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ARM: shmobile: Move r8a73a4.h
[linux-2.6/btrfs-unstable.git] / net / sched / sch_sfq.c
blob1af2f73906d07aa5bf6f428ffe37b81523178ee4
1 /*
2 * net/sched/sch_sfq.c Stochastic Fairness Queueing discipline.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/jiffies.h>
16 #include <linux/string.h>
17 #include <linux/in.h>
18 #include <linux/errno.h>
19 #include <linux/init.h>
20 #include <linux/skbuff.h>
21 #include <linux/jhash.h>
22 #include <linux/slab.h>
23 #include <linux/vmalloc.h>
24 #include <net/netlink.h>
25 #include <net/pkt_sched.h>
26 #include <net/flow_keys.h>
27 #include <net/red.h>
28
29
30 /* Stochastic Fairness Queuing algorithm.
31 =======================================
32
33 Source:
34 Paul E. McKenney "Stochastic Fairness Queuing",
35 IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
36
37 Paul E. McKenney "Stochastic Fairness Queuing",
38 "Interworking: Research and Experience", v.2, 1991, p.113-131.
39
40
41 See also:
42 M. Shreedhar and George Varghese "Efficient Fair
43 Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
44
45
46 This is not the thing that is usually called (W)FQ nowadays.
47 It does not use any timestamp mechanism, but instead
48 processes queues in round-robin order.
49
50 ADVANTAGE:
51
52 - It is very cheap. Both CPU and memory requirements are minimal.
53
54 DRAWBACKS:
55
56 - "Stochastic" -> It is not 100% fair.
57 When hash collisions occur, several flows are considered as one.
58
59 - "Round-robin" -> It introduces larger delays than virtual clock
60 based schemes, and should not be used for isolating interactive
61 traffic from non-interactive. It means, that this scheduler
62 should be used as leaf of CBQ or P3, which put interactive traffic
63 to higher priority band.
64
65 We still need true WFQ for top level CSZ, but using WFQ
66 for the best effort traffic is absolutely pointless:
67 SFQ is superior for this purpose.
68
69 IMPLEMENTATION:
70 This implementation limits :
71 - maximal queue length per flow to 127 packets.
72 - max mtu to 2^18-1;
73 - max 65408 flows,
74 - number of hash buckets to 65536.
75
76 It is easy to increase these values, but not in flight. */
77
78 #define SFQ_MAX_DEPTH 127 /* max number of packets per flow */
79 #define SFQ_DEFAULT_FLOWS 128
80 #define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
81 #define SFQ_EMPTY_SLOT 0xffff
82 #define SFQ_DEFAULT_HASH_DIVISOR 1024
83
84 /* We use 16 bits to store allot, and want to handle packets up to 64K
85 * Scale allot by 8 (1<<3) so that no overflow occurs.
86 */
87 #define SFQ_ALLOT_SHIFT 3
88 #define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
89
90 /* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
91 typedef u16 sfq_index;
92
93 /*
94 * We dont use pointers to save space.
