posix_fadvise

From: Ulrich Drepper (drepper@redhat.com)
Date: Fri Apr 14 2000 - 02:26:53 EST


Another function from a recent POSIX standard which requires a kernel
implementation:

        int posix_fadvise (int fd, off_t offset, size_t len, int advise)

This function works very similar to madvise (which has the name
posix_madvise in the standard) except that it works on a file and not
a mmap()ed region.

The standard defines the advises

#define POSIX_FADV_NORMAL 0 /* No further special treatment. */
#define POSIX_FADV_RANDOM 1 /* Expect random page references. */
#define POSIX_FADV_SEQUENTIAL 2 /* Expect sequential page references. */
#define POSIX_FADV_WILLNEED 3 /* Will need these pages. */
#define POSIX_FADV_DONTNEED 4 /* Don't need these pages. */
#define POSIX_FADV_NOREUSE 5 /* Data will be accessed once. */

(I've reused the numbers already used for the MADV_* values and added
POSIX_FADV_NOREUSE at the end.)

With madvise already in place it should not be too hard to implement
this function.

I can provide more information to somebody who wants to give it a shot.

As far posix_fallocate, this function should implemented in the kernel
with a 64-bit offset (like pread/pwrite).

-- 
---------------.      drepper at gnu.org  ,-.   1325 Chesapeake Terrace
Ulrich Drepper  \    ,-------------------'   \  Sunnyvale, CA 94089 USA
Red Hat          `--' drepper at redhat.com   `------------------------

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