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e552b661 PE |
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 | * | |
12 | */ | |
13 | ||
14 | #include <linux/cgroup.h> | |
15 | ||
16 | /* | |
17 | * The core object. the cgroup that wishes to account for some | |
18 | * resource may include this counter into its structures and use | |
19 | * the helpers described beyond | |
20 | */ | |
21 | ||
22 | struct res_counter { | |
23 | /* | |
24 | * the current resource consumption level | |
25 | */ | |
0eea1030 | 26 | unsigned long long usage; |
c84872e1 PE |
27 | /* |
28 | * the maximal value of the usage from the counter creation | |
29 | */ | |
30 | unsigned long long max_usage; | |
e552b661 PE |
31 | /* |
32 | * the limit that usage cannot exceed | |
33 | */ | |
0eea1030 | 34 | unsigned long long limit; |
e552b661 PE |
35 | /* |
36 | * the number of unsuccessful attempts to consume the resource | |
37 | */ | |
0eea1030 | 38 | unsigned long long failcnt; |
e552b661 PE |
39 | /* |
40 | * the lock to protect all of the above. | |
41 | * the routines below consider this to be IRQ-safe | |
42 | */ | |
43 | spinlock_t lock; | |
44 | }; | |
45 | ||
2c7eabf3 | 46 | /** |
e552b661 | 47 | * Helpers to interact with userspace |
2c7eabf3 | 48 | * res_counter_read_u64() - returns the value of the specified member. |
e552b661 PE |
49 | * res_counter_read/_write - put/get the specified fields from the |
50 | * res_counter struct to/from the user | |
51 | * | |
52 | * @counter: the counter in question | |
53 | * @member: the field to work with (see RES_xxx below) | |
54 | * @buf: the buffer to opeate on,... | |
55 | * @nbytes: its size... | |
56 | * @pos: and the offset. | |
57 | */ | |
58 | ||
2c7eabf3 PM |
59 | u64 res_counter_read_u64(struct res_counter *counter, int member); |
60 | ||
e552b661 | 61 | ssize_t res_counter_read(struct res_counter *counter, int member, |
0eea1030 BS |
62 | const char __user *buf, size_t nbytes, loff_t *pos, |
63 | int (*read_strategy)(unsigned long long val, char *s)); | |
e552b661 | 64 | ssize_t res_counter_write(struct res_counter *counter, int member, |
0eea1030 BS |
65 | const char __user *buf, size_t nbytes, loff_t *pos, |
66 | int (*write_strategy)(char *buf, unsigned long long *val)); | |
e552b661 PE |
67 | |
68 | /* | |
69 | * the field descriptors. one for each member of res_counter | |
70 | */ | |
71 | ||
72 | enum { | |
73 | RES_USAGE, | |
c84872e1 | 74 | RES_MAX_USAGE, |
e552b661 PE |
75 | RES_LIMIT, |
76 | RES_FAILCNT, | |
77 | }; | |
78 | ||
79 | /* | |
80 | * helpers for accounting | |
81 | */ | |
82 | ||
83 | void res_counter_init(struct res_counter *counter); | |
84 | ||
85 | /* | |
86 | * charge - try to consume more resource. | |
87 | * | |
88 | * @counter: the counter | |
89 | * @val: the amount of the resource. each controller defines its own | |
90 | * units, e.g. numbers, bytes, Kbytes, etc | |
91 | * | |
92 | * returns 0 on success and <0 if the counter->usage will exceed the | |
93 | * counter->limit _locked call expects the counter->lock to be taken | |
94 | */ | |
95 | ||
96 | int res_counter_charge_locked(struct res_counter *counter, unsigned long val); | |
97 | int res_counter_charge(struct res_counter *counter, unsigned long val); | |
98 | ||
99 | /* | |
100 | * uncharge - tell that some portion of the resource is released | |
101 | * | |
102 | * @counter: the counter | |
103 | * @val: the amount of the resource | |
104 | * | |
105 | * these calls check for usage underflow and show a warning on the console | |
106 | * _locked call expects the counter->lock to be taken | |
107 | */ | |
108 | ||
109 | void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val); | |
110 | void res_counter_uncharge(struct res_counter *counter, unsigned long val); | |
111 | ||
66e1707b BS |
112 | static inline bool res_counter_limit_check_locked(struct res_counter *cnt) |
113 | { | |
114 | if (cnt->usage < cnt->limit) | |
115 | return true; | |
116 | ||
117 | return false; | |
118 | } | |
119 | ||
120 | /* | |
121 | * Helper function to detect if the cgroup is within it's limit or | |
122 | * not. It's currently called from cgroup_rss_prepare() | |
123 | */ | |
124 | static inline bool res_counter_check_under_limit(struct res_counter *cnt) | |
125 | { | |
126 | bool ret; | |
127 | unsigned long flags; | |
128 | ||
129 | spin_lock_irqsave(&cnt->lock, flags); | |
130 | ret = res_counter_limit_check_locked(cnt); | |
131 | spin_unlock_irqrestore(&cnt->lock, flags); | |
132 | return ret; | |
133 | } | |
134 | ||
c84872e1 PE |
135 | static inline void res_counter_reset_max(struct res_counter *cnt) |
136 | { | |
137 | unsigned long flags; | |
138 | ||
139 | spin_lock_irqsave(&cnt->lock, flags); | |
140 | cnt->max_usage = cnt->usage; | |
141 | spin_unlock_irqrestore(&cnt->lock, flags); | |
142 | } | |
143 | ||
e552b661 | 144 | #endif |