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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090012#include <linux/slab.h>
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080013#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
21struct drr_class {
22 struct Qdisc_class_common common;
23 unsigned int refcnt;
24 unsigned int filter_cnt;
25
Eric Dumazetc1a8f1f2009-08-16 09:36:49 +000026 struct gnet_stats_basic_packed bstats;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080027 struct gnet_stats_queue qstats;
28 struct gnet_stats_rate_est rate_est;
29 struct list_head alist;
30 struct Qdisc *qdisc;
31
32 u32 quantum;
33 u32 deficit;
34};
35
36struct drr_sched {
37 struct list_head active;
38 struct tcf_proto *filter_list;
39 struct Qdisc_class_hash clhash;
40};
41
42static 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
53static void drr_purge_queue(struct drr_class *cl)
54{
55 unsigned int len = cl->qdisc->q.qlen;
56
57 qdisc_reset(cl->qdisc);
58 qdisc_tree_decrease_qlen(cl->qdisc, len);
59}
60
61static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
62 [TCA_DRR_QUANTUM] = { .type = NLA_U32 },
63};
64
65static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
66 struct nlattr **tca, unsigned long *arg)
67{
68 struct drr_sched *q = qdisc_priv(sch);
69 struct drr_class *cl = (struct drr_class *)*arg;
Jarek Poplawski1844f742009-02-27 02:42:38 -080070 struct nlattr *opt = tca[TCA_OPTIONS];
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080071 struct nlattr *tb[TCA_DRR_MAX + 1];
72 u32 quantum;
73 int err;
74
Jarek Poplawski1844f742009-02-27 02:42:38 -080075 if (!opt)
76 return -EINVAL;
77
78 err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy);
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080079 if (err < 0)
80 return err;
81
82 if (tb[TCA_DRR_QUANTUM]) {
83 quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
84 if (quantum == 0)
85 return -EINVAL;
86 } else
87 quantum = psched_mtu(qdisc_dev(sch));
88
89 if (cl != NULL) {
Stephen Hemminger71bcb092008-11-25 21:13:31 -080090 if (tca[TCA_RATE]) {
91 err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
92 qdisc_root_sleeping_lock(sch),
93 tca[TCA_RATE]);
94 if (err)
95 return err;
96 }
97
Patrick McHardy13d2a1d2008-11-20 04:10:00 -080098 sch_tree_lock(sch);
99 if (tb[TCA_DRR_QUANTUM])
100 cl->quantum = quantum;
101 sch_tree_unlock(sch);
102
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800103 return 0;
104 }
105
106 cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
107 if (cl == NULL)
108 return -ENOBUFS;
109
110 cl->refcnt = 1;
111 cl->common.classid = classid;
112 cl->quantum = quantum;
Changli Gao3511c912010-10-16 13:04:08 +0000113 cl->qdisc = qdisc_create_dflt(sch->dev_queue,
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800114 &pfifo_qdisc_ops, classid);
115 if (cl->qdisc == NULL)
116 cl->qdisc = &noop_qdisc;
117
Stephen Hemminger71bcb092008-11-25 21:13:31 -0800118 if (tca[TCA_RATE]) {
119 err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
120 qdisc_root_sleeping_lock(sch),
121 tca[TCA_RATE]);
122 if (err) {
123 qdisc_destroy(cl->qdisc);
124 kfree(cl);
125 return err;
126 }
127 }
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800128
129 sch_tree_lock(sch);
130 qdisc_class_hash_insert(&q->clhash, &cl->common);
131 sch_tree_unlock(sch);
132
133 qdisc_class_hash_grow(sch, &q->clhash);
134
135 *arg = (unsigned long)cl;
136 return 0;
137}
138
139static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
140{
141 gen_kill_estimator(&cl->bstats, &cl->rate_est);
142 qdisc_destroy(cl->qdisc);
143 kfree(cl);
144}
145
146static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
147{
148 struct drr_sched *q = qdisc_priv(sch);
149 struct drr_class *cl = (struct drr_class *)arg;
150
151 if (cl->filter_cnt > 0)
152 return -EBUSY;
153
154 sch_tree_lock(sch);
155
156 drr_purge_queue(cl);
157 qdisc_class_hash_remove(&q->clhash, &cl->common);
158
Jarek Poplawski7cd0a632009-03-15 20:00:19 -0700159 BUG_ON(--cl->refcnt == 0);
160 /*
161 * This shouldn't happen: we "hold" one cops->get() when called
162 * from tc_ctl_tclass; the destroy method is done from cops->put().
