linux/kernel/power/snapshot.c
Rafael J. Wysocki e5e2fa7857 [PATCH] swsusp: fix enough_free_mem
This patch fixes a problem with the function enough_free_mem() used by
swsusp to verify if there is a sufficient number of memory pages available
to it to create and save the suspend image.

Namely, enough_free_mem() uses nr_free_pages() to obtain the number of free
memory pages, which is incorrect, because this function returns the total
number of free pages, including free highmem pages, and the highmem pages
cannot be used by swsusp for storing the image data.

The patch makes enough_free_mem() avoid counting the free highmem
pages as available to swsusp.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:40 -08:00

512 lines
12 KiB
C

/*
* linux/kernel/power/snapshot.c
*
* This file provide system snapshot/restore functionality.
*
* Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
*
* This file is released under the GPLv2, and is based on swsusp.c.
*
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/console.h>
#include <linux/highmem.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
#include "power.h"
struct pbe *pagedir_nosave;
unsigned int nr_copy_pages;
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
unsigned int n = 0;
for_each_zone (zone)
if (is_highmem(zone)) {
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; zone_pfn++) {
struct page *page;
unsigned long pfn = zone_pfn + zone->zone_start_pfn;
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (PageReserved(page))
continue;
if (PageNosaveFree(page))
continue;
n++;
}
}
return n;
}
struct highmem_page {
char *data;
struct page *page;
struct highmem_page *next;
};
static struct highmem_page *highmem_copy;
static int save_highmem_zone(struct zone *zone)
{
unsigned long zone_pfn;
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
struct page *page;
struct highmem_page *save;
void *kaddr;
unsigned long pfn = zone_pfn + zone->zone_start_pfn;
if (!(pfn%1000))
printk(".");
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
/*
* This condition results from rvmalloc() sans vmalloc_32()
* and architectural memory reservations. This should be
* corrected eventually when the cases giving rise to this
* are better understood.
*/
if (PageReserved(page)) {
printk("highmem reserved page?!\n");
continue;
}
BUG_ON(PageNosave(page));
if (PageNosaveFree(page))
continue;
save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
if (!save)
return -ENOMEM;
save->next = highmem_copy;
save->page = page;
save->data = (void *) get_zeroed_page(GFP_ATOMIC);
if (!save->data) {
kfree(save);
return -ENOMEM;
}
kaddr = kmap_atomic(page, KM_USER0);
memcpy(save->data, kaddr, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
highmem_copy = save;
}
return 0;
}
int save_highmem(void)
{
struct zone *zone;
int res = 0;
pr_debug("swsusp: Saving Highmem\n");
for_each_zone (zone) {
if (is_highmem(zone))
res = save_highmem_zone(zone);
if (res)
return res;
}
return 0;
}
int restore_highmem(void)
{
printk("swsusp: Restoring Highmem\n");
while (highmem_copy) {
struct highmem_page *save = highmem_copy;
void *kaddr;
highmem_copy = save->next;
kaddr = kmap_atomic(save->page, KM_USER0);
memcpy(kaddr, save->data, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
free_page((long) save->data);
kfree(save);
}
return 0;
}
#endif
static int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
}
/**
* saveable - Determine whether a page should be cloned or not.
* @pfn: The page
*
* We save a page if it's Reserved, and not in the range of pages
* statically defined as 'unsaveable', or if it isn't reserved, and
* isn't part of a free chunk of pages.
*/
static int saveable(struct zone *zone, unsigned long *zone_pfn)
{
unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
struct page *page;
if (!pfn_valid(pfn))
return 0;
page = pfn_to_page(pfn);
BUG_ON(PageReserved(page) && PageNosave(page));
if (PageNosave(page))
return 0;
if (PageReserved(page) && pfn_is_nosave(pfn))
return 0;
if (PageNosaveFree(page))
return 0;
return 1;
}
unsigned int count_data_pages(void)
{
struct zone *zone;
unsigned long zone_pfn;
unsigned int n = 0;
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
n += saveable(zone, &zone_pfn);
}
return n;
}
static void copy_data_pages(struct pbe *pblist)
{
struct zone *zone;
unsigned long zone_pfn;
struct pbe *pbe, *p;
pbe = pblist;
for_each_zone (zone) {
if (is_highmem(zone))
continue;
mark_free_pages(zone);
/* This is necessary for swsusp_free() */
for_each_pb_page (p, pblist)
SetPageNosaveFree(virt_to_page(p));
for_each_pbe (p, pblist)
SetPageNosaveFree(virt_to_page(p->address));
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
if (saveable(zone, &zone_pfn)) {
struct page *page;
page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
BUG_ON(!pbe);
pbe->orig_address = (unsigned long)page_address(page);
/* copy_page is not usable for copying task structs. */
memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
pbe = pbe->next;
}
}
}
BUG_ON(pbe);
}
/**
* free_pagedir - free pages allocated with alloc_pagedir()
*/
void free_pagedir(struct pbe *pblist)
{
struct pbe *pbe;
while (pblist) {
pbe = (pblist + PB_PAGE_SKIP)->next;
ClearPageNosave(virt_to_page(pblist));
ClearPageNosaveFree(virt_to_page(pblist));
free_page((unsigned long)pblist);
pblist = pbe;
}
}
/**
* fill_pb_page - Create a list of PBEs on a given memory page
*/
static inline void fill_pb_page(struct pbe *pbpage)
{
struct pbe *p;
