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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 | */ | |
22e2c507 JA |
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 | /* | |
598971bf | 44 | * Fallback BE priority |
22e2c507 JA |
45 | */ |
46 | #define IOPRIO_NORM (4) | |
c2dea2d1 | 47 | |
598971bf TH |
48 | /* |
49 | * if process has set io priority explicitly, use that. if not, convert | |
50 | * the cpu scheduler nice value to an io priority | |
51 | */ | |
22e2c507 JA |
52 | static inline int task_nice_ioprio(struct task_struct *task) |
53 | { | |
54 | return (task_nice(task) + 20) / 5; | |
55 | } | |
56 | ||
6d63c275 JA |
57 | /* |
58 | * This is for the case where the task hasn't asked for a specific IO class. | |
59 | * Check for idle and rt task process, and return appropriate IO class. | |
60 | */ | |
61 | static inline int task_nice_ioclass(struct task_struct *task) | |
62 | { | |
63 | if (task->policy == SCHED_IDLE) | |
64 | return IOPRIO_CLASS_IDLE; | |
65 | else if (task->policy == SCHED_FIFO || task->policy == SCHED_RR) | |
66 | return IOPRIO_CLASS_RT; | |
67 | else | |
68 | return IOPRIO_CLASS_BE; | |
69 | } | |
70 | ||
22e2c507 JA |
71 | /* |
72 | * For inheritance, return the highest of the two given priorities | |
73 | */ | |
e014ff8d | 74 | extern int ioprio_best(unsigned short aprio, unsigned short bprio); |
22e2c507 | 75 | |
b3881f74 TT |
76 | extern int set_task_ioprio(struct task_struct *task, int ioprio); |
77 | ||
22e2c507 | 78 | #endif |