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1da177e4 LT |
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 | ||
1da177e4 | 12 | #include <linux/module.h> |
1da177e4 LT |
13 | #include <linux/types.h> |
14 | #include <linux/kernel.h> | |
15 | #include <linux/jiffies.h> | |
16 | #include <linux/string.h> | |
1da177e4 LT |
17 | #include <linux/in.h> |
18 | #include <linux/errno.h> | |
1da177e4 | 19 | #include <linux/init.h> |
1da177e4 | 20 | #include <linux/skbuff.h> |
32740ddc | 21 | #include <linux/jhash.h> |
5a0e3ad6 | 22 | #include <linux/slab.h> |
817fb15d | 23 | #include <linux/vmalloc.h> |
0ba48053 | 24 | #include <net/netlink.h> |
1da177e4 | 25 | #include <net/pkt_sched.h> |
cf1facda | 26 | #include <net/pkt_cls.h> |
ddecf0f4 | 27 | #include <net/red.h> |
1da177e4 LT |
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 | ||
10297b99 | 46 | This is not the thing that is usually called (W)FQ nowadays. |
1da177e4 LT |
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 | ||
10297b99 | 56 | - "Stochastic" -> It is not 100% fair. |
1da177e4 LT |
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: | |
18cb8098 ED |
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. | |
1da177e4 LT |
75 | |
76 | It is easy to increase these values, but not in flight. */ | |
77 | ||
18cb8098 ED |
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 | |
817fb15d ED |
82 | #define SFQ_DEFAULT_HASH_DIVISOR 1024 |
83 | ||
eeaeb068 ED |
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) | |
1da177e4 | 89 | |
18cb8098 ED |
90 | /* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */ |
91 | typedef u16 sfq_index; | |
1da177e4 | 92 | |
eda83e3b ED |
93 | /* |
94 | * We dont use pointers to save space. | |
18cb8098 ED |
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] | |
eda83e3b ED |
97 | * are 'pointers' to dep[] array |
98 | */ | |
cc7ec456 | 99 | struct sfq_head { |
1da177e4 LT |
100 | sfq_index next; |
101 | sfq_index prev; | |
102 | }; | |
103 | ||
eda83e3b ED |
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 */ | |
18cb8098 | 108 | sfq_index next; /* next slot in sfq RR chain */ |
eda83e3b ED |
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 */ | |
ddecf0f4 ED |
112 | |
113 | unsigned int backlog; | |
114 | struct red_vars vars; | |
eda83e3b ED |
115 | }; |
116 | ||
cc7ec456 | 117 | struct sfq_sched_data { |
18cb8098 ED |
118 | /* frequently used fields */ |
119 | int limit; /* limit of total number of packets in this qdisc */ | |
817fb15d | 120 | unsigned int divisor; /* number of slots in hash table */ |
ddecf0f4 ED |
121 | u8 headdrop; |
122 | u8 maxdepth; /* limit of packets per flow */ | |
18cb8098 | 123 | |
32740ddc | 124 | u32 perturbation; |
ddecf0f4 ED |
125 | u8 cur_depth; /* depth of longest slot */ |
126 | u8 flags; | |
eeaeb068 | 127 | unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */ |
25d8c0d5 | 128 | struct tcf_proto __rcu *filter_list; |
18cb8098 ED |
129 | sfq_index *ht; /* Hash table ('divisor' slots) */ |
130 | struct sfq_slot *slots; /* Flows table ('maxflows' entries) */ | |
131 | ||
ddecf0f4 ED |
132 | struct red_parms *red_parms; |
133 | struct tc_sfqred_stats stats; | |
134 | struct sfq_slot *tail; /* current slot in round */ | |
135 | ||
18cb8098 ED |
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 | ||
ddecf0f4 | 143 | unsigned int maxflows; /* number of flows in flows array */ |
18cb8098 ED |
144 | int perturb_period; |
145 | unsigned int quantum; /* Allotment per round: MUST BE >= MTU */ | |
146 | struct timer_list perturb_timer; | |
1da177e4 LT |
147 | }; |
148 | ||
eda83e3b ED |
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 | { | |
18cb8098 | 154 | if (val < SFQ_MAX_FLOWS) |
eda83e3b | 155 | return &q->slots[val].dep; |
18cb8098 | 156 | return &q->dep[val - SFQ_MAX_FLOWS]; |
eda83e3b ED |
157 | } |
158 | ||
11fca931 ED |
