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