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SubjectRe: [PATCH 1/3] swsusp add architecture special saveable pages support
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On Wed, 2006-04-12 at 14:16 -0700, Andrew Morton wrote:
> Shaohua Li <shaohua.li@intel.com> wrote:
> >
> > +static int save_arch_mem(void)
> > +{
> > + void *kaddr;
> > + struct arch_saveable_page *tmp = arch_pages;
> > +
> > + pr_debug("swsusp: Saving arch specific memory");
> > + while (tmp) {
> > + tmp->data = (void *)get_zeroed_page(GFP_ATOMIC);
>
> There's no need to zero the page here.
Ok.
>
> > + if (!tmp->data)
> > + return -ENOMEM;
> > + /* arch pages might haven't a 'struct page' */
> > + kaddr = kmap_atomic_pfn(tmp->pfn, KM_PTE0);
> > + memcpy(tmp->data, kaddr, PAGE_SIZE);
> > + kunmap_atomic(kaddr, KM_PTE0);
>
> Why was KM_PTE0 chosen here?
Any one is ok here, but maybe KM_USER0 is better. Fixed.

1. Add architecture specific pages save/restore support. Next two patches will
use this to save/restore 'ACPI NVS' pages.
2. Allow reserved pages 'nosave'. This could avoid save/restore BIOS reserved
pages.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
---

linux-2.6.17-rc1-root/include/linux/suspend.h | 1
linux-2.6.17-rc1-root/kernel/power/power.h | 4 +
linux-2.6.17-rc1-root/kernel/power/snapshot.c | 100 +++++++++++++++++++++++++-
linux-2.6.17-rc1-root/kernel/power/swsusp.c | 18 +---
4 files changed, 108 insertions(+), 15 deletions(-)

diff -puN kernel/power/snapshot.c~swsusp_save_pages kernel/power/snapshot.c
--- linux-2.6.17-rc1/kernel/power/snapshot.c~swsusp_save_pages 2006-04-10 09:14:35.000000000 +0800
+++ linux-2.6.17-rc1-root/kernel/power/snapshot.c 2006-04-12 07:11:31.000000000 +0800
@@ -39,6 +39,78 @@ static unsigned int nr_copy_pages;
static unsigned int nr_meta_pages;
static unsigned long *buffer;

+struct arch_saveable_page {
+ unsigned long pfn;
+ void *data;
+ struct arch_saveable_page *next;
+};
+static struct arch_saveable_page *arch_pages;
+
+int swsusp_add_arch_pages(unsigned long start, unsigned long end)
+{
+ struct arch_saveable_page *tmp;
+
+ while (start <= end) {
+ tmp = kzalloc(sizeof(struct arch_saveable_page), GFP_KERNEL);
+ if (!tmp)
+ return -ENOMEM;
+ tmp->pfn = start;
+ tmp->next = arch_pages;
+ start++;
+ arch_pages = tmp;
+ }
+ return 0;
+}
+
+static unsigned int count_arch_pages(void)
+{
+ unsigned int count = 0;
+ struct arch_saveable_page *tmp = arch_pages;
+ while (tmp) {
+ count++;
+ tmp = tmp->next;
+ }
+ return count;
+}
+
+static int save_arch_mem(void)
+{
+ void *kaddr;
+ struct arch_saveable_page *tmp = arch_pages;
+
+ pr_debug("swsusp: Saving arch specific memory");
+ while (tmp) {
+ tmp->data = (void *)__get_free_page(GFP_ATOMIC);
+ if (!tmp->data)
+ return -ENOMEM;
+ /* arch pages might haven't a 'struct page' */
+ kaddr = kmap_atomic_pfn(tmp->pfn, KM_USER0);
+ memcpy(tmp->data, kaddr, PAGE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ tmp = tmp->next;
+ }
+ return 0;
+}
+
+static int restore_arch_mem(void)
+{
+ void *kaddr;
+ struct arch_saveable_page *tmp = arch_pages;
+
+ while (tmp) {
+ if (!tmp->data)
+ continue;
+ kaddr = kmap_atomic_pfn(tmp->pfn, KM_USER0);
+ memcpy(kaddr, tmp->data, PAGE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+ free_page((long)tmp->data);
+ tmp->data = NULL;
+ tmp = tmp->next;
+ }
+ return 0;
+}
+
#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void)
{
@@ -150,8 +222,35 @@ int restore_highmem(void)
}
return 0;
}
+#else
+static unsigned int count_highmem_pages(void) {return 0;}
+static int save_highmem(void) {return 0;}
+static int restore_highmem(void) {return 0;}
#endif