159 | static unsigned int sfq_hash(const struct sfq_sched_data *q, |
160 | const struct sk_buff *skb) | |
1da177e4 | 161 | { |
ada1dba0 | 162 | return skb_get_hash_perturb(skb, q->perturbation) & (q->divisor - 1); |
1da177e4 LT |
163 | } |
164 | ||
7d2681a6 PM |
165 | static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch, |
166 | int *qerr) | |
167 | { | |
168 | struct sfq_sched_data *q = qdisc_priv(sch); | |
169 | struct tcf_result res; | |
25d8c0d5 | 170 | struct tcf_proto *fl; |
7d2681a6 PM |
171 | int result; |
172 | ||
173 | if (TC_H_MAJ(skb->priority) == sch->handle && | |
174 | TC_H_MIN(skb->priority) > 0 && | |
817fb15d | 175 | TC_H_MIN(skb->priority) <= q->divisor) |
7d2681a6 PM |
176 | return TC_H_MIN(skb->priority); |
177 | ||
25d8c0d5 | 178 | fl = rcu_dereference_bh(q->filter_list); |
ada1dba0 | 179 | if (!fl) |
7d2681a6 PM |
180 | return sfq_hash(q, skb) + 1; |
181 | ||
c27f339a | 182 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; |
3b3ae880 | 183 | result = tc_classify(skb, fl, &res, false); |
7d2681a6 PM |
184 | if (result >= 0) { |
185 | #ifdef CONFIG_NET_CLS_ACT | |
186 | switch (result) { | |
187 | case TC_ACT_STOLEN: | |
188 | case TC_ACT_QUEUED: | |
378a2f09 | 189 | *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; |
7d2681a6 PM |
190 | case TC_ACT_SHOT: |
191 | return 0; | |
192 | } | |
193 | #endif | |
817fb15d | 194 | if (TC_H_MIN(res.classid) <= q->divisor) |
7d2681a6 PM |
195 | return TC_H_MIN(res.classid); |
196 | } | |
197 | return 0; | |
198 | } | |
199 | ||
eda83e3b | 200 | /* |
18cb8098 | 201 | * x : slot number [0 .. SFQ_MAX_FLOWS - 1] |
eda83e3b | 202 | */ |
1da177e4 LT |
203 | static inline void sfq_link(struct sfq_sched_data *q, sfq_index x) |
204 | { | |
205 | sfq_index p, n; | |
18cb8098 ED |
206 | struct sfq_slot *slot = &q->slots[x]; |
207 | int qlen = slot->qlen; | |
eda83e3b | 208 | |
18cb8098 | 209 | p = qlen + SFQ_MAX_FLOWS; |
eda83e3b | 210 | n = q->dep[qlen].next; |
1da177e4 | 211 | |
18cb8098 ED |
212 | slot->dep.next = n; |
213 | slot->dep.prev = p; | |
eda83e3b ED |
214 | |
215 | q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */ | |
216 | sfq_dep_head(q, n)->prev = x; | |
1da177e4 LT |
217 | } |
218 | ||
eda83e3b | 219 | #define sfq_unlink(q, x, n, p) \ |
fa08943b YY |
220 | do { \ |
221 | n = q->slots[x].dep.next; \ | |
222 | p = q->slots[x].dep.prev; \ | |
223 | sfq_dep_head(q, p)->next = n; \ | |
224 | sfq_dep_head(q, n)->prev = p; \ | |
225 | } while (0) | |
eda83e3b ED |
226 | |
227 | ||
1da177e4 LT |
228 | static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x) |
229 | { | |
230 | sfq_index p, n; | |
eda83e3b | 231 | int d; |
1da177e4 | 232 | |
eda83e3b | 233 | sfq_unlink(q, x, n, p); |
1da177e4 | 234 | |
eda83e3b ED |
235 | d = q->slots[x].qlen--; |
236 | if (n == p && q->cur_depth == d) | |
237 | q->cur_depth--; | |
1da177e4 LT |
238 | sfq_link(q, x); |
239 | } | |
240 | ||
241 | static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x) | |
242 | { | |
243 | sfq_index p, n; | |
244 | int d; | |
245 | ||
eda83e3b | 246 | sfq_unlink(q, x, n, p); |
1da177e4 | 247 | |
eda83e3b ED |
248 | d = ++q->slots[x].qlen; |
249 | if (q->cur_depth < d) | |
250 | q->cur_depth = d; | |
1da177e4 LT |
251 | sfq_link(q, x); |
252 | } | |
253 | ||
eda83e3b ED |
254 | /* helper functions : might be changed when/if skb use a standard list_head */ |
255 | ||
256 | /* remove one skb from tail of slot queue */ | |
257 | static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot) | |
258 | { | |
259 | struct sk_buff *skb = slot->skblist_prev; | |
260 | ||
261 | slot->skblist_prev = skb->prev; | |
ee09b3c1 | 262 | skb->prev->next = (struct sk_buff *)slot; |
eda83e3b ED |
263 | skb->next = skb->prev = NULL; |
264 | return skb; | |
265 | } | |
266 | ||
267 | /* remove one skb from head of slot queue */ | |
268 | static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot) | |
