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d4b36210 VS |
1 | /* Copyright (C) 2013 Cisco Systems, Inc, 2013. |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of the GNU General Public License | |
5 | * as published by the Free Software Foundation; either version 2 | |
6 | * of the License. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * Author: Vijay Subramanian <vijaynsu@cisco.com> | |
14 | * Author: Mythili Prabhu <mysuryan@cisco.com> | |
15 | * | |
16 | * ECN support is added by Naeem Khademi <naeemk@ifi.uio.no> | |
17 | * University of Oslo, Norway. | |
219e288e VS |
18 | * |
19 | * References: | |
20 | * IETF draft submission: http://tools.ietf.org/html/draft-pan-aqm-pie-00 | |
21 | * IEEE Conference on High Performance Switching and Routing 2013 : | |
22 | * "PIE: A * Lightweight Control Scheme to Address the Bufferbloat Problem" | |
d4b36210 VS |
23 | */ |
24 | ||
25 | #include <linux/module.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/types.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/skbuff.h> | |
31 | #include <net/pkt_sched.h> | |
32 | #include <net/inet_ecn.h> | |
33 | ||
34 | #define QUEUE_THRESHOLD 10000 | |
35 | #define DQCOUNT_INVALID -1 | |
36 | #define MAX_PROB 0xffffffff | |
37 | #define PIE_SCALE 8 | |
38 | ||
39 | /* parameters used */ | |
40 | struct pie_params { | |
41 | psched_time_t target; /* user specified target delay in pschedtime */ | |
42 | u32 tupdate; /* timer frequency (in jiffies) */ | |
43 | u32 limit; /* number of packets that can be enqueued */ | |
219e288e | 44 | u32 alpha; /* alpha and beta are between 0 and 32 */ |
d4b36210 VS |
45 | u32 beta; /* and are used for shift relative to 1 */ |
46 | bool ecn; /* true if ecn is enabled */ | |
47 | bool bytemode; /* to scale drop early prob based on pkt size */ | |
48 | }; | |
49 | ||
50 | /* variables used */ | |
51 | struct pie_vars { | |
52 | u32 prob; /* probability but scaled by u32 limit. */ | |
53 | psched_time_t burst_time; | |
54 | psched_time_t qdelay; | |
55 | psched_time_t qdelay_old; | |
56 | u64 dq_count; /* measured in bytes */ | |
57 | psched_time_t dq_tstamp; /* drain rate */ | |
58 | u32 avg_dq_rate; /* bytes per pschedtime tick,scaled */ | |
59 | u32 qlen_old; /* in bytes */ | |
60 | }; | |
61 | ||
62 | /* statistics gathering */ | |
63 | struct pie_stats { | |
64 | u32 packets_in; /* total number of packets enqueued */ | |
65 | u32 dropped; /* packets dropped due to pie_action */ | |
66 | u32 overlimit; /* dropped due to lack of space in queue */ | |
67 | u32 maxq; /* maximum queue size */ | |
68 | u32 ecn_mark; /* packets marked with ECN */ | |
69 | }; | |
70 | ||
71 | /* private data for the Qdisc */ | |
72 | struct pie_sched_data { | |
73 | struct pie_params params; | |
74 | struct pie_vars vars; | |
75 | struct pie_stats stats; | |
76 | struct timer_list adapt_timer; | |
cdeabbb8 | 77 | struct Qdisc *sch; |
d4b36210 VS |
78 | }; |
79 | ||
80 | static void pie_params_init(struct pie_params *params) | |
81 | { | |
82 | params->alpha = 2; | |
83 | params->beta = 20; | |
84 | params->tupdate = usecs_to_jiffies(30 * USEC_PER_MSEC); /* 30 ms */ | |
85 | params->limit = 1000; /* default of 1000 packets */ | |
86 | params->target = PSCHED_NS2TICKS(20 * NSEC_PER_MSEC); /* 20 ms */ | |
87 | params->ecn = false; | |
88 | params->bytemode = false; | |
89 | } | |
90 | ||
91 | static void pie_vars_init(struct pie_vars *vars) | |
92 | { | |
93 | vars->dq_count = DQCOUNT_INVALID; | |
94 | vars->avg_dq_rate = 0; | |
