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 * The MAX_USER_RT_PRIO value allows the actual maximum 16 * RT priority to be separate from the value exported to 17 * user-space. This allows kernel threads to set their 18 * priority to a value higher than any user task. Note: 19 * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO. 20 */ 21 22 #define MAX_USER_RT_PRIO 100 23 #define MAX_RT_PRIO MAX_USER_RT_PRIO 24 25 #define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH) 26 #define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2) 27 28 /* 29 * Convert user-nice values [ -20 ... 0 ... 19 ] 30 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], 31 * and back. 32 */ 33 #define NICE_TO_PRIO(nice) ((nice) + DEFAULT_PRIO) 34 #define PRIO_TO_NICE(prio) ((prio) - DEFAULT_PRIO) 35 36 /* 37 * 'User priority' is the nice value converted to something we 38 * can work with better when scaling various scheduler parameters, 39 * it's a [ 0 ... 39 ] range. 40 */ 41 #define USER_PRIO(p) ((p)-MAX_RT_PRIO) 42 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) 43 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) 44 45 /* 46 * Convert nice value [19,-20] to rlimit style value [1,40]. 47 */ nice_to_rlimit(long nice)48static inline long nice_to_rlimit(long nice) 49 { 50 return (MAX_NICE - nice + 1); 51 } 52 53 /* 54 * Convert rlimit style value [1,40] to nice value [-20, 19]. 55 */ rlimit_to_nice(long prio)56static inline long rlimit_to_nice(long prio) 57 { 58 return (MAX_NICE - prio + 1); 59 } 60 61 #endif /* _LINUX_SCHED_PRIO_H */ 62