269 | { | |
270 | struct sk_buff *skb = slot->skblist_next; | |
271 | ||
272 | slot->skblist_next = skb->next; | |
18c8d82a | 273 | skb->next->prev = (struct sk_buff *)slot; |
eda83e3b ED |
274 | skb->next = skb->prev = NULL; |
275 | return skb; | |
276 | } | |
277 | ||
278 | static inline void slot_queue_init(struct sfq_slot *slot) | |
279 | { | |
18cb8098 | 280 | memset(slot, 0, sizeof(*slot)); |
eda83e3b ED |
281 | slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot; |
282 | } | |
283 | ||
284 | /* add skb to slot queue (tail add) */ | |
285 | static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb) | |
286 | { | |
287 | skb->prev = slot->skblist_prev; | |
288 | skb->next = (struct sk_buff *)slot; | |
289 | slot->skblist_prev->next = skb; | |
290 | slot->skblist_prev = skb; | |
291 | } | |
292 | ||
1da177e4 LT |
293 | static unsigned int sfq_drop(struct Qdisc *sch) |
294 | { | |
295 | struct sfq_sched_data *q = qdisc_priv(sch); | |
eda83e3b | 296 | sfq_index x, d = q->cur_depth; |
1da177e4 LT |
297 | struct sk_buff *skb; |
298 | unsigned int len; | |
eda83e3b | 299 | struct sfq_slot *slot; |
1da177e4 | 300 | |
eda83e3b | 301 | /* Queue is full! Find the longest slot and drop tail packet from it */ |
1da177e4 | 302 | if (d > 1) { |
eda83e3b ED |
303 | x = q->dep[d].next; |
304 | slot = &q->slots[x]; | |
305 | drop: | |
18cb8098 | 306 | skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot); |
0abf77e5 | 307 | len = qdisc_pkt_len(skb); |
ddecf0f4 | 308 | slot->backlog -= len; |
1da177e4 LT |
309 | sfq_dec(q, x); |
310 | sch->q.qlen--; | |
25331d6c JF |
311 | qdisc_qstats_drop(sch); |
312 | qdisc_qstats_backlog_dec(sch, skb); | |
e8d092aa | 313 | kfree_skb(skb); |
1da177e4 LT |
314 | return len; |
315 | } | |
316 | ||
317 | if (d == 1) { | |
318 | /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */ | |
eda83e3b ED |
319 | x = q->tail->next; |
320 | slot = &q->slots[x]; | |
321 | q->tail->next = slot->next; | |
322 | q->ht[slot->hash] = SFQ_EMPTY_SLOT; | |
323 | goto drop; | |
1da177e4 LT |
324 | } |
325 | ||
326 | return 0; | |
327 | } | |
328 | ||
ddecf0f4 ED |
329 | /* Is ECN parameter configured */ |
330 | static int sfq_prob_mark(const struct sfq_sched_data *q) | |
331 | { | |
332 | return q->flags & TC_RED_ECN; | |
333 | } | |
334 | ||
335 | /* Should packets over max threshold just be marked */ | |
336 | static int sfq_hard_mark(const struct sfq_sched_data *q) | |
337 | { | |
338 | return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN; | |
339 | } | |
340 | ||
341 | static int sfq_headdrop(const struct sfq_sched_data *q) | |
342 | { | |
343 | return q->headdrop; | |
344 | } | |
345 | ||
1da177e4 | 346 | static int |
520ac30f | 347 | sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) |
1da177e4 LT |
348 | { |
349 | struct sfq_sched_data *q = qdisc_priv(sch); | |
2ccccf5f | 350 | unsigned int hash, dropped; |
8efa8854 | 351 | sfq_index x, qlen; |
eda83e3b | 352 | struct sfq_slot *slot; |
7f3ff4f6 | 353 | int uninitialized_var(ret); |
ddecf0f4 ED |
354 | struct sk_buff *head; |
355 | int delta; | |
7d2681a6 PM |
356 | |
357 | hash = sfq_classify(skb, sch, &ret); | |
358 | if (hash == 0) { | |
c27f339a | 359 | if (ret & __NET_XMIT_BYPASS) |
25331d6c | 360 | qdisc_qstats_drop(sch); |
7d2681a6 PM |
361 | kfree_skb(skb); |
362 | return ret; | |
363 | } | |
364 | hash--; | |
1da177e4 LT |
365 | |
366 | x = q->ht[hash]; | |
eda83e3b ED |
367 | slot = &q->slots[x]; |
368 | if (x == SFQ_EMPTY_SLOT) { | |
369 | x = q->dep[0].next; /* get a free slot */ | |
18cb8098 | 370 | if (x >= SFQ_MAX_FLOWS) |
520ac30f | 371 | return qdisc_drop(skb, sch, to_free); |
eda83e3b ED |
372 | q->ht[hash] = x; |
373 | slot = &q->slots[x]; | |
374 | slot->hash = hash; | |
ddecf0f4 ED |
375 | slot->backlog = 0; /* should already be 0 anyway... */ |
376 | red_set_vars(&slot->vars); | |
