aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/res_counter.h
blob: 5ae8456d967010b8cb35b1d861d28a487e2103ba (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
#ifndef __RES_COUNTER_H__
#define __RES_COUNTER_H__

/*
 * Resource Counters
 * Contain common data types and routines for resource accounting
 *
 * Copyright 2007 OpenVZ SWsoft Inc
 *
 * Author: Pavel Emelianov <xemul@openvz.org>
 *
 * See Documentation/cgroups/resource_counter.txt for more
 * info about what this counter is.
 */

#include <linux/cgroup.h>

/*
 * The core object. the cgroup that wishes to account for some
 * resource may include this counter into its structures and use
 * the helpers described beyond
 */

struct res_counter {
	/*
	 * the current resource consumption level
	 */
	unsigned long long usage;
	/*
	 * the maximal value of the usage from the counter creation
	 */
	unsigned long long max_usage;
	/*
	 * the limit that usage cannot exceed
	 */
	unsigned long long limit;
	/*
	 * the limit that usage can be exceed
	 */
	unsigned long long soft_limit;
	/*
	 * the number of unsuccessful attempts to consume the resource
	 */
	unsigned long long failcnt;
	/*
	 * the lock to protect all of the above.
	 * the routines below consider this to be IRQ-safe
	 */
	spinlock_t lock;
	/*
	 * Parent counter, used for hierarchial resource accounting
	 */
	struct res_counter *parent;
};

#define RESOURCE_MAX (unsigned long long)LLONG_MAX

/**
 * Helpers to interact with userspace
 * res_counter_read_u64() - returns the value of the specified member.
 * res_counter_read/_write - put/get the specified fields from the
 * res_counter struct to/from the user
 *
 * @counter:     the counter in question
 * @member:  the field to work with (see RES_xxx below)
 * @buf:     the buffer to opeate on,...
 * @nbytes:  its size...
 * @pos:     and the offset.
 */

u64 res_counter_read_u64(struct res_counter *counter, int member);

ssize_t res_counter_read(struct res_counter *counter, int member,
		const char __user *buf, size_t nbytes, loff_t *pos,
		int (*read_strategy)(unsigned long long val, char *s));

int res_counter_memparse_write_strategy(const char *buf,
					unsigned long long *res);

/*
 * the field descriptors. one for each member of res_counter
 */

enum {
	RES_USAGE,
	RES_MAX_USAGE,
	RES_LIMIT,
	RES_FAILCNT,
	RES_SOFT_LIMIT,
};

/*
 * helpers for accounting
 */

void res_counter_init(struct res_counter *counter, struct res_counter *parent);

/*
 * charge - try to consume more resource.
 *
 * @counter: the counter
 * @val: the amount of the resource. each controller defines its own
 *       units, e.g. numbers, bytes, Kbytes, etc
 *
 * returns 0 on success and <0 if the counter->usage will exceed the
 * counter->limit _locked call expects the counter->lock to be taken
 *
 * charge_nofail works the same, except that it charges the resource
 * counter unconditionally, and returns < 0 if the after the current
 * charge we are over limit.
 */

int __must_check res_counter_charge_locked(struct res_counter *counter,
					   unsigned long val, bool force);
int __must_check res_counter_charge(struct res_counter *counter,
		unsigned long val, struct res_counter **limit_fail_at);
int res_counter_charge_nofail(struct res_counter *counter,
		unsigned long val, struct res_counter **limit_fail_at);

/*
 * uncharge - tell that some portion of the resource is released
 *
 * @counter: the counter
 * @val: the amount of the resource
 *
 * these calls check for usage underflow and show a warning on the console
 * _locked call expects the counter->lock to be taken
 *
 * returns the total charges still present in @counter.
 */

u64 res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
u64 res_counter_uncharge(struct res_counter *counter, unsigned long val);

u64 res_counter_uncharge_until(struct res_counter *counter,
			       struct res_counter *top,
			       unsigned long val);
/**
 * res_counter_margin - calculate chargeable space of a counter
 * @cnt: the counter
 *
 * Returns the difference between the hard limit and the current usage
 * of resource counter @cnt.
 */
static inline unsigned long long res_counter_margin(struct res_counter *cnt)
{
	unsigned long long margin;
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	if (cnt->limit > cnt->usage)
		margin = cnt->limit - cnt->usage;
	else
		margin = 0;
	spin_unlock_irqrestore(&cnt->lock, flags);
	return margin;
}

/**
 * Get the difference between the usage and the soft limit
 * @cnt: The counter
 *
 * Returns 0 if usage is less than or equal to soft limit
 * The difference between usage and soft limit, otherwise.
 */
static inline unsigned long long
res_counter_soft_limit_excess(struct res_counter *cnt)
{
	unsigned long long excess;
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	if (cnt->usage <= cnt->soft_limit)
		excess = 0;
	else
		excess = cnt->usage - cnt->soft_limit;
	spin_unlock_irqrestore(&cnt->lock, flags);
	return excess;
}

static inline void res_counter_reset_max(struct res_counter *cnt)
{
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	cnt->max_usage = cnt->usage;
	spin_unlock_irqrestore(&cnt->lock, flags);
}

static inline void res_counter_reset_failcnt(struct res_counter *cnt)
{
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	cnt->failcnt = 0;
	spin_unlock_irqrestore(&cnt->lock, flags);
}

static inline int res_counter_set_limit(struct res_counter *cnt,
		unsigned long long limit)
{
	unsigned long flags;
	int ret = -EBUSY;

	spin_lock_irqsave(&cnt->lock, flags);
	if (cnt->usage <= limit) {
		cnt->limit = limit;
		ret = 0;
	}
	spin_unlock_irqrestore(&cnt->lock, flags);
	return ret;
}

static inline int
res_counter_set_soft_limit(struct res_counter *cnt,
				unsigned long long soft_limit)
{
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	cnt->soft_limit = soft_limit;
	spin_unlock_irqrestore(&cnt->lock, flags);
	return 0;
}

#endif

Privacy Policy