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

   1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2#ifndef _UAPI_LINUX_SCHED_TYPES_H
   3#define _UAPI_LINUX_SCHED_TYPES_H
   4
   5#include <linux/types.h>
   6
   7struct sched_param {
   8        int sched_priority;
   9};
  10
  11#define SCHED_ATTR_SIZE_VER0    48      /* sizeof first published struct */
  12
  13/*
  14 * Extended scheduling parameters data structure.
  15 *
  16 * This is needed because the original struct sched_param can not be
  17 * altered without introducing ABI issues with legacy applications
  18 * (e.g., in sched_getparam()).
  19 *
  20 * However, the possibility of specifying more than just a priority for
  21 * the tasks may be useful for a wide variety of application fields, e.g.,
  22 * multimedia, streaming, automation and control, and many others.
  23 *
  24 * This variant (sched_attr) is meant at describing a so-called
  25 * sporadic time-constrained task. In such model a task is specified by:
  26 *  - the activation period or minimum instance inter-arrival time;
  27 *  - the maximum (or average, depending on the actual scheduling
  28 *    discipline) computation time of all instances, a.k.a. runtime;
  29 *  - the deadline (relative to the actual activation time) of each
  30 *    instance.
  31 * Very briefly, a periodic (sporadic) task asks for the execution of
  32 * some specific computation --which is typically called an instance--
  33 * (at most) every period. Moreover, each instance typically lasts no more
  34 * than the runtime and must be completed by time instant t equal to
  35 * the instance activation time + the deadline.
  36 *
  37 * This is reflected by the actual fields of the sched_attr structure:
  38 *
  39 *  @size               size of the structure, for fwd/bwd compat.
  40 *
  41 *  @sched_policy       task's scheduling policy
  42 *  @sched_flags        for customizing the scheduler behaviour
  43 *  @sched_nice         task's nice value      (SCHED_NORMAL/BATCH)
  44 *  @sched_priority     task's static priority (SCHED_FIFO/RR)
  45 *  @sched_deadline     representative of the task's deadline
  46 *  @sched_runtime      representative of the task's runtime
  47 *  @sched_period       representative of the task's period
  48 *
  49 * Given this task model, there are a multiplicity of scheduling algorithms
  50 * and policies, that can be used to ensure all the tasks will make their
  51 * timing constraints.
  52 *
  53 * As of now, the SCHED_DEADLINE policy (sched_dl scheduling class) is the
  54 * only user of this new interface. More information about the algorithm
  55 * available in the scheduling class file or in Documentation/.
  56 */
  57struct sched_attr {
  58        __u32 size;
  59
  60        __u32 sched_policy;
  61        __u64 sched_flags;
  62
  63        /* SCHED_NORMAL, SCHED_BATCH */
  64        __s32 sched_nice;
  65
  66        /* SCHED_FIFO, SCHED_RR */
  67        __u32 sched_priority;
  68
  69        /* SCHED_DEADLINE */
  70        __u64 sched_runtime;
  71        __u64 sched_deadline;
  72        __u64 sched_period;
  73};
  74
  75#endif /* _UAPI_LINUX_SCHED_TYPES_H */
  76