67 строки
1.6 KiB
C
67 строки
1.6 KiB
C
#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)
|
|
{
|
|
if (ioprio_valid(task->ioprio))
|
|
return IOPRIO_PRIO_DATA(task->ioprio);
|
|
|
|
return IOPRIO_NORM;
|
|
}
|
|
|
|
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
|