377 | goto enqueue; | |
378 | } | |
379 | if (q->red_parms) { | |
380 | slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms, | |
381 | &slot->vars, | |
382 | slot->backlog); | |
383 | switch (red_action(q->red_parms, | |
384 | &slot->vars, | |
385 | slot->vars.qavg)) { | |
386 | case RED_DONT_MARK: | |
387 | break; | |
388 | ||
389 | case RED_PROB_MARK: | |
25331d6c | 390 | qdisc_qstats_overlimit(sch); |
ddecf0f4 ED |
391 | if (sfq_prob_mark(q)) { |
392 | /* We know we have at least one packet in queue */ | |
393 | if (sfq_headdrop(q) && | |
394 | INET_ECN_set_ce(slot->skblist_next)) { | |
395 | q->stats.prob_mark_head++; | |
396 | break; | |
397 | } | |
398 | if (INET_ECN_set_ce(skb)) { | |
399 | q->stats.prob_mark++; | |
400 | break; | |
401 | } | |
402 | } | |
403 | q->stats.prob_drop++; | |
404 | goto congestion_drop; | |
405 | ||
406 | case RED_HARD_MARK: | |
25331d6c | 407 | qdisc_qstats_overlimit(sch); |
ddecf0f4 ED |
408 | if (sfq_hard_mark(q)) { |
409 | /* We know we have at least one packet in queue */ | |
410 | if (sfq_headdrop(q) && | |
411 | INET_ECN_set_ce(slot->skblist_next)) { | |
412 | q->stats.forced_mark_head++; | |
413 | break; | |
414 | } | |
415 | if (INET_ECN_set_ce(skb)) { | |
416 | q->stats.forced_mark++; | |
417 | break; | |
418 | } | |
419 | } | |
420 | q->stats.forced_drop++; | |
421 | goto congestion_drop; | |
422 | } | |
1da177e4 | 423 | } |
6f9e98f7 | 424 | |
18cb8098 | 425 | if (slot->qlen >= q->maxdepth) { |
ddecf0f4 ED |
426 | congestion_drop: |
427 | if (!sfq_headdrop(q)) | |
520ac30f | 428 | return qdisc_drop(skb, sch, to_free); |
18cb8098 | 429 | |
ddecf0f4 | 430 | /* We know we have at least one packet in queue */ |
18cb8098 | 431 | head = slot_dequeue_head(slot); |
ddecf0f4 ED |
432 | delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb); |
433 | sch->qstats.backlog -= delta; | |
434 | slot->backlog -= delta; | |
520ac30f | 435 | qdisc_drop(head, sch, to_free); |
18cb8098 | 436 | |
18cb8098 ED |
437 | slot_queue_add(slot, skb); |
438 | return NET_XMIT_CN; | |
439 | } | |
32740ddc | 440 | |
ddecf0f4 | 441 | enqueue: |
25331d6c | 442 | qdisc_qstats_backlog_inc(sch, skb); |
ddecf0f4 | 443 | slot->backlog += qdisc_pkt_len(skb); |
eda83e3b | 444 | slot_queue_add(slot, skb); |
1da177e4 | 445 | sfq_inc(q, x); |
eda83e3b ED |
446 | if (slot->qlen == 1) { /* The flow is new */ |
447 | if (q->tail == NULL) { /* It is the first flow */ | |
448 | slot->next = x; | |
1da177e4 | 449 | } else { |
eda83e3b ED |
450 | slot->next = q->tail->next; |
451 | q->tail->next = x; | |
1da177e4 | 452 | } |
cc34eb67 ED |
453 | /* We put this flow at the end of our flow list. |
454 | * This might sound unfair for a new flow to wait after old ones, | |
455 | * but we could endup servicing new flows only, and freeze old ones. | |
456 | */ | |
457 | q->tail = slot; | |
ddecf0f4 | 458 | /* We could use a bigger initial quantum for new flows */ |
eeaeb068 | 459 | slot->allot = q->scaled_quantum; |
1da177e4 | 460 | } |
9190b3b3 | 461 | if (++sch->q.qlen <= q->limit) |
9871e50e | 462 | return NET_XMIT_SUCCESS; |
1da177e4 | 463 | |
8efa8854 | 464 | qlen = slot->qlen; |
2ccccf5f | 465 | dropped = sfq_drop(sch); |
8efa8854 ED |
466 | /* Return Congestion Notification only if we dropped a packet |
467 | * from this flow. | |
468 | */ | |
e1738bd9 ED |
469 | if (qlen != slot->qlen) |
470 | return NET_XMIT_CN; | |
471 | ||
472 | /* As we dropped a packet, better let upper stack know this */ | |
2ccccf5f | 473 | qdisc_tree_reduce_backlog(sch, 1, dropped); |
e1738bd9 | 474 | return NET_XMIT_SUCCESS; |
1da177e4 LT |
475 | } |
476 | ||
1da177e4 | 477 | static struct sk_buff * |
6f9e98f7 | 478 | sfq_dequeue(struct Qdisc *sch) |
1da177e4 LT |
479 | { |
480 | struct sfq_sched_data *q = qdisc_priv(sch); | |
481 | struct sk_buff *skb; | |
aa3e2199 | 482 | sfq_index a, next_a; |
eda83e3b | 483 | struct sfq_slot *slot; |
