swsusp: do not use page flags

Make swsusp use memory bitmaps instead of page flags for marking 'nosave' and free pages. This allows us to 'recycle' two page flags that can be used for other purposes. Also, the memory needed to store the bitmaps is allocated when necessary (ie. before the suspend) and freed after the resume which is more reasonable. The patch is designed to minimize the amount of changes and there are some nice simplifications and optimizations possible on top of it. I am going to implement them separately in the future. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
git-mirror · May 7, 2007 · 74dfd66 · 74dfd66
1 parent 7be9823
commit 74dfd66
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Showing 7 changed files with 283 additions and 82 deletions.
diff --git a/arch/x86_64/kernel/e820.c b/arch/x86_64/kernel/e820.c
@@ -17,6 +17,8 @@
 #include <linux/kexec.h>
 #include <linux/module.h>
 #include <linux/mm.h>
+#include <linux/suspend.h>
+#include <linux/pfn.h>
 
 #include <asm/pgtable.h>
 #include <asm/page.h>
@@ -256,22 +258,6 @@ void __init e820_reserve_resources(void)
 	}
 }
 
-/* Mark pages corresponding to given address range as nosave */
-static void __init
-e820_mark_nosave_range(unsigned long start, unsigned long end)
-{
-	unsigned long pfn, max_pfn;
-
-	if (start >= end)
-		return;
-
-	printk("Nosave address range: %016lx - %016lx\n", start, end);
-	max_pfn = end >> PAGE_SHIFT;
-	for (pfn = start >> PAGE_SHIFT; pfn < max_pfn; pfn++)
-		if (pfn_valid(pfn))
-			SetPageNosave(pfn_to_page(pfn));
-}
-
 /*
  * Find the ranges of physical addresses that do not correspond to
  * e820 RAM areas and mark the corresponding pages as nosave for software
@@ -290,13 +276,13 @@ void __init e820_mark_nosave_regions(void)
 		struct e820entry *ei = &e820.map[i];
 
 		if (paddr < ei->addr)
-			e820_mark_nosave_range(paddr,
-					round_up(ei->addr, PAGE_SIZE));
+			register_nosave_region(PFN_DOWN(paddr),
+						PFN_UP(ei->addr));
 
 		paddr = round_down(ei->addr + ei->size, PAGE_SIZE);
 		if (ei->type != E820_RAM)
-			e820_mark_nosave_range(round_up(ei->addr, PAGE_SIZE),
-					paddr);
+			register_nosave_region(PFN_UP(ei->addr),
+						PFN_DOWN(paddr));
 
 		if (paddr >= (end_pfn << PAGE_SHIFT))
 			break;

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
@@ -24,63 +24,41 @@ struct pbe {
 extern void drain_local_pages(void);
 extern void mark_free_pages(struct zone *zone);
 
-#ifdef CONFIG_PM
-/* kernel/power/swsusp.c */
-extern int software_suspend(void);
-
-#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
+#if defined(CONFIG_PM) && defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
 extern int pm_prepare_console(void);
 extern void pm_restore_console(void);
 #else
 static inline int pm_prepare_console(void) { return 0; }
 static inline void pm_restore_console(void) {}
-#endif /* defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE) */
+#endif
+
+#if defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND)
+/* kernel/power/swsusp.c */
+extern int software_suspend(void);
+/* kernel/power/snapshot.c */
+extern void __init register_nosave_region(unsigned long, unsigned long);
+extern int swsusp_page_is_forbidden(struct page *);
+extern void swsusp_set_page_free(struct page *);
+extern void swsusp_unset_page_free(struct page *);
+extern unsigned long get_safe_page(gfp_t gfp_mask);
 #else
 static inline int software_suspend(void)
 {
 	printk("Warning: fake suspend called\n");
 	return -ENOSYS;
 }
-#endif /* CONFIG_PM */
+
+static inline void register_nosave_region(unsigned long b, unsigned long e) {}
+static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }
+static inline void swsusp_set_page_free(struct page *p) {}
+static inline void swsusp_unset_page_free(struct page *p) {}
+#endif /* defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND) */
 