163 */
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800164
165 sch_tree_unlock(sch);
166 return 0;
167}
168
169static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
170{
171 struct drr_class *cl = drr_find_class(sch, classid);
172
173 if (cl != NULL)
174 cl->refcnt++;
175
176 return (unsigned long)cl;
177}
178
179static void drr_put_class(struct Qdisc *sch, unsigned long arg)
180{
181 struct drr_class *cl = (struct drr_class *)arg;
182
183 if (--cl->refcnt == 0)
184 drr_destroy_class(sch, cl);
185}
186
187static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl)
188{
189 struct drr_sched *q = qdisc_priv(sch);
190
191 if (cl)
192 return NULL;
193
194 return &q->filter_list;
195}
196
197static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
198 u32 classid)
199{
200 struct drr_class *cl = drr_find_class(sch, classid);
201
202 if (cl != NULL)
203 cl->filter_cnt++;
204
205 return (unsigned long)cl;
206}
207
208static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
209{
210 struct drr_class *cl = (struct drr_class *)arg;
211
212 cl->filter_cnt--;
213}
214
215static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
216 struct Qdisc *new, struct Qdisc **old)
217{
218 struct drr_class *cl = (struct drr_class *)arg;
219
220 if (new == NULL) {
Changli Gao3511c912010-10-16 13:04:08 +0000221 new = qdisc_create_dflt(sch->dev_queue,
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800222 &pfifo_qdisc_ops, cl->common.classid);
223 if (new == NULL)
224 new = &noop_qdisc;
225 }
226
227 sch_tree_lock(sch);
228 drr_purge_queue(cl);
Patrick McHardyb94c8af2008-11-20 04:11:36 -0800229 *old = cl->qdisc;
230 cl->qdisc = new;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800231 sch_tree_unlock(sch);
232 return 0;
233}
234
235static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
236{
237 struct drr_class *cl = (struct drr_class *)arg;
238
239 return cl->qdisc;
240}
241
242static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
243{
244 struct drr_class *cl = (struct drr_class *)arg;
245
246 if (cl->qdisc->q.qlen == 0)
247 list_del(&cl->alist);
248}
249
250static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
251 struct sk_buff *skb, struct tcmsg *tcm)
252{
253 struct drr_class *cl = (struct drr_class *)arg;
254 struct nlattr *nest;
255
256 tcm->tcm_parent = TC_H_ROOT;
257 tcm->tcm_handle = cl->common.classid;
258 tcm->tcm_info = cl->qdisc->handle;
259
260 nest = nla_nest_start(skb, TCA_OPTIONS);
261 if (nest == NULL)
262 goto nla_put_failure;
263 NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
264 return nla_nest_end(skb, nest);
265
266nla_put_failure:
267 nla_nest_cancel(skb, nest);
268 return -EMSGSIZE;
269}
270
271static 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;
275 struct tc_drr_stats xstats;
276
277 memset(&xstats, 0, sizeof(xstats));
Jarek Poplawskia19d2152009-09-17 10:26:07 -0700278 if (cl->qdisc->q.qlen) {
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800279 xstats.deficit = cl->deficit;
Jarek Poplawskia19d2152009-09-17 10:26:07 -0700280 cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
281 }
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800282
283 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
Eric Dumazetd250a5f2009-10-02 10:32:18 +0000284 gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800285 gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
286 return -1;
287
288 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
289}
290
291static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
292{
293 struct drr_sched *q = qdisc_priv(sch);
294 struct drr_class *cl;
295 struct hlist_node *n;
296 unsigned int i;
297
298 if (arg->stop)
299 return;
300
301 for (i = 0; i < q->clhash.hashsize; i++) {
302 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
303 if (arg->count < arg->skip) {
304 arg->count++;
305 continue;
306 }
307 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
308 arg->stop = 1;
309 return;
310 }
311 arg->count++;
312 }
313 }
314}
315
316static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
317 int *qerr)
318{
319 struct drr_sched *q = qdisc_priv(sch);
320 struct drr_class *cl;
321 struct tcf_result res;
322 int result;
323
324 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
325 cl = drr_find_class(sch, skb->priority);
326 if (cl != NULL)
327 return cl;
328 }
329
330 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
331 result = tc_classify(skb, q->filter_list, &res);
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
350static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
351{
352 struct drr_sched *q = qdisc_priv(sch);
