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1 | #ifndef __RES_COUNTER_H__ |
2 | #define __RES_COUNTER_H__ | |
3 | ||
4 | /* | |
5 | * Resource Counters | |
6 | * Contain common data types and routines for resource accounting | |
7 | * | |
8 | * Copyright 2007 OpenVZ SWsoft Inc | |
9 | * | |
10 | * Author: Pavel Emelianov <xemul@openvz.org> | |
11 | * | |
45ce80fb | 12 | * See Documentation/cgroups/resource_counter.txt for more |
faebe9fd | 13 | * info about what this counter is. |
e552b661 PE |
14 | */ |
15 | ||
16 | #include <linux/cgroup.h> | |
17 | ||
18 | /* | |
19 | * The core object. the cgroup that wishes to account for some | |
20 | * resource may include this counter into its structures and use | |
21 | * the helpers described beyond | |
22 | */ | |
23 | ||
24 | struct res_counter { | |
25 | /* | |
26 | * the current resource consumption level | |
27 | */ | |
0eea1030 | 28 | unsigned long long usage; |
c84872e1 PE |
29 | /* |
30 | * the maximal value of the usage from the counter creation | |
31 | */ | |
32 | unsigned long long max_usage; | |
e552b661 PE |
33 | /* |
34 | * the limit that usage cannot exceed | |
35 | */ | |
0eea1030 | 36 | unsigned long long limit; |
296c81d8 BS |
37 | /* |
38 | * the limit that usage can be exceed | |
39 | */ | |
40 | unsigned long long soft_limit; | |
e552b661 PE |
41 | /* |
42 | * the number of unsuccessful attempts to consume the resource | |
43 | */ | |
0eea1030 | 44 | unsigned long long failcnt; |
e552b661 PE |
45 | /* |
46 | * the lock to protect all of the above. | |
47 | * the routines below consider this to be IRQ-safe | |
48 | */ | |
49 | spinlock_t lock; | |
28dbc4b6 BS |
50 | /* |
51 | * Parent counter, used for hierarchial resource accounting | |
52 | */ | |
53 | struct res_counter *parent; | |
e552b661 PE |
54 | }; |
55 | ||
c5b947b2 DN |
56 | #define RESOURCE_MAX (unsigned long long)LLONG_MAX |
57 | ||
2c7eabf3 | 58 | /** |
e552b661 | 59 | * Helpers to interact with userspace |
2c7eabf3 | 60 | * res_counter_read_u64() - returns the value of the specified member. |
e552b661 PE |
61 | * res_counter_read/_write - put/get the specified fields from the |
62 | * res_counter struct to/from the user | |
63 | * | |
64 | * @counter: the counter in question | |
65 | * @member: the field to work with (see RES_xxx below) | |
66 | * @buf: the buffer to opeate on,... | |
67 | * @nbytes: its size... | |
68 | * @pos: and the offset. | |
69 | */ | |
70 | ||
2c7eabf3 PM |
71 | u64 res_counter_read_u64(struct res_counter *counter, int member); |
72 | ||
e552b661 | 73 | ssize_t res_counter_read(struct res_counter *counter, int member, |
0eea1030 BS |
74 | const char __user *buf, size_t nbytes, loff_t *pos, |
75 | int (*read_strategy)(unsigned long long val, char *s)); | |
856c13aa PM |
76 | |
77 | typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val); | |
78 | ||
79 | int res_counter_memparse_write_strategy(const char *buf, | |
80 | unsigned long long *res); | |
81 | ||
82 | int res_counter_write(struct res_counter *counter, int member, | |
83 | const char *buffer, write_strategy_fn write_strategy); | |
e552b661 PE |
84 | |
85 | /* | |
86 | * the field descriptors. one for each member of res_counter | |
87 | */ | |
88 | ||
89 | enum { | |
90 | RES_USAGE, | |
c84872e1 | 91 | RES_MAX_USAGE, |
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92 | RES_LIMIT, |
93 | RES_FAILCNT, | |
296c81d8 | 94 | RES_SOFT_LIMIT, |
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95 | }; |
96 | ||
97 | /* | |
98 | * helpers for accounting | |
99 | */ | |
100 | ||
28dbc4b6 | 101 | void res_counter_init(struct res_counter *counter, struct res_counter *parent); |
e552b661 PE |
102 | |
103 | /* | |
104 | * charge - try to consume more resource. | |
105 | * | |
106 | * @counter: the counter | |
107 | * @val: the amount of the resource. each controller defines its own | |
108 | * units, e.g. numbers, bytes, Kbytes, etc | |
109 | * | |
110 | * returns 0 on success and <0 if the counter->usage will exceed the | |
111 | * counter->limit _locked call expects the counter->lock to be taken | |
112 | */ | |
113 | ||
f2992db2 PE |
114 | int __must_check res_counter_charge_locked(struct res_counter *counter, |
115 | unsigned long val); | |
116 | int __must_check res_counter_charge(struct res_counter *counter, | |
