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Merge branches 'pm-cpufreq-fixes' and 'pm-cpuidle-fixes'
[linux/fpc-iii.git] / net / sched / sch_red.c
blob249b2a18acbd99288eb0a2579a0f29c2ab0b3ded
1 /*
2 * net/sched/sch_red.c Random Early Detection queue.
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 * Changes:
12 * J Hadi Salim 980914: computation fixes
13 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
14 * J Hadi Salim 980816: ECN support
15 */
16
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/skbuff.h>
21 #include <net/pkt_sched.h>
22 #include <net/inet_ecn.h>
23 #include <net/red.h>
24
25
26 /* Parameters, settable by user:
27 -----------------------------
28
29 limit - bytes (must be > qth_max + burst)
30
31 Hard limit on queue length, should be chosen >qth_max
32 to allow packet bursts. This parameter does not
33 affect the algorithms behaviour and can be chosen
34 arbitrarily high (well, less than ram size)
35 Really, this limit will never be reached
36 if RED works correctly.
37 */
38
39 struct red_sched_data {
40 u32 limit; /* HARD maximal queue length */
41 unsigned char flags;
42 struct timer_list adapt_timer;
43 struct red_parms parms;
44 struct red_vars vars;
45 struct red_stats stats;
46 struct Qdisc *qdisc;
47 };
48
49 static inline int red_use_ecn(struct red_sched_data *q)
50 {
51 return q->flags & TC_RED_ECN;
52 }
53
54 static inline int red_use_harddrop(struct red_sched_data *q)
55 {
56 return q->flags & TC_RED_HARDDROP;
57 }
58
59 static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
60 struct sk_buff **to_free)
61 {
62 struct red_sched_data *q = qdisc_priv(sch);
63 struct Qdisc *child = q->qdisc;
64 int ret;
65
66 q->vars.qavg = red_calc_qavg(&q->parms,
67 &q->vars,
68 child->qstats.backlog);
69
70 if (red_is_idling(&q->vars))
71 red_end_of_idle_period(&q->vars);
72
73 switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
74 case RED_DONT_MARK:
75 break;
76
77 case RED_PROB_MARK:
78 qdisc_qstats_overlimit(sch);
79 if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
80 q->stats.prob_drop++;
81 goto congestion_drop;
82 }
83
84 q->stats.prob_mark++;
85 break;
86
87 case RED_HARD_MARK:
88 qdisc_qstats_overlimit(sch);
89 if (red_use_harddrop(q) || !red_use_ecn(q) ||
90 !INET_ECN_set_ce(skb)) {
91 q->stats.forced_drop++;
92 goto congestion_drop;
93 }
94
95 q->stats.forced_mark++;
96 break;
97 }
98
99 ret = qdisc_enqueue(skb, child, to_free);
100 if (likely(ret == NET_XMIT_SUCCESS)) {
101 qdisc_qstats_backlog_inc(sch, skb);
102 sch->q.qlen++;
103 } else if (net_xmit_drop_count(ret)) {
104 q->stats.pdrop++;
105 qdisc_qstats_drop(sch);
106 }
107 return ret;
108
109 congestion_drop:
110 qdisc_drop(skb, sch, to_free);
111 return NET_XMIT_CN;
112 }
113
114 static struct sk_buff *red_dequeue(struct Qdisc *sch)
115 {
116 struct sk_buff *skb;
117 struct red_sched_data *q = qdisc_priv(sch);
118 struct Qdisc *child = q->qdisc;
119
120 skb = child->dequeue(child);
121 if (skb) {
122 qdisc_bstats_update(sch, skb);
123 qdisc_qstats_backlog_dec(sch, skb);
124 sch->q.qlen--;
125 } else {
126 if (!red_is_idling(&q->vars))
127 red_start_of_idle_period(&q->vars);
128 }
129 return skb;
130 }
131
132 static struct sk_buff *red_peek(struct Qdisc *sch)
133 {
134 struct red_sched_data *q = qdisc_priv(sch);
135 struct Qdisc *child = q->qdisc;
136
137 return child->ops->peek(child);
138 }
139
140 static void red_reset(struct Qdisc *sch)
141 {
142 struct red_sched_data *q = qdisc_priv(sch);
143
144 qdisc_reset(q->qdisc);
145 sch->qstats.backlog = 0;
146 sch->q.qlen = 0;
147 red_restart(&q->vars);
148 }
149
150 static void red_destroy(struct Qdisc *sch)
151 {
152 struct red_sched_data *q = qdisc_priv(sch);
153
154 del_timer_sync(&q->adapt_timer);
155 qdisc_destroy(q->qdisc);
156 }
157
158 static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
159 [TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
160 [TCA_RED_STAB] = { .len = RED_STAB_SIZE },
161 [TCA_RED_MAX_P] = { .type = NLA_U32 },
162 };
163
164 static int red_change(struct Qdisc *sch, struct nlattr *opt)
165 {
166 struct red_sched_data *q = qdisc_priv(sch);
167 struct nlattr *tb[TCA_RED_MAX + 1];
168 struct tc_red_qopt *ctl;
169 struct Qdisc *child = NULL;
170 int err;
171 u32 max_P;
172
173 if (opt == NULL)
174 return -EINVAL;
175
176 err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy);
177 if (err < 0)
178 return err;
179
180 if (tb[TCA_RED_PARMS] == NULL ||
181 tb[TCA_RED_STAB] == NULL)
182 return -EINVAL;
183
184 max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
185
186 ctl = nla_data(tb[TCA_RED_PARMS]);
187
188 if (ctl->limit > 0) {
189 child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