95 | /* default of 100 ms in pschedtime */ | |
96 | vars->burst_time = PSCHED_NS2TICKS(100 * NSEC_PER_MSEC); | |
97 | } | |
98 | ||
99 | static bool drop_early(struct Qdisc *sch, u32 packet_size) | |
100 | { | |
101 | struct pie_sched_data *q = qdisc_priv(sch); | |
102 | u32 rnd; | |
103 | u32 local_prob = q->vars.prob; | |
104 | u32 mtu = psched_mtu(qdisc_dev(sch)); | |
105 | ||
106 | /* If there is still burst allowance left skip random early drop */ | |
107 | if (q->vars.burst_time > 0) | |
108 | return false; | |
109 | ||
110 | /* If current delay is less than half of target, and | |
111 | * if drop prob is low already, disable early_drop | |
112 | */ | |
113 | if ((q->vars.qdelay < q->params.target / 2) | |
114 | && (q->vars.prob < MAX_PROB / 5)) | |
115 | return false; | |
116 | ||
117 | /* If we have fewer than 2 mtu-sized packets, disable drop_early, | |
118 | * similar to min_th in RED | |
119 | */ | |
120 | if (sch->qstats.backlog < 2 * mtu) | |
121 | return false; | |
122 | ||
123 | /* If bytemode is turned on, use packet size to compute new | |
124 | * probablity. Smaller packets will have lower drop prob in this case | |
125 | */ | |
126 | if (q->params.bytemode && packet_size <= mtu) | |
127 | local_prob = (local_prob / mtu) * packet_size; | |
128 | else | |
129 | local_prob = q->vars.prob; | |
130 | ||
63862b5b | 131 | rnd = prandom_u32(); |
d4b36210 VS |
132 | if (rnd < local_prob) |
133 | return true; | |
134 | ||
135 | return false; | |
136 | } | |
137 | ||
520ac30f ED |
138 | static int pie_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch, |
139 | struct sk_buff **to_free) | |
d4b36210 VS |
140 | { |
141 | struct pie_sched_data *q = qdisc_priv(sch); | |
142 | bool enqueue = false; | |
143 | ||
144 | if (unlikely(qdisc_qlen(sch) >= sch->limit)) { | |
145 | q->stats.overlimit++; | |
146 | goto out; | |
147 | } | |
148 | ||
149 | if (!drop_early(sch, skb->len)) { | |
150 | enqueue = true; | |
151 | } else if (q->params.ecn && (q->vars.prob <= MAX_PROB / 10) && | |
152 | INET_ECN_set_ce(skb)) { | |
153 | /* If packet is ecn capable, mark it if drop probability | |
154 | * is lower than 10%, else drop it. | |
155 | */ | |
156 | q->stats.ecn_mark++; | |
157 | enqueue = true; | |
158 | } | |
159 | ||
160 | /* we can enqueue the packet */ | |
161 | if (enqueue) { | |
162 | q->stats.packets_in++; | |
163 | if (qdisc_qlen(sch) > q->stats.maxq) | |
164 | q->stats.maxq = qdisc_qlen(sch); | |
165 | ||
166 | return qdisc_enqueue_tail(skb, sch); | |
167 | } | |
168 | ||
169 | out: | |
170 | q->stats.dropped++; | |
520ac30f | 171 | return qdisc_drop(skb, sch, to_free); |
d4b36210 VS |
172 | } |
173 | ||
174 | static const struct nla_policy pie_policy[TCA_PIE_MAX + 1] = { | |
175 | [TCA_PIE_TARGET] = {.type = NLA_U32}, | |
176 | [TCA_PIE_LIMIT] = {.type = NLA_U32}, | |
177 | [TCA_PIE_TUPDATE] = {.type = NLA_U32}, | |
178 | [TCA_PIE_ALPHA] = {.type = NLA_U32}, | |
179 | [TCA_PIE_BETA] = {.type = NLA_U32}, | |
180 | [TCA_PIE_ECN] = {.type = NLA_U32}, | |
181 | [TCA_PIE_BYTEMODE] = {.type = NLA_U32}, | |
182 | }; | |
183 | ||
2030721c AA |
184 | static int pie_change(struct Qdisc *sch, struct nlattr *opt, |
185 | struct netlink_ext_ack *extack) | |
d4b36210 VS |
186 | { |
187 | struct pie_sched_data *q = qdisc_priv(sch); | |
188 | struct nlattr *tb[TCA_PIE_MAX + 1]; | |
2ccccf5f | 189 | unsigned int qlen, dropped = 0; |
d4b36210 VS |
190 | int err; |
191 | ||
192 | if (!opt) | |
193 | return -EINVAL; | |
