prio.h 1.7 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061
  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _LINUX_SCHED_PRIO_H
  3. #define _LINUX_SCHED_PRIO_H
  4. #define MAX_NICE 19
  5. #define MIN_NICE -20
  6. #define NICE_WIDTH (MAX_NICE - MIN_NICE + 1)
  7. /*
  8. * Priority of a process goes from 0..MAX_PRIO-1, valid RT
  9. * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
  10. * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
  11. * values are inverted: lower p->prio value means higher priority.
  12. *
  13. * The MAX_USER_RT_PRIO value allows the actual maximum
  14. * RT priority to be separate from the value exported to
  15. * user-space. This allows kernel threads to set their
  16. * priority to a value higher than any user task. Note:
  17. * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
  18. */
  19. #define MAX_USER_RT_PRIO 100
  20. #define MAX_RT_PRIO MAX_USER_RT_PRIO
  21. #define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
  22. #define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
  23. /*
  24. * Convert user-nice values [ -20 ... 0 ... 19 ]
  25. * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
  26. * and back.
  27. */
  28. #define NICE_TO_PRIO(nice) ((nice) + DEFAULT_PRIO)
  29. #define PRIO_TO_NICE(prio) ((prio) - DEFAULT_PRIO)
  30. /*
  31. * 'User priority' is the nice value converted to something we
  32. * can work with better when scaling various scheduler parameters,
  33. * it's a [ 0 ... 39 ] range.
  34. */
  35. #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
  36. #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
  37. #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
  38. /*
  39. * Convert nice value [19,-20] to rlimit style value [1,40].
  40. */
  41. static inline long nice_to_rlimit(long nice)
  42. {
  43. return (MAX_NICE - nice + 1);
  44. }
  45. /*
  46. * Convert rlimit style value [1,40] to nice value [-20, 19].
  47. */
  48. static inline long rlimit_to_nice(long prio)
  49. {
  50. return (MAX_NICE - prio + 1);
  51. }
  52. #endif /* _LINUX_SCHED_PRIO_H */