linux/kernel/power/swsusp.c
Rafael J. Wysocki d6277db4ab [PATCH] swsusp: rework memory shrinker
Rework the swsusp's memory shrinker in the following way:

- Simplify balance_pgdat() by removing all of the swsusp-related code
  from it.

- Make shrink_all_memory() use shrink_slab() and a new function
  shrink_all_zones() which calls shrink_active_list() and
  shrink_inactive_list() directly for each zone in a way that's optimized
  for suspend.

In shrink_all_memory() we try to free exactly as many pages as the caller
asks for, preferably in one shot, starting from easier targets.   If slab
caches are huge, they are most likely to have enough pages to reclaim.
 The inactive lists are next (the zones with more inactive pages go first)
etc.

Each time shrink_all_memory() attempts to shrink the active and inactive
lists for each zone in 5 passes.   In the first pass, only the inactive
lists are taken into consideration.   In the next two passes the active
lists are also shrunk, but mapped pages are not reclaimed.   In the last
two passes the active and inactive lists are shrunk and mapped pages are
reclaimed as well.  The aim of this is to alter the reclaim logic to choose
the best pages to keep on resume and improve the responsiveness of the
resumed system.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:48 -07:00

279 lines
6.7 KiB
C

/*
* linux/kernel/power/swsusp.c
*
* This file provides code to write suspend image to swap and read it back.
*
* Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
* Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2.
*
* I'd like to thank the following people for their work:
*
* Pavel Machek <pavel@ucw.cz>:
* Modifications, defectiveness pointing, being with me at the very beginning,
* suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
*
* Steve Doddi <dirk@loth.demon.co.uk>:
* Support the possibility of hardware state restoring.
*
* Raph <grey.havens@earthling.net>:
* Support for preserving states of network devices and virtual console
* (including X and svgatextmode)
*
* Kurt Garloff <garloff@suse.de>:
* Straightened the critical function in order to prevent compilers from
* playing tricks with local variables.
*
* Andreas Mohr <a.mohr@mailto.de>
*
* Alex Badea <vampire@go.ro>:
* Fixed runaway init
*
* Rafael J. Wysocki <rjw@sisk.pl>
* Reworked the freeing of memory and the handling of swap
*
* More state savers are welcome. Especially for the scsi layer...
*
* For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
*/
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/swap.h>
#include <linux/pm.h>
#include <linux/swapops.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/highmem.h>
#include "power.h"
/*
* Preferred image size in bytes (tunable via /sys/power/image_size).
* When it is set to N, swsusp will do its best to ensure the image
* size will not exceed N bytes, but if that is impossible, it will
* try to create the smallest image possible.
*/
unsigned long image_size = 500 * 1024 * 1024;
int in_suspend __nosavedata = 0;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void);
int save_highmem(void);
int restore_highmem(void);
#else
static int save_highmem(void) { return 0; }
static int restore_highmem(void) { return 0; }
static unsigned int count_highmem_pages(void) { return 0; }
#endif
/**
* The following functions are used for tracing the allocated
* swap pages, so that they can be freed in case of an error.
*
* The functions operate on a linked bitmap structure defined
* in power.h
*/
void free_bitmap(struct bitmap_page *bitmap)
{
struct bitmap_page *bp;
while (bitmap) {
bp = bitmap->next;
free_page((unsigned long)bitmap);
bitmap = bp;
}
}
struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
{
struct bitmap_page *bitmap, *bp;
unsigned int n;
if (!nr_bits)
return NULL;
bitmap = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bitmap;