95 * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
96 * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
97 * are 'pointers' to dep[] array
98 */
99 struct sfq_head {
100 sfq_index next;
101 sfq_index prev;
102 };
103
104 struct sfq_slot {
105 struct sk_buff *skblist_next;
106 struct sk_buff *skblist_prev;
107 sfq_index qlen; /* number of skbs in skblist */
108 sfq_index next; /* next slot in sfq RR chain */
109 struct sfq_head dep; /* anchor in dep[] chains */
110 unsigned short hash; /* hash value (index in ht[]) */
111 short allot; /* credit for this slot */
112
113 unsigned int backlog;
114 struct red_vars vars;
115 };
116
117 struct sfq_sched_data {
118 /* frequently used fields */
119 int limit; /* limit of total number of packets in this qdisc */
120 unsigned int divisor; /* number of slots in hash table */
121 u8 headdrop;
122 u8 maxdepth; /* limit of packets per flow */
123
124 u32 perturbation;
125 u8 cur_depth; /* depth of longest slot */
126 u8 flags;
127 unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
128 struct tcf_proto *filter_list;
129 sfq_index *ht; /* Hash table ('divisor' slots) */
130 struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
131
132 struct red_parms *red_parms;
133 struct tc_sfqred_stats stats;
134 struct sfq_slot *tail; /* current slot in round */
135
136 struct sfq_head dep[SFQ_MAX_DEPTH + 1];
137 /* Linked lists of slots, indexed by depth
138 * dep[0] : list of unused flows
139 * dep[1] : list of flows with 1 packet
140 * dep[X] : list of flows with X packets
141 */
142
143 unsigned int maxflows; /* number of flows in flows array */
144 int perturb_period;
145 unsigned int quantum; /* Allotment per round: MUST BE >= MTU */
146 struct timer_list perturb_timer;
147 };
148
149 /*
150 * sfq_head are either in a sfq_slot or in dep[] array
151 */
152 static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
153 {
154 if (val < SFQ_MAX_FLOWS)
155 return &q->slots[val].dep;
156 return &q->dep[val - SFQ_MAX_FLOWS];
157 }
158
159 /*
160 * In order to be able to quickly rehash our queue when timer changes
161 * q->perturbation, we store flow_keys in skb->cb[]
162 */
163 struct sfq_skb_cb {
164 struct flow_keys keys;
165 };
166
167 static inline struct sfq_skb_cb *sfq_skb_cb(const struct sk_buff *skb)
168 {
169 qdisc_cb_private_validate(skb, sizeof(struct sfq_skb_cb));
170 return (struct sfq_skb_cb *)qdisc_skb_cb(skb)->data;
171 }
172
173 static unsigned int sfq_hash(const struct sfq_sched_data *q,
174 const struct sk_buff *skb)
175 {
176 const struct flow_keys *keys = &sfq_skb_cb(skb)->keys;
177 unsigned int hash;
178
179 hash = jhash_3words((__force u32)keys->dst,
180 (__force u32)keys->src ^ keys->ip_proto,
181 (__force u32)keys->ports, q->perturbation);
182 return hash & (q->divisor - 1);
183 }
184
185 static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
186 int *qerr)
187 {
188 struct sfq_sched_data *q = qdisc_priv(sch);
189 struct tcf_result res;
190 int result;
191
192 if (TC_H_MAJ(skb->priority) == sch->handle &&
193 TC_H_MIN(skb->priority) > 0 &&
194 TC_H_MIN(skb->priority) <= q->divisor)
195 return TC_H_MIN(skb->priority);
196
197 if (!q->filter_list) {
198 skb_flow_dissect(skb, &sfq_skb_cb(skb)->keys);
199 return sfq_hash(q, skb) + 1;
200 }
201
202 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
203 result = tc_classify(skb, q->filter_list, &res);
204 if (result >= 0) {
205 #ifdef CONFIG_NET_CLS_ACT
206 switch (result) {
207 case TC_ACT_STOLEN:
208 case TC_ACT_QUEUED:
209 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
210 case TC_ACT_SHOT:
211 return 0;
212 }
213 #endif
214 if (TC_H_MIN(res.classid) <= q->divisor)
215 return TC_H_MIN(res.classid);
216 }
217 return 0;
218 }
219
220 /*
221 * x : slot number [0 .. SFQ_MAX_FLOWS - 1]
222 */
223 static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
224 {
225 sfq_index p, n;
226 struct sfq_slot *slot = &q->slots[x];
227 int qlen = slot->qlen;
228
229 p = qlen + SFQ_MAX_FLOWS;
230 n = q->dep[qlen].next;
231
232 slot->dep.next = n;
233 slot->dep.prev = p;
