skel

Section: VM Functions (9)
Updated: $Date:$
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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.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
AVAILABILITY
SEE ALSO
AUTHOR
BUGS
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