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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 | * | |
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12 | * See Documentation/controllers/resource_counter.txt for more |
13 | * info about what this counter is. | |
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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; |
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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; |
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37 | /* |
38 | * the number of unsuccessful attempts to consume the resource | |
39 | */ | |
0eea1030 | 40 | unsigned long long failcnt; |
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41 | /* |
42 | * the lock to protect all of the above. | |
43 | * the routines below consider this to be IRQ-safe | |
44 | */ | |
45 | spinlock_t lock; | |
46 | }; | |
47 | ||
2c7eabf3 | 48 | /** |
e552b661 | 49 | * Helpers to interact with userspace |
2c7eabf3 | 50 | * res_counter_read_u64() - returns the value of the specified member. |
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51 | * res_counter_read/_write - put/get the specified fields from the |
52 | * res_counter struct to/from the user | |
53 | * | |
54 | * @counter: the counter in question | |
55 | * @member: the field to work with (see RES_xxx below) | |
56 | * @buf: the buffer to opeate on,... | |
57 | * @nbytes: its size... | |
58 | * @pos: and the offset. | |
59 | */ | |
60 | ||
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61 | u64 res_counter_read_u64(struct res_counter *counter, int member); |
62 | ||
e552b661 | 63 | ssize_t res_counter_read(struct res_counter *counter, int member, |
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64 | const char __user *buf, size_t nbytes, loff_t *pos, |
65 | int (*read_strategy)(unsigned long long val, char *s)); | |
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66 | |
67 | typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val); | |
68 | ||
69 | int res_counter_memparse_write_strategy(const char *buf, | |
70 | unsigned long long *res); | |
71 | ||
72 | int res_counter_write(struct res_counter *counter, int member, | |
73 | const char *buffer, write_strategy_fn write_strategy); | |
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74 | |
75 | /* | |
76 | * the field descriptors. one for each member of res_counter | |
77 | */ | |
78 | ||
79 | enum { | |
80 | RES_USAGE, | |
c84872e1 | 81 | RES_MAX_USAGE, |
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82 | RES_LIMIT, |
83 | RES_FAILCNT, | |
84 | }; | |
85 | ||
86 | /* | |
87 | * helpers for accounting | |
88 | */ | |
89 | ||
90 | void res_counter_init(struct res_counter *counter); | |
91 | ||
92 | /* | |
93 | * charge - try to consume more resource. | |
94 | * | |
95 | * @counter: the counter | |
96 | * @val: the amount of the resource. each controller defines its own | |
97 | * units, e.g. numbers, bytes, Kbytes, etc | |
98 | * | |
99 | * returns 0 on success and <0 if the counter->usage will exceed the | |
100 | * counter->limit _locked call expects the counter->lock to be taken | |
101 | */ | |
102 | ||
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103 | int __must_check res_counter_charge_locked(struct res_counter *counter, |
104 | unsigned long val); | |
105 | int __must_check res_counter_charge(struct res_counter *counter, | |
106 | unsigned long val); | |
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107 | |
108 | /* | |
109 | * uncharge - tell that some portion of the resource is released | |
110 | * | |
111 | * @counter: the counter | |
112 | * @val: the amount of the resource | |
113 | * | |
114 | * these calls check for usage underflow and show a warning on the console | |
115 | * _locked call expects the counter->lock to be taken | |
116 | */ | |
117 | ||
118 | void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val); | |
119 | void res_counter_uncharge(struct res_counter *counter, unsigned long val); | |
120 | ||
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121 | static inline bool res_counter_limit_check_locked(struct res_counter *cnt) |
122 | { | |
123 | if (cnt->usage < cnt->limit) | |
124 | return true; | |
125 | ||
126 | return false; | |
127 | } | |
128 | ||
129 | /* | |
130 | * Helper function to detect if the cgroup is within it's limit or | |
131 | * not. It's currently called from cgroup_rss_prepare() | |
132 | */ | |
133 | static inline bool res_counter_check_under_limit(struct res_counter *cnt) | |
134 | { | |
135 | bool ret; | |
136 | unsigned long flags; | |
137 | ||
138 | spin_lock_irqsave(&cnt->lock, flags); | |
139 | ret = res_counter_limit_check_locked(cnt); | |
140 | spin_unlock_irqrestore(&cnt->lock, flags); | |
141 | return ret; | |
142 | } | |
143 | ||
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144 | static inline void res_counter_reset_max(struct res_counter *cnt) |
145 | { | |
146 | unsigned long flags; | |
147 | ||
148 | spin_lock_irqsave(&cnt->lock, flags); | |
149 | cnt->max_usage = cnt->usage; | |
150 | spin_unlock_irqrestore(&cnt->lock, flags); | |
151 | } | |
152 | ||
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153 | static inline void res_counter_reset_failcnt(struct res_counter *cnt) |
154 | { | |
155 | unsigned long flags; | |
156 | ||
157 | spin_lock_irqsave(&cnt->lock, flags); | |
158 | cnt->failcnt = 0; | |
159 | spin_unlock_irqrestore(&cnt->lock, flags); | |
160 | } | |
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161 | |
162 | static inline int res_counter_set_limit(struct res_counter *cnt, | |
163 | unsigned long long limit) | |
164 | { | |
165 | unsigned long flags; | |
166 | int ret = -EBUSY; | |
167 | ||
168 | spin_lock_irqsave(&cnt->lock, flags); | |
11d55d2c | 169 | if (cnt->usage <= limit) { |
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170 | cnt->limit = limit; |
171 | ret = 0; | |
172 | } | |
173 | spin_unlock_irqrestore(&cnt->lock, flags); | |
174 | return ret; | |
175 | } | |
176 | ||
e552b661 | 177 | #endif |