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MAP_NR

NAME

MAP_NR - get memory map index for page in kernel memory

SYNOPSIS

#include <linux/mm.h>

#define MAP_NR(page)

DESCRIPTION

This macro maps the page of kernel memory to an index into the mem_map array. The input page is kernel-space page addresses such as those that come from the get_free_page(9) function. The expression mem_map[MAP_NR(page)] returns a pointer to a mem_map_t for the page in question.

Device drivers need access to the page structure if it is implimenting some special kind of memory segment, i.e. cache for a virtual frame buffer.

RETURN VALUE

Returns an index into the mem_map array.

AVAILABILITY

Linux 2.0+

SEE ALSO

get_free_pages(9)

/usr/include/asm/page.h

AUTHOR

Stephen Williams <steve@icarus.com>

BUGS

There is no check that the page you are passing really is a valid page address.