1da177e4 LT |
484 | |
485 | /* No active slots */ | |
eda83e3b | 486 | if (q->tail == NULL) |
1da177e4 LT |
487 | return NULL; |
488 | ||
eeaeb068 | 489 | next_slot: |
eda83e3b ED |
490 | a = q->tail->next; |
491 | slot = &q->slots[a]; | |
eeaeb068 ED |
492 | if (slot->allot <= 0) { |
493 | q->tail = slot; | |
494 | slot->allot += q->scaled_quantum; | |
495 | goto next_slot; | |
496 | } | |
eda83e3b | 497 | skb = slot_dequeue_head(slot); |
1da177e4 | 498 | sfq_dec(q, a); |
9190b3b3 | 499 | qdisc_bstats_update(sch, skb); |
1da177e4 | 500 | sch->q.qlen--; |
25331d6c | 501 | qdisc_qstats_backlog_dec(sch, skb); |
ddecf0f4 | 502 | slot->backlog -= qdisc_pkt_len(skb); |
1da177e4 | 503 | /* Is the slot empty? */ |
eda83e3b ED |
504 | if (slot->qlen == 0) { |
505 | q->ht[slot->hash] = SFQ_EMPTY_SLOT; | |
506 | next_a = slot->next; | |
aa3e2199 | 507 | if (a == next_a) { |
eda83e3b | 508 | q->tail = NULL; /* no more active slots */ |
1da177e4 LT |
509 | return skb; |
510 | } | |
eda83e3b | 511 | q->tail->next = next_a; |
eeaeb068 ED |
512 | } else { |
513 | slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb)); | |
1da177e4 LT |
514 | } |
515 | return skb; | |
516 | } | |
517 | ||
518 | static void | |
6f9e98f7 | 519 | sfq_reset(struct Qdisc *sch) |
1da177e4 LT |
520 | { |
521 | struct sk_buff *skb; | |
522 | ||
523 | while ((skb = sfq_dequeue(sch)) != NULL) | |
fea02478 | 524 | rtnl_kfree_skbs(skb, skb); |
1da177e4 LT |
525 | } |
526 | ||
225d9b89 ED |
527 | /* |
528 | * When q->perturbation is changed, we rehash all queued skbs | |
529 | * to avoid OOO (Out Of Order) effects. | |
530 | * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change | |
531 | * counters. | |
532 | */ | |
18cb8098 | 533 | static void sfq_rehash(struct Qdisc *sch) |
225d9b89 | 534 | { |
18cb8098 | 535 | struct sfq_sched_data *q = qdisc_priv(sch); |
225d9b89 ED |
536 | struct sk_buff *skb; |
537 | int i; | |
538 | struct sfq_slot *slot; | |
539 | struct sk_buff_head list; | |
18cb8098 | 540 | int dropped = 0; |
2ccccf5f | 541 | unsigned int drop_len = 0; |
225d9b89 ED |
542 | |
543 | __skb_queue_head_init(&list); | |
544 | ||
18cb8098 | 545 | for (i = 0; i < q->maxflows; i++) { |
225d9b89 ED |
546 | slot = &q->slots[i]; |
547 | if (!slot->qlen) | |
548 | continue; | |
549 | while (slot->qlen) { | |
550 | skb = slot_dequeue_head(slot); | |
551 | sfq_dec(q, i); | |
552 | __skb_queue_tail(&list, skb); | |
553 | } | |
ddecf0f4 ED |
554 | slot->backlog = 0; |
555 | red_set_vars(&slot->vars); | |
225d9b89 ED |
556 | q->ht[slot->hash] = SFQ_EMPTY_SLOT; |
557 | } | |
558 | q->tail = NULL; | |
559 | ||
560 | while ((skb = __skb_dequeue(&list)) != NULL) { | |
561 | unsigned int hash = sfq_hash(q, skb); | |
562 | sfq_index x = q->ht[hash]; | |
563 | ||
564 | slot = &q->slots[x]; | |
565 | if (x == SFQ_EMPTY_SLOT) { | |
566 | x = q->dep[0].next; /* get a free slot */ | |
18cb8098 | 567 | if (x >= SFQ_MAX_FLOWS) { |
25331d6c JF |
568 | drop: |
569 | qdisc_qstats_backlog_dec(sch, skb); | |
2ccccf5f | 570 | drop_len += qdisc_pkt_len(skb); |
18cb8098 ED |
571 | kfree_skb(skb); |
572 | dropped++; | |
573 | continue; | |
574 | } | |
225d9b89 ED |
575 | q->ht[hash] = x; |
576 | slot = &q->slots[x]; | |
577 | slot->hash = hash; | |
578 | } | |
18cb8098 ED |
579 | if (slot->qlen >= q->maxdepth) |
580 | goto drop; | |
225d9b89 | 581 | slot_queue_add(slot, skb); |
ddecf0f4 ED |
582 | if (q->red_parms) |
583 | slot->vars.qavg = red_calc_qavg(q->red_parms, | |
584 | &slot->vars, | |
585 | slot->backlog); | |
586 | slot->backlog += qdisc_pkt_len(skb); | |
225d9b89 ED |
587 | sfq_inc(q, x); |
588 | if (slot->qlen == 1) { /* The flow is new */ | |
589 | if (q->tail == NULL) { /* It is the first flow */ | |
590 | slot->next = x; | |
591 | } else { | |
592 | slot->next = q->tail->next; | |
593 | q->tail->next = x; | |
594 | } | |
595 | q->tail = slot; | |