194 | ||
fceb6435 | 195 | err = nla_parse_nested(tb, TCA_PIE_MAX, opt, pie_policy, NULL); |
d4b36210 VS |
196 | if (err < 0) |
197 | return err; | |
198 | ||
199 | sch_tree_lock(sch); | |
200 | ||
201 | /* convert from microseconds to pschedtime */ | |
202 | if (tb[TCA_PIE_TARGET]) { | |
203 | /* target is in us */ | |
204 | u32 target = nla_get_u32(tb[TCA_PIE_TARGET]); | |
205 | ||
206 | /* convert to pschedtime */ | |
207 | q->params.target = PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC); | |
208 | } | |
209 | ||
210 | /* tupdate is in jiffies */ | |
211 | if (tb[TCA_PIE_TUPDATE]) | |
212 | q->params.tupdate = usecs_to_jiffies(nla_get_u32(tb[TCA_PIE_TUPDATE])); | |
213 | ||
214 | if (tb[TCA_PIE_LIMIT]) { | |
215 | u32 limit = nla_get_u32(tb[TCA_PIE_LIMIT]); | |
216 | ||
217 | q->params.limit = limit; | |
218 | sch->limit = limit; | |
219 | } | |
220 | ||
221 | if (tb[TCA_PIE_ALPHA]) | |
222 | q->params.alpha = nla_get_u32(tb[TCA_PIE_ALPHA]); | |
223 | ||
224 | if (tb[TCA_PIE_BETA]) | |
225 | q->params.beta = nla_get_u32(tb[TCA_PIE_BETA]); | |
226 | ||
227 | if (tb[TCA_PIE_ECN]) | |
228 | q->params.ecn = nla_get_u32(tb[TCA_PIE_ECN]); | |
229 | ||
230 | if (tb[TCA_PIE_BYTEMODE]) | |
231 | q->params.bytemode = nla_get_u32(tb[TCA_PIE_BYTEMODE]); | |
232 | ||
233 | /* Drop excess packets if new limit is lower */ | |
234 | qlen = sch->q.qlen; | |
235 | while (sch->q.qlen > sch->limit) { | |
ed760cb8 | 236 | struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); |
d4b36210 | 237 | |
2ccccf5f | 238 | dropped += qdisc_pkt_len(skb); |
25331d6c | 239 | qdisc_qstats_backlog_dec(sch, skb); |
db4879d9 | 240 | rtnl_qdisc_drop(skb, sch); |
d4b36210 | 241 | } |
2ccccf5f | 242 | qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped); |
d4b36210 VS |
243 | |
244 | sch_tree_unlock(sch); | |
245 | return 0; | |
246 | } | |
247 | ||
248 | static void pie_process_dequeue(struct Qdisc *sch, struct sk_buff *skb) | |
249 | { | |
250 | ||
251 | struct pie_sched_data *q = qdisc_priv(sch); | |
252 | int qlen = sch->qstats.backlog; /* current queue size in bytes */ | |
253 | ||
254 | /* If current queue is about 10 packets or more and dq_count is unset | |
255 | * we have enough packets to calculate the drain rate. Save | |
256 | * current time as dq_tstamp and start measurement cycle. | |
257 | */ | |
258 | if (qlen >= QUEUE_THRESHOLD && q->vars.dq_count == DQCOUNT_INVALID) { | |
259 | q->vars.dq_tstamp = psched_get_time(); | |
260 | q->vars.dq_count = 0; | |
261 | } | |
262 | ||
263 | /* Calculate the average drain rate from this value. If queue length | |
264 | * has receded to a small value viz., <= QUEUE_THRESHOLD bytes,reset | |
265 | * the dq_count to -1 as we don't have enough packets to calculate the | |
266 | * drain rate anymore The following if block is entered only when we | |
267 | * have a substantial queue built up (QUEUE_THRESHOLD bytes or more) | |
268 | * and we calculate the drain rate for the threshold here. dq_count is | |
269 | * in bytes, time difference in psched_time, hence rate is in | |
270 | * bytes/psched_time. | |
271 | */ | |
272 | if (q->vars.dq_count != DQCOUNT_INVALID) { | |
273 | q->vars.dq_count += skb->len; | |
274 | ||
275 | if (q->vars.dq_count >= QUEUE_THRESHOLD) { | |
276 | psched_time_t now = psched_get_time(); | |
277 | u32 dtime = now - q->vars.dq_tstamp; | |
278 | u32 count = q->vars.dq_count << PIE_SCALE; | |
279 | ||
280 | if (dtime == 0) | |
281 | return; | |
282 | ||
283 | count = count / dtime; | |
