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>

2 files changed, 6 insertions, 4 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index cd985530f102..ea5a93659488 100644
--- a/mm/memory-failure.c
+++ b/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",
diff --git a/mm/migrate.c b/mm/migrate.c
index f2415be7d93b..eb4267107d1f 100644
--- a/mm/migrate.c
+++ b/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;
         }