summaryrefslogtreecommitdiff
path: root/include/net/fq_impl.h
blob: 9467e33dfb3642c3ea5bab26485bb06070caa9b8 (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
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2016 Qualcomm Atheros, Inc
 *
 * Based on net/sched/sch_fq_codel.c
 */
#ifndef __NET_SCHED_FQ_IMPL_H
#define __NET_SCHED_FQ_IMPL_H

#include <net/fq.h>

/* functions that are embedded into includer */


static void
__fq_adjust_removal(struct fq *fq, struct fq_flow *flow, unsigned int packets,
		    unsigned int bytes, unsigned int truesize)
{
	struct fq_tin *tin = flow->tin;
	int idx;

	tin->backlog_bytes -= bytes;
	tin->backlog_packets -= packets;
	flow->backlog -= bytes;
	fq->backlog -= packets;
	fq->memory_usage -= truesize;

	if (flow->backlog)
		return;

	if (flow == &tin->default_flow) {
		list_del_init(&tin->tin_list);
		return;
	}

	idx = flow - fq->flows;
	__clear_bit(idx, fq->flows_bitmap);
}

static void fq_adjust_removal(struct fq *fq,
			      struct fq_flow *flow,
			      struct sk_buff *skb)
{
	__fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
}

static struct sk_buff *fq_flow_dequeue(struct fq *fq,
				       struct fq_flow *flow)
{
	struct sk_buff *skb;

	lockdep_assert_held(&fq->lock);

	skb = __skb_dequeue(&flow->queue);
	if (!skb)
		return NULL;

	fq_adjust_removal(fq, flow, skb);

	return skb;
}

static int fq_flow_drop(struct fq *fq, struct fq_flow *flow,
			fq_skb_free_t free_func)
{
	unsigned int packets = 0, bytes = 0, truesize = 0;
	struct fq_tin *tin = flow->tin;
	struct sk_buff *skb;
	int pending;

	lockdep_assert_held(&fq->lock);

	pending = min_t(int, 32, skb_queue_len(&flow->queue) / 2);
	do {
		skb = __skb_dequeue(&flow->queue);
		if (!skb)
			break;

		packets++;
		bytes += skb->len;
		truesize += skb->truesize;
		free_func(fq, tin, flow, skb);
	} while (packets < pending);

	__fq_adjust_removal(fq, flow, packets, bytes, truesize);

	return packets;
}

static struct sk_buff *fq_tin_dequeue(struct fq *fq,
				      struct fq_tin *tin,
				      fq_tin_dequeue_t dequeue_func)
{
	struct fq_flow *flow;
	struct list_head *head;
	struct sk_buff *skb;

	lockdep_assert_held(&fq->lock);

begin:
	head = &tin->new_flows;
	if (list_empty(head)) {
		head = &tin->old_flows;
		if (list_empty(head))
			return NULL;
	}

	flow = list_first_entry(head, struct fq_flow, flowchain);

	if (flow->deficit <= 0) {
		flow->deficit += fq->quantum;
		list_move_tail(&flow->flowchain,
			       &tin->old_flows);
		goto begin;
	}

	skb = dequeue_func(fq, tin, flow);
	if (!skb) {
		/* force a pass through old_flows to prevent starvation */
		if ((head == &tin->new_flows) &&
		    !list_empty(&tin->old_flows)) {
			list_move_tail(&flow->flowchain, &tin->old_flows);
		} else {
			list_del_init(&flow->flowchain);
			flow->tin = NULL;
		}
		goto begin;
	}

	flow->deficit -= skb->len;
	tin->tx_bytes += skb->len;
	tin->tx_packets++;

	return skb;
}

static u32 fq_flow_idx(struct fq *fq, struct sk_buff *skb)
{
	u32 hash = skb_get_hash(skb);

	return reciprocal_scale(hash, fq->flows_cnt);
}

static struct fq_flow *fq_flow_classify(struct fq *fq,
					struct fq_tin *tin, u32 idx,
					struct sk_buff *skb)
{
	struct fq_flow *flow;

	lockdep_assert_held(&fq->lock);

	flow = &fq->flows[idx];
	if (flow->tin && flow->tin != tin) {
		flow = &tin->default_flow;
		tin->collisions++;
		fq->collisions++;
	}

	if (!flow->tin)
		tin->flows++;

	return flow;
}

static struct fq_flow *fq_find_fattest_flow(struct fq *fq)
{
	struct fq_tin *tin;
	struct fq_flow *flow = NULL;
	u32 len = 0;
	int i;

	for_each_set_bit(i, fq->flows_bitmap, fq->flows_cnt) {
		struct fq_flow *cur = &fq->flows[i];
		unsigned int cur_len;

		cur_len = cur->backlog;
		if (cur_len <= len)
			continue;

		flow = cur;
		len = cur_len;
	}

	list_for_each_entry(tin, &fq->tin_backlog, tin_list) {
		unsigned int cur_len = tin->default_flow.backlog;

		if (cur_len <= len)
			continue;

		flow = &tin->default_flow;
		len = cur_len;
	}

	return flow;
}

static void fq_tin_enqueue(struct fq *fq,
			   struct fq_tin *tin, u32 idx,
			   struct sk_buff *skb,
			   fq_skb_free_t free_func)
{
	struct fq_flow *flow;
	struct sk_buff *next;
	bool oom;

	lockdep_assert_held(&fq->lock);

	flow = fq_flow_classify(fq, tin, idx, skb);

	if (!flow->backlog) {
		if (flow != &tin->default_flow)
			__set_bit(idx, fq->flows_bitmap);
		else if (list_empty(&tin->tin_list))
			list_add(&tin->tin_list, &fq->tin_backlog);
	}

	flow->tin = tin;
	skb_list_walk_safe(skb, skb, next) {
		skb_mark_not_on_list(skb);
		flow->backlog += skb->len;
		tin->backlog_bytes += skb->len;
		tin->backlog_packets++;
		fq->memory_usage += skb->truesize;
		fq->backlog++;
		__skb_queue_tail(&flow->queue, skb);
	}

	if (list_empty(&flow->flowchain)) {
		flow->deficit = fq->quantum;
		list_add_tail(&flow->flowchain,
			      &tin->new_flows);
	}

	oom = (fq->memory_usage > fq->memory_limit);
	while (fq->backlog > fq->limit || oom) {
		flow = fq_find_fattest_flow(fq);
		if (!flow)
			return;

		if (!fq_flow_drop(fq, flow, free_func))
			return;

		flow->tin->overlimit++;
		fq->overlimit++;
		if (oom) {
			fq->overmemory++;
			oom = (fq->memory_usage > fq->memory_limit);
		}
	}
}

static void fq_flow_filter(struct fq *fq,
			   struct fq_flow *flow,
			   fq_skb_filter_t filter_func,
			   void *filter_data,
			   fq_skb_free_t free_func)
{
	struct fq_tin *tin = flow->tin;
	struct sk_buff *skb, *tmp;

	lockdep_assert_held(&fq->lock);

	skb_queue_walk_safe(&flow->queue, skb, tmp) {
		if (!filter_func(fq, tin, flow, skb, filter_data))
			continue;

		__skb_unlink(skb, &flow->queue);
		fq_adjust_removal(fq, flow, skb);
		free_func(fq, tin, flow, skb);
	}
}

static void fq_tin_filter(struct fq *fq,
			  struct fq_tin *tin,
			  fq_skb_filter_t filter_func,
			  void *filter_data,
			  fq_skb_free_t free_func)
{
	struct fq_flow *flow;

	lockdep_assert_held(&fq->lock);

	list_for_each_entry(flow, &tin->new_flows, flowchain)
		fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
	list_for_each_entry(flow, &tin->old_flows, flowchain)
		fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
}

static void fq_flow_reset(struct fq *fq,
			  struct fq_flow *flow,
			  fq_skb_free_t free_func)
{
	struct fq_tin *tin = flow->tin;
	struct sk_buff *skb;

	while ((skb = fq_flow_dequeue(fq, flow)))
		free_func(fq, tin, flow, skb);

	if (!list_empty(&flow->flowchain)) {
		list_del_init(&flow->flowchain);
		if (list_empty(&tin->new_flows) &&
		    list_empty(&tin->old_flows))
			list_del_init(&tin->tin_list);
	}

	flow->tin = NULL;

	WARN_ON_ONCE(flow->backlog);
}

static void fq_tin_reset(struct fq *fq,
			 struct fq_tin *tin,
			 fq_skb_free_t free_func)
{
	struct list_head *head;
	struct fq_flow *flow;

	for (;;) {
		head = &tin->new_flows;
		if (list_empty(head)) {
			head = &tin->old_flows;
			if (list_empty(head))
				break;
		}

		flow = list_first_entry(head, struct fq_flow, flowchain);
		fq_flow_reset(fq, flow, free_func);
	}

	WARN_ON_ONCE(!list_empty(&tin->tin_list));
	WARN_ON_ONCE(tin->backlog_bytes);
	WARN_ON_ONCE(tin->backlog_packets);
}

static void fq_flow_init(struct fq_flow *flow)
{
	INIT_LIST_HEAD(&flow->flowchain);
	__skb_queue_head_init(&flow->queue);
}

static void fq_tin_init(struct fq_tin *tin)
{
	INIT_LIST_HEAD(&tin->new_flows);
	INIT_LIST_HEAD(&tin->old_flows);
	INIT_LIST_HEAD(&tin->tin_list);
	fq_flow_init(&tin->default_flow);
}

static int fq_init(struct fq *fq, int flows_cnt)
{
	int i;

	memset(fq, 0, sizeof(fq[0]));
	spin_lock_init(&fq->lock);
	INIT_LIST_HEAD(&fq->tin_backlog);
	fq->flows_cnt = max_t(u32, flows_cnt, 1);
	fq->quantum = 300;
	fq->limit = 8192;
	fq->memory_limit = 16 << 20; /* 16 MBytes */

	fq->flows = kvcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
	if (!fq->flows)
		return -ENOMEM;

	fq->flows_bitmap = bitmap_zalloc(fq->flows_cnt, GFP_KERNEL);
	if (!fq->flows_bitmap) {
		kvfree(fq->flows);
		fq->flows = NULL;
		return -ENOMEM;
	}

	for (i = 0; i < fq->flows_cnt; i++)
		fq_flow_init(&fq->flows[i]);

	return 0;
}

static void fq_reset(struct fq *fq,
		     fq_skb_free_t free_func)
{
	int i;

	for (i = 0; i < fq->flows_cnt; i++)
		fq_flow_reset(fq, &fq->flows[i], free_func);

	kvfree(fq->flows);
	fq->flows = NULL;

	bitmap_free(fq->flows_bitmap);
	fq->flows_bitmap = NULL;
}

#endif