284 | ||
285 | if (q->vars.avg_dq_rate == 0) | |
286 | q->vars.avg_dq_rate = count; | |
287 | else | |
288 | q->vars.avg_dq_rate = | |
289 | (q->vars.avg_dq_rate - | |
290 | (q->vars.avg_dq_rate >> 3)) + (count >> 3); | |
291 | ||
292 | /* If the queue has receded below the threshold, we hold | |
293 | * on to the last drain rate calculated, else we reset | |
294 | * dq_count to 0 to re-enter the if block when the next | |
295 | * packet is dequeued | |
296 | */ | |
297 | if (qlen < QUEUE_THRESHOLD) | |
298 | q->vars.dq_count = DQCOUNT_INVALID; | |
299 | else { | |
300 | q->vars.dq_count = 0; | |
301 | q->vars.dq_tstamp = psched_get_time(); | |
302 | } | |
303 | ||
304 | if (q->vars.burst_time > 0) { | |
305 | if (q->vars.burst_time > dtime) | |
306 | q->vars.burst_time -= dtime; | |
307 | else | |
308 | q->vars.burst_time = 0; | |
309 | } | |
310 | } | |
311 | } | |
312 | } | |
313 | ||
314 | static void calculate_probability(struct Qdisc *sch) | |
315 | { | |
316 | struct pie_sched_data *q = qdisc_priv(sch); | |
317 | u32 qlen = sch->qstats.backlog; /* queue size in bytes */ | |
318 | psched_time_t qdelay = 0; /* in pschedtime */ | |
319 | psched_time_t qdelay_old = q->vars.qdelay; /* in pschedtime */ | |
320 | s32 delta = 0; /* determines the change in probability */ | |
321 | u32 oldprob; | |
322 | u32 alpha, beta; | |
323 | bool update_prob = true; | |
324 | ||
325 | q->vars.qdelay_old = q->vars.qdelay; | |
326 | ||
327 | if (q->vars.avg_dq_rate > 0) | |
328 | qdelay = (qlen << PIE_SCALE) / q->vars.avg_dq_rate; | |
329 | else | |
330 | qdelay = 0; | |
331 | ||
332 | /* If qdelay is zero and qlen is not, it means qlen is very small, less | |
333 | * than dequeue_rate, so we do not update probabilty in this round | |
334 | */ | |
335 | if (qdelay == 0 && qlen != 0) | |
336 | update_prob = false; | |
337 | ||
219e288e VS |
338 | /* In the algorithm, alpha and beta are between 0 and 2 with typical |
339 | * value for alpha as 0.125. In this implementation, we use values 0-32 | |
340 | * passed from user space to represent this. Also, alpha and beta have | |
341 | * unit of HZ and need to be scaled before they can used to update | |
342 | * probability. alpha/beta are updated locally below by 1) scaling them | |
343 | * appropriately 2) scaling down by 16 to come to 0-2 range. | |
344 | * Please see paper for details. | |
345 | * | |
346 | * We scale alpha and beta differently depending on whether we are in | |
347 | * light, medium or high dropping mode. | |
d4b36210 VS |
348 | */ |
349 | if (q->vars.prob < MAX_PROB / 100) { | |
350 | alpha = | |
351 | (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 7; | |
352 | beta = | |
353 | (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 7; | |
354 | } else if (q->vars.prob < MAX_PROB / 10) { | |
355 | alpha = | |
356 | (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 5; | |
357 | beta = | |
358 | (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 5; | |
359 | } else { | |
360 | alpha = | |
361 | (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 4; | |
362 | beta = | |
363 | (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 4; | |
364 | } | |
365 | ||
366 | /* alpha and beta should be between 0 and 32, in multiples of 1/16 */ | |
367 | delta += alpha * ((qdelay - q->params.target)); | |
368 | delta += beta * ((qdelay - qdelay_old)); | |
369 | ||
370 | oldprob = q->vars.prob; | |
371 | ||
372 | /* to ensure we increase probability in steps of no more than 2% */ | |
