NAME

     mem_map_reserve, mem_map_unreserve - Manipulate flags of
     virtual memory pages.

SYNOPSIS

     #include <linux/mm.h>
     #include <linux/wrapper.h>

     #define mem_map_reserve(page_nr))
     #define mem_map_unreserve(page_nr))

DESCRIPTION
These macros cause a page to become reserved/unreserved. A reserved page is reserved from any further consideration by the linux kernel, meaning it is not scanned as potentially pageable, or available for page allocation. The kernel treats reserved pages as memory-mapped hardware. It makes sense for a driver to mark a page reserved, for example, if the driver supports mmap(2) with dynamically allocated pages that the target device can access via DMA.

RETURN VALUE
None

AVAILABILITY
Linux 2.0+

SEE ALSO
MAP_NR(9), get_free_pages(9), mmap(2)

AUTHOR
Stephen Williams <steve@icarus.com>

BUGS
If a page is marked reserved, a call to free_page(9) will silenty ignore it. If the page was originally allocated by get_free_page, you must remember to unmark the page before releasing it to the system. Otherwise, the page is lost.