]> git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - net/sched/sch_gred.c
projects / mirror_ubuntu-jammy-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
net_sched: gred: eliminate redundant DP prio comparisons
[mirror_ubuntu-jammy-kernel.git] / net / sched / sch_gred.c
1 /*
2 * net/sched/sch_gred.c Generic Random Early Detection queue.
3 *
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * Authors: J Hadi Salim (hadi@cyberus.ca) 1998-2002
11 *
12 * 991129: - Bug fix with grio mode
13 * - a better sing. AvgQ mode with Grio(WRED)
14 * - A finer grained VQ dequeue based on sugestion
15 * from Ren Liu
16 * - More error checks
17 *
18 * For all the glorious comments look at include/net/red.h
19 */
20
21 #include <linux/slab.h>
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
25 #include <linux/skbuff.h>
26 #include <net/pkt_sched.h>
27 #include <net/red.h>
28
29 #define GRED_DEF_PRIO (MAX_DPs / 2)
30 #define GRED_VQ_MASK (MAX_DPs - 1)
31
32 struct gred_sched_data;
33 struct gred_sched;
34
35 struct gred_sched_data {
36 u32 limit; /* HARD maximal queue length */
37 u32 DP; /* the drop parameters */
38 u32 bytesin; /* bytes seen on virtualQ so far*/
39 u32 packetsin; /* packets seen on virtualQ so far*/
40 u32 backlog; /* bytes on the virtualQ */
41 u8 prio; /* the prio of this vq */
42
43 struct red_parms parms;
44 struct red_vars vars;
45 struct red_stats stats;
46 };
47
48 enum {
49 GRED_WRED_MODE = 1,
50 GRED_RIO_MODE,
51 };
52
53 struct gred_sched {
54 struct gred_sched_data *tab[MAX_DPs];
55 unsigned long flags;
56 u32 red_flags;
57 u32 DPs;
58 u32 def;
59 struct red_vars wred_set;
60 };
61
62 static inline int gred_wred_mode(struct gred_sched *table)
63 {
64 return test_bit(GRED_WRED_MODE, &table->flags);
65 }
66
67 static inline void gred_enable_wred_mode(struct gred_sched *table)
68 {
69 __set_bit(GRED_WRED_MODE, &table->flags);
70 }
71
72 static inline void gred_disable_wred_mode(struct gred_sched *table)
73 {
74 __clear_bit(GRED_WRED_MODE, &table->flags);
75 }
76
77 static inline int gred_rio_mode(struct gred_sched *table)
78 {
79 return test_bit(GRED_RIO_MODE, &table->flags);
80 }
81
82 static inline void gred_enable_rio_mode(struct gred_sched *table)
83 {
84 __set_bit(GRED_RIO_MODE, &table->flags);
85 }
86
87 static inline void gred_disable_rio_mode(struct gred_sched *table)
88 {
89 __clear_bit(GRED_RIO_MODE, &table->flags);
90 }
91
92 static inline int gred_wred_mode_check(struct Qdisc *sch)
93 {
94 struct gred_sched *table = qdisc_priv(sch);
95 int i;
96
97 /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
98 for (i = 0; i < table->DPs; i++) {
99 struct gred_sched_data *q = table->tab[i];
100 int n;
101
102 if (q == NULL)
103 continue;
104
105 for (n = i + 1; n < table->DPs; n++)
106 if (table->tab[n] && table->tab[n]->prio == q->prio)
107 return 1;
108 }
109
110 return 0;
111 }
112
113 static inline unsigned int gred_backlog(struct gred_sched *table,