+unsigned int count_special_pages(void)
+{
+ return count_arch_pages() + count_highmem_pages();
+}
+
+int save_special_mem(void)
+{
+ int ret;
+ ret = save_arch_mem();
+ if (!ret)
+ ret = save_highmem();
+ return ret;
+}
+
+int restore_special_mem(void)
+{
+ int ret;
+ ret = restore_arch_mem();
+ if (!ret)
+ ret = restore_highmem();
+ return ret;
+}
+
static int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
@@ -177,7 +276,6 @@ static int saveable(struct zone *zone, u
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))
diff -puN kernel/power/swsusp.c~swsusp_save_pages kernel/power/swsusp.c
--- linux-2.6.17-rc1/kernel/power/swsusp.c~swsusp_save_pages 2006-04-10 09:14:35.000000000 +0800
+++ linux-2.6.17-rc1-root/kernel/power/swsusp.c 2006-04-11 08:02:02.000000000 +0800
@@ -62,16 +62,6 @@ unsigned long image_size = 500 * 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.
@@ -186,7 +176,7 @@ int swsusp_shrink_memory(void)

printk("Shrinking memory... ");
do {
- size = 2 * count_highmem_pages();
+ size = 2 * count_special_pages();
size += size / 50 + count_data_pages();
size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE +
PAGES_FOR_IO;
@@ -228,7 +218,7 @@ int swsusp_suspend(void)
goto Enable_irqs;
}

- if ((error = save_highmem())) {
+ if ((error = save_special_mem())) {
printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
goto Restore_highmem;
}
@@ -239,7 +229,7 @@ int swsusp_suspend(void)
/* Restore control flow magically appears here */
restore_processor_state();
Restore_highmem:
- restore_highmem();
+ restore_special_mem();
device_power_up();
Enable_irqs:
local_irq_enable();
@@ -265,7 +255,7 @@ int swsusp_resume(void)
*/
swsusp_free();
restore_processor_state();
- restore_highmem();
+ restore_special_mem();
touch_softlockup_watchdog();
device_power_up();
local_irq_enable();
diff -puN include/linux/suspend.h~swsusp_save_pages include/linux/suspend.h
--- linux-2.6.17-rc1/include/linux/suspend.h~swsusp_save_pages 2006-04-10 09:14:35.000000000 +0800
+++ linux-2.6.17-rc1-root/include/linux/suspend.h 2006-04-10 09:14:35.000000000 +0800
@@ -72,6 +72,7 @@ struct saved_context;
void __save_processor_state(struct saved_context *ctxt);
void __restore_processor_state(struct saved_context *ctxt);
unsigned long get_safe_page(gfp_t gfp_mask);
+int swsusp_add_arch_pages(unsigned long start, unsigned long end);

/*
* XXX: We try to keep some more pages free so that I/O operations succeed
diff -puN kernel/power/power.h~swsusp_save_pages kernel/power/power.h
--- linux-2.6.17-rc1/kernel/power/power.h~swsusp_save_pages 2006-04-11 08:00:30.000000000 +0800
+++ linux-2.6.17-rc1-root/kernel/power/power.h 2006-04-11 08:02:03.000000000 +0800
@@ -105,6 +105,10 @@ extern struct bitmap_page *alloc_bitmap(
extern unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap);
extern void free_all_swap_pages(int swap, struct bitmap_page *bitmap);

+extern unsigned int count_special_pages(void);
+extern int save_special_mem(void);
+extern int restore_special_mem(void);
+
extern int swsusp_check(void);
extern int swsusp_shrink_memory(void);
extern void swsusp_free(void);
_

-
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