[PATCH 2/3] mm: Avoid putting a bad page back on the LRU v5

[Russ Anderson <rja@sgi.com>]

Prevent a page with a physical memory error from being placed back
on the LRU.  A new page flag (PG_memerror) is added on 64 bit
architectures.  

Signed-off-by: Russ Anderson <rja@sgi.com>

---
 include/linux/migrate.h    |    1 +
 include/linux/page-flags.h |   11 ++++++++++-
 mm/migrate.c               |   12 ++++++++++--
 mm/page_alloc.c            |    8 ++++----
 4 files changed, 25 insertions(+), 7 deletions(-)

Index: linus/mm/page_alloc.c
=================================--- linus.orig/mm/page_alloc.c	2008-05-15 12:59:03.334381011 -0500
+++ linus/mm/page_alloc.c	2008-05-15 12:59:04.958581070 -0500
@@ -602,10 +602,10 @@ static int prep_new_page(struct page *pa
 		bad_page(page);
 
 	/*
-	 * For now, we report if PG_reserved was found set, but do not
-	 * clear it, and do not allocate the page: as a safety net.
+	 * For now, we report if PG_reserved or PG_memerror was found set, but
+	 * do not clear it, and do not allocate the page: as a safety net.
 	 */
-	if (PageReserved(page))
+	if (PageReserved(page) || PageMemError(page))
 		return 1;
 
 	page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_reclaim |
@@ -2474,7 +2474,7 @@ static void setup_zone_migrate_reserve(s
 		page = pfn_to_page(pfn);
 
 		/* Blocks with reserved pages will never free, skip them. */
-		if (PageReserved(page))
+		if (PageReserved(page) || PageMemError(page))
 			continue;
 
 		block_migratetype = get_pageblock_migratetype(page);
Index: linus/mm/migrate.c
=================================--- linus.orig/mm/migrate.c	2008-05-15 12:58:25.165679802 -0500
+++ linus/mm/migrate.c	2008-05-16 12:25:16.145557095 -0500
@@ -35,6 +35,8 @@
 
 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
 
+unsigned int totalbad_pages;
+
 /*
  * Isolate one page from the LRU lists. If successful put it onto
  * the indicated list with elevated page count.
@@ -110,6 +112,8 @@ int putback_lru_pages(struct list_head *
 
 	list_for_each_entry_safe(page, page2, l, lru) {
 		list_del(&page->lru);
+		if (unlikely(PageMemError(page)))
+			continue;
 		move_to_lru(page);
 		count++;
 	}
@@ -717,10 +721,14 @@ unlock:
  		 * A page that has been migrated has all references
  		 * removed and will be freed. A page that has not been
  		 * migrated will have kepts its references and be
- 		 * restored.
+		 * restored.  A page with a memory error will not
+		 * be moved to the LRU.
  		 */
  		list_del(&page->lru);
- 		move_to_lru(page);
+		if (PageMemError(page))
+			totalbad_pages++;
+		else
+			move_to_lru(page);
 	}
 
 move_newpage:
Index: linus/include/linux/page-flags.h
=================================--- linus.orig/include/linux/page-flags.h	2008-05-15 12:59:03.362384460 -0500
+++ linus/include/linux/page-flags.h	2008-05-15 12:59:05.002586491 -0500
@@ -84,6 +84,7 @@ enum pageflags {
 	PG_private,		/* If pagecache, has fs-private data */
 	PG_writeback,		/* Page is under writeback */
 #ifdef CONFIG_PAGEFLAGS_EXTENDED
+	PG_memerror,		/* Page has a physical memory error */
 	PG_head,		/* A head page */
 	PG_tail,		/* A tail page */
 #else
@@ -307,9 +308,17 @@ static inline void __ClearPageTail(struc
 
 #endif /* !PAGEFLAGS_EXTENDED */
 
-#define PAGE_FLAGS	(1 << PG_lru   | 1 << PG_private   | 1 << PG_locked | \
+#define PAGE_FLAGS_BASE	(1 << PG_lru   | 1 << PG_private   | 1 << PG_locked | \
 			 1 << PG_buddy | 1 << PG_writeback | \
 			 1 << PG_slab  | 1 << PG_swapcache | 1 << PG_active)
+
+#ifdef CONFIG_PAGEFLAGS_EXTENDED
+PAGEFLAG(MemError, memerror)
+#define	PAGE_FLAGS	(PAGE_FLAGS_BASE | 1UL << PG_memerror)
+#else
+PAGEFLAG_FALSE(MemError)
+#define	PAGE_FLAGS	(PAGE_FLAGS_BASE)
+#endif
 
 /*
  * Flags checked in bad_page().  Pages on the free list should not have
Index: linus/include/linux/migrate.h
=================================--- linus.orig/include/linux/migrate.h	2008-05-15 12:58:25.165679802 -0500
+++ linus/include/linux/migrate.h	2008-05-15 12:59:05.026589447 -0500
@@ -38,6 +38,7 @@ extern int migrate_prep(void);
 extern int migrate_vmas(struct mm_struct *mm,
 		const nodemask_t *from, const nodemask_t *to,
 		unsigned long flags);
+extern unsigned int totalbad_pages;
 #else
 static inline int vma_migratable(struct vm_area_struct *vma)
 					{ return 0; }
-- 
Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc          rja@sgi.com