[deliverable/linux.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>
 *
 * See Documentation/cgroups/resource_counter.txt for more
 * info about what this counter is.
 */

#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 long usage;
	/*
	 * the maximal value of the usage from the counter creation
	 */
	unsigned long long max_usage;
	/*
	 * the limit that usage cannot exceed
	 */
	unsigned long long limit;
	/*
	 * the number of unsuccessful attempts to consume the resource
	 */
	unsigned long long failcnt;
	/*
	 * the lock to protect all of the above.
	 * the routines below consider this to be IRQ-safe
	 */
	spinlock_t lock;
	/*
	 * Parent counter, used for hierarchial resource accounting
	 */
	struct res_counter *parent;
};

#define RESOURCE_MAX (unsigned long long)LLONG_MAX

/**
 * Helpers to interact with userspace
 * res_counter_read_u64() - returns the value of the specified member.
 * 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.
 */

u64 res_counter_read_u64(struct res_counter *counter, int member);

ssize_t res_counter_read(struct res_counter *counter, int member,
		const char __user *buf, size_t nbytes, loff_t *pos,
		int (*read_strategy)(unsigned long long val, char *s));

typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val);

int res_counter_memparse_write_strategy(const char *buf,
					unsigned long long *res);

int res_counter_write(struct res_counter *counter, int member,
		      const char *buffer, write_strategy_fn write_strategy);

/*
 * the field descriptors. one for each member of res_counter
 */

enum {
	RES_USAGE,
	RES_MAX_USAGE,
	RES_LIMIT,
	RES_FAILCNT,
};

/*
 * helpers for accounting
 */

void res_counter_init(struct res_counter *counter, struct res_counter *parent);

/*
 * 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 __must_check res_counter_charge_locked(struct res_counter *counter,
		unsigned long val);
int __must_check res_counter_charge(struct res_counter *counter,
		unsigned long val, struct res_counter **limit_fail_at);

/*
 * 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;
}

static inline void res_counter_reset_max(struct res_counter *cnt)
{
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	cnt->max_usage = cnt->usage;
	spin_unlock_irqrestore(&cnt->lock, flags);
}

static inline void res_counter_reset_failcnt(struct res_counter *cnt)
{
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	cnt->failcnt = 0;
	spin_unlock_irqrestore(&cnt->lock, flags);
}

static inline int res_counter_set_limit(struct res_counter *cnt,
		unsigned long long limit)
{
	unsigned long flags;
	int ret = -EBUSY;