373 | if (delta > (s32) (MAX_PROB / (100 / 2)) && | |
374 | q->vars.prob >= MAX_PROB / 10) | |
375 | delta = (MAX_PROB / 100) * 2; | |
376 | ||
377 | /* Non-linear drop: | |
378 | * Tune drop probability to increase quickly for high delays(>= 250ms) | |
379 | * 250ms is derived through experiments and provides error protection | |
380 | */ | |
381 | ||
382 | if (qdelay > (PSCHED_NS2TICKS(250 * NSEC_PER_MSEC))) | |
383 | delta += MAX_PROB / (100 / 2); | |
384 | ||
385 | q->vars.prob += delta; | |
386 | ||
387 | if (delta > 0) { | |
388 | /* prevent overflow */ | |
389 | if (q->vars.prob < oldprob) { | |
390 | q->vars.prob = MAX_PROB; | |
391 | /* Prevent normalization error. If probability is at | |
392 | * maximum value already, we normalize it here, and | |
393 | * skip the check to do a non-linear drop in the next | |
394 | * section. | |
395 | */ | |
396 | update_prob = false; | |
397 | } | |
398 | } else { | |
399 | /* prevent underflow */ | |
400 | if (q->vars.prob > oldprob) | |
401 | q->vars.prob = 0; | |
402 | } | |
403 | ||
404 | /* Non-linear drop in probability: Reduce drop probability quickly if | |
405 | * delay is 0 for 2 consecutive Tupdate periods. | |
406 | */ | |
407 | ||
408 | if ((qdelay == 0) && (qdelay_old == 0) && update_prob) | |
409 | q->vars.prob = (q->vars.prob * 98) / 100; | |
410 | ||
411 | q->vars.qdelay = qdelay; | |
412 | q->vars.qlen_old = qlen; | |
413 | ||
414 | /* We restart the measurement cycle if the following conditions are met | |
415 | * 1. If the delay has been low for 2 consecutive Tupdate periods | |
416 | * 2. Calculated drop probability is zero | |
417 | * 3. We have atleast one estimate for the avg_dq_rate ie., | |
418 | * is a non-zero value | |
419 | */ | |
420 | if ((q->vars.qdelay < q->params.target / 2) && | |
421 | (q->vars.qdelay_old < q->params.target / 2) && | |
422 | (q->vars.prob == 0) && | |
423 | (q->vars.avg_dq_rate > 0)) | |
424 | pie_vars_init(&q->vars); | |
425 | } | |
426 | ||
cdeabbb8 | 427 | static void pie_timer(struct timer_list *t) |
d4b36210 | 428 | { |
cdeabbb8 KC |
429 | struct pie_sched_data *q = from_timer(q, t, adapt_timer); |
430 | struct Qdisc *sch = q->sch; | |
d4b36210 VS |
431 | spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch)); |
432 | ||
433 | spin_lock(root_lock); | |
434 | calculate_probability(sch); | |
435 | ||
436 | /* reset the timer to fire after 'tupdate'. tupdate is in jiffies. */ | |
437 | if (q->params.tupdate) | |
438 | mod_timer(&q->adapt_timer, jiffies + q->params.tupdate); | |
439 | spin_unlock(root_lock); | |
440 | ||
441 | } | |
442 | ||
e63d7dfd AA |
443 | static int pie_init(struct Qdisc *sch, struct nlattr *opt, |
444 | struct netlink_ext_ack *extack) | |
d4b36210 VS |
445 | { |
446 | struct pie_sched_data *q = qdisc_priv(sch); | |
447 | ||
448 | pie_params_init(&q->params); | |
449 | pie_vars_init(&q->vars); | |
450 | sch->limit = q->params.limit; | |
451 | ||
cdeabbb8 KC |
452 | q->sch = sch; |
453 | timer_setup(&q->adapt_timer, pie_timer, 0); | |
d4b36210 VS |
454 | |
455 | if (opt) { | |
2030721c | 456 | int err = pie_change(sch, opt, extack); |
d4b36210 VS |
457 | |
458 | if (err) | |
459 | return err; | |
460 | } | |
461 | ||
d5610902 | 462 | mod_timer(&q->adapt_timer, jiffies + HZ / 2); |
d4b36210 VS |
463 | return 0; |
464 | } | |
465 | ||
466 | static int pie_dump(struct Qdisc *sch, struct sk_buff *skb) | |
467 | { | |
468 | struct pie_sched_data *q = qdisc_priv(sch); | |