596 | slot->allot = q->scaled_quantum; | |
597 | } | |
598 | } | |
18cb8098 | 599 | sch->q.qlen -= dropped; |
2ccccf5f | 600 | qdisc_tree_reduce_backlog(sch, dropped, drop_len); |
225d9b89 ED |
601 | } |
602 | ||
1da177e4 LT |
603 | static void sfq_perturbation(unsigned long arg) |
604 | { | |
6f9e98f7 | 605 | struct Qdisc *sch = (struct Qdisc *)arg; |
1da177e4 | 606 | struct sfq_sched_data *q = qdisc_priv(sch); |
225d9b89 | 607 | spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); |
1da177e4 | 608 | |
225d9b89 | 609 | spin_lock(root_lock); |
63862b5b | 610 | q->perturbation = prandom_u32(); |
225d9b89 | 611 | if (!q->filter_list && q->tail) |
18cb8098 | 612 | sfq_rehash(sch); |
225d9b89 | 613 | spin_unlock(root_lock); |
1da177e4 | 614 | |
32740ddc AK |
615 | if (q->perturb_period) |
616 | mod_timer(&q->perturb_timer, jiffies + q->perturb_period); | |
1da177e4 LT |
617 | } |
618 | ||
1e90474c | 619 | static int sfq_change(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
620 | { |
621 | struct sfq_sched_data *q = qdisc_priv(sch); | |
1e90474c | 622 | struct tc_sfq_qopt *ctl = nla_data(opt); |
18cb8098 | 623 | struct tc_sfq_qopt_v1 *ctl_v1 = NULL; |
2ccccf5f | 624 | unsigned int qlen, dropped = 0; |
ddecf0f4 | 625 | struct red_parms *p = NULL; |
1da177e4 | 626 | |
1e90474c | 627 | if (opt->nla_len < nla_attr_size(sizeof(*ctl))) |
1da177e4 | 628 | return -EINVAL; |
18cb8098 ED |
629 | if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1))) |
630 | ctl_v1 = nla_data(opt); | |
119b3d38 | 631 | if (ctl->divisor && |
632 | (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536)) | |
633 | return -EINVAL; | |
ddecf0f4 ED |
634 | if (ctl_v1 && ctl_v1->qth_min) { |
635 | p = kmalloc(sizeof(*p), GFP_KERNEL); | |
636 | if (!p) | |
637 | return -ENOMEM; | |
638 | } | |
1da177e4 | 639 | sch_tree_lock(sch); |
18cb8098 ED |
640 | if (ctl->quantum) { |
641 | q->quantum = ctl->quantum; | |
642 | q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); | |
643 | } | |
6f9e98f7 | 644 | q->perturb_period = ctl->perturb_period * HZ; |
18cb8098 ED |
645 | if (ctl->flows) |
646 | q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS); | |
647 | if (ctl->divisor) { | |
817fb15d | 648 | q->divisor = ctl->divisor; |
18cb8098 ED |
649 | q->maxflows = min_t(u32, q->maxflows, q->divisor); |
650 | } | |
651 | if (ctl_v1) { | |
652 | if (ctl_v1->depth) | |
653 | q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH); | |
ddecf0f4 ED |
654 | if (p) { |
655 | swap(q->red_parms, p); | |
656 | red_set_parms(q->red_parms, | |
657 | ctl_v1->qth_min, ctl_v1->qth_max, | |
658 | ctl_v1->Wlog, | |
659 | ctl_v1->Plog, ctl_v1->Scell_log, | |
660 | NULL, | |
661 | ctl_v1->max_P); | |
662 | } | |
663 | q->flags = ctl_v1->flags; | |
18cb8098 ED |
664 | q->headdrop = ctl_v1->headdrop; |
665 | } | |
666 | if (ctl->limit) { | |
667 | q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows); | |
668 | q->maxflows = min_t(u32, q->maxflows, q->limit); | |
669 | } | |
670 | ||
5e50da01 | 671 | qlen = sch->q.qlen; |
5588b40d | 672 | while (sch->q.qlen > q->limit) |
2ccccf5f WC |
673 | dropped += sfq_drop(sch); |
674 | qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped); | |
1da177e4 LT |
675 | |
676 | del_timer(&q->perturb_timer); | |
677 | if (q->perturb_period) { | |
32740ddc | 678 | mod_timer(&q->perturb_timer, jiffies + q->perturb_period); |
63862b5b | 679 | q->perturbation = prandom_u32(); |
1da177e4 LT |
680 | } |
681 | sch_tree_unlock(sch); | |
ddecf0f4 | 682 | kfree(p); |
1da177e4 LT |
683 | return 0; |
684 | } | |
685 | ||
bd16a6cc ED |
686 | static void *sfq_alloc(size_t sz) |
687 | { | |
688 | void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN); | |
689 | ||
690 | if (!ptr) | |
691 | ptr = vmalloc(sz); | |
692 | return ptr; | |
693 | } | |
694 | ||
695 | static void sfq_free(void *addr) | |
696 | { | |
4cb28970 | 697 | kvfree(addr); |