114 struct gred_sched_data *q,
115 struct Qdisc *sch)
116 {
117 if (gred_wred_mode(table))
118 return sch->qstats.backlog;
119 else
120 return q->backlog;
121 }
122
123 static inline u16 tc_index_to_dp(struct sk_buff *skb)
124 {
125 return skb->tc_index & GRED_VQ_MASK;
126 }
127
128 static inline void gred_load_wred_set(const struct gred_sched *table,
129 struct gred_sched_data *q)
130 {
131 q->vars.qavg = table->wred_set.qavg;
132 q->vars.qidlestart = table->wred_set.qidlestart;
133 }
134
135 static inline void gred_store_wred_set(struct gred_sched *table,
136 struct gred_sched_data *q)
137 {
138 table->wred_set.qavg = q->vars.qavg;
139 }
140
141 static inline int gred_use_ecn(struct gred_sched *t)
142 {
143 return t->red_flags & TC_RED_ECN;
144 }
145
146 static inline int gred_use_harddrop(struct gred_sched *t)
147 {
148 return t->red_flags & TC_RED_HARDDROP;
149 }
150
151 static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
152 {
153 struct gred_sched_data *q = NULL;
154 struct gred_sched *t = qdisc_priv(sch);
155 unsigned long qavg = 0;
156 u16 dp = tc_index_to_dp(skb);
157
158 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
159 dp = t->def;
160
161 q = t->tab[dp];
162 if (!q) {
163 /* Pass through packets not assigned to a DP
164 * if no default DP has been configured. This
165 * allows for DP flows to be left untouched.
166 */
167 if (skb_queue_len(&sch->q) < qdisc_dev(sch)->tx_queue_len)
168 return qdisc_enqueue_tail(skb, sch);
169 else
170 goto drop;
171 }
172
173 /* fix tc_index? --could be controversial but needed for
174 requeueing */
175 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
176 }
177
178 /* sum up all the qaves of prios < ours to get the new qave */
179 if (!gred_wred_mode(t) && gred_rio_mode(t)) {
180 int i;
181
182 for (i = 0; i < t->DPs; i++) {
183 if (t->tab[i] && t->tab[i]->prio < q->prio &&
184 !red_is_idling(&t->tab[i]->vars))
185 qavg += t->tab[i]->vars.qavg;
186 }
187
188 }
189
190 q->packetsin++;
191 q->bytesin += qdisc_pkt_len(skb);
192
193 if (gred_wred_mode(t))
194 gred_load_wred_set(t, q);
195
196 q->vars.qavg = red_calc_qavg(&q->parms,
197 &q->vars,
198 gred_backlog(t, q, sch));
199
200 if (red_is_idling(&q->vars))
201 red_end_of_idle_period(&q->vars);
202
203 if (gred_wred_mode(t))
204 gred_store_wred_set(t, q);
205
206 switch (red_action(&q->parms, &q->vars, q->vars.qavg + qavg)) {
207 case RED_DONT_MARK:
208 break;
209
210 case RED_PROB_MARK:
211 sch->qstats.overlimits++;
212 if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
213 q->stats.prob_drop++;
214 goto congestion_drop;
215 }
216
217 q->stats.prob_mark++;
218 break;
219
220 case RED_HARD_MARK:
221 sch->qstats.overlimits++;
222 if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
223 !INET_ECN_set_ce(skb)) {
224 q->stats.forced_drop++;
225 goto congestion_drop;
226 }
227 q->stats.forced_mark++;
228 break;
229 }
230
