summaryrefslogtreecommitdiffstats
path: root/net/sched/sch_multiq.c
blob: 7410ce4d03213d315696ec933722edbc6c542f2a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
/*
 * Copyright (c) 2008, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * Author: Alexander Duyck <alexander.h.duyck@intel.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>

struct multiq_sched_data {
	u16 bands;
	u16 max_bands;
	u16 curband;
	struct tcf_proto __rcu *filter_list;
	struct tcf_block *block;
	struct Qdisc **queues;
};


static struct Qdisc *
multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	u32 band;
	struct tcf_result res;
	struct tcf_proto *fl = rcu_dereference_bh(q->filter_list);
	int err;

	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
	err = tcf_classify(skb, fl, &res, false);
#ifdef CONFIG_NET_CLS_ACT
	switch (err) {
	case TC_ACT_STOLEN:
	case TC_ACT_QUEUED:
	case TC_ACT_TRAP:
		*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
		/* fall through */
	case TC_ACT_SHOT:
		return NULL;
	}
#endif
	band = skb_get_queue_mapping(skb);

	if (band >= q->bands)
		return q->queues[0];

	return q->queues[band];
}

static int
multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
	       struct sk_buff **to_free)
{
	struct Qdisc *qdisc;
	int ret;

	qdisc = multiq_classify(skb, sch, &ret);
#ifdef CONFIG_NET_CLS_ACT
	if (qdisc == NULL) {

		if (ret & __NET_XMIT_BYPASS)
			qdisc_qstats_drop(sch);
		__qdisc_drop(skb, to_free);
		return ret;
	}
#endif

	ret = qdisc_enqueue(skb, qdisc, to_free);
	if (ret == NET_XMIT_SUCCESS) {
		sch->q.qlen++;
		return NET_XMIT_SUCCESS;
	}
	if (net_xmit_drop_count(ret))
		qdisc_qstats_drop(sch);
	return ret;
}

static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	struct Qdisc *qdisc;
	struct sk_buff *skb;
	int band;

	for (band = 0; band < q->bands; band++) {
		/* cycle through bands to ensure fairness */
		q->curband++;
		if (q->curband >= q->bands)
			q->curband = 0;

		/* Check that target subqueue is available before
		 * pulling an skb to avoid head-of-line blocking.
		 */
		if (!netif_xmit_stopped(
		    netdev_get_tx_queue(qdisc_dev(sch), q->curband))) {
			qdisc = q->queues[q->curband];
			skb = qdisc->dequeue(qdisc);
			if (skb) {
				qdisc_bstats_update(sch, skb);
				sch->q.qlen--;
				return skb;
			}
		}
	}
	return NULL;

}

static struct sk_buff *multiq_peek(struct Qdisc *sch)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	unsigned int curband = q->curband;
	struct Qdisc *qdisc;
	struct sk_buff *skb;
	int band;

	for (band = 0; band < q->bands; band++) {
		/* cycle through bands to ensure fairness */
		curband++;
		if (curband >= q->bands)
			curband = 0;

		/* Check that target subqueue is available before
		 * pulling an skb to avoid head-of-line blocking.
		 */
		if (!netif_xmit_stopped(
		    netdev_get_tx_queue(qdisc_dev(sch), curband))) {
			qdisc = q->queues[curband];
			skb = qdisc->ops->peek(qdisc);
			if (skb)
				return skb;
		}
	}
	return NULL;

}

static void
multiq_reset(struct Qdisc *sch)
{
	u16 band;
	struct multiq_sched_data *q = qdisc_priv(sch);

	for (band = 0; band < q->bands; band++)
		qdisc_reset(q->queues[band]);
	sch->q.qlen = 0;
	q->curband = 0;
}

static void
multiq_destroy(struct Qdisc *sch)
{
	int band;
	struct multiq_sched_data *q = qdisc_priv(sch);

	tcf_block_put(q->block);
	for (band = 0; band < q->bands; band++)
		qdisc_put(q->queues[band]);

	kfree(q->queues);
}

static int multiq_tune(struct Qdisc *sch, struct nlattr *opt,
		       struct netlink_ext_ack *extack)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	struct tc_multiq_qopt *qopt;
	int i;

	if (!netif_is_multiqueue(qdisc_dev(sch)))
		return -EOPNOTSUPP;
	if (nla_len(opt) < sizeof(*qopt))
		return -EINVAL;

	qopt = nla_data(opt);

	qopt->bands = qdisc_dev(sch)->real_num_tx_queues;

	sch_tree_lock(sch);
	q->bands = qopt->bands;
	for (i = q->bands; i < q->max_bands; i++) {
		if (q->queues[i] != &noop_qdisc) {
			struct Qdisc *child = q->queues[i];
			q->queues[i] = &noop_qdisc;
			qdisc_tree_reduce_backlog(child, child->q.qlen,
						  child->qstats.backlog);
			qdisc_put(child);
		}
	}

	sch_tree_unlock(sch);

