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author | Luke Shumaker <lukeshu@sbcglobal.net> | 2016-07-27 21:13:44 -0400 |
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committer | Luke Shumaker <lukeshu@sbcglobal.net> | 2016-07-27 21:13:44 -0400 |
commit | 569a9b5aa9258ca9ec7f201f1348aaa5494798a1 (patch) | |
tree | 8d16f6ed0c30bae7c9093fa9f392d6f94811971f /src/libbasic/ioprio.h | |
parent | 68f92176c58e185292b9fa53a558031fb901797d (diff) |
./move.sh
Diffstat (limited to 'src/libbasic/ioprio.h')
-rw-r--r-- | src/libbasic/ioprio.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/src/libbasic/ioprio.h b/src/libbasic/ioprio.h new file mode 100644 index 0000000000..d8bb6eb497 --- /dev/null +++ b/src/libbasic/ioprio.h @@ -0,0 +1,55 @@ +#ifndef IOPRIO_H +#define IOPRIO_H + +/* This is minimal version of Linux' linux/ioprio.h header file, which + * is licensed GPL2 */ + +#include <sys/syscall.h> +#include <unistd.h> + +/* + * Gives us 8 prio classes with 13-bits of data for each class + */ +#define IOPRIO_BITS (16) +#define IOPRIO_CLASS_SHIFT (13) +#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) + +#define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT) +#define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK) +#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data) + +#define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE) + +/* + * These are the io priority groups as implemented by CFQ. RT is the realtime + * class, it always gets premium service. BE is the best-effort scheduling + * class, the default for any process. IDLE is the idle scheduling class, it + * is only served when no one else is using the disk. + */ +enum { + IOPRIO_CLASS_NONE, + IOPRIO_CLASS_RT, + IOPRIO_CLASS_BE, + IOPRIO_CLASS_IDLE, +}; + +/* + * 8 best effort priority levels are supported + */ +#define IOPRIO_BE_NR (8) + +enum { + IOPRIO_WHO_PROCESS = 1, + IOPRIO_WHO_PGRP, + IOPRIO_WHO_USER, +}; + +static inline int ioprio_set(int which, int who, int ioprio) { + return syscall(__NR_ioprio_set, which, who, ioprio); +} + +static inline int ioprio_get(int which, int who) { + return syscall(__NR_ioprio_get, which, who); +} + +#endif |