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  */
nice_to_rlimit(long nice)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  */
rlimit_to_nice(long prio)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