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b9f880f4 LP |
1 | #ifndef IOPRIO_H |
2 | #define IOPRIO_H | |
3 | ||
4 | /* This is minimal version of Linux' linux/ioprio.h header file, which | |
5 | * is licensed GPL2 */ | |
6 | ||
7 | #include <unistd.h> | |
8 | #include <sys/syscall.h> | |
9 | ||
10 | /* | |
11 | * Gives us 8 prio classes with 13-bits of data for each class | |
12 | */ | |
13 | #define IOPRIO_BITS (16) | |
14 | #define IOPRIO_CLASS_SHIFT (13) | |
15 | #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) | |
16 | ||
17 | #define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT) | |
18 | #define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK) | |
19 | #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data) | |
20 | ||
21 | #define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE) | |
22 | ||
23 | /* | |
24 | * These are the io priority groups as implemented by CFQ. RT is the realtime | |
25 | * class, it always gets premium service. BE is the best-effort scheduling | |
26 | * class, the default for any process. IDLE is the idle scheduling class, it | |
27 | * is only served when no one else is using the disk. | |
28 | */ | |
29 | enum { | |
30 | IOPRIO_CLASS_NONE, | |
31 | IOPRIO_CLASS_RT, | |
32 | IOPRIO_CLASS_BE, | |
33 | IOPRIO_CLASS_IDLE, | |
34 | }; | |
35 | ||
36 | /* | |
37 | * 8 best effort priority levels are supported | |
38 | */ | |
39 | #define IOPRIO_BE_NR (8) | |
40 | ||
41 | enum { | |
42 | IOPRIO_WHO_PROCESS = 1, | |
43 | IOPRIO_WHO_PGRP, | |
44 | IOPRIO_WHO_USER, | |
45 | }; | |
46 | ||
f168c273 | 47 | static inline int ioprio_set(int which, int who, int ioprio) { |
b9f880f4 LP |
48 | return syscall(__NR_ioprio_set, which, who, ioprio); |
49 | } | |
50 | ||
f168c273 | 51 | static inline int ioprio_get(int which, int who) { |
b9f880f4 LP |
52 | return syscall(__NR_ioprio_get, which, who); |
53 | } | |
54 | ||
55 | #endif |