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#define MAX_DL_PRIO 0
18
19#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
20#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
21
22/*
23 * Convert user-nice values [ -20 ... 0 ... 19 ]
24 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
25 * and back.
26 */
27#define NICE_TO_PRIO(nice) ((nice) + DEFAULT_PRIO)
28#define PRIO_TO_NICE(prio) ((prio) - DEFAULT_PRIO)
29
30/*
31 * Convert nice value [19,-20] to rlimit style value [1,40].
32 */
33static inline long nice_to_rlimit(long nice)
34{
35 return (MAX_NICE - nice + 1);
36}
37
38/*
39 * Convert rlimit style value [1,40] to nice value [-20, 19].
40 */
41static inline long rlimit_to_nice(long prio)
42{
43 return (MAX_NICE - prio + 1);
44}
45
46#endif /* _LINUX_SCHED_PRIO_H */
47

source code of linux/include/linux/sched/prio.h