Re: [PATCH 1/3] swsusp add architecture special saveable pages support

[Pavel Machek]

> 
> 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.

I'm not 100% convinced that it is needed, but if BIOS people say it
is, lets believe them. Code looks ok.

							Pavel
> 
> Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
> ---
> 
>  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	2006-04-11 08:03:21.000000000 +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_zeroed_page(GFP_ATOMIC);
> +		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);
> +
> +		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_PTE0);
> +		memcpy(kaddr, tmp->data, PAGE_SIZE);
> +		kunmap_atomic(kaddr, KM_PTE0);
> +		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);
> _
> 
> 

-- 
Thanks, Sharp!
-
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