[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 <[email protected]>
 *
 * 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 limit that usage can be exceed
	 */
	unsigned long long soft_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,
	RES_SOFT_LIMIT,
};

/*
 * 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
 *
 * charge_nofail works the same, except that it charges the resource
 * counter unconditionally, and returns < 0 if the after the current
 * charge we are over limit.
 */

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);
int __must_check res_counter_charge_nofail(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);

/**
 * res_counter_margin - calculate chargeable space of a counter
 * @cnt: the counter
 *
 * Returns the difference between the hard limit and the current usage
 * of resource counter @cnt.
 */
static inline unsigned long long res_counter_margin(struct res_counter *cnt)
{
	unsigned long long margin;
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	if (cnt->limit > cnt->usage)
		margin = cnt->limit - cnt->usage;
	else
		margin = 0;
	spin_unlock_irqrestore(&cnt->lock, flags);
	return margin;
}

/**
 * Get the difference between the usage and the soft limit
 * @cnt: The counter
 *
 * Returns 0 if usage is less than or equal to soft limit
 * The difference between usage and soft limit, otherwise.
 */
static inline unsigned long long
res_counter_soft_limit_excess(struct res_counter *cnt)
{
	unsigned long long excess;
	unsigned long flags;

	spin_lock_irqsave(&cnt->lock, flags);
	if (cnt->usage <= cnt->soft_limit)
		excess = 0;
	else
		excess = cnt->usage - cnt->soft_limit;
	spin_unlock_irqrestore(&cnt->lock, flags);
	return excess;
}

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;
}

static inline int
res_counter_set_soft_limit(struct res_counter *cnt,
				unsigned long long soft_limit)
{
	unsigned long flags;

