FADVISE64,FADVISE64_64(2) Linux Programmer's Guide FADVISE64,FADVISE64_64(2)NAME
fadvise64,fadvise64_64 - Give advice about file access
SYNOPSIS
long fadvise64_64 (int fs, loff_t offset, loff_t len, int advice,
int fs, loff_t offset,
loff_t len, int advice);
long sys_fadvise64 (int fs, loff_t offset, loff_t len, int advice,
int fs, loff_t offset, loff_t len, int advice);
DESCRIPTION
Allows an application to to tell the kernel how it expects to use a
file handle, so that the kernel can choose appropriate read-ahead and
caching techniques for access to the corresponding file. This is simi‐
lar to the POSIX version of the madvise system call, but for file ac‐
cess instead of memory access. The sys_fadvise64() function is obsolete
and corresponds to a broken glibc API, sys_fadvise64_64() is the fixed
version. The following are the values for the advice parameter:
FADV_NORMAL
No special treatment.
FADV_RANDOM
Expect page references in random order.
FADV_SEQUENTIAL
Expect page references in sequential order.
FADV_WILLNEED
Expect access in the near future.
FADV_DONTNEED
Do not expect access in the near future. Subsequent access of
pages in this range will succeed, but will result either in
reloading of the memory contents from the underlying mapped file
or zero-fill-in-demand pages for mappings without an underlying
file.
FADV_NOREUSE
Access data only once.
ERRORS-EBADF An invalid file descriptor was specified. to modify the modules.
-EINVAL
An invalid f_mapping of file, len value smaller than 0 or advice
value unknown.
SEE ALSOmadvise(2)AUTHOR
Niki Rahimi
Linux 2.6 2004-March-12 FADVISE64,FADVISE64_64(2)