for (n = BITMAP_PAGE_BITS; n < nr_bits; n += BITMAP_PAGE_BITS) {
bp->next = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
bp = bp->next;
if (!bp) {
free_bitmap(bitmap);
return NULL;
}
}
return bitmap;
}
static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
{
unsigned int n;
n = BITMAP_PAGE_BITS;
while (bitmap && n <= bit) {
n += BITMAP_PAGE_BITS;
bitmap = bitmap->next;
}
if (!bitmap)
return -EINVAL;
n -= BITMAP_PAGE_BITS;
bit -= n;
n = 0;
while (bit >= BITS_PER_CHUNK) {
bit -= BITS_PER_CHUNK;
n++;
}
bitmap->chunks[n] |= (1UL << bit);
return 0;
}
unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
{
unsigned long offset;
offset = swp_offset(get_swap_page_of_type(swap));
if (offset) {
if (bitmap_set(bitmap, offset)) {
swap_free(swp_entry(swap, offset));
offset = 0;
}
}
return offset;
}
void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
{
unsigned int bit, n;
unsigned long test;
bit = 0;
while (bitmap) {
for (n = 0; n < BITMAP_PAGE_CHUNKS; n++)
for (test = 1UL; test; test <<= 1) {
if (bitmap->chunks[n] & test)
swap_free(swp_entry(swap, bit));
bit++;
}
bitmap = bitmap->next;
}
}
/**
* swsusp_shrink_memory - Try to free as much memory as needed
*
* ... but do not OOM-kill anyone
*
* Notice: all userland should be stopped before it is called, or
* livelock is possible.
*/
#define SHRINK_BITE 10000
static inline unsigned long __shrink_memory(long tmp)
{
if (tmp > SHRINK_BITE)
tmp = SHRINK_BITE;
return shrink_all_memory(tmp);
}
int swsusp_shrink_memory(void)
{
long size, tmp;
struct zone *zone;
unsigned long pages = 0;
unsigned int i = 0;
char *p = "-\\|/";
printk("Shrinking memory... ");
do {
size = 2 * count_highmem_pages();
size += size / 50 + count_data_pages();
size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE +
PAGES_FOR_IO;
tmp = size;
for_each_zone (zone)
if (!is_highmem(zone))
tmp -= zone->free_pages;
if (tmp > 0) {
tmp = __shrink_memory(tmp);
if (!tmp)
return -ENOMEM;
pages += tmp;
} else if (size > image_size / PAGE_SIZE) {
tmp = __shrink_memory(size - (image_size / PAGE_SIZE));
pages += tmp;
}
printk("\b%c", p[i++%4]);
} while (tmp > 0);
printk("\bdone (%lu pages freed)\n", pages);
return 0;
}
int swsusp_suspend(void)
{
int error;
if ((error = arch_prepare_suspend()))
return error;
local_irq_disable();
/* At this point, device_suspend() has been called, but *not*
* device_power_down(). We *must* device_power_down() now.
* Otherwise, drivers for some devices (e.g. interrupt controllers)
* become desynchronized with the actual state of the hardware
* at resume time, and evil weirdness ensues.
*/
if ((error = device_power_down(PMSG_FREEZE))) {
printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
goto Enable_irqs;
}
if ((error = save_highmem())) {
printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
goto Restore_highmem;
}
save_processor_state();
if ((error = swsusp_arch_suspend()))
printk(KERN_ERR "Error %d suspending\n", error);
/* Restore control flow magically appears here */
restore_processor_state();
Restore_highmem:
restore_highmem();
device_power_up();
Enable_irqs:
local_irq_enable();
return error;
}
int swsusp_resume(void)
{
int error;
local_irq_disable();
if (device_power_down(PMSG_FREEZE))
printk(KERN_ERR "Some devices failed to power down, very bad\n");
/* We'll ignore saved state, but this gets preempt count (etc) right */
save_processor_state();
error = swsusp_arch_resume();
/* Code below is only ever reached in case of failure. Otherwise
* execution continues at place where swsusp_arch_suspend was called
*/
BUG_ON(!error);
/* The only reason why swsusp_arch_resume() can fail is memory being
* very tight, so we have to free it as soon as we can to avoid
* subsequent failures
*/
swsusp_free();
restore_processor_state();
restore_highmem();
touch_softlockup_watchdog();
device_power_up();
local_irq_enable();
return error;
}