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) 15#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data) 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 */ 25enum { 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 37enum { 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) 48static 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 54static 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 */ 62extern int ioprio_best(unsigned short aprio, unsigned short bprio); 63 64#endif 65