blob: 71e50c80315fe00437461f59aee17a2b5b2b09b1 [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>
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;
David S. Miller1b34ec42012-03-29 05:11:39 -0400263 if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum))
264 goto nla_put_failure;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800265 return nla_nest_end(skb, nest);
266
267nla_put_failure:
268 nla_nest_cancel(skb, nest);
269 return -EMSGSIZE;
270}
271
272static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
273 struct gnet_dump *d)
274{
275 struct drr_class *cl = (struct drr_class *)arg;
276 struct tc_drr_stats xstats;
277
278 memset(&xstats, 0, sizeof(xstats));
Jarek Poplawskia19d2152009-09-17 10:26:07 -0700279 if (cl->qdisc->q.qlen) {
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800280 xstats.deficit = cl->deficit;
Jarek Poplawskia19d2152009-09-17 10:26:07 -0700281 cl->qdisc->qstats.qlen = cl->qdisc->q.qlen;
282 }
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800283
284 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
Eric Dumazetd250a5f2009-10-02 10:32:18 +0000285 gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800286 gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
287 return -1;
288
289 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
290}
291
292static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
293{
294 struct drr_sched *q = qdisc_priv(sch);
295 struct drr_class *cl;
296 struct hlist_node *n;
297 unsigned int i;
298
299 if (arg->stop)
300 return;
301
302 for (i = 0; i < q->clhash.hashsize; i++) {
303 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
304 if (arg->count < arg->skip) {
305 arg->count++;
306 continue;
307 }
308 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
309 arg->stop = 1;
310 return;
311 }
312 arg->count++;
313 }
314 }
315}
316
317static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
318 int *qerr)
319{
320 struct drr_sched *q = qdisc_priv(sch);
321 struct drr_class *cl;
322 struct tcf_result res;
323 int result;
324
325 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
326 cl = drr_find_class(sch, skb->priority);
327 if (cl != NULL)
328 return cl;
329 }
330
331 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
332 result = tc_classify(skb, q->filter_list, &res);
333 if (result >= 0) {
334#ifdef CONFIG_NET_CLS_ACT
335 switch (result) {
336 case TC_ACT_QUEUED:
337 case TC_ACT_STOLEN:
338 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
339 case TC_ACT_SHOT:
340 return NULL;
341 }
342#endif
343 cl = (struct drr_class *)res.class;
344 if (cl == NULL)
345 cl = drr_find_class(sch, res.classid);
346 return cl;
347 }
348 return NULL;
349}
350
351static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
352{
353 struct drr_sched *q = qdisc_priv(sch);
354 struct drr_class *cl;
David S. Millerf54ba772012-09-27 18:35:47 -0400355 int err = 0;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800356
357 cl = drr_classify(skb, sch, &err);
358 if (cl == NULL) {
359 if (err & __NET_XMIT_BYPASS)
360 sch->qstats.drops++;
361 kfree_skb(skb);
362 return err;
363 }
364
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800365 err = qdisc_enqueue(skb, cl->qdisc);
366 if (unlikely(err != NET_XMIT_SUCCESS)) {
367 if (net_xmit_drop_count(err)) {
368 cl->qstats.drops++;
369 sch->qstats.drops++;
370 }
371 return err;
372 }
373
374 if (cl->qdisc->q.qlen == 1) {
375 list_add_tail(&cl->alist, &q->active);
376 cl->deficit = cl->quantum;
377 }
378
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800379 sch->q.qlen++;
380 return err;
381}
382
383static struct sk_buff *drr_dequeue(struct Qdisc *sch)
384{
385 struct drr_sched *q = qdisc_priv(sch);
386 struct drr_class *cl;
387 struct sk_buff *skb;
388 unsigned int len;
389
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800390 if (list_empty(&q->active))
391 goto out;
392 while (1) {
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800393 cl = list_first_entry(&q->active, struct drr_class, alist);
394 skb = cl->qdisc->ops->peek(cl->qdisc);
395 if (skb == NULL)
Patrick McHardy3f0947c2008-11-24 15:46:08 -0800396 goto out;
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800397
398 len = qdisc_pkt_len(skb);
399 if (len <= cl->deficit) {
400 cl->deficit -= len;
401 skb = qdisc_dequeue_peeked(cl->qdisc);
402 if (cl->qdisc->q.qlen == 0)
403 list_del(&cl->alist);
Eric Dumazet2dd875f2012-05-10 05:36:34 +0000404
405 bstats_update(&cl->bstats, skb);
Eric Dumazet9190b3b2011-01-20 23:31:33 -0800406 qdisc_bstats_update(sch, skb);
Patrick McHardy13d2a1d2008-11-20 04:10:00 -0800407 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");