234
235 q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */
236 sfq_dep_head(q, n)->prev = x;
237 }
238
239 #define sfq_unlink(q, x, n, p) \
240 do { \
241 n = q->slots[x].dep.next; \
242 p = q->slots[x].dep.prev; \
243 sfq_dep_head(q, p)->next = n; \
244 sfq_dep_head(q, n)->prev = p; \
245 } while (0)
246
247
248 static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
249 {
250 sfq_index p, n;
251 int d;
252
253 sfq_unlink(q, x, n, p);
254
255 d = q->slots[x].qlen--;
256 if (n == p && q->cur_depth == d)
257 q->cur_depth--;
258 sfq_link(q, x);
259 }
260
261 static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
262 {
263 sfq_index p, n;
264 int d;
265
266 sfq_unlink(q, x, n, p);
267
268 d = ++q->slots[x].qlen;
269 if (q->cur_depth < d)
270 q->cur_depth = d;
271 sfq_link(q, x);
272 }
273
274 /* helper functions : might be changed when/if skb use a standard list_head */
275
276 /* remove one skb from tail of slot queue */
277 static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
278 {
279 struct sk_buff *skb = slot->skblist_prev;
280
281 slot->skblist_prev = skb->prev;
282 skb->prev->next = (struct sk_buff *)slot;
283 skb->next = skb->prev = NULL;
284 return skb;
285 }
286
287 /* remove one skb from head of slot queue */
288 static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
289 {
290 struct sk_buff *skb = slot->skblist_next;
291
292 slot->skblist_next = skb->next;
293 skb->next->prev = (struct sk_buff *)slot;
294 skb->next = skb->prev = NULL;
295 return skb;
296 }
297
298 static inline void slot_queue_init(struct sfq_slot *slot)
299 {
300 memset(slot, 0, sizeof(*slot));
301 slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
302 }
303
304 /* add skb to slot queue (tail add) */
305 static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
306 {
307 skb->prev = slot->skblist_prev;
308 skb->next = (struct sk_buff *)slot;
309 slot->skblist_prev->next = skb;
310 slot->skblist_prev = skb;
311 }
312
313 #define slot_queue_walk(slot, skb) \
314 for (skb = slot->skblist_next; \
315 skb != (struct sk_buff *)slot; \
316 skb = skb->next)
317
318 static unsigned int sfq_drop(struct Qdisc *sch)
319 {
320 struct sfq_sched_data *q = qdisc_priv(sch);
321 sfq_index x, d = q->cur_depth;
322 struct sk_buff *skb;
323 unsigned int len;
324 struct sfq_slot *slot;
325
326 /* Queue is full! Find the longest slot and drop tail packet from it */
327 if (d > 1) {
328 x = q->dep[d].next;
329 slot = &q->slots[x];
330 drop:
331 skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
332 len = qdisc_pkt_len(skb);
333 slot->backlog -= len;
334 sfq_dec(q, x);
335 kfree_skb(skb);
336 sch->q.qlen--;
337 sch->qstats.drops++;
338 sch->qstats.backlog -= len;
339 return len;
340 }
341
342 if (d == 1) {
343 /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
344 x = q->tail->next;
345 slot = &q->slots[x];
346 q->tail->next = slot->next;
347 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
348 goto drop;
349 }
350
351 return 0;
352 }
353
354 /* Is ECN parameter configured */
355 static int sfq_prob_mark(const struct sfq_sched_data *q)
356 {
357 return q->flags & TC_RED_ECN;
358 }
359
360 /* Should packets over max threshold just be marked */
361 static int sfq_hard_mark(const struct sfq_sched_data *q)
362 {
363 return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
364 }
365
366 static int sfq_headdrop(const struct sfq_sched_data *q)
367 {
368 return q->headdrop;
369 }
370
371 static int
372 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
373 {
374 struct sfq_sched_data *q = qdisc_priv(sch);
375 unsigned int hash;
376 sfq_index x, qlen;
377 struct sfq_slot *slot;
378 int uninitialized_var(ret);
379 struct sk_buff *head;
380 int delta;
381
382 hash = sfq_classify(skb, sch, &ret);
383 if (hash == 0) {
384 if (ret & __NET_XMIT_BYPASS)
385 sch->qstats.drops++;
386 kfree_skb(skb);
387 return ret;
388 }
389 hash--;
390
391 x = q->ht[hash];
392 slot = &q->slots[x];
393 if (x == SFQ_EMPTY_SLOT) {
394 x = q->dep[0].next; /* get a free slot */
395 if (x >= SFQ_MAX_FLOWS)