231 if (q->backlog + qdisc_pkt_len(skb) <= q->limit) {
232 q->backlog += qdisc_pkt_len(skb);
233 return qdisc_enqueue_tail(skb, sch);
234 }
235
236 q->stats.pdrop++;
237 drop:
238 return qdisc_drop(skb, sch);
239
240 congestion_drop:
241 qdisc_drop(skb, sch);
242 return NET_XMIT_CN;
243 }
244
245 static struct sk_buff *gred_dequeue(struct Qdisc *sch)
246 {
247 struct sk_buff *skb;
248 struct gred_sched *t = qdisc_priv(sch);
249
250 skb = qdisc_dequeue_head(sch);
251
252 if (skb) {
253 struct gred_sched_data *q;
254 u16 dp = tc_index_to_dp(skb);
255
256 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
257 net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x after dequeue, screwing up backlog\n",
258 tc_index_to_dp(skb));
259 } else {
260 q->backlog -= qdisc_pkt_len(skb);
261
262 if (!q->backlog && !gred_wred_mode(t))
263 red_start_of_idle_period(&q->vars);
264 }
265
266 return skb;
267 }
268
269 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
270 red_start_of_idle_period(&t->wred_set);
271
272 return NULL;
273 }
274
275 static unsigned int gred_drop(struct Qdisc *sch)
276 {
277 struct sk_buff *skb;
278 struct gred_sched *t = qdisc_priv(sch);
279
280 skb = qdisc_dequeue_tail(sch);
281 if (skb) {
282 unsigned int len = qdisc_pkt_len(skb);
283 struct gred_sched_data *q;
284 u16 dp = tc_index_to_dp(skb);
285
286 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
287 net_warn_ratelimited("GRED: Unable to relocate VQ 0x%x while dropping, screwing up backlog\n",
288 tc_index_to_dp(skb));
289 } else {
290 q->backlog -= len;
291 q->stats.other++;
292
293 if (!q->backlog && !gred_wred_mode(t))
294 red_start_of_idle_period(&q->vars);
295 }
296
297 qdisc_drop(skb, sch);
298 return len;
299 }
300
301 if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
302 red_start_of_idle_period(&t->wred_set);
303
304 return 0;
305
306 }
307
308 static void gred_reset(struct Qdisc *sch)
309 {
310 int i;
311 struct gred_sched *t = qdisc_priv(sch);
312
313 qdisc_reset_queue(sch);
314
315 for (i = 0; i < t->DPs; i++) {
316 struct gred_sched_data *q = t->tab[i];
317
318 if (!q)
319 continue;
320
321 red_restart(&q->vars);
322 q->backlog = 0;
323 }
324 }
325
326 static inline void gred_destroy_vq(struct gred_sched_data *q)
327 {
328 kfree(q);
329 }
330
331 static inline int gred_change_table_def(struct Qdisc *sch, struct nlattr *dps)
332 {
333 struct gred_sched *table = qdisc_priv(sch);
334 struct tc_gred_sopt *sopt;
335 int i;
336
337 if (dps == NULL)
338 return -EINVAL;
339
340 sopt = nla_data(dps);
341
342 if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
343 return -EINVAL;
344
345 sch_tree_lock(sch);
346 table->DPs = sopt->DPs;
347 table->def = sopt->def_DP;
348 table->red_flags = sopt->flags;
349
350 /*
351 * Every entry point to GRED is synchronized with the above code
352 * and the DP is checked against DPs, i.e. shadowed VQs can no
353 * longer be found so we can unlock right here.
