1 .\" Copyright (C) 2003, Michael Kerrisk (mtk.manpages@gmail.com)
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23 .\" 2003-12-10 Initial creation, Michael Kerrisk <mtk.manpages@gmail.com>
24 .\" 2004-10-28 aeb, corrected prototype, prot must be 0
26 .TH REMAP_FILE_PAGES 2 2008-04-22 "Linux" "Linux Programmer's Manual"
28 remap_file_pages \- create a nonlinear file mapping
31 .BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
32 .B #include <sys/mman.h>
34 .BI "int remap_file_pages(void *" addr ", size_t " size ", int " prot ,
35 .BI " ssize_t " pgoff ", int " flags );
39 .BR remap_file_pages ()
40 system call is used to create a nonlinear mapping, that is, a mapping
41 in which the pages of the file are mapped into a nonsequential order
43 The advantage of using
44 .BR remap_file_pages ()
45 over using repeated calls to
47 is that the former approach does not require the kernel to create
48 additional VMA (Virtual Memory Area) data structures.
50 To create a nonlinear mapping we perform the following steps:
55 to create a mapping (which is initially linear).
56 This mapping must be created with the
61 Use one or more calls to
62 .BR remap_file_pages ()
63 to rearrange the correspondence between the pages of the mapping
64 and the pages of the file.
65 It is possible to map the same page of a file
66 into multiple locations within the mapped region.
72 arguments specify the region of the file that is to be relocated
75 is a file offset in units of the system page size;
77 is the length of the region in bytes.
81 argument serves two purposes.
82 First, it identifies the mapping whose pages we want to rearrange.
85 must be an address that falls within
86 a region previously mapped by a call to
90 specifies the address at which the file pages
97 The values specified in
101 should be multiples of the system page size.
102 If they are not, then the kernel rounds
106 to the nearest multiple of the page size.
107 .\" This rounding is weird, and not consistent with the treatment of
108 .\" the analogous arguments for munmap()/mprotect() and for mlock().
113 argument must be specified as 0.
117 argument has the same meaning as for
119 but all flags other than
124 .BR remap_file_pages ()
126 On error, \-1 is returned, and
128 is set appropriately.
133 does not refer to a valid mapping
145 .\" And possibly others from vma->vm_ops->populate()
148 .BR remap_file_pages ()
149 system call appeared in Linux 2.5.46;
150 glibc support was added in version 2.3.3.
153 .BR remap_file_pages ()
154 system call is Linux-specific.