396 return qdisc_drop(skb, sch);
397 q->ht[hash] = x;
398 slot = &q->slots[x];
399 slot->hash = hash;
400 slot->backlog = 0; /* should already be 0 anyway... */
401 red_set_vars(&slot->vars);
402 goto enqueue;
403 }
404 if (q->red_parms) {
405 slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
406 &slot->vars,
407 slot->backlog);
408 switch (red_action(q->red_parms,
409 &slot->vars,
410 slot->vars.qavg)) {
411 case RED_DONT_MARK:
412 break;
413
414 case RED_PROB_MARK:
415 sch->qstats.overlimits++;
416 if (sfq_prob_mark(q)) {
417 /* We know we have at least one packet in queue */
418 if (sfq_headdrop(q) &&
419 INET_ECN_set_ce(slot->skblist_next)) {
420 q->stats.prob_mark_head++;
421 break;
422 }
423 if (INET_ECN_set_ce(skb)) {
424 q->stats.prob_mark++;
425 break;
426 }
427 }
428 q->stats.prob_drop++;
429 goto congestion_drop;
430
431 case RED_HARD_MARK:
432 sch->qstats.overlimits++;
433 if (sfq_hard_mark(q)) {
434 /* We know we have at least one packet in queue */
435 if (sfq_headdrop(q) &&
436 INET_ECN_set_ce(slot->skblist_next)) {
437 q->stats.forced_mark_head++;
438 break;
439 }
440 if (INET_ECN_set_ce(skb)) {
441 q->stats.forced_mark++;
442 break;
443 }
444 }
445 q->stats.forced_drop++;
446 goto congestion_drop;
447 }
448 }
449
450 if (slot->qlen >= q->maxdepth) {
451 congestion_drop:
452 if (!sfq_headdrop(q))
453 return qdisc_drop(skb, sch);
454
455 /* We know we have at least one packet in queue */
456 head = slot_dequeue_head(slot);
457 delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
458 sch->qstats.backlog -= delta;
459 slot->backlog -= delta;
460 qdisc_drop(head, sch);
461
462 slot_queue_add(slot, skb);
463 return NET_XMIT_CN;
464 }
465
466 enqueue:
467 sch->qstats.backlog += qdisc_pkt_len(skb);
468 slot->backlog += qdisc_pkt_len(skb);
469 slot_queue_add(slot, skb);
470 sfq_inc(q, x);
471 if (slot->qlen == 1) { /* The flow is new */
472 if (q->tail == NULL) { /* It is the first flow */
473 slot->next = x;
474 } else {
475 slot->next = q->tail->next;
476 q->tail->next = x;
477 }
478 /* We put this flow at the end of our flow list.
479 * This might sound unfair for a new flow to wait after old ones,
480 * but we could endup servicing new flows only, and freeze old ones.
481 */
482 q->tail = slot;
483 /* We could use a bigger initial quantum for new flows */
484 slot->allot = q->scaled_quantum;
485 }
486 if (++sch->q.qlen <= q->limit)
487 return NET_XMIT_SUCCESS;
488
489 qlen = slot->qlen;
490 sfq_drop(sch);
491 /* Return Congestion Notification only if we dropped a packet
492 * from this flow.
493 */
494 if (qlen != slot->qlen)
495 return NET_XMIT_CN;
496
497 /* As we dropped a packet, better let upper stack know this */
498 qdisc_tree_decrease_qlen(sch, 1);
499 return NET_XMIT_SUCCESS;
500 }
501
502 static struct sk_buff *
503 sfq_dequeue(struct Qdisc *sch)
504 {
505 struct sfq_sched_data *q = qdisc_priv(sch);
506 struct sk_buff *skb;
507 sfq_index a, next_a;
508 struct sfq_slot *slot;
509
510 /* No active slots */
511 if (q->tail == NULL)
512 return NULL;
513
514 next_slot:
515 a = q->tail->next;
516 slot = &q->slots[a];
517 if (slot->allot <= 0) {
518 q->tail = slot;
519 slot->allot += q->scaled_quantum;
520 goto next_slot;
521 }
522 skb = slot_dequeue_head(slot);
523 sfq_dec(q, a);
524 qdisc_bstats_update(sch, skb);
525 sch->q.qlen--;
526 sch->qstats.backlog -= qdisc_pkt_len(skb);
527 slot->backlog -= qdisc_pkt_len(skb);
528 /* Is the slot empty? */
529 if (slot->qlen == 0) {
530 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
531 next_a = slot->next;
532 if (a == next_a) {
533 q->tail = NULL; /* no more active slots */
534 return skb;
535 }
536 q->tail->next = next_a;
537 } else {
538 slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
539 }
540 return skb;
541 }
542
543 static void
544 sfq_reset(struct Qdisc *sch)
545 {
546 struct sk_buff *skb;
547
548 while ((skb = sfq_dequeue(sch)) != NULL)
549 kfree_skb(skb);
550 }
551
552 /*
553 * When q->perturbation is changed, we rehash all queued skbs
554 * to avoid OOO (Out Of Order) effects.
