); | |
6e765a00 FW |
394 | if (skb == NULL) { |
395 | qdisc_warn_nonwc(__func__, cl->qdisc); | |
3f0947c3 | 396 | goto out; |
6e765a00 | 397 | } |
13d2a1d2 PM |
398 | |
399 | len = qdisc_pkt_len(skb); | |
400 | if (len <= cl->deficit) { | |
401 | cl->deficit -= len; | |
402 | skb = qdisc_dequeue_peeked(cl->qdisc); | |
df3eb6cd BH |
403 | if (unlikely(skb == NULL)) |
404 | goto out; | |
13d2a1d2 PM |
405 | if (cl->qdisc->q.qlen == 0) |
406 | list_del(&cl->alist); | |
2dd875ff ED |
407 | |
408 | bstats_update(&cl->bstats, skb); | |
9190b3b3 | 409 | qdisc_bstats_update(sch, skb); |
13d2a1d2 PM |
410 | sch->q.qlen--; |
411 | return skb; | |
412 | } | |
413 | ||
414 | cl->deficit += cl->quantum; | |
13d2a1d2 PM |
415 | list_move_tail(&cl->alist, &q->active); |
416 | } | |
3f0947c3 | 417 | out: |
13d2a1d2 PM |
418 | return NULL; |
419 | } | |
420 | ||
421 | static unsigned int drr_drop(struct Qdisc *sch) | |
422 | { | |
423 | struct drr_sched *q = qdisc_priv(sch); | |
424 | struct drr_class *cl; | |
425 | unsigned int len; | |
426 | ||
427 | list_for_each_entry(cl, &q->active, alist) { | |
428 | if (cl->qdisc->ops->drop) { | |
429 | len = cl->qdisc->ops->drop(cl->qdisc); | |
430 | if (len > 0) { | |
98aa9c80 | 431 | sch->q.qlen--; |
13d2a1d2 PM |
432 | if (cl->qdisc->q.qlen == 0) |
433 | list_del(&cl->alist); | |
434 | return len; | |
435 | } | |
436 | } | |
437 | } | |
438 | return 0; | |
439 | } | |
440 | ||
441 | static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt) | |
442 | { | |
443 | struct drr_sched *q = qdisc_priv(sch); | |
444 | int err; | |
445 | ||
446 | err = qdisc_class_hash_init(&q->clhash); | |
447 | if (err < 0) | |
448 | return err; | |
449 | INIT_LIST_HEAD(&q->active); | |
450 | return 0; | |
451 | } | |
452 | ||
453 | static void drr_reset_qdisc(struct Qdisc *sch) | |
454 | { | |
455 | struct drr_sched *q = qdisc_priv(sch); | |
456 | struct drr_class *cl; | |
13d2a1d2 PM |
457 | unsigned int i; |
458 | ||
459 | for (i = 0; i < q->clhash.hashsize; i++) { | |
b67bfe0d | 460 | hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { |
13d2a1d2 PM |
461 | if (cl->qdisc->q.qlen) |
462 | list_del(&cl->alist); | |
463 | qdisc_reset(cl->qdisc); | |
464 | } | |
465 | } | |
466 | sch->q.qlen = 0; | |
467 | } | |
468 | ||
469 | static void drr_destroy_qdisc(struct Qdisc *sch) | |
470 | { | |
471 | struct drr_sched *q = qdisc_priv(sch); | |
472 | struct drr_class *cl; | |
b67bfe0d | 473 | struct hlist_node *next; |
13d2a1d2 PM |
474 | unsigned int i; |
475 | ||
476 | tcf_destroy_chain(&q->filter_list); | |
477 | ||
478 | for (i = 0; i < q->clhash.hashsize; i++) { | |
b67bfe0d | 479 | hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i], |
13d2a1d2 PM |
480 | common.hnode) |
481 | drr_destroy_class(sch, cl); | |
482 | } | |
483 | qdisc_class_hash_destroy(&q->clhash); | |
484 | } | |
485 | ||
486 | static const struct Qdisc_class_ops drr_class_ops = { | |
487 | .change = drr_change_class, | |
488 | .delete = drr_delete_class, | |
489 | .get = drr_get_class, | |
490 | .put = drr_put_class, | |
491 | .tcf_chain = drr_tcf_chain, | |
492 | .bind_tcf = drr_bind_tcf, | |
493 | .unbind_tcf = drr_unbind_tcf, | |
494 | .graft = drr_graft_class, | |
495 | .leaf = drr_class_leaf, | |
496 | .qlen_notify = drr_qlen_notify, | |
497 | .dump = drr_dump_class, | |
498 | .dump_stats = drr_dump_class_stats, | |
499 | .walk = drr_walk, | |
500 | }; | |
501 | ||
502 | static struct Qdisc_ops drr_qdisc_ops __read_mostly = { | |
503 | .cl_ops = &drr_class_ops, | |
504 | .id = "drr", | |
505 | .priv_size = sizeof(struct drr_sched), | |
506 | .enqueue = drr_enqueue, | |
507 | .dequeue = drr_dequeue, | |
508 | .peek = qdisc_peek_dequeued, | |
509 | .drop = drr_drop, | |
510 | .init = drr_init_qdisc, | |
511 | .reset = drr_reset_qdisc, | |
512 | .destroy = drr_destroy_qdisc, | |
513 | .owner = THIS_MODULE, | |
514 | }; | |
515 | ||
516 | static int __init drr_init(void) | |
517 | { | |
518 | return register_qdisc(&drr_qdisc_ops); | |
519 | } | |
520 | ||
521 | static void __exit drr_exit(void) | |
522 | { | |
523 | unregister_qdisc(&drr_qdisc_ops); | |
524 | } | |
525 | ||
526 | module_init(drr_init); | |
527 | module_exit(drr_exit); | |
528 | MODULE_LICENSE("GPL"); |