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Currently swsusp saves the contents of highmem pages by copying them to the normal zone which is quite inefficient (eg. it requires two normal pages to be used for saving one highmem page). This may be improved by using highmem for saving the contents of saveable highmem pages. Namely, during the suspend phase of the suspend-resume cycle we try to allocate as many free highmem pages as there are saveable highmem pages. If there are not enough highmem image pages to store the contents of all of the saveable highmem pages, some of them will be stored in the "normal" memory. Next, we allocate as many free "normal" pages as needed to store the (remaining) image data. We use a memory bitmap to mark the allocated free pages (ie. highmem as well as "normal" image pages). Now, we use another memory bitmap to mark all of the saveable pages (highmem as well as "normal") and the contents of the saveable pages are copied into the image pages. Then, the second bitmap is used to save the pfns corresponding to the saveable pages and the first one is used to save their data. During the resume phase the pfns of the pages that were saveable during the suspend are loaded from the image and used to mark the "unsafe" page frames. Next, we try to allocate as many free highmem page frames as to load all of the image data that had been in the highmem before the suspend and we allocate so many free "normal" page frames that the total number of allocated free pages (highmem and "normal") is equal to the size of the image. While doing this we have to make sure that there will be some extra free "normal" and "safe" page frames for two lists of PBEs constructed later. Now, the image data are loaded, if possible, into their "original" page frames. The image data that cannot be written into their "original" page frames are loaded into "safe" page frames and their "original" kernel virtual addresses, as well as the addresses of the "safe" pages containing their copies, are stored in one of two lists of PBEs. One list of PBEs is for the copies of "normal" suspend pages (ie. "normal" pages that were saveable during the suspend) and it is used in the same way as previously (ie. by the architecture-dependent parts of swsusp). The other list of PBEs is for the copies of highmem suspend pages. The pages in this list are restored (in a reversible way) right before the arch-dependent code is called. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
#ifndef _LINUX_SWSUSP_H
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#define _LINUX_SWSUSP_H
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#if defined(CONFIG_X86) || defined(CONFIG_FRV) || defined(CONFIG_PPC32)
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#include <asm/suspend.h>
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#endif
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#include <linux/swap.h>
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#include <linux/notifier.h>
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#include <linux/init.h>
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#include <linux/pm.h>
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/* struct pbe is used for creating lists of pages that should be restored
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* atomically during the resume from disk, because the page frames they have
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* occupied before the suspend are in use.
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*/
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struct pbe {
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void *address; /* address of the copy */
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void *orig_address; /* original address of a page */
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struct pbe *next;
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};
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/* mm/page_alloc.c */
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extern void drain_local_pages(void);
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extern void mark_free_pages(struct zone *zone);
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#ifdef CONFIG_PM
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/* kernel/power/swsusp.c */
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extern int software_suspend(void);
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#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
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extern int pm_prepare_console(void);
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extern void pm_restore_console(void);
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#else
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static inline int pm_prepare_console(void) { return 0; }
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static inline void pm_restore_console(void) {}
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#endif /* defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE) */
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#else
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static inline int software_suspend(void)
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{
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printk("Warning: fake suspend called\n");
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return -ENOSYS;
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}
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#endif /* CONFIG_PM */
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void save_processor_state(void);
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void restore_processor_state(void);
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struct saved_context;
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void __save_processor_state(struct saved_context *ctxt);
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void __restore_processor_state(struct saved_context *ctxt);
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unsigned long get_safe_page(gfp_t gfp_mask);
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/*
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* XXX: We try to keep some more pages free so that I/O operations succeed
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* without paging. Might this be more?
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*/
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#define PAGES_FOR_IO 1024
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#endif /* _LINUX_SWSUSP_H */
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