353 struct drr_class *cl;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800354 int err;
355
356 cl = drr_classify(skb, sch, &err);
357 if (cl == NULL) {
358 if (err & __NET_XMIT_BYPASS)
359 sch->qstats.drops++;
360 kfree_skb(skb);
361 return err;
362 }
363
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800364 err = qdisc_enqueue(skb, cl->qdisc);
365 if (unlikely(err != NET_XMIT_SUCCESS)) {
366 if (net_xmit_drop_count(err)) {
367 cl->qstats.drops++;
368 sch->qstats.drops++;
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
Eric Dumazetbfe0d022011-01-09 08:30:54 +0000378 bstats_update(&cl->bstats, skb);
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800379
380 sch->q.qlen++;
381 return err;
382}
383
384static struct sk_buff *drr_dequeue(struct Qdisc *sch)
385{
386 struct drr_sched *q = qdisc_priv(sch);
387 struct drr_class *cl;
388 struct sk_buff *skb;
389 unsigned int len;
390
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800391 if (list_empty(&q->active))
392 goto out;
393 while (1) {
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800394 cl = list_first_entry(&q->active, struct drr_class, alist);
395 skb = cl->qdisc->ops->peek(cl->qdisc);
396 if (skb == NULL)
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800397 goto out;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800398
399 len = qdisc_pkt_len(skb);
400 if (len <= cl->deficit) {
401 cl->deficit -= len;
402 skb = qdisc_dequeue_peeked(cl->qdisc);
403 if (cl->qdisc->q.qlen == 0)
404 list_del(&cl->alist);
Eric Dumazet9190b3b2011-01-20 23:31:33 -0800405 qdisc_bstats_update(sch, skb);
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800406 sch->q.qlen--;
407 return skb;
408 }
409
410 cl->deficit += cl->quantum;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800411 list_move_tail(&cl->alist, &q->active);
412 }
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800413out:
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800414 return NULL;
415}
416
417static unsigned int drr_drop(struct Qdisc *sch)
418{
419 struct drr_sched *q = qdisc_priv(sch);
420 struct drr_class *cl;
421 unsigned int len;
422
423 list_for_each_entry(cl, &q->active, alist) {
424 if (cl->qdisc->ops->drop) {
425 len = cl->qdisc->ops->drop(cl->qdisc);
426 if (len > 0) {
Jarek Poplawski98aa9c82008-11-21 04:37:27 -0800427 sch->q.qlen--;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800428 if (cl->qdisc->q.qlen == 0)
429 list_del(&cl->alist);
430 return len;
431 }
432 }
433 }
434 return 0;
435}
436
437static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
438{
439 struct drr_sched *q = qdisc_priv(sch);
440 int err;
441
442 err = qdisc_class_hash_init(&q->clhash);
443 if (err < 0)
444 return err;
445 INIT_LIST_HEAD(&q->active);
446 return 0;
447}
448
449static void drr_reset_qdisc(struct Qdisc *sch)
450{
451 struct drr_sched *q = qdisc_priv(sch);
452 struct drr_class *cl;
453 struct hlist_node *n;
454 unsigned int i;
455
456 for (i = 0; i < q->clhash.hashsize; i++) {
457 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
458 if (cl->qdisc->q.qlen)
459 list_del(&cl->alist);
460 qdisc_reset(cl->qdisc);
461 }
462 }
463 sch->q.qlen = 0;
464}
465
466static void drr_destroy_qdisc(struct Qdisc *sch)
467{
468 struct drr_sched *q = qdisc_priv(sch);
469 struct drr_class *cl;
470 struct hlist_node *n, *next;
471 unsigned int i;
472
473 tcf_destroy_chain(&q->filter_list);
474
475 for (i = 0; i < q->clhash.hashsize; i++) {
476 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
477 common.hnode)
478 drr_destroy_class(sch, cl);
479 }
480 qdisc_class_hash_destroy(&q->clhash);
481}
482
483static const struct Qdisc_class_ops drr_class_ops = {
484 .change = drr_change_class,
485 .delete = drr_delete_class,
486 .get = drr_get_class,
487 .put = drr_put_class,
488 .tcf_chain = drr_tcf_chain,
489 .bind_tcf = drr_bind_tcf,
490 .unbind_tcf = drr_unbind_tcf,
491 .graft = drr_graft_class,
492 .leaf = drr_class_leaf,
493 .qlen_notify = drr_qlen_notify,
494 .dump = drr_dump_class,
495 .dump_stats = drr_dump_class_stats,
496 .walk = drr_walk,
497};
498
499static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
500 .cl_ops = &drr_class_ops,
501 .id = "drr",
502 .priv_size = sizeof(struct drr_sched),
503 .enqueue = drr_enqueue,
504 .dequeue = drr_dequeue,
505 .peek = qdisc_peek_dequeued,
506 .drop = drr_drop,
507 .init = drr_init_qdisc,
508 .reset = drr_reset_qdisc,
509 .destroy = drr_destroy_qdisc,
510 .owner = THIS_MODULE,
511};
512
513static int __init drr_init(void)
514{
515 return register_qdisc(&drr_qdisc_ops);
516}
517
518static void __exit drr_exit(void)
519{
520 unregister_qdisc(&drr_qdisc_ops);
521}
522
523module_init(drr_init);
524module_exit(drr_exit);
525MODULE_LICENSE("GPL");