1#ifndef _SCHED_PRIO_H
2#define _SCHED_PRIO_H
3
4#define MAX_NICE	19
5#define MIN_NICE	-20
6#define NICE_WIDTH	(MAX_NICE - MIN_NICE + 1)
7
8/*
9 * Priority of a process goes from 0..MAX_PRIO-1, valid RT
10 * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
11 * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
12 * values are inverted: lower p->prio value means higher priority.
13 *
14 * The MAX_USER_RT_PRIO value allows the actual maximum
15 * RT priority to be separate from the value exported to
16 * user-space.  This allows kernel threads to set their
17 * priority to a value higher than any user task. Note:
18 * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
19 */
20
21#define MAX_USER_RT_PRIO	100
22#define MAX_RT_PRIO		MAX_USER_RT_PRIO
23
24#define MAX_PRIO		(MAX_RT_PRIO + NICE_WIDTH)
25#define DEFAULT_PRIO		(MAX_RT_PRIO + NICE_WIDTH / 2)
26
27/*
28 * Convert user-nice values [ -20 ... 0 ... 19 ]
29 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
30 * and back.
31 */
32#define NICE_TO_PRIO(nice)	((nice) + DEFAULT_PRIO)
33#define PRIO_TO_NICE(prio)	((prio) - DEFAULT_PRIO)
34
35/*
36 * 'User priority' is the nice value converted to something we
37 * can work with better when scaling various scheduler parameters,
38 * it's a [ 0 ... 39 ] range.
39 */
40#define USER_PRIO(p)		((p)-MAX_RT_PRIO)
41#define TASK_USER_PRIO(p)	USER_PRIO((p)->static_prio)
42#define MAX_USER_PRIO		(USER_PRIO(MAX_PRIO))
43
44/*
45 * Convert nice value [19,-20] to rlimit style value [1,40].
46 */
47static inline long nice_to_rlimit(long nice)
48{
49	return (MAX_NICE - nice + 1);
50}
51
52/*
53 * Convert rlimit style value [1,40] to nice value [-20, 19].
54 */
55static inline long rlimit_to_nice(long prio)
56{
57	return (MAX_NICE - prio + 1);
58}
59
60#endif /* _SCHED_PRIO_H */
61