mmap2(2) [minix man page]

MMAP2(2)						     Linux Programmer's Manual							  MMAP2(2)

NAME

       mmap2 - map files or devices into memory

SYNOPSIS

       #include <sys/mman.h>

       void *mmap2(void *addr, size_t length, int prot,
		    int flags, int fd, off_t pgoffset);

DESCRIPTION

       This  is  probably  not	the  system call that you are interested in; instead, see mmap(2), which describes the glibc wrapper function that
       invokes this system call.

       The mmap2() system call provides the same interface as mmap(2), except that the final argument  specifies  the  offset  into  the  file	in
       4096-byte  units  (instead  of  bytes, as is done by mmap(2)).  This enables applications that use a 32-bit off_t to map large files (up to
       2^44 bytes).

RETURN VALUE

       On success, mmap2() returns a pointer to the mapped area.  On error, -1 is returned and errno is set appropriately.

ERRORS

       EFAULT Problem with getting the data from user space.

       EINVAL (Various platforms where the page size is not 4096 bytes.)  offset * 4096 is not a multiple of the system page size.

       mmap2() can also return any of the errors described in mmap(2).

VERSIONS

       mmap2() is available since Linux 2.3.31.

CONFORMING TO

       This system call is Linux-specific.

NOTES

       On architectures where this system call is present, the glibc mmap() wrapper function invokes this system call rather than the mmap(2) sys-
       tem call.

       This system call does not exist on x86-64.

       On ia64, the unit for offset is actually the system page size, rather than 4096 bytes.

SEE ALSO

       getpagesize(2), mmap(2), mremap(2), msync(2), shm_open(3)

COLOPHON

       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15								  MMAP2(2)

REMAP_FILE_PAGES(2)					     Linux Programmer's Manual					       REMAP_FILE_PAGES(2)

NAME

       remap_file_pages - create a nonlinear file mapping

SYNOPSIS

       #define _GNU_SOURCE
       #include <sys/mman.h>

       int remap_file_pages(void *addr, size_t size, int prot,
			    ssize_t pgoff, int flags);

DESCRIPTION

       The remap_file_pages() system call is used to create a nonlinear mapping, that is, a mapping in which the pages of the file are mapped into
       a nonsequential 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 nonlinear 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.

RETURN VALUE

       On success, remap_file_pages() returns 0.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EINVAL addr does not refer to a valid mapping created with the MAP_SHARED flag.

       EINVAL addr, size, prot, or pgoff is invalid.

VERSIONS

       The remap_file_pages() system call appeared in Linux 2.5.46; glibc support was added in version 2.3.3.

CONFORMING TO

       The remap_file_pages() system call is Linux-specific.

SEE ALSO

       getpagesize(2), mmap(2), mmap2(2), mprotect(2), mremap(2), msync(2), feature_test_macros(7)

COLOPHON

       This page is part of release 3.27 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)