 void save_processor_state(void);
 void restore_processor_state(void);
 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);
-
-/* Page management functions for the software suspend (swsusp) */
-
-static inline void swsusp_set_page_forbidden(struct page *page)
-{
-	SetPageNosave(page);
-}
-
-static inline int swsusp_page_is_forbidden(struct page *page)
-{
-	return PageNosave(page);
-}
-
-static inline void swsusp_unset_page_forbidden(struct page *page)
-{
-	ClearPageNosave(page);
-}
-
-static inline void swsusp_set_page_free(struct page *page)
-{
-	SetPageNosaveFree(page);
-}
-
-static inline int swsusp_page_is_free(struct page *page)
-{
-	return PageNosaveFree(page);
-}
-
-static inline void swsusp_unset_page_free(struct page *page)
-{
-	ClearPageNosaveFree(page);
-}
 
 /*
  * XXX: We try to keep some more pages free so that I/O operations succeed

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
@@ -139,14 +139,19 @@ int pm_suspend_disk(void)
 		mdelay(5000);
 		goto Thaw;
 	}
+	/* Allocate memory management structures */
+	error = create_basic_memory_bitmaps();
+	if (error)
+		goto Thaw;
+
 	/* Free memory before shutting down devices. */
 	error = swsusp_shrink_memory();
 	if (error)
-		goto Thaw;
+		goto Finish;
 
 	error = platform_prepare();
 	if (error)
-		goto Thaw;
+		goto Finish;
 
 	suspend_console();
 	error = device_suspend(PMSG_FREEZE);
@@ -181,7 +186,7 @@ int pm_suspend_disk(void)
 			power_down();
 		else {
 			swsusp_free();
-			goto Thaw;
+			goto Finish;
 		}
 	} else {
 		pr_debug("PM: Image restored successfully.\n");
@@ -194,6 +199,8 @@ int pm_suspend_disk(void)
 	platform_finish();
 	device_resume();
 	resume_console();
+ Finish:
+	free_basic_memory_bitmaps();
  Thaw:
 	unprepare_processes();
 	return error;
@@ -239,13 +246,15 @@ static int software_resume(void)
 	}
 
 	pr_debug("PM: Checking swsusp image.\n");
-
 	error = swsusp_check();
 	if (error)
-		goto Done;
+		goto Unlock;
 
-	pr_debug("PM: Preparing processes for restore.\n");
+	error = create_basic_memory_bitmaps();
+	if (error)
+		goto Unlock;
 
+	pr_debug("PM: Preparing processes for restore.\n");
 	error = prepare_processes();
 	if (error) {
 		swsusp_close();
@@ -280,7 +289,9 @@ static int software_resume(void)
 	printk(KERN_ERR "PM: Restore failed, recovering.\n");
 	unprepare_processes();
  Done:
+	free_basic_memory_bitmaps();
 	/* For success case, the suspend path will release the lock */
+ Unlock:
 	mutex_unlock(&pm_mutex);
 	pr_debug("PM: Resume from disk failed.\n");
 	return 0;

diff --git a/kernel/power/main.c b/kernel/power/main.c
@@ -244,6 +244,7 @@ static int enter_state(suspend_state_t state)
 	return error;
 }
 
+#ifdef CONFIG_SOFTWARE_SUSPEND
 /*
  * This is main interface to the outside world. It needs to be
  * called from process context.
@@ -252,6 +253,7 @@ int software_suspend(void)
 {
 	return enter_state(PM_SUSPEND_DISK);
 }
+#endif
 
 
 /**

diff --git a/kernel/power/power.h b/kernel/power/power.h
@@ -48,6 +48,8 @@ extern sector_t swsusp_resume_block;
 extern asmlinkage int swsusp_arch_suspend(void);
 extern asmlinkage int swsusp_arch_resume(void);
 
+extern int create_basic_memory_bitmaps(void);
+extern void free_basic_memory_bitmaps(void);
 extern unsigned int count_data_pages(void);
 
 /**