LXR linux/include/uapi/linux/ioprio.h

   1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2#ifndef _UAPI_LINUX_IOPRIO_H
   3#define _UAPI_LINUX_IOPRIO_H
   4
   5/*
   6 * Gives us 8 prio classes with 13-bits of data for each class
   7 */
   8#define IOPRIO_CLASS_SHIFT      13
   9#define IOPRIO_CLASS_MASK       0x07
  10#define IOPRIO_PRIO_MASK        ((1UL << IOPRIO_CLASS_SHIFT) - 1)
  11
  12#define IOPRIO_PRIO_CLASS(ioprio)       \
  13        (((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK)
  14#define IOPRIO_PRIO_DATA(ioprio)        ((ioprio) & IOPRIO_PRIO_MASK)
  15#define IOPRIO_PRIO_VALUE(class, data)  \
  16        ((((class) & IOPRIO_CLASS_MASK) << IOPRIO_CLASS_SHIFT) | \
  17         ((data) & IOPRIO_PRIO_MASK))
  18
  19/*
  20 * These are the io priority groups as implemented by the BFQ and mq-deadline
  21 * schedulers. RT is the realtime class, it always gets premium service. For
  22 * ATA disks supporting NCQ IO priority, RT class IOs will be processed using
  23 * high priority NCQ commands. BE is the best-effort scheduling class, the
  24 * default for any process. IDLE is the idle scheduling class, it is only
  25 * served when no one else is using the disk.
  26 */
  27enum {
  28        IOPRIO_CLASS_NONE,
  29        IOPRIO_CLASS_RT,
  30        IOPRIO_CLASS_BE,
  31        IOPRIO_CLASS_IDLE,
  32};
  33
  34/*
  35 * The RT and BE priority classes both support up to 8 priority levels.
  36 */
  37#define IOPRIO_NR_LEVELS        8
  38#define IOPRIO_BE_NR            IOPRIO_NR_LEVELS
  39
  40enum {
  41        IOPRIO_WHO_PROCESS = 1,
  42        IOPRIO_WHO_PGRP,
  43        IOPRIO_WHO_USER,
  44};
  45
  46/*
  47 * Fallback BE priority level.
  48 */
  49#define IOPRIO_NORM     4
  50#define IOPRIO_BE_NORM  IOPRIO_NORM
  51
  52#endif /* _UAPI_LINUX_IOPRIO_H */
  53