	for (i = 0; i < q->bands; i++) {
		if (q->queues[i] == &noop_qdisc) {
			struct Qdisc *child, *old;
			child = qdisc_create_dflt(sch->dev_queue,
						  &pfifo_qdisc_ops,
						  TC_H_MAKE(sch->handle,
							    i + 1), extack);
			if (child) {
				sch_tree_lock(sch);
				old = q->queues[i];
				q->queues[i] = child;
				if (child != &noop_qdisc)
					qdisc_hash_add(child, true);

				if (old != &noop_qdisc) {
					qdisc_tree_reduce_backlog(old,
								  old->q.qlen,
								  old->qstats.backlog);
					qdisc_put(old);
				}
				sch_tree_unlock(sch);
			}
		}
	}
	return 0;
}

static int multiq_init(struct Qdisc *sch, struct nlattr *opt,
		       struct netlink_ext_ack *extack)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	int i, err;

	q->queues = NULL;

	if (!opt)
		return -EINVAL;

	err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
	if (err)
		return err;

	q->max_bands = qdisc_dev(sch)->num_tx_queues;

	q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
	if (!q->queues)
		return -ENOBUFS;
	for (i = 0; i < q->max_bands; i++)
		q->queues[i] = &noop_qdisc;

	return multiq_tune(sch, opt, extack);
}

static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	unsigned char *b = skb_tail_pointer(skb);
	struct tc_multiq_qopt opt;

	opt.bands = q->bands;
	opt.max_bands = q->max_bands;

	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
		goto nla_put_failure;

	return skb->len;

nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
			struct Qdisc **old, struct netlink_ext_ack *extack)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	unsigned long band = arg - 1;

	if (new == NULL)
		new = &noop_qdisc;

	*old = qdisc_replace(sch, new, &q->queues[band]);
	return 0;
}

static struct Qdisc *
multiq_leaf(struct Qdisc *sch, unsigned long arg)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	unsigned long band = arg - 1;

	return q->queues[band];
}

static unsigned long multiq_find(struct Qdisc *sch, u32 classid)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	unsigned long band = TC_H_MIN(classid);

	if (band - 1 >= q->bands)
		return 0;
	return band;
}

static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
				 u32 classid)
{
	return multiq_find(sch, classid);
}


static void multiq_unbind(struct Qdisc *q, unsigned long cl)
{
}

static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
			     struct sk_buff *skb, struct tcmsg *tcm)
{
	struct multiq_sched_data *q = qdisc_priv(sch);

	tcm->tcm_handle |= TC_H_MIN(cl);
	tcm->tcm_info = q->queues[cl - 1]->handle;
	return 0;
}

static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
				 struct gnet_dump *d)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	struct Qdisc *cl_q;

	cl_q = q->queues[cl - 1];
	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
				  d, NULL, &cl_q->bstats) < 0 ||
	    gnet_stats_copy_queue(d, NULL, &cl_q->qstats, cl_q->q.qlen) < 0)
		return -1;

	return 0;
}

static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
	struct multiq_sched_data *q = qdisc_priv(sch);
	int band;

	if (arg->stop)
		return;

	for (band = 0; band < q->bands; band++) {
		if (arg->count < arg->skip) {
			arg->count++;
			continue;
		}
		if (arg->fn(sch, band + 1, arg) < 0) {
			arg->stop = 1;
			break;
		}
		arg->count++;
	}
}

static struct tcf_block *multiq_tcf_block(struct Qdisc *sch, unsigned long cl,
					  struct netlink_ext_ack *extack)
{
	struct multiq_sched_data *q = qdisc_priv(sch);

	if (cl)
		return NULL;
	return q->block;
}

static const struct Qdisc_class_ops multiq_class_ops = {
	.graft		=	multiq_graft,
	.leaf		=	multiq_leaf,
	.find		=	multiq_find,
	.walk		=	multiq_walk,
	.tcf_block	=	multiq_tcf_block,
	.bind_tcf	=	multiq_bind,
	.unbind_tcf	=	multiq_unbind,
	.dump		=	multiq_dump_class,
	.dump_stats	=	multiq_dump_class_stats,
};

static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
	.next		=	NULL,
	.cl_ops		=	&multiq_class_ops,
	.id		=	"multiq",
	.priv_size	=	sizeof(struct multiq_sched_data),
	.enqueue	=	multiq_enqueue,
	.dequeue	=	multiq_dequeue,
	.peek		=	multiq_peek,
	.init		=	multiq_init,
	.reset		=	multiq_reset,
	.destroy	=	multiq_destroy,
	.change		=	multiq_tune,
	.dump		=	multiq_dump,
	.owner		=	THIS_MODULE,
};

static int __init multiq_module_init(void)
{
	return register_qdisc(&multiq_qdisc_ops);
}

static void __exit multiq_module_exit(void)
{
	unregister_qdisc(&multiq_qdisc_ops);
}

module_init(multiq_module_init)
module_exit(multiq_module_exit)

MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud