Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 7c1ffd6f950172c1915d8e5fa2b5e3f77e4f4c78 (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
/*
 * net/sched/gen_estimator.c	Simple rate estimator.
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *		Eric Dumazet <edumazet@google.com>
 *
 * Changes:
 *              Jamal Hadi Salim - moved it to net/core and reshulfed
 *              names to make it usable in general net subsystem.
 */

#include <linux/uaccess.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/seqlock.h>
#include <net/sock.h>
#include <net/gen_stats.h>

/* This code is NOT intended to be used for statistics collection,
 * its purpose is to provide a base for statistical multiplexing
 * for controlled load service.
 * If you need only statistics, run a user level daemon which
 * periodically reads byte counters.
 */

struct net_rate_estimator {
	struct gnet_stats_basic_packed	*bstats;
	spinlock_t		*stats_lock;
	seqcount_t		*running;
	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
	u8			ewma_log;
	u8			intvl_log; /* period : (250ms << intvl_log) */

	seqcount_t		seq;
	u32			last_packets;
	u64			last_bytes;

	u64			avpps;
	u64			avbps;

	unsigned long           next_jiffies;
	struct timer_list       timer;
	struct rcu_head		rcu;
};

static void est_fetch_counters(struct net_rate_estimator *e,
			       struct gnet_stats_basic_packed *b)
{
	if (e->stats_lock)
		spin_lock(e->stats_lock);

	__gnet_stats_copy_basic(e->running, b, e->cpu_bstats, e->bstats);

	if (e->stats_lock)
		spin_unlock(e->stats_lock);

}

static void est_timer(unsigned long arg)
{
	struct net_rate_estimator *est = (struct net_rate_estimator *)arg;
	struct gnet_stats_basic_packed b;
	u64 rate, brate;

	est_fetch_counters(est, &b);
	brate = (b.bytes - est->last_bytes) << (10 - est->ewma_log - est->intvl_log);
	brate -= (est->avbps >> est->ewma_log);

	rate = (u64)(b.packets - est->last_packets) << (10 - est->ewma_log - est->intvl_log);
	rate -= (est->avpps >> est->ewma_log);

	write_seqcount_begin(&est->seq);
	est->avbps += brate;
	est->avpps += rate;
	write_seqcount_end(&est->seq);

	est->last_bytes = b.bytes;
	est->last_packets = b.packets;

	est->next_jiffies += ((HZ/4) << est->intvl_log);

	if (unlikely(time_after_eq(jiffies, est->next_jiffies))) {
		/* Ouch... timer was delayed. */
		est->next_jiffies = jiffies + 1;
	}
	mod_timer(&est->timer, est->next_jiffies);
}

/**
 * gen_new_estimator - create a new rate estimator
 * @bstats: basic statistics
 * @cpu_bstats: bstats per cpu
 * @rate_est: rate estimator statistics
 * @stats_lock: statistics lock
 * @running: qdisc running seqcount
 * @opt: rate estimator configuration TLV
 *
 * Creates a new rate estimator with &bstats as source and &rate_est
 * as destination. A new timer with the interval specified in the
 * configuration TLV is created. Upon each interval, the latest statistics
 * will be read from &bstats and the estimated rate will be stored in
 * &rate_est with the statistics lock grabbed during this period.
 *
 * Returns 0 on success or a negative error code.
 *
 */
int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
		      struct net_rate_estimator __rcu **rate_est,
		      spinlock_t *stats_lock,
		      seqcount_t *running,
		      struct nlattr *opt)
{
	struct gnet_estimator *parm = nla_data(opt);
	struct net_rate_estimator *old, *est;
	struct gnet_stats_basic_packed b;
	int intvl_log;

	if (nla_len(opt) < sizeof(*parm))
		return -EINVAL;

	/* allowed timer periods are :
	 * -2 : 250ms,   -1 : 500ms,    0 : 1 sec
	 *  1 : 2 sec,    2 : 4 sec,    3 : 8 sec
	 */
	if (parm->interval < -2 || parm->interval > 3)
		return -EINVAL;

	est = kzalloc(sizeof(*est), GFP_KERNEL);
	if (!est)
		return -ENOBUFS;

	seqcount_init(&est->seq);
	intvl_log = parm->interval + 2;
	est->bstats = bstats;
	est->stats_lock = stats_lock;
	est->running  = running;
	est->ewma_log = parm->ewma_log;
	est->intvl_log = intvl_log;
	est->cpu_bstats = cpu_bstats;

	est_fetch_counters(est, &b);
	est->last_bytes = b.bytes;
	est->last_packets = b.packets;
	old = rcu_dereference_protected(*rate_est, 1);
	if (old) {
		del_timer_sync(&old->timer);
		est->avbps = old->avbps;
		est->avpps = old->avpps;
	}

	est->next_jiffies = jiffies + ((HZ/4) << intvl_log);
	setup_timer(&est->timer, est_timer, (unsigned long)est);
	mod_timer(&est->timer, est->next_jiffies);

	rcu_assign_pointer(*rate_est, est);
	if (old)
		kfree_rcu(old, rcu);
	return 0;
}
EXPORT_SYMBOL(gen_new_estimator);

/**
 * gen_kill_estimator - remove a rate estimator
 * @rate_est: rate estimator
 *
 * Removes the rate estimator.
 *
 */
void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est)
{
	struct net_rate_estimator *est;

	est = xchg((__force struct net_rate_estimator **)rate_est, NULL);
	if (est) {
		del_timer_sync(&est->timer);
		kfree_rcu(est, rcu);
	}
}
EXPORT_SYMBOL(gen_kill_estimator);

/**
 * gen_replace_estimator - replace rate estimator configuration
 * @bstats: basic statistics
 * @cpu_bstats: bstats per cpu
 * @rate_est: rate estimator statistics
 * @stats_lock: statistics lock
 * @running: qdisc running seqcount (might be NULL)
 * @opt: rate estimator configuration TLV
 *
 * Replaces the configuration of a rate estimator by calling
 * gen_kill_estimator() and gen_new_estimator().
 *
 * Returns 0 on success or a negative error code.
 */
int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
			  struct net_rate_estimator __rcu **rate_est,
			  spinlock_t *stats_lock,
			  seqcount_t *running, struct nlattr *opt)
{
	return gen_new_estimator(bstats, cpu_bstats, rate_est,
				 stats_lock, running, opt);
}
EXPORT_SYMBOL(gen_replace_estimator);

/**
 * gen_estimator_active - test if estimator is currently in use
 * @rate_est: rate estimator
 *
 * Returns true if estimator is active, and false if not.
 */
bool gen_estimator_active(struct net_rate_estimator __rcu **rate_est)
{
	return !!rcu_access_pointer(*rate_est);
}
EXPORT_SYMBOL(gen_estimator_active);

bool gen_estimator_read(struct net_rate_estimator __rcu **rate_est,
			struct gnet_stats_rate_est64 *sample)
{
	struct net_rate_estimator *est;
	unsigned seq;

	rcu_read_lock();
	est = rcu_dereference(*rate_est);
	if (!est) {
		rcu_read_unlock();
		return false;
	}

	do {
		seq = read_seqcount_begin(&est->seq);
		sample->bps = est->avbps >> 8;
		sample->pps = est->avpps >> 8;
	} while (read_seqcount_retry(&est->seq, seq));

	rcu_read_unlock();
	return true;
}
EXPORT_SYMBOL(gen_estimator_read);