555 * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
556 * counters.
557 */
558 static void sfq_rehash(struct Qdisc *sch)
559 {
560 struct sfq_sched_data *q = qdisc_priv(sch);
561 struct sk_buff *skb;
562 int i;
563 struct sfq_slot *slot;
564 struct sk_buff_head list;
565 int dropped = 0;
566
567 __skb_queue_head_init(&list);
568
569 for (i = 0; i < q->maxflows; i++) {
570 slot = &q->slots[i];
571 if (!slot->qlen)
572 continue;
573 while (slot->qlen) {
574 skb = slot_dequeue_head(slot);
575 sfq_dec(q, i);
576 __skb_queue_tail(&list, skb);
577 }
578 slot->backlog = 0;
579 red_set_vars(&slot->vars);
580 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
581 }
582 q->tail = NULL;
583
584 while ((skb = __skb_dequeue(&list)) != NULL) {
585 unsigned int hash = sfq_hash(q, skb);
586 sfq_index x = q->ht[hash];
587
588 slot = &q->slots[x];
589 if (x == SFQ_EMPTY_SLOT) {
590 x = q->dep[0].next; /* get a free slot */
591 if (x >= SFQ_MAX_FLOWS) {
592 drop: sch->qstats.backlog -= qdisc_pkt_len(skb);
593 kfree_skb(skb);
594 dropped++;
595 continue;
596 }
597 q->ht[hash] = x;
598 slot = &q->slots[x];
599 slot->hash = hash;
600 }
601 if (slot->qlen >= q->maxdepth)
602 goto drop;
603 slot_queue_add(slot, skb);
604 if (q->red_parms)
605 slot->vars.qavg = red_calc_qavg(q->red_parms,
606 &slot->vars,
607 slot->backlog);
608 slot->backlog += qdisc_pkt_len(skb);
609 sfq_inc(q, x);
610 if (slot->qlen == 1) { /* The flow is new */
611 if (q->tail == NULL) { /* It is the first flow */
612 slot->next = x;
613 } else {
614 slot->next = q->tail->next;
615 q->tail->next = x;
616 }
617 q->tail = slot;
618 slot->allot = q->scaled_quantum;
619 }
620 }
621 sch->q.qlen -= dropped;
622 qdisc_tree_decrease_qlen(sch, dropped);
623 }
624
625 static void sfq_perturbation(unsigned long arg)
626 {
627 struct Qdisc *sch = (struct Qdisc *)arg;
628 struct sfq_sched_data *q = qdisc_priv(sch);
629 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
630
631 spin_lock(root_lock);
632 q->perturbation = prandom_u32();
633 if (!q->filter_list && q->tail)
634 sfq_rehash(sch);
635 spin_unlock(root_lock);
636
637 if (q->perturb_period)
638 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
639 }
640
641 static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
642 {
643 struct sfq_sched_data *q = qdisc_priv(sch);
644 struct tc_sfq_qopt *ctl = nla_data(opt);
645 struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
646 unsigned int qlen;
647 struct red_parms *p = NULL;
648
649 if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
650 return -EINVAL;
651 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
652 ctl_v1 = nla_data(opt);
653 if (ctl->divisor &&
654 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
655 return -EINVAL;
656 if (ctl_v1 && ctl_v1->qth_min) {
657 p = kmalloc(sizeof(*p), GFP_KERNEL);
658 if (!p)
659 return -ENOMEM;
660 }
661 sch_tree_lock(sch);
662 if (ctl->quantum) {
663 q->quantum = ctl->quantum;
664 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
665 }
666 q->perturb_period = ctl->perturb_period * HZ;
667 if (ctl->flows)
668 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
669 if (ctl->divisor) {
670 q->divisor = ctl->divisor;
671 q->maxflows = min_t(u32, q->maxflows, q->divisor);
672 }
673 if (ctl_v1) {
674 if (ctl_v1->depth)
675 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