	spin_lock_irqsave(&cnt->lock, flags);
	if (cnt->usage <= limit) {
		cnt->limit = limit;
		ret = 0;
	}
	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	*
45ce80fb	12	* See Documentation/cgroups/resource_counter.txt for more
faebe9fd	13	* info about what this counter is.
e552b661 PE	14	*/
	15
	16	#include <linux/cgroup.h>
	17
	18	/*
	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
	22	*/
	23
	24	struct res_counter {
	25	/*
	26	* the current resource consumption level
	27	*/
0eea1030	28	unsigned long long usage;
c84872e1 PE	29	/*
	30	* the maximal value of the usage from the counter creation
	31	*/
	32	unsigned long long max_usage;
e552b661 PE	33	/*
	34	* the limit that usage cannot exceed
	35	*/
0eea1030	36	unsigned long long limit;
e552b661 PE	37	/*
	38	* the number of unsuccessful attempts to consume the resource
	39	*/
0eea1030	40	unsigned long long failcnt;
e552b661 PE	41	/*
	42	* the lock to protect all of the above.
	43	* the routines below consider this to be IRQ-safe
	44	*/
	45	spinlock_t lock;
28dbc4b6 BS	46	/*
	47	* Parent counter, used for hierarchial resource accounting
	48	*/
	49	struct res_counter *parent;
e552b661 PE	50	};
e552b661 PE	51
c5b947b2 DN	52	#define RESOURCE_MAX (unsigned long long)LLONG_MAX
c5b947b2 DN	53
2c7eabf3	54	/**
e552b661	55	* Helpers to interact with userspace
2c7eabf3	56	* res_counter_read_u64() - returns the value of the specified member.
e552b661 PE	57	* res_counter_read/_write - put/get the specified fields from the
	58	* res_counter struct to/from the user
	59	*
	60	* @counter: the counter in question
	61	* @member: the field to work with (see RES_xxx below)
	62	* @buf: the buffer to opeate on,...
	63	* @nbytes: its size...
	64	* @pos: and the offset.
	65	*/
	66
2c7eabf3 PM	67	u64 res_counter_read_u64(struct res_counter *counter, int member);
2c7eabf3 PM	68
e552b661	69	ssize_t res_counter_read(struct res_counter *counter, int member,
0eea1030 BS	70	const char __user buf, size_t nbytes, loff_t pos,
0eea1030 BS	71	int (read_strategy)(unsigned long long val, char s));
856c13aa PM	72
	73	typedef int (write_strategy_fn)(const char buf, unsigned long long *val);
	74
	75	int res_counter_memparse_write_strategy(const char *buf,
	76	unsigned long long *res);
	77
	78	int res_counter_write(struct res_counter *counter, int member,
	79	const char *buffer, write_strategy_fn write_strategy);
e552b661 PE	80
	81	/*
	82	* the field descriptors. one for each member of res_counter
	83	*/
	84
	85	enum {
	86	RES_USAGE,
c84872e1	87	RES_MAX_USAGE,
e552b661 PE	88	RES_LIMIT,
	89	RES_FAILCNT,
	90	};
	91
	92	/*
	93	* helpers for accounting
	94	*/
	95
28dbc4b6	96	void res_counter_init(struct res_counter counter, struct res_counter parent);
e552b661 PE	97
	98	/*
	99	* charge - try to consume more resource.
	100	*
	101	* @counter: the counter
	102	* @val: the amount of the resource. each controller defines its own
	103	* units, e.g. numbers, bytes, Kbytes, etc
	104	*
	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
	107	*/
	108
f2992db2 PE	109	int __must_check res_counter_charge_locked(struct res_counter *counter,
	110	unsigned long val);
	111	int __must_check res_counter_charge(struct res_counter *counter,
28dbc4b6	112	unsigned long val, struct res_counter **limit_fail_at);
e552b661 PE	113
	114	/*
	115	* uncharge - tell that some portion of the resource is released
	116	*
	117	* @counter: the counter
	118	* @val: the amount of the resource
	119	*
	120	* these calls check for usage underflow and show a warning on the console
	121	* _locked call expects the counter->lock to be taken
	122	*/
	123
	124	void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
	125	void res_counter_uncharge(struct res_counter *counter, unsigned long val);
	126
66e1707b BS	127	static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
	128	{
	129	if (cnt->usage < cnt->limit)
	130	return true;
	131
	132	return false;
	133	}
	134
	135	/*
	136	* Helper function to detect if the cgroup is within it's limit or
	137	* not. It's currently called from cgroup_rss_prepare()
	138	*/
	139	static inline bool res_counter_check_under_limit(struct res_counter *cnt)
	140	{
	141	bool ret;
	142	unsigned long flags;
	143
	144	spin_lock_irqsave(&cnt->lock, flags);
	145	ret = res_counter_limit_check_locked(cnt);
	146	spin_unlock_irqrestore(&cnt->lock, flags);
	147	return ret;
	148	}
	149
c84872e1 PE	150	static inline void res_counter_reset_max(struct res_counter *cnt)
	151	{
	152	unsigned long flags;
	153
	154	spin_lock_irqsave(&cnt->lock, flags);
	155	cnt->max_usage = cnt->usage;
	156	spin_unlock_irqrestore(&cnt->lock, flags);
	157	}
	158
29f2a4da PE	159	static inline void res_counter_reset_failcnt(struct res_counter *cnt)
	160	{
	161	unsigned long flags;
	162
	163	spin_lock_irqsave(&cnt->lock, flags);
	164	cnt->failcnt = 0;
	165	spin_unlock_irqrestore(&cnt->lock, flags);
	166	}
12b98044 KH	167
	168	static inline int res_counter_set_limit(struct res_counter *cnt,
	169	unsigned long long limit)
	170	{
	171	unsigned long flags;
	172	int ret = -EBUSY;
	173
	174	spin_lock_irqsave(&cnt->lock, flags);
11d55d2c	175	if (cnt->usage <= limit) {
12b98044 KH	176	cnt->limit = limit;
	177	ret = 0;
	178	}
	179	spin_unlock_irqrestore(&cnt->lock, flags);
	180	return ret;
	181	}
	182
e552b661	183	#endif