[PATCH] [1/16] HWPOISON: Add page flag for poisoned pages

Andi Kleen
2009-06-03T18:47:07Z

Hardware poisoned pages need special handling in the VM and shouldn't be
touched again. This requires a new page flag. Define it here.

The page flags wars seem to be over, so it shouldn't be a problem
to get a new one.

v2: Add TestSetHWPoison (suggested by Johannes Weiner)

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
include/linux/page-flags.h | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

Index: linux/include/linux/page-flags.h
===================================================================
--- linux.orig/include/linux/page-flags.h 2009-06-03 19:36:23.000000000 +0200
+++ linux/include/linux/page-flags.h 2009-06-03 19:36:23.000000000 +0200
@@ -51,6 +51,9 @@
* PG_buddy is set to indicate that the page is free and in the buddy system
* (see mm/page_alloc.c).
*
+ * PG_hwpoison indicates that a page got corrupted in hardware and contains
+ * data with incorrect ECC bits that triggered a machine check. Accessing is
+ * not safe since it may cause another machine check. Don't touch!
*/

/*
@@ -102,6 +105,9 @@
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PG_uncached, /* Page has been mapped as uncached */
#endif
+#ifdef CONFIG_MEMORY_FAILURE
+ PG_hwpoison, /* hardware poisoned page. Don't touch */
+#endif
__NR_PAGEFLAGS,

/* Filesystems */
@@ -263,6 +269,15 @@
PAGEFLAG_FALSE(Uncached)
#endif

+#ifdef CONFIG_MEMORY_FAILURE
+PAGEFLAG(HWPoison, hwpoison)
+TESTSETFLAG(HWPoison, hwpoison)
+#define __PG_HWPOISON (1UL << PG_hwpoison)
+#else
+PAGEFLAG_FALSE(HWPoison)
+#define __PG_HWPOISON 0
+#endif
+
static inline int PageUptodate(struct page *page)
{
int ret = test_bit(PG_uptodate, &(page)->flags);
@@ -387,7 +402,7 @@
1 << PG_private | 1 << PG_private_2 | \
1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
- 1 << PG_unevictable | __PG_MLOCKED)
+ 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON)

/*
* Flags checked when a page is prepped for return by the page allocator.