354 */
355 sch_tree_unlock(sch);
356
357 if (sopt->grio) {
358 gred_enable_rio_mode(table);
359 gred_disable_wred_mode(table);
360 if (gred_wred_mode_check(sch))
361 gred_enable_wred_mode(table);
362 } else {
363 gred_disable_rio_mode(table);
364 gred_disable_wred_mode(table);
365 }
366
367 for (i = table->DPs; i < MAX_DPs; i++) {
368 if (table->tab[i]) {
369 pr_warning("GRED: Warning: Destroying "
370 "shadowed VQ 0x%x\n", i);
371 gred_destroy_vq(table->tab[i]);
372 table->tab[i] = NULL;
373 }
374 }
375
376 return 0;
377 }
378
379 static inline int gred_change_vq(struct Qdisc *sch, int dp,
380 struct tc_gred_qopt *ctl, int prio,
381 u8 *stab, u32 max_P,
382 struct gred_sched_data **prealloc)
383 {
384 struct gred_sched *table = qdisc_priv(sch);
385 struct gred_sched_data *q = table->tab[dp];
386
387 if (!q) {
388 table->tab[dp] = q = *prealloc;
389 *prealloc = NULL;
390 if (!q)
391 return -ENOMEM;
392 }
393
394 q->DP = dp;
395 q->prio = prio;
396 q->limit = ctl->limit;
397
398 if (q->backlog == 0)
399 red_end_of_idle_period(&q->vars);
400
401 red_set_parms(&q->parms,
402 ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
403 ctl->Scell_log, stab, max_P);
404 red_set_vars(&q->vars);
405 return 0;
406 }
407
408 static const struct nla_policy gred_policy[TCA_GRED_MAX + 1] = {
409 [TCA_GRED_PARMS] = { .len = sizeof(struct tc_gred_qopt) },
410 [TCA_GRED_STAB] = { .len = 256 },
411 [TCA_GRED_DPS] = { .len = sizeof(struct tc_gred_sopt) },
412 [TCA_GRED_MAX_P] = { .type = NLA_U32 },
413 };
414
415 static int gred_change(struct Qdisc *sch, struct nlattr *opt)
416 {
417 struct gred_sched *table = qdisc_priv(sch);
418 struct tc_gred_qopt *ctl;
419 struct nlattr *tb[TCA_GRED_MAX + 1];
420 int err, prio = GRED_DEF_PRIO;
421 u8 *stab;
422 u32 max_P;
423 struct gred_sched_data *prealloc;
424
425 if (opt == NULL)
426 return -EINVAL;
427
428 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
429 if (err < 0)
430 return err;
431
432 if (tb[TCA_GRED_PARMS] == NULL && tb[TCA_GRED_STAB] == NULL)
433 return gred_change_table_def(sch, opt);
434
435 if (tb[TCA_GRED_PARMS] == NULL ||
436 tb[TCA_GRED_STAB] == NULL)
437 return -EINVAL;
438
439 max_P = tb[TCA_GRED_MAX_P] ? nla_get_u32(tb[TCA_GRED_MAX_P]) : 0;
440
441 err = -EINVAL;
442 ctl = nla_data(tb[TCA_GRED_PARMS]);
443 stab = nla_data(tb[TCA_GRED_STAB]);
444
445 if (ctl->DP >= table->DPs)
446 goto errout;
447
448 if (gred_rio_mode(table)) {
449 if (ctl->prio == 0) {
450 int def_prio = GRED_DEF_PRIO;
451
452 if (table->tab[table->def])
453 def_prio = table->tab[table->def]->prio;
454
455 printk(KERN_DEBUG "GRED: DP %u does not have a prio "
456 "setting default to %d\n", ctl->DP, def_prio);
457
458 prio = def_prio;
459 } else
460 prio = ctl->prio;
461 }
462
463 prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
464 sch_tree_lock(sch);
465
466 err = gred_change_vq(sch, ctl->DP, ctl, prio, stab, max_P, &prealloc);
467 if (err < 0)
468 goto errout_locked;
469
470 if (gred_rio_mode(table)) {
471 gred_disable_wred_mode(table);
472 if (gred_wred_mode_check(sch))
473 gred_enable_wred_mode(table);
474 }
475
476 err = 0;
477
478 errout_locked:
479 sch_tree_unlock(sch);
480 kfree(prealloc);
481 errout:
482 return err;
483 }
484
485 static int gred_init(struct Qdisc *sch, struct nlattr *opt)
486 {
487 struct nlattr *tb[TCA_GRED_MAX + 1];
488 int err;
489
490 if (opt == NULL)
