[PATCH] [10/16] HWPOISON: Handle hardware poisoned pages in try_to_unmap

Andi Kleen
2009-05-27T20:15:57Z

When a page has the poison bit set replace the PTE with a poison entry.
This causes the right error handling to be done later when a process runs
into it.

Also add a new flag to not do that (needed for the memory-failure handler
later)

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
include/linux/rmap.h | 1 +
mm/rmap.c | 9 ++++++++-
2 files changed, 9 insertions(+), 1 deletion(-)

Index: linux/mm/rmap.c
===================================================================
--- linux.orig/mm/rmap.c 2009-05-27 21:14:21.000000000 +0200
+++ linux/mm/rmap.c 2009-05-27 21:14:21.000000000 +0200
@@ -801,7 +801,14 @@
/* Update high watermark before we lower rss */
update_hiwater_rss(mm);

- if (PageAnon(page)) {
+ if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
+ if (PageAnon(page))
+ dec_mm_counter(mm, anon_rss);
+ else if (!is_migration_entry(pte_to_swp_entry(*pte)))
+ dec_mm_counter(mm, file_rss);
+ set_pte_at(mm, address, pte,
+ swp_entry_to_pte(make_hwpoison_entry(page)));
+ } else if (PageAnon(page)) {
swp_entry_t entry = { .val = page_private(page) };

if (PageSwapCache(page)) {
Index: linux/include/linux/rmap.h
===================================================================
--- linux.orig/include/linux/rmap.h 2009-05-27 21:14:21.000000000 +0200
+++ linux/include/linux/rmap.h 2009-05-27 21:14:21.000000000 +0200
@@ -93,6 +93,7 @@

TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
+ TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
};
#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)