linux-stable/arch/um/include/mem_user.h
Jeff Dike 02dea0875b [PATCH] UML: Hotplug memory, take 2
Changes since first version
	added check for MADV_REMOVE support on the host
	fixed error return botch
	shrunk sprintf array by one character

This adds hotplug memory support to UML.  The mconsole syntax is
 	config mem=[+-]n[KMG]
In other words, add or subtract some number of kilobytes, megabytes, or
gigabytes.

Unplugged pages are allocated and then madvise(MADV_TRUNCATE), which is a
currently experimental madvise extension.  These pages are tracked so they
can be plugged back in later if the admin decides to give them back.  The
first page to be unplugged is used to keep track of about 4M of other
pages.  A list_head is the first thing on this page.  The rest is filled
with addresses of other unplugged pages.  This first page is not madvised,
obviously.

When this page is filled, the next page is used in a similar way and linked
onto a list with the first page.  Etc.  This whole process reverses when
pages are plugged back in.  When a tracking page no longer tracks any
unplugged pages, then it is next in line for plugging, which is done by
freeing pages back to the kernel.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:18:50 -08:00

67 lines
2.5 KiB
C

/*
* arch/um/include/mem_user.h
*
* BRIEF MODULE DESCRIPTION
* user side memory interface for support IO memory inside user mode linux
*
* Copyright (C) 2001 RidgeRun, Inc.
* Author: RidgeRun, Inc.
* Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _MEM_USER_H
#define _MEM_USER_H
struct iomem_region {
struct iomem_region *next;
char *driver;
int fd;
int size;
unsigned long phys;
unsigned long virt;
};
extern struct iomem_region *iomem_regions;
extern int iomem_size;
#define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))
extern unsigned long host_task_size;
extern unsigned long task_size;
extern int init_mem_user(void);
extern void setup_memory(void *entry);
extern unsigned long find_iomem(char *driver, unsigned long *len_out);
extern int init_maps(unsigned long physmem, unsigned long iomem,
unsigned long highmem);
extern unsigned long get_vm(unsigned long len);
extern void setup_physmem(unsigned long start, unsigned long usable,
unsigned long len, unsigned long long highmem);
extern void add_iomem(char *name, int fd, unsigned long size);
extern unsigned long phys_offset(unsigned long phys);
extern void unmap_physmem(void);
extern void map_memory(unsigned long virt, unsigned long phys,
unsigned long len, int r, int w, int x);
extern unsigned long get_kmem_end(void);
#endif