[PATCH 2/3] mm: Avoid putting a bad page back on the LRU v4

From: Russ Anderson
Date: Tue May 13 2008 - 19:03:26 EST


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@xxxxxxx>

---
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 2008-05-13 15:27:32.308804354 -0500
+++ linus/mm/page_alloc.c 2008-05-13 15:35:57.071584039 -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 2008-05-13 15:27:32.308804354 -0500
+++ linus/mm/migrate.c 2008-05-13 16:14:04.695801820 -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 2008-05-13 15:27:32.308804354 -0500
+++ linus/include/linux/page-flags.h 2008-05-13 15:28:06.589058491 -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

#define PAGE_FLAGS_RECLAIM (PAGE_FLAGS | 1 << PG_reclaim | 1 << PG_dirty)
#define PAGE_FLAGS_RESERVE (PAGE_FLAGS | 1 << PG_reserved)
Index: linus/include/linux/migrate.h
===================================================================
--- linus.orig/include/linux/migrate.h 2008-05-13 15:27:32.308804354 -0500
+++ linus/include/linux/migrate.h 2008-05-13 15:28:06.605060477 -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@xxxxxxx
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