diff options
Diffstat (limited to 'include/uapi/linux/ioprio.h')
| -rw-r--r-- | include/uapi/linux/ioprio.h | 100 |
1 files changed, 87 insertions, 13 deletions
diff --git a/include/uapi/linux/ioprio.h b/include/uapi/linux/ioprio.h index f70f2596a6bf..99440b2e8c35 100644 --- a/include/uapi/linux/ioprio.h +++ b/include/uapi/linux/ioprio.h @@ -2,22 +2,23 @@ #ifndef _UAPI_LINUX_IOPRIO_H #define _UAPI_LINUX_IOPRIO_H +#include <linux/stddef.h> +#include <linux/types.h> + /* * Gives us 8 prio classes with 13-bits of data for each class */ #define IOPRIO_CLASS_SHIFT 13 -#define IOPRIO_CLASS_MASK 0x07 +#define IOPRIO_NR_CLASSES 8 +#define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1) #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) #define IOPRIO_PRIO_CLASS(ioprio) \ (((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK) #define IOPRIO_PRIO_DATA(ioprio) ((ioprio) & IOPRIO_PRIO_MASK) -#define IOPRIO_PRIO_VALUE(class, data) \ - ((((class) & IOPRIO_CLASS_MASK) << IOPRIO_CLASS_SHIFT) | \ - ((data) & IOPRIO_PRIO_MASK)) /* - * These are the io priority groups as implemented by the BFQ and mq-deadline + * These are the io priority classes as implemented by the BFQ and mq-deadline * schedulers. RT is the realtime class, it always gets premium service. For * ATA disks supporting NCQ IO priority, RT class IOs will be processed using * high priority NCQ commands. BE is the best-effort scheduling class, the @@ -25,18 +26,30 @@ * served when no one else is using the disk. */ enum { - IOPRIO_CLASS_NONE, - IOPRIO_CLASS_RT, - IOPRIO_CLASS_BE, - IOPRIO_CLASS_IDLE, + IOPRIO_CLASS_NONE = 0, + IOPRIO_CLASS_RT = 1, + IOPRIO_CLASS_BE = 2, + IOPRIO_CLASS_IDLE = 3, + + /* Special class to indicate an invalid ioprio value */ + IOPRIO_CLASS_INVALID = 7, }; /* - * The RT and BE priority classes both support up to 8 priority levels. + * The RT and BE priority classes both support up to 8 priority levels that + * can be specified using the lower 3-bits of the priority data. */ -#define IOPRIO_NR_LEVELS 8 -#define IOPRIO_BE_NR IOPRIO_NR_LEVELS +#define IOPRIO_LEVEL_NR_BITS 3 +#define IOPRIO_NR_LEVELS (1 << IOPRIO_LEVEL_NR_BITS) +#define IOPRIO_LEVEL_MASK (IOPRIO_NR_LEVELS - 1) +#define IOPRIO_PRIO_LEVEL(ioprio) ((ioprio) & IOPRIO_LEVEL_MASK) + +#define IOPRIO_BE_NR IOPRIO_NR_LEVELS +/* + * Possible values for the "which" argument of the ioprio_get() and + * ioprio_set() system calls (see "man ioprio_set"). + */ enum { IOPRIO_WHO_PROCESS = 1, IOPRIO_WHO_PGRP, @@ -44,9 +57,70 @@ enum { }; /* - * Fallback BE priority level. + * Fallback BE class priority level. */ #define IOPRIO_NORM 4 #define IOPRIO_BE_NORM IOPRIO_NORM +/* + * The 10 bits between the priority class and the priority level are used to + * optionally define I/O hints for any combination of I/O priority class and + * level. Depending on the kernel configuration, I/O scheduler being used and + * the target I/O device being used, hints can influence how I/Os are processed + * without affecting the I/O scheduling ordering defined by the I/O priority + * class and level. + */ +#define IOPRIO_HINT_SHIFT IOPRIO_LEVEL_NR_BITS +#define IOPRIO_HINT_NR_BITS 10 +#define IOPRIO_NR_HINTS (1 << IOPRIO_HINT_NR_BITS) +#define IOPRIO_HINT_MASK (IOPRIO_NR_HINTS - 1) +#define IOPRIO_PRIO_HINT(ioprio) \ + (((ioprio) >> IOPRIO_HINT_SHIFT) & IOPRIO_HINT_MASK) + +/* + * I/O hints. + */ +enum { + /* No hint */ + IOPRIO_HINT_NONE = 0, + + /* + * Device command duration limits: indicate to the device a desired + * duration limit for the commands that will be used to process an I/O. + * These will currently only be effective for SCSI and ATA devices that + * support the command duration limits feature. If this feature is + * enabled, then the commands issued to the device to process an I/O with + * one of these hints set will have the duration limit index (dld field) + * set to the value of the hint. + */ + IOPRIO_HINT_DEV_DURATION_LIMIT_1 = 1, + IOPRIO_HINT_DEV_DURATION_LIMIT_2 = 2, + IOPRIO_HINT_DEV_DURATION_LIMIT_3 = 3, + IOPRIO_HINT_DEV_DURATION_LIMIT_4 = 4, + IOPRIO_HINT_DEV_DURATION_LIMIT_5 = 5, + IOPRIO_HINT_DEV_DURATION_LIMIT_6 = 6, + IOPRIO_HINT_DEV_DURATION_LIMIT_7 = 7, +}; + +#define IOPRIO_BAD_VALUE(val, max) ((val) < 0 || (val) >= (max)) + +/* + * Return an I/O priority value based on a class, a level and a hint. + */ +static __always_inline __u16 ioprio_value(int class, int level, int hint) +{ + if (IOPRIO_BAD_VALUE(class, IOPRIO_NR_CLASSES) || + IOPRIO_BAD_VALUE(level, IOPRIO_NR_LEVELS) || + IOPRIO_BAD_VALUE(hint, IOPRIO_NR_HINTS)) + return IOPRIO_CLASS_INVALID << IOPRIO_CLASS_SHIFT; + + return (class << IOPRIO_CLASS_SHIFT) | + (hint << IOPRIO_HINT_SHIFT) | level; +} + +#define IOPRIO_PRIO_VALUE(class, level) \ + ioprio_value(class, level, IOPRIO_HINT_NONE) +#define IOPRIO_PRIO_VALUE_HINT(class, level, hint) \ + ioprio_value(class, level, hint) + #endif /* _UAPI_LINUX_IOPRIO_H */ |