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Dongsheng Yang5c228072014-01-27 17:15:37 -05001#ifndef _SCHED_PRIO_H
2#define _SCHED_PRIO_H
3
Dongsheng Yang3ee237d2014-02-11 15:34:46 +08004#define MAX_NICE 19
5#define MIN_NICE -20
6#define NICE_WIDTH (MAX_NICE - MIN_NICE + 1)
7
Dongsheng Yang5c228072014-01-27 17:15:37 -05008/*
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
Dongsheng Yang3ee237d2014-02-11 15:34:46 +080024#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
25#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
Dongsheng Yang5c228072014-01-27 17:15:37 -050026
Dongsheng Yang6b6350f2014-01-27 17:15:38 -050027/*
28 * Convert user-nice values [ -20 ... 0 ... 19 ]
29 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
30 * and back.
31 */
Dongsheng Yang7e298d62014-02-11 15:34:45 +080032#define NICE_TO_PRIO(nice) ((nice) + DEFAULT_PRIO)
33#define PRIO_TO_NICE(prio) ((prio) - DEFAULT_PRIO)
Dongsheng Yang6b6350f2014-01-27 17:15:38 -050034
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
Dongsheng Yang7aa2c012014-05-08 18:33:49 +090044/*
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
Dongsheng Yang5c228072014-01-27 17:15:37 -050060#endif /* _SCHED_PRIO_H */