4e649152 | 117 | unsigned long val, struct res_counter **limit_fail_at); |
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118 | |
119 | /* | |
120 | * uncharge - tell that some portion of the resource is released | |
121 | * | |
122 | * @counter: the counter | |
123 | * @val: the amount of the resource | |
124 | * | |
125 | * these calls check for usage underflow and show a warning on the console | |
126 | * _locked call expects the counter->lock to be taken | |
127 | */ | |
128 | ||
129 | void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val); | |
4e649152 | 130 | void res_counter_uncharge(struct res_counter *counter, unsigned long val); |
e552b661 | 131 | |
66e1707b BS |
132 | static inline bool res_counter_limit_check_locked(struct res_counter *cnt) |
133 | { | |
134 | if (cnt->usage < cnt->limit) | |
135 | return true; | |
136 | ||
137 | return false; | |
138 | } | |
139 | ||
296c81d8 BS |
140 | static inline bool res_counter_soft_limit_check_locked(struct res_counter *cnt) |
141 | { | |
142 | if (cnt->usage < cnt->soft_limit) | |
143 | return true; | |
144 | ||
145 | return false; | |
146 | } | |
147 | ||
148 | /** | |
149 | * Get the difference between the usage and the soft limit | |
150 | * @cnt: The counter | |
151 | * | |
152 | * Returns 0 if usage is less than or equal to soft limit | |
153 | * The difference between usage and soft limit, otherwise. | |
154 | */ | |
155 | static inline unsigned long long | |
156 | res_counter_soft_limit_excess(struct res_counter *cnt) | |
157 | { | |
158 | unsigned long long excess; | |
159 | unsigned long flags; | |
160 | ||
161 | spin_lock_irqsave(&cnt->lock, flags); | |
162 | if (cnt->usage <= cnt->soft_limit) | |
163 | excess = 0; | |
164 | else | |
165 | excess = cnt->usage - cnt->soft_limit; | |
166 | spin_unlock_irqrestore(&cnt->lock, flags); | |
167 | return excess; | |
168 | } | |
169 | ||
66e1707b BS |
170 | /* |
171 | * Helper function to detect if the cgroup is within it's limit or | |
172 | * not. It's currently called from cgroup_rss_prepare() | |
173 | */ | |
174 | static inline bool res_counter_check_under_limit(struct res_counter *cnt) | |
175 | { | |
176 | bool ret; | |
177 | unsigned long flags; | |
178 | ||
179 | spin_lock_irqsave(&cnt->lock, flags); | |
180 | ret = res_counter_limit_check_locked(cnt); | |
181 | spin_unlock_irqrestore(&cnt->lock, flags); | |
182 | return ret; | |
183 | } | |
184 | ||
296c81d8 BS |
185 | static inline bool res_counter_check_under_soft_limit(struct res_counter *cnt) |
186 | { | |
187 | bool ret; | |
188 | unsigned long flags; | |
189 | ||
190 | spin_lock_irqsave(&cnt->lock, flags); | |
191 | ret = res_counter_soft_limit_check_locked(cnt); | |
192 | spin_unlock_irqrestore(&cnt->lock, flags); | |
193 | return ret; | |
194 | } | |
195 | ||
c84872e1 PE |
196 | static inline void res_counter_reset_max(struct res_counter *cnt) |
197 | { | |
198 | unsigned long flags; | |
199 | ||
200 | spin_lock_irqsave(&cnt->lock, flags); | |
201 | cnt->max_usage = cnt->usage; | |
202 | spin_unlock_irqrestore(&cnt->lock, flags); | |
203 | } | |
204 | ||
29f2a4da PE |
205 | static inline void res_counter_reset_failcnt(struct res_counter *cnt) |
206 | { | |
207 | unsigned long flags; | |
208 | ||
209 | spin_lock_irqsave(&cnt->lock, flags); | |
210 | cnt->failcnt = 0; | |
211 | spin_unlock_irqrestore(&cnt->lock, flags); | |
212 | } | |
12b98044 KH |
213 | |
214 | static inline int res_counter_set_limit(struct res_counter *cnt, | |
215 | unsigned long long limit) | |
216 | { | |
217 | unsigned long flags; | |
218 | int ret = -EBUSY; | |
219 | ||
220 | spin_lock_irqsave(&cnt->lock, flags); | |
11d55d2c | 221 | if (cnt->usage <= limit) { |
12b98044 KH |
222 | cnt->limit = limit; |
223 | ret = 0; | |
224 | } | |
225 | spin_unlock_irqrestore(&cnt->lock, flags); | |
226 | return ret; | |
227 | } | |
228 | ||
296c81d8 BS |
229 | static inline int |
230 | res_counter_set_soft_limit(struct res_counter *cnt, | |
231 | unsigned long long soft_limit) | |
232 | { | |
233 | unsigned long flags; | |
234 | ||
235 | spin_lock_irqsave(&cnt->lock, flags); | |
236 | cnt->soft_limit = soft_limit; | |
237 | spin_unlock_irqrestore(&cnt->lock, flags); | |
238 | return 0; | |
239 | } | |
240 | ||
e552b661 | 241 | #endif |