LXR linux/include/uapi/linux/sched/types.h

   1#ifndef _UAPI_LINUX_SCHED_TYPES_H
   2#define _UAPI_LINUX_SCHED_TYPES_H
   3
   4#include <linux/types.h>
   5
   6struct sched_param {
   7        int sched_priority;
   8};
   9
  10#define SCHED_ATTR_SIZE_VER0    48      /* sizeof first published struct */
  11
  12/*
  13 * Extended scheduling parameters data structure.
  14 *
  15 * This is needed because the original struct sched_param can not be
  16 * altered without introducing ABI issues with legacy applications
  17 * (e.g., in sched_getparam()).
  18 *
  19 * However, the possibility of specifying more than just a priority for
  20 * the tasks may be useful for a wide variety of application fields, e.g.,
  21 * multimedia, streaming, automation and control, and many others.
  22 *
  23 * This variant (sched_attr) is meant at describing a so-called
  24 * sporadic time-constrained task. In such model a task is specified by:
  25 *  - the activation period or minimum instance inter-arrival time;
  26 *  - the maximum (or average, depending on the actual scheduling
  27 *    discipline) computation time of all instances, a.k.a. runtime;
  28 *  - the deadline (relative to the actual activation time) of each
  29 *    instance.
  30 * Very briefly, a periodic (sporadic) task asks for the execution of
  31 * some specific computation --which is typically called an instance--
  32 * (at most) every period. Moreover, each instance typically lasts no more
  33 * than the runtime and must be completed by time instant t equal to
  34 * the instance activation time + the deadline.
  35 *
  36 * This is reflected by the actual fields of the sched_attr structure:
  37 *
  38 *  @size               size of the structure, for fwd/bwd compat.
  39 *
  40 *  @sched_policy       task's scheduling policy
  41 *  @sched_flags        for customizing the scheduler behaviour
  42 *  @sched_nice         task's nice value      (SCHED_NORMAL/BATCH)
  43 *  @sched_priority     task's static priority (SCHED_FIFO/RR)
  44 *  @sched_deadline     representative of the task's deadline
  45 *  @sched_runtime      representative of the task's runtime
  46 *  @sched_period       representative of the task's period
  47 *
  48 * Given this task model, there are a multiplicity of scheduling algorithms
  49 * and policies, that can be used to ensure all the tasks will make their
  50 * timing constraints.
  51 *
  52 * As of now, the SCHED_DEADLINE policy (sched_dl scheduling class) is the
  53 * only user of this new interface. More information about the algorithm
  54 * available in the scheduling class file or in Documentation/.
  55 */
  56struct sched_attr {
  57        u32 size;
  58
  59        u32 sched_policy;
  60        u64 sched_flags;
  61
  62        /* SCHED_NORMAL, SCHED_BATCH */
  63        s32 sched_nice;
  64
  65        /* SCHED_FIFO, SCHED_RR */
  66        u32 sched_priority;
  67
  68        /* SCHED_DEADLINE */
  69        u64 sched_runtime;
  70        u64 sched_deadline;
  71        u64 sched_period;
  72};
  73
  74#endif /* _UAPI_LINUX_SCHED_TYPES_H */
  75