676 if (p) {
677 swap(q->red_parms, p);
678 red_set_parms(q->red_parms,
679 ctl_v1->qth_min, ctl_v1->qth_max,
680 ctl_v1->Wlog,
681 ctl_v1->Plog, ctl_v1->Scell_log,
682 NULL,
683 ctl_v1->max_P);
684 }
685 q->flags = ctl_v1->flags;
686 q->headdrop = ctl_v1->headdrop;
687 }
688 if (ctl->limit) {
689 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
690 q->maxflows = min_t(u32, q->maxflows, q->limit);
691 }
692
693 qlen = sch->q.qlen;
694 while (sch->q.qlen > q->limit)
695 sfq_drop(sch);
696 qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
697
698 del_timer(&q->perturb_timer);
699 if (q->perturb_period) {
700 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
701 q->perturbation = prandom_u32();
702 }
703 sch_tree_unlock(sch);
704 kfree(p);
705 return 0;
706 }
707
708 static void *sfq_alloc(size_t sz)
709 {
710 void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN);
711
712 if (!ptr)
713 ptr = vmalloc(sz);
714 return ptr;
715 }
716
717 static void sfq_free(void *addr)
718 {
719 kvfree(addr);
720 }
721
722 static void sfq_destroy(struct Qdisc *sch)
723 {
724 struct sfq_sched_data *q = qdisc_priv(sch);
725
726 tcf_destroy_chain(&q->filter_list);
727 q->perturb_period = 0;
728 del_timer_sync(&q->perturb_timer);
729 sfq_free(q->ht);
730 sfq_free(q->slots);
731 kfree(q->red_parms);
732 }
733
734 static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
735 {
736 struct sfq_sched_data *q = qdisc_priv(sch);
737 int i;
738
739 q->perturb_timer.function = sfq_perturbation;
740 q->perturb_timer.data = (unsigned long)sch;
741 init_timer_deferrable(&q->perturb_timer);
742
743 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
744 q->dep[i].next = i + SFQ_MAX_FLOWS;
745 q->dep[i].prev = i + SFQ_MAX_FLOWS;
746 }
747
748 q->limit = SFQ_MAX_DEPTH;
749 q->maxdepth = SFQ_MAX_DEPTH;
750 q->cur_depth = 0;
751 q->tail = NULL;
752 q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
753 q->maxflows = SFQ_DEFAULT_FLOWS;
754 q->quantum = psched_mtu(qdisc_dev(sch));
755 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
756 q->perturb_period = 0;
757 q->perturbation = prandom_u32();
758
759 if (opt) {
760 int err = sfq_change(sch, opt);
761 if (err)
762 return err;
763 }
764
765 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
766 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
767 if (!q->ht || !q->slots) {
768 sfq_destroy(sch);
769 return -ENOMEM;
770 }
771 for (i = 0; i < q->divisor; i++)
772 q->ht[i] = SFQ_EMPTY_SLOT;
773
774 for (i = 0; i < q->maxflows; i++) {
775 slot_queue_init(&q->slots[i]);
776 sfq_link(q, i);
777 }
778 if (q->limit >= 1)
779 sch->flags |= TCQ_F_CAN_BYPASS;
780 else
781 sch->flags &= ~TCQ_F_CAN_BYPASS;
782 return 0;
783 }
784
785 static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
786 {
787 struct sfq_sched_data *q = qdisc_priv(sch);
788 unsigned char *b = skb_tail_pointer(skb);
789 struct tc_sfq_qopt_v1 opt;
790 struct red_parms *p = q->red_parms;
791
792 memset(&opt, 0, sizeof(opt));
793 opt.v0.quantum = q->quantum;
794 opt.v0.perturb_period = q->perturb_period / HZ;
795 opt.v0.limit = q->limit;
796 opt.v0.divisor = q->divisor;
797 opt.v0.flows = q->maxflows;
798 opt.depth = q->maxdepth;
799 opt.headdrop = q->headdrop;
800
801 if (p) {
802 opt.qth_min = p->qth_min >> p->Wlog;
803 opt.qth_max = p->qth_max >> p->Wlog;
