Announce an intention to access data in a specific pattern.
Announce an intention to access data in a specific pattern, thus
allowing the kernel to make optimizations.
The advice applies to the region of the file specified by fd starting at
offset and continuing for length bytes.
advice is one of POSIX_FADV_NORMAL, POSIX_FADV_SEQUENTIAL,
POSIX_FADV_RANDOM, POSIX_FADV_NOREUSE, POSIX_FADV_WILLNEED, or
POSIX_FADV_DONTNEED.