[net-next-2.6.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);
}

/*
 * Limit the time part in order to ensure there are some bits left for the
 * cycle counter and fraction multiply.
 */
#define PROP_MAX_SHIFT (3*BITS_PER_LONG/4)

#define PROP_FRAC_SHIFT		(BITS_PER_LONG - PROP_MAX_SHIFT - 1)
#define PROP_FRAC_BASE		(1UL << PROP_FRAC_SHIFT)

void __prop_inc_percpu_max(struct prop_descriptor *pd,
			   struct prop_local_percpu *pl, long frac);


/*
 * ----- 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
	 */
	unsigned long period;
	int shift;
	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
a42dde04 PZ	80	/*
	81	* Limit the time part in order to ensure there are some bits left for the
	82	* cycle counter and fraction multiply.
	83	*/
	84	#define PROP_MAX_SHIFT (3*BITS_PER_LONG/4)
	85
	86	#define PROP_FRAC_SHIFT (BITS_PER_LONG - PROP_MAX_SHIFT - 1)
	87	#define PROP_FRAC_BASE (1UL << PROP_FRAC_SHIFT)
	88
	89	void __prop_inc_percpu_max(struct prop_descriptor *pd,
	90	struct prop_local_percpu *pl, long frac);
	91
	92
145ca25e PZ	93	/*
	94	* ----- SINGLE ------
	95	*/
	96
	97	struct prop_local_single {
	98	/*
	99	* the local events counter
	100	*/
	101	unsigned long events;
	102
	103	/*
	104	* snapshot of the last seen global state
	105	* and a lock protecting this state
	106	*/
145ca25e	107	unsigned long period;
3fb669dd	108	int shift;
145ca25e PZ	109	spinlock_t lock; /* protect the snapshot state */
	110	};
	111
	112	#define INIT_PROP_LOCAL_SINGLE(name) \
	113	{ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
	114	}
	115
	116	int prop_local_init_single(struct prop_local_single *pl);
	117	void prop_local_destroy_single(struct prop_local_single *pl);
	118	void __prop_inc_single(struct prop_descriptor pd, struct prop_local_single pl);
	119	void prop_fraction_single(struct prop_descriptor pd, struct prop_local_single pl,
	120	long numerator, long denominator);
	121
	122	static inline
	123	void prop_inc_single(struct prop_descriptor pd, struct prop_local_single pl)
	124	{
	125	unsigned long flags;
	126
	127	local_irq_save(flags);
	128	__prop_inc_single(pd, pl);
	129	local_irq_restore(flags);
	130	}
	131
	132	#endif /* _LINUX_PROPORTIONS_H */