diff options
Diffstat (limited to 'include/linux/res_counter.h')
-rw-r--r-- | include/linux/res_counter.h | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h new file mode 100644 index 000000000000..eeb3f7749772 --- /dev/null +++ b/include/linux/res_counter.h @@ -0,0 +1,102 @@ +#ifndef __RES_COUNTER_H__ +#define __RES_COUNTER_H__ + +/* + * Resource Counters + * Contain common data types and routines for resource accounting + * + * Copyright 2007 OpenVZ SWsoft Inc + * + * Author: Pavel Emelianov <xemul@openvz.org> + * + */ + +#include <linux/cgroup.h> + +/* + * The core object. the cgroup that wishes to account for some + * resource may include this counter into its structures and use + * the helpers described beyond + */ + +struct res_counter { + /* + * the current resource consumption level + */ + unsigned long usage; + /* + * the limit that usage cannot exceed + */ + unsigned long limit; + /* + * the number of unsuccessful attempts to consume the resource + */ + unsigned long failcnt; + /* + * the lock to protect all of the above. + * the routines below consider this to be IRQ-safe + */ + spinlock_t lock; +}; + +/* + * Helpers to interact with userspace + * res_counter_read/_write - put/get the specified fields from the + * res_counter struct to/from the user + * + * @counter: the counter in question + * @member: the field to work with (see RES_xxx below) + * @buf: the buffer to opeate on,... + * @nbytes: its size... + * @pos: and the offset. + */ + +ssize_t res_counter_read(struct res_counter *counter, int member, + const char __user *buf, size_t nbytes, loff_t *pos); +ssize_t res_counter_write(struct res_counter *counter, int member, + const char __user *buf, size_t nbytes, loff_t *pos); + +/* + * the field descriptors. one for each member of res_counter + */ + +enum { + RES_USAGE, + RES_LIMIT, + RES_FAILCNT, +}; + +/* + * helpers for accounting + */ + +void res_counter_init(struct res_counter *counter); + +/* + * charge - try to consume more resource. + * + * @counter: the counter + * @val: the amount of the resource. each controller defines its own + * units, e.g. numbers, bytes, Kbytes, etc + * + * returns 0 on success and <0 if the counter->usage will exceed the + * counter->limit _locked call expects the counter->lock to be taken + */ + +int res_counter_charge_locked(struct res_counter *counter, unsigned long val); +int res_counter_charge(struct res_counter *counter, unsigned long val); + +/* + * uncharge - tell that some portion of the resource is released + * + * @counter: the counter + * @val: the amount of the resource + * + * these calls check for usage underflow and show a warning on the console + * _locked call expects the counter->lock to be taken + */ + +void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val); +void res_counter_uncharge(struct res_counter *counter, unsigned long val); + +#endif |