Branch data Line data Source code
1 : : #ifndef IOPRIO_H
2 : : #define IOPRIO_H
3 : :
4 : : #include <linux/sched.h>
5 : : #include <linux/iocontext.h>
6 : :
7 : : /*
8 : : * Gives us 8 prio classes with 13-bits of data for each class
9 : : */
10 : : #define IOPRIO_BITS (16)
11 : : #define IOPRIO_CLASS_SHIFT (13)
12 : : #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
13 : :
14 : : #define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
15 : : #define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK)
16 : : #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
17 : :
18 : : #define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
19 : :
20 : : /*
21 : : * These are the io priority groups as implemented by CFQ. RT is the realtime
22 : : * class, it always gets premium service. BE is the best-effort scheduling
23 : : * class, the default for any process. IDLE is the idle scheduling class, it
24 : : * is only served when no one else is using the disk.
25 : : */
26 : : enum {
27 : : IOPRIO_CLASS_NONE,
28 : : IOPRIO_CLASS_RT,
29 : : IOPRIO_CLASS_BE,
30 : : IOPRIO_CLASS_IDLE,
31 : : };
32 : :
33 : : /*
34 : : * 8 best effort priority levels are supported
35 : : */
36 : : #define IOPRIO_BE_NR (8)
37 : :
38 : : enum {
39 : : IOPRIO_WHO_PROCESS = 1,
40 : : IOPRIO_WHO_PGRP,
41 : : IOPRIO_WHO_USER,
42 : : };
43 : :
44 : : /*
45 : : * Fallback BE priority
46 : : */
47 : : #define IOPRIO_NORM (4)
48 : :
49 : : /*
50 : : * if process has set io priority explicitly, use that. if not, convert
51 : : * the cpu scheduler nice value to an io priority
52 : : */
53 : : static inline int task_nice_ioprio(struct task_struct *task)
54 : : {
55 : 3424 : return (task_nice(task) + 20) / 5;
56 : : }
57 : :
58 : : /*
59 : : * This is for the case where the task hasn't asked for a specific IO class.
60 : : * Check for idle and rt task process, and return appropriate IO class.
61 : : */
62 : : static inline int task_nice_ioclass(struct task_struct *task)
63 : : {
64 [ + - ]: 792402 : if (task->policy == SCHED_IDLE)
65 : : return IOPRIO_CLASS_IDLE;
66 [ + - ]: 3424 : else if (task->policy == SCHED_FIFO || task->policy == SCHED_RR)
67 : : return IOPRIO_CLASS_RT;
68 : : else
69 : : return IOPRIO_CLASS_BE;
70 : : }
71 : :
72 : : /*
73 : : * For inheritance, return the highest of the two given priorities
74 : : */
75 : : extern int ioprio_best(unsigned short aprio, unsigned short bprio);
76 : :
77 : : extern int set_task_ioprio(struct task_struct *task, int ioprio);
78 : :
79 : : #endif
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