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 */ 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 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 */ 62 extern int ioprio_best(unsigned short aprio, unsigned short bprio); 63 64 #endif 65
