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

#ifndef IOPRIO_H
#define IOPRIO_H

#include <linux/sched.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 task_struct *task)
{
	WARN_ON(!ioprio_valid(task->ioprio));
	return IOPRIO_PRIO_DATA(task->ioprio);
}

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

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

#endif
Commit	Line	Data
22e2c507 JA	1	#ifndef IOPRIO_H
	2	#define IOPRIO_H
	3
	4	#include <linux/sched.h>
	5
	6	/*
	7	* Gives us 8 prio classes with 13-bits of data for each class
	8	*/
	9	#define IOPRIO_BITS (16)
	10	#define IOPRIO_CLASS_SHIFT (13)
	11	#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
	12
	13	#define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
	14	#define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK)
3b18152c	15	#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) \| data)
22e2c507 JA	16
	17	#define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
	18
	19	/*
	20	* These are the io priority groups as implemented by CFQ. RT is the realtime
	21	* class, it always gets premium service. BE is the best-effort scheduling
	22	* class, the default for any process. IDLE is the idle scheduling class, it
	23	* is only served when no one else is using the disk.
	24	*/
	25	enum {
	26	IOPRIO_CLASS_NONE,
	27	IOPRIO_CLASS_RT,
	28	IOPRIO_CLASS_BE,
	29	IOPRIO_CLASS_IDLE,
	30	};
	31
	32	/*
	33	* 8 best effort priority levels are supported
	34	*/
	35	#define IOPRIO_BE_NR (8)
	36
22e2c507 JA	37	enum {
	38	IOPRIO_WHO_PROCESS = 1,
	39	IOPRIO_WHO_PGRP,
	40	IOPRIO_WHO_USER,
	41	};
	42
	43	/*
	44	* if process has set io priority explicitly, use that. if not, convert
	45	* the cpu scheduler nice value to an io priority
	46	*/
	47	#define IOPRIO_NORM (4)
	48	static inline int task_ioprio(struct task_struct *task)
	49	{
	50	WARN_ON(!ioprio_valid(task->ioprio));
	51	return IOPRIO_PRIO_DATA(task->ioprio);
	52	}
	53
	54	static inline int task_nice_ioprio(struct task_struct *task)
	55	{
	56	return (task_nice(task) + 20) / 5;
	57	}
	58
	59	/*
	60	* For inheritance, return the highest of the two given priorities
	61	*/
e014ff8d	62	extern int ioprio_best(unsigned short aprio, unsigned short bprio);
22e2c507 JA	63
22e2c507 JA	64	#endif