NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | SEE ALSO | COLOPHON
REMAP_FILE_PAGES(2) Linux Programmer's Manual REMAP_FILE_PAGES(2)
remap_file_pages - create a non-linear file mapping
#define _GNU_SOURCE
#include <sys/mman.h>
int remap_file_pages(void *addr, size_t size, int prot,
ssize_t pgoff, int flags);
The remap_file_pages() system call is used to create a non-linear mapping,
that is, a mapping in which the pages of the file are mapped into a non-
sequential order in memory. The advantage of using remap_file_pages() over
using repeated calls to mmap(2) is that the former approach does not require
the kernel to create additional VMA (Virtual Memory Area) data structures.
To create a non-linear mapping we perform the following steps:
1. Use mmap(2) to create a mapping (which is initially linear). This mapping
must be created with the MAP_SHARED flag.
2. Use one or more calls to remap_file_pages() to rearrange the correspondence
between the pages of the mapping and the pages of the file. It is possible
to map the same page of a file into multiple locations within the mapped
region.
The pgoff and size arguments specify the region of the file that is to be
relocated within the mapping: pgoff is a file offset in units of the system
page size; size is the length of the region in bytes.
The addr argument serves two purposes. First, it identifies the mapping whose
pages we want to rearrange. Thus, addr must be an address that falls within a
region previously mapped by a call to mmap(2). Second, addr specifies the
address at which the file pages identified by pgoff and size will be placed.
The values specified in addr and size should be multiples of the system page
size. If they are not, then the kernel rounds both values down to the nearest
multiple of the page size.
The prot argument must be specified as 0.
The flags argument has the same meaning as for mmap(2), but all flags other
than MAP_NONBLOCK are ignored.
On success, remap_file_pages() returns 0. On error, -1 is returned, and errno
is set appropriately.
EINVAL addr does not refer to a valid mapping created with the MAP_SHARED
flag.
EINVAL addr, size, prot, or pgoff is invalid.
The remap_file_pages() system call appeared in Linux 2.5.46; glibc support was
added in version 2.3.3.
The remap_file_pages() system call is Linux-specific.
getpagesize(2), mmap(2), mmap2(2), mprotect(2), mremap(2), msync(2),
feature_test_macros(7)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
Linux 2008-04-22 REMAP_FILE_PAGES(2)