ASoC: Only run power_check() on a widget once per run
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / include / linux / res_counter.h
blobc9d625ca659ec387c6b9456c4d03d0bb4af80fb9
1 #ifndef __RES_COUNTER_H__
2 #define __RES_COUNTER_H__
4 /*
5 * Resource Counters
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
24 struct res_counter {
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
49 spinlock_t lock;
51 * Parent counter, used for hierarchial resource accounting
53 struct res_counter *parent;
56 #define RESOURCE_MAX (unsigned long long)LLONG_MAX
58 /**
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 typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val);
79 int res_counter_memparse_write_strategy(const char *buf,
80 unsigned long long *res);
82 int res_counter_write(struct res_counter *counter, int member,
83 const char *buffer, write_strategy_fn write_strategy);
86 * the field descriptors. one for each member of res_counter
89 enum {
90 RES_USAGE,
91 RES_MAX_USAGE,
92 RES_LIMIT,
93 RES_FAILCNT,
94 RES_SOFT_LIMIT,
98 * helpers for accounting
101 void res_counter_init(struct res_counter *counter, struct res_counter *parent);
104 * charge - try to consume more resource.
106 * @counter: the counter
107 * @val: the amount of the resource. each controller defines its own
108 * units, e.g. numbers, bytes, Kbytes, etc
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
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,
117 unsigned long val, struct res_counter **limit_fail_at);
120 * uncharge - tell that some portion of the resource is released
122 * @counter: the counter
123 * @val: the amount of the resource
125 * these calls check for usage underflow and show a warning on the console
126 * _locked call expects the counter->lock to be taken
129 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
130 void res_counter_uncharge(struct res_counter *counter, unsigned long val);
133 * res_counter_margin - calculate chargeable space of a counter
134 * @cnt: the counter
136 * Returns the difference between the hard limit and the current usage
137 * of resource counter @cnt.
139 static inline unsigned long long res_counter_margin(struct res_counter *cnt)
141 unsigned long long margin;
142 unsigned long flags;
144 spin_lock_irqsave(&cnt->lock, flags);
145 margin = cnt->limit - cnt->usage;
146 spin_unlock_irqrestore(&cnt->lock, flags);
147 return margin;
151 * Get the difference between the usage and the soft limit
152 * @cnt: The counter
154 * Returns 0 if usage is less than or equal to soft limit
155 * The difference between usage and soft limit, otherwise.
157 static inline unsigned long long
158 res_counter_soft_limit_excess(struct res_counter *cnt)
160 unsigned long long excess;
161 unsigned long flags;
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;
172 static inline void res_counter_reset_max(struct res_counter *cnt)
174 unsigned long flags;
176 spin_lock_irqsave(&cnt->lock, flags);
177 cnt->max_usage = cnt->usage;
178 spin_unlock_irqrestore(&cnt->lock, flags);
181 static inline void res_counter_reset_failcnt(struct res_counter *cnt)
183 unsigned long flags;
185 spin_lock_irqsave(&cnt->lock, flags);
186 cnt->failcnt = 0;
187 spin_unlock_irqrestore(&cnt->lock, flags);
190 static inline int res_counter_set_limit(struct res_counter *cnt,
191 unsigned long long limit)
193 unsigned long flags;
194 int ret = -EBUSY;
196 spin_lock_irqsave(&cnt->lock, flags);
197 if (cnt->usage <= limit) {
198 cnt->limit = limit;
199 ret = 0;
201 spin_unlock_irqrestore(&cnt->lock, flags);
202 return ret;
205 static inline int
206 res_counter_set_soft_limit(struct res_counter *cnt,
207 unsigned long long soft_limit)
209 unsigned long flags;
211 spin_lock_irqsave(&cnt->lock, flags);
212 cnt->soft_limit = soft_limit;
213 spin_unlock_irqrestore(&cnt->lock, flags);
214 return 0;
217 #endif