bd16a6cc ED |
698 | } |
699 | ||
700 | static void sfq_destroy(struct Qdisc *sch) | |
701 | { | |
702 | struct sfq_sched_data *q = qdisc_priv(sch); | |
703 | ||
704 | tcf_destroy_chain(&q->filter_list); | |
705 | q->perturb_period = 0; | |
706 | del_timer_sync(&q->perturb_timer); | |
707 | sfq_free(q->ht); | |
18cb8098 | 708 | sfq_free(q->slots); |
ddecf0f4 | 709 | kfree(q->red_parms); |
bd16a6cc ED |
710 | } |
711 | ||
1e90474c | 712 | static int sfq_init(struct Qdisc *sch, struct nlattr *opt) |
1da177e4 LT |
713 | { |
714 | struct sfq_sched_data *q = qdisc_priv(sch); | |
715 | int i; | |
716 | ||
3b1af93c GT |
717 | setup_deferrable_timer(&q->perturb_timer, sfq_perturbation, |
718 | (unsigned long)sch); | |
1da177e4 | 719 | |
18cb8098 ED |
720 | for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) { |
721 | q->dep[i].next = i + SFQ_MAX_FLOWS; | |
722 | q->dep[i].prev = i + SFQ_MAX_FLOWS; | |
1da177e4 | 723 | } |
6f9e98f7 | 724 | |
18cb8098 ED |
725 | q->limit = SFQ_MAX_DEPTH; |
726 | q->maxdepth = SFQ_MAX_DEPTH; | |
eda83e3b ED |
727 | q->cur_depth = 0; |
728 | q->tail = NULL; | |
817fb15d | 729 | q->divisor = SFQ_DEFAULT_HASH_DIVISOR; |
18cb8098 | 730 | q->maxflows = SFQ_DEFAULT_FLOWS; |
02a9098e ED |
731 | q->quantum = psched_mtu(qdisc_dev(sch)); |
732 | q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); | |
733 | q->perturb_period = 0; | |
63862b5b | 734 | q->perturbation = prandom_u32(); |
02a9098e ED |
735 | |
736 | if (opt) { | |
1da177e4 LT |
737 | int err = sfq_change(sch, opt); |
738 | if (err) | |
739 | return err; | |
740 | } | |
6f9e98f7 | 741 | |
bd16a6cc | 742 | q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor); |
18cb8098 ED |
743 | q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows); |
744 | if (!q->ht || !q->slots) { | |
87b60cfa | 745 | /* Note: sfq_destroy() will be called by our caller */ |
817fb15d | 746 | return -ENOMEM; |
bd16a6cc | 747 | } |
87b60cfa | 748 | |
817fb15d ED |
749 | for (i = 0; i < q->divisor; i++) |
750 | q->ht[i] = SFQ_EMPTY_SLOT; | |
751 | ||
18cb8098 | 752 | for (i = 0; i < q->maxflows; i++) { |
18c8d82a | 753 | slot_queue_init(&q->slots[i]); |
1da177e4 | 754 | sfq_link(q, i); |
18c8d82a | 755 | } |
23624935 ED |
756 | if (q->limit >= 1) |
757 | sch->flags |= TCQ_F_CAN_BYPASS; | |
758 | else | |
759 | sch->flags &= ~TCQ_F_CAN_BYPASS; | |
1da177e4 LT |
760 | return 0; |
761 | } | |
762 | ||
1da177e4 LT |
763 | static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb) |
764 | { | |
765 | struct sfq_sched_data *q = qdisc_priv(sch); | |
27a884dc | 766 | unsigned char *b = skb_tail_pointer(skb); |
18cb8098 | 767 | struct tc_sfq_qopt_v1 opt; |
ddecf0f4 | 768 | struct red_parms *p = q->red_parms; |
18cb8098 ED |
769 | |
770 | memset(&opt, 0, sizeof(opt)); | |
771 | opt.v0.quantum = q->quantum; | |
772 | opt.v0.perturb_period = q->perturb_period / HZ; | |
773 | opt.v0.limit = q->limit; | |
774 | opt.v0.divisor = q->divisor; | |
775 | opt.v0.flows = q->maxflows; | |
776 | opt.depth = q->maxdepth; | |
777 | opt.headdrop = q->headdrop; | |
1da177e4 | 778 | |
ddecf0f4 ED |
779 | if (p) { |
780 | opt.qth_min = p->qth_min >> p->Wlog; | |
781 | opt.qth_max = p->qth_max >> p->Wlog; | |
782 | opt.Wlog = p->Wlog; | |
783 | opt.Plog = p->Plog; | |
784 | opt.Scell_log = p->Scell_log; | |
785 | opt.max_P = p->max_P; | |
786 | } | |
787 | memcpy(&opt.stats, &q->stats, sizeof(opt.stats)); | |
788 | opt.flags = q->flags; | |
789 | ||
1b34ec43 DM |
790 | if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) |
791 | goto nla_put_failure; | |
1da177e4 LT |
792 | |
793 | return skb->len; | |
794 | ||
1e90474c | 795 | nla_put_failure: |
dc5fc579 | 796 | nlmsg_trim(skb, b); |
1da177e4 LT |
797 | return -1; |
798 | } | |
799 | ||
41065fba JP |
800 | static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg) |
801 | { | |
802 | return NULL; | |
803 | } | |
804 | ||