804 opt.Wlog = p->Wlog;
805 opt.Plog = p->Plog;
806 opt.Scell_log = p->Scell_log;
807 opt.max_P = p->max_P;
808 }
809 memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
810 opt.flags = q->flags;
811
812 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
813 goto nla_put_failure;
814
815 return skb->len;
816
817 nla_put_failure:
818 nlmsg_trim(skb, b);
819 return -1;
820 }
821
822 static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
823 {
824 return NULL;
825 }
826
827 static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
828 {
829 return 0;
830 }
831
832 static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
833 u32 classid)
834 {
835 /* we cannot bypass queue discipline anymore */
836 sch->flags &= ~TCQ_F_CAN_BYPASS;
837 return 0;
838 }
839
840 static void sfq_put(struct Qdisc *q, unsigned long cl)
841 {
842 }
843
844 static struct tcf_proto **sfq_find_tcf(struct Qdisc *sch, unsigned long cl)
845 {
846 struct sfq_sched_data *q = qdisc_priv(sch);
847
848 if (cl)
849 return NULL;
850 return &q->filter_list;
851 }
852
853 static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
854 struct sk_buff *skb, struct tcmsg *tcm)
855 {
856 tcm->tcm_handle |= TC_H_MIN(cl);
857 return 0;
858 }
859
860 static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
861 struct gnet_dump *d)
862 {
863 struct sfq_sched_data *q = qdisc_priv(sch);
864 sfq_index idx = q->ht[cl - 1];
865 struct gnet_stats_queue qs = { 0 };
866 struct tc_sfq_xstats xstats = { 0 };
867
868 if (idx != SFQ_EMPTY_SLOT) {
869 const struct sfq_slot *slot = &q->slots[idx];
870
871 xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
872 qs.qlen = slot->qlen;
873 qs.backlog = slot->backlog;
874 }
875 if (gnet_stats_copy_queue(d, &qs) < 0)
876 return -1;
877 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
878 }
879
880 static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
881 {
882 struct sfq_sched_data *q = qdisc_priv(sch);
883 unsigned int i;
884
885 if (arg->stop)
886 return;
887
888 for (i = 0; i < q->divisor; i++) {
889 if (q->ht[i] == SFQ_EMPTY_SLOT ||
890 arg->count < arg->skip) {
891 arg->count++;
892 continue;
893 }
894 if (arg->fn(sch, i + 1, arg) < 0) {
895 arg->stop = 1;
896 break;
897 }
898 arg->count++;
899 }
900 }
901
902 static const struct Qdisc_class_ops sfq_class_ops = {
903 .leaf = sfq_leaf,
904 .get = sfq_get,
905 .put = sfq_put,
906 .tcf_chain = sfq_find_tcf,
907 .bind_tcf = sfq_bind,
908 .unbind_tcf = sfq_put,
909 .dump = sfq_dump_class,
910 .dump_stats = sfq_dump_class_stats,
911 .walk = sfq_walk,
912 };
913
914 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
915 .cl_ops = &sfq_class_ops,
916 .id = "sfq",
917 .priv_size = sizeof(struct sfq_sched_data),
918 .enqueue = sfq_enqueue,
919 .dequeue = sfq_dequeue,
920 .peek = qdisc_peek_dequeued,
921 .drop = sfq_drop,
922 .init = sfq_init,
923 .reset = sfq_reset,
924 .destroy = sfq_destroy,
925 .change = NULL,
926 .dump = sfq_dump,
927 .owner = THIS_MODULE,
928 };
929
930 static int __init sfq_module_init(void)
931 {
932 return register_qdisc(&sfq_qdisc_ops);
933 }
934 static void __exit sfq_module_exit(void)
935 {
936 unregister_qdisc(&sfq_qdisc_ops);
937 }
938 module_init(sfq_module_init)
939 module_exit(sfq_module_exit)
940 MODULE_LICENSE("GPL");
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