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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; | |
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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; | |
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41 | /* |
42 | * the number of unsuccessful attempts to consume the resource | |
43 | */ | |
0eea1030 | 44 | unsigned long long failcnt; |
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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; | |
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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); | |
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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); |
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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, | |
f64c3f54 BS |
117 | unsigned long val, struct res_counter **limit_fail_at, |
118 | struct res_counter **soft_limit_at); | |
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119 | |
120 | /* | |
121 | * uncharge - tell that some portion of the resource is released | |
122 | * | |
123 | * @counter: the counter | |
124 | * @val: the amount of the resource | |
125 | * | |
126 | * these calls check for usage underflow and show a warning on the console | |
127 | * _locked call expects the counter->lock to be taken | |
128 | */ | |
129 | ||
130 | void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val); | |
f64c3f54 BS |
131 | void res_counter_uncharge(struct res_counter *counter, unsigned long val, |
132 | bool *was_soft_limit_excess); | |
e552b661 | 133 | |
66e1707b BS |
134 | static inline bool res_counter_limit_check_locked(struct res_counter *cnt) |
135 | { | |
136 | if (cnt->usage < cnt->limit) | |
137 | return true; | |
138 | ||
139 | return false; | |
140 | } | |
141 | ||
296c81d8 BS |
142 | static inline bool res_counter_soft_limit_check_locked(struct res_counter *cnt) |
143 | { | |
144 | if (cnt->usage < cnt->soft_limit) | |
145 | return true; | |
146 | ||
147 | return false; | |
148 | } | |
149 | ||
150 | /** | |
151 | * Get the difference between the usage and the soft limit | |
152 | * @cnt: The counter | |
153 | * | |
154 | * Returns 0 if usage is less than or equal to soft limit | |
155 | * The difference between usage and soft limit, otherwise. | |
156 | */ | |
157 | static inline unsigned long long | |
158 | res_counter_soft_limit_excess(struct res_counter *cnt) | |
159 | { | |
160 | unsigned long long excess; | |
161 | unsigned long flags; | |
162 | ||
163 | spin_lock_irqsave(&cnt->lock, flags); | |
164 | if (cnt->usage <= cnt->soft_limit) | |
165 | excess = 0; | |
166 | else | |
167 | excess = cnt->usage - cnt->soft_limit; | |
168 | spin_unlock_irqrestore(&cnt->lock, flags); | |
169 | return excess; | |
170 | } | |
171 | ||
66e1707b BS |
172 | /* |
173 | * Helper function to detect if the cgroup is within it's limit or | |
174 | * not. It's currently called from cgroup_rss_prepare() | |
175 | */ | |
176 | static inline bool res_counter_check_under_limit(struct res_counter *cnt) | |
177 | { | |
178 | bool ret; | |
179 | unsigned long flags; | |
180 | ||
181 | spin_lock_irqsave(&cnt->lock, flags); | |
182 | ret = res_counter_limit_check_locked(cnt); | |
183 | spin_unlock_irqrestore(&cnt->lock, flags); | |
184 | return ret; | |
185 | } | |
186 | ||
296c81d8 BS |
187 | static inline bool res_counter_check_under_soft_limit(struct res_counter *cnt) |
188 | { | |
189 | bool ret; | |
190 | unsigned long flags; | |
191 | ||
192 | spin_lock_irqsave(&cnt->lock, flags); | |
193 | ret = res_counter_soft_limit_check_locked(cnt); | |
194 | spin_unlock_irqrestore(&cnt->lock, flags); | |
195 | return ret; | |
196 | } | |
197 | ||
c84872e1 PE |
198 | static inline void res_counter_reset_max(struct res_counter *cnt) |
199 | { | |
200 | unsigned long flags; | |
201 | ||
202 | spin_lock_irqsave(&cnt->lock, flags); | |
203 | cnt->max_usage = cnt->usage; | |
204 | spin_unlock_irqrestore(&cnt->lock, flags); | |
205 | } | |
206 | ||
29f2a4da PE |
207 | static inline void res_counter_reset_failcnt(struct res_counter *cnt) |
208 | { | |
209 | unsigned long flags; | |
210 | ||
211 | spin_lock_irqsave(&cnt->lock, flags); | |
212 | cnt->failcnt = 0; | |
213 | spin_unlock_irqrestore(&cnt->lock, flags); | |
214 | } | |
12b98044 KH |
215 | |
216 | static inline int res_counter_set_limit(struct res_counter *cnt, | |
217 | unsigned long long limit) | |
218 | { | |
219 | unsigned long flags; | |
220 | int ret = -EBUSY; | |
221 | ||
222 | spin_lock_irqsave(&cnt->lock, flags); | |
11d55d2c | 223 | if (cnt->usage <= limit) { |
12b98044 KH |
224 | cnt->limit = limit; |
225 | ret = 0; | |
226 | } | |
227 | spin_unlock_irqrestore(&cnt->lock, flags); | |
228 | return ret; | |
229 | } | |
230 | ||
296c81d8 BS |
231 | static inline int |
232 | res_counter_set_soft_limit(struct res_counter *cnt, | |
233 | unsigned long long soft_limit) | |
234 | { | |
235 | unsigned long flags; | |
236 | ||
237 | spin_lock_irqsave(&cnt->lock, flags); | |
238 | cnt->soft_limit = soft_limit; | |
239 | spin_unlock_irqrestore(&cnt->lock, flags); | |
240 | return 0; | |
241 | } | |
242 | ||
e552b661 | 243 | #endif |