[linux-2.6-block.git] / include / linux / proportions.h

/*
 * FLoating proportions
 *
 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
 *
 * This file contains the public data structure and API definitions.
 */

#ifndef _LINUX_PROPORTIONS_H
#define _LINUX_PROPORTIONS_H

#include <linux/percpu_counter.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>

struct prop_global {
	/*
	 * The period over which we differentiate
	 *
	 *   period = 2^shift
	 */
	int shift;
	/*
	 * The total event counter aka 'time'.
	 *
	 * Treated as an unsigned long; the lower 'shift - 1' bits are the
	 * counter bits, the remaining upper bits the period counter.
	 */
	struct percpu_counter events;
};

/*
 * global proportion descriptor
 *
 * this is needed to consitently flip prop_global structures.
 */
struct prop_descriptor {
	int index;
	struct prop_global pg[2];
	struct mutex mutex;		/* serialize the prop_global switch */
};

int prop_descriptor_init(struct prop_descriptor *pd, int shift);
void prop_change_shift(struct prop_descriptor *pd, int new_shift);

/*
 * ----- PERCPU ------
 */

struct prop_local_percpu {
	/*
	 * the local events counter
	 */
	struct percpu_counter events;

	/*
	 * snapshot of the last seen global state
	 */
	int shift;
	unsigned long period;
	spinlock_t lock;		/* protect the snapshot state */
};

int prop_local_init_percpu(struct prop_local_percpu *pl);
void prop_local_destroy_percpu(struct prop_local_percpu *pl);
void __prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl);
void prop_fraction_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl,
		long *numerator, long *denominator);

static inline
void prop_inc_percpu(struct prop_descriptor *pd, struct prop_local_percpu *pl)
{
	unsigned long flags;

	local_irq_save(flags);
	__prop_inc_percpu(pd, pl);
	local_irq_restore(flags);
}

/*
 * ----- SINGLE ------
 */

struct prop_local_single {
	/*
	 * the local events counter
	 */
	unsigned long events;

	/*
	 * snapshot of the last seen global state
	 * and a lock protecting this state
	 */
	int shift;
	unsigned long period;
	spinlock_t lock;		/* protect the snapshot state */
};

#define INIT_PROP_LOCAL_SINGLE(name)			\
{	.lock = __SPIN_LOCK_UNLOCKED(name.lock),	\
}

int prop_local_init_single(struct prop_local_single *pl);
void prop_local_destroy_single(struct prop_local_single *pl);
void __prop_inc_single(struct prop_descriptor *pd, struct prop_local_single *pl);
void prop_fraction_single(struct prop_descriptor *pd, struct prop_local_single *pl,
		long *numerator, long *denominator);

static inline
void prop_inc_single(struct prop_descriptor *pd, struct prop_local_single *pl)
{
	unsigned long flags;

	local_irq_save(flags);
	__prop_inc_single(pd, pl);
	local_irq_restore(flags);
}

#endif /* _LINUX_PROPORTIONS_H */
Commit	Line	Data
145ca25e PZ	1	/*
	2	* FLoating proportions
	3	*
	4	* Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
	5	*
	6	* This file contains the public data structure and API definitions.
	7	*/
	8
	9	#ifndef _LINUX_PROPORTIONS_H
	10	#define _LINUX_PROPORTIONS_H
	11
	12	#include <linux/percpu_counter.h>
	13	#include <linux/spinlock.h>
	14	#include <linux/mutex.h>
	15
	16	struct prop_global {
	17	/*
	18	* The period over which we differentiate
	19	*
	20	* period = 2^shift
	21	*/
	22	int shift;
	23	/*
	24	* The total event counter aka 'time'.
	25	*
	26	* Treated as an unsigned long; the lower 'shift - 1' bits are the
	27	* counter bits, the remaining upper bits the period counter.
	28	*/
	29	struct percpu_counter events;
	30	};
	31
	32	/*
	33	* global proportion descriptor
	34	*
	35	* this is needed to consitently flip prop_global structures.
	36	*/
	37	struct prop_descriptor {
	38	int index;
	39	struct prop_global pg[2];
	40	struct mutex mutex; /* serialize the prop_global switch */
	41	};
	42
	43	int prop_descriptor_init(struct prop_descriptor *pd, int shift);
	44	void prop_change_shift(struct prop_descriptor *pd, int new_shift);
	45
	46	/*
	47	* ----- PERCPU ------
	48	*/
	49
	50	struct prop_local_percpu {
	51	/*
	52	* the local events counter
	53	*/
	54	struct percpu_counter events;
	55
	56	/*
	57	* snapshot of the last seen global state
	58	*/
	59	int shift;
	60	unsigned long period;
	61	spinlock_t lock; /* protect the snapshot state */
	62	};
	63
	64	int prop_local_init_percpu(struct prop_local_percpu *pl);
65	void prop_local_destroy_percpu(struct prop_local_percpu *pl);
66	void __prop_inc_percpu(struct prop_descriptor pd, struct prop_local_percpu pl);
67	void prop_fraction_percpu(struct prop_descriptor pd, struct prop_local_percpu pl,
68	long numerator, long denominator);
69
70	static inline
71	void prop_inc_percpu(struct prop_descriptor pd, struct prop_local_percpu pl)
72	{
73	unsigned long flags;
74
75	local_irq_save(flags);
76	__prop_inc_percpu(pd, pl);
77	local_irq_restore(flags);
78	}
79
80	/*
81	* ----- SINGLE ------
82	*/
83
84	struct prop_local_single {
85	/*
86	* the local events counter
87	*/
88	unsigned long events;
89
90	/*
91	* snapshot of the last seen global state
92	* and a lock protecting this state
93	*/
94	int shift;
95	unsigned long period;
96	spinlock_t lock; /* protect the snapshot state */
97	};
98
99	#define INIT_PROP_LOCAL_SINGLE(name) \
100	{ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
101	}
102
103	int prop_local_init_single(struct prop_local_single *pl);
104	void prop_local_destroy_single(struct prop_local_single *pl);
105	void __prop_inc_single(struct prop_descriptor pd, struct prop_local_single pl);
106	void prop_fraction_single(struct prop_descriptor pd, struct prop_local_single pl,
107	long numerator, long denominator);
108
109	static inline
110	void prop_inc_single(struct prop_descriptor pd, struct prop_local_single pl)
111	{
112	unsigned long flags;
113
114	local_irq_save(flags);
115	__prop_inc_single(pd, pl);
116	local_irq_restore(flags);
117	}
118
119	#endif /* _LINUX_PROPORTIONS_H */