[net-next-2.6.git] / include / linux / res_counter.h

#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);

static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
{
	if (cnt->usage < cnt->limit)
		return true;

	return false;
}

/*
 * Helper function to detect if the cgroup is within it's limit or
 * not. It's currently called from cgroup_rss_prepare()
 */
static inline bool res_counter_check_under_limit(struct res_counter *cnt)
{
	bool ret;
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	ret = res_counter_limit_check_locked(cnt);
	spin_unlock_irqrestore(&cnt->lock, flags);
	return ret;
}

#endif
Commit	Line	Data
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	*/
	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