1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SCHED_PRIO_H
3 #define _LINUX_SCHED_PRIO_H
4
5 #define MAX_NICE 19
6 #define MIN_NICE -20
7 #define NICE_WIDTH (MAX_NICE - MIN_NICE + 1)
8
9 /*
10 * Priority of a process goes from 0..MAX_PRIO-1, valid RT
11 * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
12 * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
13 * values are inverted: lower p->prio value means higher priority.
14 */
15
16 #define MAX_RT_PRIO 100
17
18 #define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
19 #define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
20
21 /*
22 * Convert user-nice values [ -20 ... 0 ... 19 ]
23 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
24 * and back.
25 */
26 #define NICE_TO_PRIO(nice) ((nice) + DEFAULT_PRIO)
27 #define PRIO_TO_NICE(prio) ((prio) - DEFAULT_PRIO)
28
29 /*
30 * Convert nice value [19,-20] to rlimit style value [1,40].
31 */
32 static inline long nice_to_rlimit(long nice)
33 {
34 return (MAX_NICE - nice + 1);
35 }
36
37 /*
38 * Convert rlimit style value [1,40] to nice value [-20, 19].
39 */
40 static inline long rlimit_to_nice(long prio)
41 {
42 return (MAX_NICE - prio + 1);
43 }
44
45 #endif /* _LINUX_SCHED_PRIO_H */
46
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