p = pbpage;
pbpage += PB_PAGE_SKIP;
do
p->next = p + 1;
while (++p < pbpage);
}
/**
* create_pbe_list - Create a list of PBEs on top of a given chain
* of memory pages allocated with alloc_pagedir()
*/
static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
{
struct pbe *pbpage, *p;
unsigned int num = PBES_PER_PAGE;
for_each_pb_page (pbpage, pblist) {
if (num >= nr_pages)
break;
fill_pb_page(pbpage);
num += PBES_PER_PAGE;
}
if (pbpage) {
for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
p->next = p + 1;
p->next = NULL;
}
}
/**
* On resume it is necessary to trace and eventually free the unsafe
* pages that have been allocated, because they are needed for I/O
* (on x86-64 we likely will "eat" these pages once again while
* creating the temporary page translation tables)
*/
struct eaten_page {
struct eaten_page *next;
char padding[PAGE_SIZE - sizeof(void *)];
};
static struct eaten_page *eaten_pages = NULL;
void release_eaten_pages(void)
{
struct eaten_page *p, *q;
p = eaten_pages;
while (p) {
q = p->next;
/* We don't want swsusp_free() to free this page again */
ClearPageNosave(virt_to_page(p));
free_page((unsigned long)p);
p = q;
}
eaten_pages = NULL;
}
/**
* @safe_needed - on resume, for storing the PBE list and the image,
* we can only use memory pages that do not conflict with the pages
* which had been used before suspend.
*
* The unsafe pages are marked with the PG_nosave_free flag
*
* Allocated but unusable (ie eaten) memory pages should be marked
* so that swsusp_free() can release them
*/
static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
{
void *res;
if (safe_needed)
do {
res = (void *)get_zeroed_page(gfp_mask);
if (res && PageNosaveFree(virt_to_page(res))) {
/* This is for swsusp_free() */
SetPageNosave(virt_to_page(res));
((struct eaten_page *)res)->next = eaten_pages;
eaten_pages = res;
}
} while (res && PageNosaveFree(virt_to_page(res)));
else
res = (void *)get_zeroed_page(gfp_mask);
if (res) {
SetPageNosave(virt_to_page(res));
SetPageNosaveFree(virt_to_page(res));
}
return res;
}
unsigned long get_safe_page(gfp_t gfp_mask)
{
return (unsigned long)alloc_image_page(gfp_mask, 1);
}
/**
* alloc_pagedir - Allocate the page directory.
*
* First, determine exactly how many pages we need and
* allocate them.
*
* We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
* struct pbe elements (pbes) and the last element in the page points
* to the next page.
*
* On each page we set up a list of struct_pbe elements.
*/
struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed)
{
unsigned int num;
struct pbe *pblist, *pbe;
if (!nr_pages)
return NULL;
pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
pblist = alloc_image_page(gfp_mask, safe_needed);
/* FIXME: rewrite this ugly loop */
for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
pbe = pbe->next, num += PBES_PER_PAGE) {
pbe += PB_PAGE_SKIP;
pbe->next = alloc_image_page(gfp_mask, safe_needed);
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist);
pblist = NULL;
} else
create_pbe_list(pblist, nr_pages);
return pblist;
}
/**
* Free pages we allocated for suspend. Suspend pages are alocated
* before atomic copy, so we need to free them after resume.
*/
void swsusp_free(void)
{
struct zone *zone;
unsigned long zone_pfn;
for_each_zone(zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
struct page *page;
page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
if (PageNosave(page) && PageNosaveFree(page)) {
ClearPageNosave(page);
ClearPageNosaveFree(page);
free_page((long) page_address(page));
}
}
}
}
/**
* enough_free_mem - Make sure we enough free memory to snapshot.
*
* Returns TRUE or FALSE after checking the number of available
* free pages.
*/
static int enough_free_mem(unsigned int nr_pages)
{
struct zone *zone;
unsigned int n = 0;
for_each_zone (zone)
if (!is_highmem(zone))
n += zone->free_pages;
pr_debug("swsusp: available memory: %u pages\n", n);
return n > (nr_pages + PAGES_FOR_IO +
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
{
struct pbe *p;
for_each_pbe (p, pblist) {
p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
if (!p->address)
return -ENOMEM;
}
return 0;
}
static struct pbe *swsusp_alloc(unsigned int nr_pages)
{
struct pbe *pblist;
if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
return NULL;
}
if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
printk(KERN_ERR "suspend: Allocating image pages failed.\n");
swsusp_free();
return NULL;
}
return pblist;
}
asmlinkage int swsusp_save(void)
{
unsigned int nr_pages;
pr_debug("swsusp: critical section: \n");
drain_local_pages();
nr_pages = count_data_pages();
printk("swsusp: Need to copy %u pages\n", nr_pages);
pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
nr_pages,
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
PAGES_FOR_IO, nr_free_pages());
if (!enough_free_mem(nr_pages)) {
printk(KERN_ERR "swsusp: Not enough free memory\n");
return -ENOMEM;
}
pagedir_nosave = swsusp_alloc(nr_pages);
if (!pagedir_nosave)
return -ENOMEM;
/* During allocating of suspend pagedir, new cold pages may appear.
* Kill them.
*/
drain_local_pages();
copy_data_pages(pagedir_nosave);
/*
* End of critical section. From now on, we can write to memory,
* but we should not touch disk. This specially means we must _not_
* touch swap space! Except we must write out our image of course.
*/
nr_copy_pages = nr_pages;
printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
return 0;
}