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

#ifndef IOPRIO_H
#define IOPRIO_H

#include <linux/sched.h>
#include <linux/iocontext.h>

/*
 * Gives us 8 prio classes with 13-bits of data for each class
 */
#define IOPRIO_BITS		(16)
#define IOPRIO_CLASS_SHIFT	(13)
#define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)

#define IOPRIO_PRIO_CLASS(mask)	((mask) >> IOPRIO_CLASS_SHIFT)
#define IOPRIO_PRIO_DATA(mask)	((mask) & IOPRIO_PRIO_MASK)
#define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)

#define ioprio_valid(mask)	(IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)

/*
 * These are the io priority groups as implemented by CFQ. RT is the realtime
 * class, it always gets premium service. BE is the best-effort scheduling
 * class, the default for any process. IDLE is the idle scheduling class, it
 * is only served when no one else is using the disk.
 */
enum {
	IOPRIO_CLASS_NONE,
	IOPRIO_CLASS_RT,
	IOPRIO_CLASS_BE,
	IOPRIO_CLASS_IDLE,
};

/*
 * 8 best effort priority levels are supported
 */
#define IOPRIO_BE_NR	(8)

enum {
	IOPRIO_WHO_PROCESS = 1,
	IOPRIO_WHO_PGRP,
	IOPRIO_WHO_USER,
};

/*
 * if process has set io priority explicitly, use that. if not, convert
 * the cpu scheduler nice value to an io priority
 */
#define IOPRIO_NORM	(4)
static inline int task_ioprio(struct io_context *ioc)
{
	if (ioprio_valid(ioc->ioprio))
		return IOPRIO_PRIO_DATA(ioc->ioprio);

	return IOPRIO_NORM;
}

static inline int task_ioprio_class(struct io_context *ioc)
{
	if (ioprio_valid(ioc->ioprio))
		return IOPRIO_PRIO_CLASS(ioc->ioprio);

	return IOPRIO_CLASS_BE;
}

static inline int task_nice_ioprio(struct task_struct *task)
{
	return (task_nice(task) + 20) / 5;
}

/*
 * This is for the case where the task hasn't asked for a specific IO class.
 * Check for idle and rt task process, and return appropriate IO class.
 */
static inline int task_nice_ioclass(struct task_struct *task)
{
	if (task->policy == SCHED_IDLE)
		return IOPRIO_CLASS_IDLE;
	else if (task->policy == SCHED_FIFO || task->policy == SCHED_RR)
		return IOPRIO_CLASS_RT;
	else
		return IOPRIO_CLASS_BE;
}

/*
 * For inheritance, return the highest of the two given priorities
 */
extern int ioprio_best(unsigned short aprio, unsigned short bprio);

extern int set_task_ioprio(struct task_struct *task, int ioprio);

#endif
Commit	Line	Data
22e2c507 JA	1	#ifndef IOPRIO_H
	2	#define IOPRIO_H
	3
	4	#include <linux/sched.h>
fd0928df	5	#include <linux/iocontext.h>
22e2c507 JA	6
	7	/*
	8	* Gives us 8 prio classes with 13-bits of data for each class
	9	*/
	10	#define IOPRIO_BITS (16)
	11	#define IOPRIO_CLASS_SHIFT (13)
	12	#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
	13
	14	#define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
	15	#define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK)
3b18152c	16	#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) \| data)
22e2c507 JA	17
	18	#define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
	19
	20	/*
	21	* These are the io priority groups as implemented by CFQ. RT is the realtime
	22	* class, it always gets premium service. BE is the best-effort scheduling
	23	* class, the default for any process. IDLE is the idle scheduling class, it
	24	* is only served when no one else is using the disk.
	25	*/
	26	enum {
	27	IOPRIO_CLASS_NONE,
	28	IOPRIO_CLASS_RT,
	29	IOPRIO_CLASS_BE,
	30	IOPRIO_CLASS_IDLE,
	31	};
	32
	33	/*
	34	* 8 best effort priority levels are supported
	35	*/
	36	#define IOPRIO_BE_NR (8)
	37
22e2c507 JA	38	enum {
	39	IOPRIO_WHO_PROCESS = 1,
	40	IOPRIO_WHO_PGRP,
	41	IOPRIO_WHO_USER,
	42	};
	43
	44	/*
	45	* if process has set io priority explicitly, use that. if not, convert
	46	* the cpu scheduler nice value to an io priority
	47	*/
	48	#define IOPRIO_NORM (4)
fd0928df	49	static inline int task_ioprio(struct io_context *ioc)
22e2c507	50	{
fd0928df JA	51	if (ioprio_valid(ioc->ioprio))
fd0928df JA	52	return IOPRIO_PRIO_DATA(ioc->ioprio);
15c31be4 JA	53
15c31be4 JA	54	return IOPRIO_NORM;
22e2c507 JA	55	}
22e2c507 JA	56
fd0928df	57	static inline int task_ioprio_class(struct io_context *ioc)
c2dea2d1	58	{
fd0928df JA	59	if (ioprio_valid(ioc->ioprio))
fd0928df JA	60	return IOPRIO_PRIO_CLASS(ioc->ioprio);
c2dea2d1 VT	61
	62	return IOPRIO_CLASS_BE;
	63	}
	64
22e2c507 JA	65	static inline int task_nice_ioprio(struct task_struct *task)
	66	{
	67	return (task_nice(task) + 20) / 5;
	68	}
	69
6d63c275 JA	70	/*
	71	* This is for the case where the task hasn't asked for a specific IO class.
	72	* Check for idle and rt task process, and return appropriate IO class.
	73	*/
	74	static inline int task_nice_ioclass(struct task_struct *task)
	75	{
	76	if (task->policy == SCHED_IDLE)
	77	return IOPRIO_CLASS_IDLE;
	78	else if (task->policy == SCHED_FIFO \|\| task->policy == SCHED_RR)
	79	return IOPRIO_CLASS_RT;
	80	else
	81	return IOPRIO_CLASS_BE;
	82	}
	83
22e2c507 JA	84	/*
	85	* For inheritance, return the highest of the two given priorities
	86	*/
e014ff8d	87	extern int ioprio_best(unsigned short aprio, unsigned short bprio);
22e2c507	88
b3881f74 TT	89	extern int set_task_ioprio(struct task_struct *task, int ioprio);
b3881f74 TT	90
22e2c507	91	#endif