1 #ifndef __RES_COUNTER_H__
2 #define __RES_COUNTER_H__
6 * Contain common data types and routines for resource accounting
8 * Copyright 2007 OpenVZ SWsoft Inc
10 * Author: Pavel Emelianov <xemul@openvz.org>
12 * See Documentation/cgroups/resource_counter.txt for more
13 * info about what this counter is.
16 #include <linux/cgroup.h>
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
26 * the current resource consumption level
28 unsigned long long usage;
30 * the maximal value of the usage from the counter creation
32 unsigned long long max_usage;
34 * the limit that usage cannot exceed
36 unsigned long long limit;
38 * the limit that usage can be exceed
40 unsigned long long soft_limit;
42 * the number of unsuccessful attempts to consume the resource
44 unsigned long long failcnt;
46 * the lock to protect all of the above.
47 * the routines below consider this to be IRQ-safe
51 * Parent counter, used for hierarchial resource accounting
53 struct res_counter *parent;
56 #define RESOURCE_MAX (unsigned long long)LLONG_MAX
59 * Helpers to interact with userspace
60 * res_counter_read_u64() - returns the value of the specified member.
61 * res_counter_read/_write - put/get the specified fields from the
62 * res_counter struct to/from the user
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.
71 u64 res_counter_read_u64(struct res_counter *counter, int member);
73 ssize_t res_counter_read(struct res_counter *counter, int member,
74 const char __user *buf, size_t nbytes, loff_t *pos,
75 int (*read_strategy)(unsigned long long val, char *s));
77 int res_counter_memparse_write_strategy(const char *buf,
78 unsigned long long *res);
81 * the field descriptors. one for each member of res_counter
93 * helpers for accounting
96 void res_counter_init(struct res_counter *counter, struct res_counter *parent);
99 * charge - try to consume more resource.
101 * @counter: the counter
102 * @val: the amount of the resource. each controller defines its own
103 * units, e.g. numbers, bytes, Kbytes, etc
105 * returns 0 on success and <0 if the counter->usage will exceed the
106 * counter->limit _locked call expects the counter->lock to be taken
108 * charge_nofail works the same, except that it charges the resource
109 * counter unconditionally, and returns < 0 if the after the current
110 * charge we are over limit.
113 int __must_check res_counter_charge_locked(struct res_counter *counter,
114 unsigned long val, bool force);
115 int __must_check res_counter_charge(struct res_counter *counter,
116 unsigned long val, struct res_counter **limit_fail_at);
117 int res_counter_charge_nofail(struct res_counter *counter,
118 unsigned long val, struct res_counter **limit_fail_at);
121 * uncharge - tell that some portion of the resource is released
123 * @counter: the counter
124 * @val: the amount of the resource
126 * these calls check for usage underflow and show a warning on the console
127 * _locked call expects the counter->lock to be taken
129 * returns the total charges still present in @counter.
132 u64 res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
133 u64 res_counter_uncharge(struct res_counter *counter, unsigned long val);
135 u64 res_counter_uncharge_until(struct res_counter *counter,
136 struct res_counter *top,
139 * res_counter_margin - calculate chargeable space of a counter
142 * Returns the difference between the hard limit and the current usage
143 * of resource counter @cnt.
145 static inline unsigned long long res_counter_margin(struct res_counter *cnt)
147 unsigned long long margin;
150 spin_lock_irqsave(&cnt->lock, flags);
151 if (cnt->limit > cnt->usage)
152 margin = cnt->limit - cnt->usage;
155 spin_unlock_irqrestore(&cnt->lock, flags);
160 * Get the difference between the usage and the soft limit
163 * Returns 0 if usage is less than or equal to soft limit
164 * The difference between usage and soft limit, otherwise.
166 static inline unsigned long long
167 res_counter_soft_limit_excess(struct res_counter *cnt)
169 unsigned long long excess;
172 spin_lock_irqsave(&cnt->lock, flags);
173 if (cnt->usage <= cnt->soft_limit)
176 excess = cnt->usage - cnt->soft_limit;
177 spin_unlock_irqrestore(&cnt->lock, flags);
181 static inline void res_counter_reset_max(struct res_counter *cnt)
185 spin_lock_irqsave(&cnt->lock, flags);
186 cnt->max_usage = cnt->usage;
187 spin_unlock_irqrestore(&cnt->lock, flags);
190 static inline void res_counter_reset_failcnt(struct res_counter *cnt)
194 spin_lock_irqsave(&cnt->lock, flags);
196 spin_unlock_irqrestore(&cnt->lock, flags);
199 static inline int res_counter_set_limit(struct res_counter *cnt,
200 unsigned long long limit)
205 spin_lock_irqsave(&cnt->lock, flags);
206 if (cnt->usage <= limit) {
210 spin_unlock_irqrestore(&cnt->lock, flags);
215 res_counter_set_soft_limit(struct res_counter *cnt,
216 unsigned long long soft_limit)
220 spin_lock_irqsave(&cnt->lock, flags);
221 cnt->soft_limit = soft_limit;
222 spin_unlock_irqrestore(&cnt->lock, flags);