190 if (IS_ERR(child))
191 return PTR_ERR(child);
192 }
193
194 sch_tree_lock(sch);
195 q->flags = ctl->flags;
196 q->limit = ctl->limit;
197 if (child) {
198 qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
199 q->qdisc->qstats.backlog);
200 qdisc_destroy(q->qdisc);
201 q->qdisc = child;
202 }
203
204 red_set_parms(&q->parms,
205 ctl->qth_min, ctl->qth_max, ctl->Wlog,
206 ctl->Plog, ctl->Scell_log,
207 nla_data(tb[TCA_RED_STAB]),
208 max_P);
209 red_set_vars(&q->vars);
210
211 del_timer(&q->adapt_timer);
212 if (ctl->flags & TC_RED_ADAPTATIVE)
213 mod_timer(&q->adapt_timer, jiffies + HZ/2);
214
215 if (!q->qdisc->q.qlen)
216 red_start_of_idle_period(&q->vars);
217
218 sch_tree_unlock(sch);
219 return 0;
220 }
221
222 static inline void red_adaptative_timer(unsigned long arg)
223 {
224 struct Qdisc *sch = (struct Qdisc *)arg;
225 struct red_sched_data *q = qdisc_priv(sch);
226 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
227
228 spin_lock(root_lock);
229 red_adaptative_algo(&q->parms, &q->vars);
230 mod_timer(&q->adapt_timer, jiffies + HZ/2);
231 spin_unlock(root_lock);
232 }
233
234 static int red_init(struct Qdisc *sch, struct nlattr *opt)
235 {
236 struct red_sched_data *q = qdisc_priv(sch);
237
238 q->qdisc = &noop_qdisc;
239 setup_timer(&q->adapt_timer, red_adaptative_timer, (unsigned long)sch);
240 return red_change(sch, opt);
241 }
242
243 static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
244 {
245 struct red_sched_data *q = qdisc_priv(sch);
246 struct nlattr *opts = NULL;
247 struct tc_red_qopt opt = {
248 .limit = q->limit,
249 .flags = q->flags,
250 .qth_min = q->parms.qth_min >> q->parms.Wlog,
251 .qth_max = q->parms.qth_max >> q->parms.Wlog,
252 .Wlog = q->parms.Wlog,
253 .Plog = q->parms.Plog,
254 .Scell_log = q->parms.Scell_log,
255 };
256
257 sch->qstats.backlog = q->qdisc->qstats.backlog;
258 opts = nla_nest_start(skb, TCA_OPTIONS);
259 if (opts == NULL)
260 goto nla_put_failure;
261 if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
262 nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
263 goto nla_put_failure;
264 return nla_nest_end(skb, opts);
265
266 nla_put_failure:
267 nla_nest_cancel(skb, opts);
268 return -EMSGSIZE;
269 }
270
271 static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
272 {
273 struct red_sched_data *q = qdisc_priv(sch);
274 struct tc_red_xstats st = {
275 .early = q->stats.prob_drop + q->stats.forced_drop,
276 .pdrop = q->stats.pdrop,
277 .other = q->stats.other,
278 .marked = q->stats.prob_mark + q->stats.forced_mark,
279 };
280
281 return gnet_stats_copy_app(d, &st, sizeof(st));
282 }
283
284 static int red_dump_class(struct Qdisc *sch, unsigned long cl,
285 struct sk_buff *skb, struct tcmsg *tcm)
286 {
287 struct red_sched_data *q = qdisc_priv(sch);
288
289 tcm->tcm_handle |= TC_H_MIN(1);
290 tcm->tcm_info = q->qdisc->handle;
291 return 0;
292 }
293
294 static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
295 struct Qdisc **old)
296 {
297 struct red_sched_data *q = qdisc_priv(sch);
298
299 if (new == NULL)
300 new = &noop_qdisc;
301
302 *old = qdisc_replace(sch, new, &q->qdisc);
303 return 0;
304 }
305
306 static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
307 {
308 struct red_sched_data *q = qdisc_priv(sch);
309 return q->qdisc;
310 }
311
312 static unsigned long red_get(struct Qdisc *sch, u32 classid)
313 {
314 return 1;
315 }
316
317 static void red_put(struct Qdisc *sch, unsigned long arg)
318 {
319 }
320
321 static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
322 {
323 if (!walker->stop) {
324 if (walker->count >= walker->skip)
325 if (walker->fn(sch, 1, walker) < 0) {
326 walker->stop = 1;
327 return;
328 }
329 walker->count++;
330 }
331 }
332
333 static const struct Qdisc_class_ops red_class_ops = {
334 .graft = red_graft,
335 .leaf = red_leaf,
336 .get = red_get,
337 .put = red_put,
338 .walk = red_walk,
339 .dump = red_dump_class,
340 };
341
342 static struct Qdisc_ops red_qdisc_ops __read_mostly = {
343 .id = "red",
344 .priv_size = sizeof(struct red_sched_data),
345 .cl_ops = &red_class_ops,
346 .enqueue = red_enqueue,
347 .dequeue = red_dequeue,
348 .peek = red_peek,
349 .init = red_init,
350 .reset = red_reset,
351 .destroy = red_destroy,
352 .change = red_change,
353 .dump = red_dump,
354 .dump_stats = red_dump_stats,
355 .owner = THIS_MODULE,
356 };
357
358 static int __init red_module_init(void)
359 {
360 return register_qdisc(&red_qdisc_ops);
361 }
362
363 static void __exit red_module_exit(void)
364 {
365 unregister_qdisc(&red_qdisc_ops);
366 }
367
368 module_init(red_module_init)
369 module_exit(red_module_exit)
370
371 MODULE_LICENSE("GPL");
Linux with added FPC-III support