mm/memory-failure: set PageHWPoison before migrate_pages()

Now page freeing code doesn't consider PageHWPoison as a bad page, so by
setting it before completing the page containment, we can prevent the
error page from being reused just after successful page migration.

I added TTU_IGNORE_HWPOISON for try_to_unmap() to make sure that the
page table entry is transformed into migration entry, not to hwpoison
entry.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dean Nelson <dnelson@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory-failure.c

@@ -1659,6 +1659,8 @@ static int __soft_offline_page(struct page *page, int flags)
  inc_zone_page_state(page, NR_ISOLATED_ANON +
  page_is_file_cache(page));
  list_add(&page->lru, &pagelist);
+ if (!TestSetPageHWPoison(page))
+ atomic_long_inc(&num_poisoned_pages);
  ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
  MIGRATE_SYNC, MR_MEMORY_FAILURE);
  if (ret) {
@@ -1673,9 +1675,8 @@ static int __soft_offline_page(struct page *page, int flags)
  pfn, ret, page->flags);
  if (ret > 0)
  ret = -EIO;
- } else {
- if (!TestSetPageHWPoison(page))
- atomic_long_inc(&num_poisoned_pages);
+ if (TestClearPageHWPoison(page))
+ atomic_long_dec(&num_poisoned_pages);
  }
  } else {
  pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx\n",

mm/migrate.c

@@ -880,7 +880,8 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
  /* Establish migration ptes or remove ptes */
  if (page_mapped(page)) {
  try_to_unmap(page,
- TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
+ TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS|
+ TTU_IGNORE_HWPOISON);
  page_was_mapped = 1;
  }