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

#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 <[email protected]>
	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;
296c81d8 BS	37	/*
	38	* the limit that usage can be exceed
	39	*/
	40	unsigned long long soft_limit;
e552b661 PE	41	/*
	42	* the number of unsuccessful attempts to consume the resource
	43	*/
0eea1030	44	unsigned long long failcnt;
e552b661 PE	45	/*
	46	* the lock to protect all of the above.
	47	* the routines below consider this to be IRQ-safe
	48	*/
	49	spinlock_t lock;
28dbc4b6 BS	50	/*
	51	* Parent counter, used for hierarchial resource accounting
	52	*/
	53	struct res_counter *parent;
e552b661 PE	54	};
e552b661 PE	55
c5b947b2 DN	56	#define RESOURCE_MAX (unsigned long long)LLONG_MAX
c5b947b2 DN	57
2c7eabf3	58	/**
e552b661	59	* Helpers to interact with userspace
2c7eabf3	60	* res_counter_read_u64() - returns the value of the specified member.
e552b661 PE	61	* res_counter_read/_write - put/get the specified fields from the
	62	* res_counter struct to/from the user
	63	*
	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.
	69	*/
	70
2c7eabf3 PM	71	u64 res_counter_read_u64(struct res_counter *counter, int member);
2c7eabf3 PM	72
e552b661	73	ssize_t res_counter_read(struct res_counter *counter, int member,
0eea1030 BS	74	const char __user buf, size_t nbytes, loff_t pos,
0eea1030 BS	75	int (read_strategy)(unsigned long long val, char s));
856c13aa PM	76
	77	typedef int (write_strategy_fn)(const char buf, unsigned long long *val);
	78
	79	int res_counter_memparse_write_strategy(const char *buf,
	80	unsigned long long *res);
	81
	82	int res_counter_write(struct res_counter *counter, int member,
	83	const char *buffer, write_strategy_fn write_strategy);
e552b661 PE	84
	85	/*
	86	* the field descriptors. one for each member of res_counter
	87	*/
	88
	89	enum {
	90	RES_USAGE,
c84872e1	91	RES_MAX_USAGE,
e552b661 PE	92	RES_LIMIT,
e552b661 PE	93	RES_FAILCNT,
296c81d8	94	RES_SOFT_LIMIT,
e552b661 PE	95	};
	96
	97	/*
	98	* helpers for accounting
	99	*/
	100
28dbc4b6	101	void res_counter_init(struct res_counter counter, struct res_counter parent);
e552b661 PE	102
	103	/*
	104	* charge - try to consume more resource.
	105	*
	106	* @counter: the counter
	107	* @val: the amount of the resource. each controller defines its own
	108	* units, e.g. numbers, bytes, Kbytes, etc
	109	*
	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
0e90b31f GC	112	*
	113	* charge_nofail works the same, except that it charges the resource
	114	* counter unconditionally, and returns < 0 if the after the current
	115	* charge we are over limit.
e552b661 PE	116	*/
e552b661 PE	117
f2992db2 PE	118	int __must_check res_counter_charge_locked(struct res_counter *counter,
	119	unsigned long val);
	120	int __must_check res_counter_charge(struct res_counter *counter,
4e649152	121	unsigned long val, struct res_counter **limit_fail_at);
0e90b31f GC	122	int __must_check res_counter_charge_nofail(struct res_counter *counter,
0e90b31f GC	123	unsigned long val, struct res_counter **limit_fail_at);
e552b661 PE	124
	125	/*
	126	* uncharge - tell that some portion of the resource is released
	127	*
	128	* @counter: the counter
	129	* @val: the amount of the resource
	130	*
	131	* these calls check for usage underflow and show a warning on the console
	132	* _locked call expects the counter->lock to be taken
	133	*/
	134
	135	void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
4e649152	136	void res_counter_uncharge(struct res_counter *counter, unsigned long val);
e552b661	137
9d11ea9f JW	138	/**
	139	* res_counter_margin - calculate chargeable space of a counter
	140	* @cnt: the counter
	141	*
	142	* Returns the difference between the hard limit and the current usage
	143	* of resource counter @cnt.
	144	*/
	145	static inline unsigned long long res_counter_margin(struct res_counter *cnt)
296c81d8	146	{
9d11ea9f JW	147	unsigned long long margin;
9d11ea9f JW	148	unsigned long flags;
296c81d8	149
9d11ea9f	150	spin_lock_irqsave(&cnt->lock, flags);
8cfd14ad GC	151	if (cnt->limit > cnt->usage)
	152	margin = cnt->limit - cnt->usage;
	153	else
	154	margin = 0;
9d11ea9f JW	155	spin_unlock_irqrestore(&cnt->lock, flags);
9d11ea9f JW	156	return margin;
296c81d8 BS	157	}
	158
	159	/**
	160	* Get the difference between the usage and the soft limit
	161	* @cnt: The counter
	162	*
	163	* Returns 0 if usage is less than or equal to soft limit
	164	* The difference between usage and soft limit, otherwise.
	165	*/
	166	static inline unsigned long long
	167	res_counter_soft_limit_excess(struct res_counter *cnt)
	168	{
	169	unsigned long long excess;
	170	unsigned long flags;
	171
	172	spin_lock_irqsave(&cnt->lock, flags);
	173	if (cnt->usage <= cnt->soft_limit)
	174	excess = 0;
	175	else
	176	excess = cnt->usage - cnt->soft_limit;
	177	spin_unlock_irqrestore(&cnt->lock, flags);
	178	return excess;
	179	}
	180
c84872e1 PE	181	static inline void res_counter_reset_max(struct res_counter *cnt)
	182	{
	183	unsigned long flags;
	184
	185	spin_lock_irqsave(&cnt->lock, flags);
	186	cnt->max_usage = cnt->usage;
	187	spin_unlock_irqrestore(&cnt->lock, flags);
	188	}
	189
29f2a4da PE	190	static inline void res_counter_reset_failcnt(struct res_counter *cnt)
	191	{
	192	unsigned long flags;
	193
	194	spin_lock_irqsave(&cnt->lock, flags);
	195	cnt->failcnt = 0;
	196	spin_unlock_irqrestore(&cnt->lock, flags);
	197	}
12b98044 KH	198
	199	static inline int res_counter_set_limit(struct res_counter *cnt,
	200	unsigned long long limit)
	201	{
	202	unsigned long flags;
	203	int ret = -EBUSY;
	204
	205	spin_lock_irqsave(&cnt->lock, flags);
11d55d2c	206	if (cnt->usage <= limit) {
12b98044 KH	207	cnt->limit = limit;
	208	ret = 0;
	209	}
	210	spin_unlock_irqrestore(&cnt->lock, flags);
	211	return ret;
	212	}
	213
296c81d8 BS	214	static inline int
	215	res_counter_set_soft_limit(struct res_counter *cnt,
	216	unsigned long long soft_limit)
	217	{
	218	unsigned long flags;
	219
	220	spin_lock_irqsave(&cnt->lock, flags);
	221	cnt->soft_limit = soft_limit;
	222	spin_unlock_irqrestore(&cnt->lock, flags);
	223	return 0;
	224	}
	225
e552b661	226	#endif