491 return -EINVAL;
492
493 err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy);
494 if (err < 0)
495 return err;
496
497 if (tb[TCA_GRED_PARMS] || tb[TCA_GRED_STAB])
498 return -EINVAL;
499
500 return gred_change_table_def(sch, tb[TCA_GRED_DPS]);
501 }
502
503 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
504 {
505 struct gred_sched *table = qdisc_priv(sch);
506 struct nlattr *parms, *opts = NULL;
507 int i;
508 u32 max_p[MAX_DPs];
509 struct tc_gred_sopt sopt = {
510 .DPs = table->DPs,
511 .def_DP = table->def,
512 .grio = gred_rio_mode(table),
513 .flags = table->red_flags,
514 };
515
516 opts = nla_nest_start(skb, TCA_OPTIONS);
517 if (opts == NULL)
518 goto nla_put_failure;
519 if (nla_put(skb, TCA_GRED_DPS, sizeof(sopt), &sopt))
520 goto nla_put_failure;
521
522 for (i = 0; i < MAX_DPs; i++) {
523 struct gred_sched_data *q = table->tab[i];
524
525 max_p[i] = q ? q->parms.max_P : 0;
526 }
527 if (nla_put(skb, TCA_GRED_MAX_P, sizeof(max_p), max_p))
528 goto nla_put_failure;
529
530 parms = nla_nest_start(skb, TCA_GRED_PARMS);
531 if (parms == NULL)
532 goto nla_put_failure;
533
534 for (i = 0; i < MAX_DPs; i++) {
535 struct gred_sched_data *q = table->tab[i];
536 struct tc_gred_qopt opt;
537
538 memset(&opt, 0, sizeof(opt));
539
540 if (!q) {
541 /* hack -- fix at some point with proper message
542 This is how we indicate to tc that there is no VQ
543 at this DP */
544
545 opt.DP = MAX_DPs + i;
546 goto append_opt;
547 }
548
549 opt.limit = q->limit;
550 opt.DP = q->DP;
551 opt.backlog = q->backlog;
552 opt.prio = q->prio;
553 opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
554 opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
555 opt.Wlog = q->parms.Wlog;
556 opt.Plog = q->parms.Plog;
557 opt.Scell_log = q->parms.Scell_log;
558 opt.other = q->stats.other;
559 opt.early = q->stats.prob_drop;
560 opt.forced = q->stats.forced_drop;
561 opt.pdrop = q->stats.pdrop;
562 opt.packets = q->packetsin;
563 opt.bytesin = q->bytesin;
564
565 if (gred_wred_mode(table))
566 gred_load_wred_set(table, q);
567
568 opt.qave = red_calc_qavg(&q->parms, &q->vars, q->vars.qavg);
569
570 append_opt:
571 if (nla_append(skb, sizeof(opt), &opt) < 0)
572 goto nla_put_failure;
573 }
574
575 nla_nest_end(skb, parms);
576
577 return nla_nest_end(skb, opts);
578
579 nla_put_failure:
580 nla_nest_cancel(skb, opts);
581 return -EMSGSIZE;
582 }
583
584 static void gred_destroy(struct Qdisc *sch)
585 {
586 struct gred_sched *table = qdisc_priv(sch);
587 int i;
588
589 for (i = 0; i < table->DPs; i++) {
590 if (table->tab[i])
591 gred_destroy_vq(table->tab[i]);
592 }
593 }
594
595 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
596 .id = "gred",
597 .priv_size = sizeof(struct gred_sched),
598 .enqueue = gred_enqueue,
599 .dequeue = gred_dequeue,
600 .peek = qdisc_peek_head,
601 .drop = gred_drop,
602 .init = gred_init,
603 .reset = gred_reset,
604 .destroy = gred_destroy,
605 .change = gred_change,
606 .dump = gred_dump,
607 .owner = THIS_MODULE,
608 };
609
610 static int __init gred_module_init(void)
611 {
612 return register_qdisc(&gred_qdisc_ops);
613 }
614
615 static void __exit gred_module_exit(void)
616 {
617 unregister_qdisc(&gred_qdisc_ops);
618 }
619
620 module_init(gred_module_init)
621 module_exit(gred_module_exit)
622
623 MODULE_LICENSE("GPL");
Ubuntu Jammy Linux kernel mirror