7d2681a6 PM |
805 | static unsigned long sfq_get(struct Qdisc *sch, u32 classid) |
806 | { | |
807 | return 0; | |
808 | } | |
809 | ||
eb4a5527 JP |
810 | static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent, |
811 | u32 classid) | |
812 | { | |
23624935 ED |
813 | /* we cannot bypass queue discipline anymore */ |
814 | sch->flags &= ~TCQ_F_CAN_BYPASS; | |
eb4a5527 JP |
815 | return 0; |
816 | } | |
817 | ||
da7115d9 JP |
818 | static void sfq_put(struct Qdisc *q, unsigned long cl) |
819 | { | |
820 | } | |
821 | ||
25d8c0d5 JF |
822 | static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch, |
823 | unsigned long cl) | |
7d2681a6 PM |
824 | { |
825 | struct sfq_sched_data *q = qdisc_priv(sch); | |
826 | ||
827 | if (cl) | |
828 | return NULL; | |
829 | return &q->filter_list; | |
830 | } | |
831 | ||
94de78d1 PM |
832 | static int sfq_dump_class(struct Qdisc *sch, unsigned long cl, |
833 | struct sk_buff *skb, struct tcmsg *tcm) | |
834 | { | |
835 | tcm->tcm_handle |= TC_H_MIN(cl); | |
836 | return 0; | |
837 | } | |
838 | ||
839 | static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl, | |
840 | struct gnet_dump *d) | |
841 | { | |
842 | struct sfq_sched_data *q = qdisc_priv(sch); | |
ee09b3c1 ED |
843 | sfq_index idx = q->ht[cl - 1]; |
844 | struct gnet_stats_queue qs = { 0 }; | |
845 | struct tc_sfq_xstats xstats = { 0 }; | |
c4266263 | 846 | |
ee09b3c1 ED |
847 | if (idx != SFQ_EMPTY_SLOT) { |
848 | const struct sfq_slot *slot = &q->slots[idx]; | |
94de78d1 | 849 | |
eeaeb068 | 850 | xstats.allot = slot->allot << SFQ_ALLOT_SHIFT; |
ee09b3c1 | 851 | qs.qlen = slot->qlen; |
ddecf0f4 | 852 | qs.backlog = slot->backlog; |
ee09b3c1 | 853 | } |
b0ab6f92 | 854 | if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0) |
94de78d1 PM |
855 | return -1; |
856 | return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); | |
857 | } | |
858 | ||
7d2681a6 PM |
859 | static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg) |
860 | { | |
94de78d1 PM |
861 | struct sfq_sched_data *q = qdisc_priv(sch); |
862 | unsigned int i; | |
863 | ||
864 | if (arg->stop) | |
865 | return; | |
866 | ||
817fb15d | 867 | for (i = 0; i < q->divisor; i++) { |
eda83e3b | 868 | if (q->ht[i] == SFQ_EMPTY_SLOT || |
94de78d1 PM |
869 | arg->count < arg->skip) { |
870 | arg->count++; | |
871 | continue; | |
872 | } | |
873 | if (arg->fn(sch, i + 1, arg) < 0) { | |
874 | arg->stop = 1; | |
875 | break; | |
876 | } | |
877 | arg->count++; | |
878 | } | |
7d2681a6 PM |
879 | } |
880 | ||
881 | static const struct Qdisc_class_ops sfq_class_ops = { | |
41065fba | 882 | .leaf = sfq_leaf, |
7d2681a6 | 883 | .get = sfq_get, |
da7115d9 | 884 | .put = sfq_put, |
7d2681a6 | 885 | .tcf_chain = sfq_find_tcf, |
eb4a5527 | 886 | .bind_tcf = sfq_bind, |
da7115d9 | 887 | .unbind_tcf = sfq_put, |
94de78d1 PM |
888 | .dump = sfq_dump_class, |
889 | .dump_stats = sfq_dump_class_stats, | |
7d2681a6 PM |
890 | .walk = sfq_walk, |
891 | }; | |
892 | ||
20fea08b | 893 | static struct Qdisc_ops sfq_qdisc_ops __read_mostly = { |
7d2681a6 | 894 | .cl_ops = &sfq_class_ops, |
1da177e4 LT |
895 | .id = "sfq", |
896 | .priv_size = sizeof(struct sfq_sched_data), | |
897 | .enqueue = sfq_enqueue, | |
898 | .dequeue = sfq_dequeue, | |
07bd8df5 | 899 | .peek = qdisc_peek_dequeued, |
1da177e4 LT |
900 | .init = sfq_init, |
901 | .reset = sfq_reset, | |
902 | .destroy = sfq_destroy, | |
903 | .change = NULL, | |
904 | .dump = sfq_dump, | |
905 | .owner = THIS_MODULE, | |
906 | }; | |
907 | ||
908 | static int __init sfq_module_init(void) | |
909 | { | |
910 | return register_qdisc(&sfq_qdisc_ops); | |
911 | } | |
10297b99 | 912 | static void __exit sfq_module_exit(void) |
1da177e4 LT |
913 | { |
914 | unregister_qdisc(&sfq_qdisc_ops); | |
915 | } | |
916 | module_init(sfq_module_init) | |
917 | module_exit(sfq_module_exit) | |
918 | MODULE_LICENSE("GPL"); |