469 | struct nlattr *opts; | |
470 | ||
471 | opts = nla_nest_start(skb, TCA_OPTIONS); | |
472 | if (opts == NULL) | |
473 | goto nla_put_failure; | |
474 | ||
475 | /* convert target from pschedtime to us */ | |
476 | if (nla_put_u32(skb, TCA_PIE_TARGET, | |
477 | ((u32) PSCHED_TICKS2NS(q->params.target)) / | |
478 | NSEC_PER_USEC) || | |
479 | nla_put_u32(skb, TCA_PIE_LIMIT, sch->limit) || | |
480 | nla_put_u32(skb, TCA_PIE_TUPDATE, jiffies_to_usecs(q->params.tupdate)) || | |
481 | nla_put_u32(skb, TCA_PIE_ALPHA, q->params.alpha) || | |
482 | nla_put_u32(skb, TCA_PIE_BETA, q->params.beta) || | |
483 | nla_put_u32(skb, TCA_PIE_ECN, q->params.ecn) || | |
484 | nla_put_u32(skb, TCA_PIE_BYTEMODE, q->params.bytemode)) | |
485 | goto nla_put_failure; | |
486 | ||
487 | return nla_nest_end(skb, opts); | |
488 | ||
489 | nla_put_failure: | |
490 | nla_nest_cancel(skb, opts); | |
491 | return -1; | |
492 | ||
493 | } | |
494 | ||
495 | static int pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d) | |
496 | { | |
497 | struct pie_sched_data *q = qdisc_priv(sch); | |
498 | struct tc_pie_xstats st = { | |
499 | .prob = q->vars.prob, | |
500 | .delay = ((u32) PSCHED_TICKS2NS(q->vars.qdelay)) / | |
501 | NSEC_PER_USEC, | |
502 | /* unscale and return dq_rate in bytes per sec */ | |
503 | .avg_dq_rate = q->vars.avg_dq_rate * | |
504 | (PSCHED_TICKS_PER_SEC) >> PIE_SCALE, | |
505 | .packets_in = q->stats.packets_in, | |
506 | .overlimit = q->stats.overlimit, | |
507 | .maxq = q->stats.maxq, | |
508 | .dropped = q->stats.dropped, | |
509 | .ecn_mark = q->stats.ecn_mark, | |
510 | }; | |
511 | ||
512 | return gnet_stats_copy_app(d, &st, sizeof(st)); | |
513 | } | |
514 | ||
515 | static struct sk_buff *pie_qdisc_dequeue(struct Qdisc *sch) | |
516 | { | |
517 | struct sk_buff *skb; | |
1486587b | 518 | skb = qdisc_dequeue_head(sch); |
d4b36210 VS |
519 | |
520 | if (!skb) | |
521 | return NULL; | |
522 | ||
523 | pie_process_dequeue(sch, skb); | |
524 | return skb; | |
525 | } | |
526 | ||
527 | static void pie_reset(struct Qdisc *sch) | |
528 | { | |
529 | struct pie_sched_data *q = qdisc_priv(sch); | |
530 | qdisc_reset_queue(sch); | |
531 | pie_vars_init(&q->vars); | |
532 | } | |
533 | ||
534 | static void pie_destroy(struct Qdisc *sch) | |
535 | { | |
536 | struct pie_sched_data *q = qdisc_priv(sch); | |
537 | q->params.tupdate = 0; | |
538 | del_timer_sync(&q->adapt_timer); | |
539 | } | |
540 | ||
541 | static struct Qdisc_ops pie_qdisc_ops __read_mostly = { | |
542 | .id = "pie", | |
543 | .priv_size = sizeof(struct pie_sched_data), | |
544 | .enqueue = pie_qdisc_enqueue, | |
545 | .dequeue = pie_qdisc_dequeue, | |
546 | .peek = qdisc_peek_dequeued, | |
547 | .init = pie_init, | |
548 | .destroy = pie_destroy, | |
549 | .reset = pie_reset, | |
550 | .change = pie_change, | |
551 | .dump = pie_dump, | |
552 | .dump_stats = pie_dump_stats, | |
553 | .owner = THIS_MODULE, | |
554 | }; | |
555 | ||
556 | static int __init pie_module_init(void) | |
557 | { | |
558 | return register_qdisc(&pie_qdisc_ops); | |
559 | } | |
560 | ||
561 | static void __exit pie_module_exit(void) | |
562 | { | |
563 | unregister_qdisc(&pie_qdisc_ops); | |
564 | } | |
565 | ||
566 | module_init(pie_module_init); | |
567 | module_exit(pie_module_exit); | |
568 | ||
569 | MODULE_DESCRIPTION("Proportional Integral controller Enhanced (PIE) scheduler"); | |
570 | MODULE_AUTHOR("Vijay Subramanian"); | |
571 | MODULE_AUTHOR("Mythili Prabhu"); | |
572 | MODULE_LICENSE("GPL"); |