[PATCH] Allow migration of mlocked pages

Hugh clarified the role of VM_LOCKED.  So we can now implement page
migration for mlocked pages.

Allow the migration of mlocked pages.  This means that try_to_unmap must
unmap mlocked pages in the migration case.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 6 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 0576c0535988..3f1e0c2c942c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -616,15 +616,13 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
         /*
          * Establish migration ptes or remove ptes
          */
-        if (try_to_unmap(page, 1) != SWAP_FAIL) {
-                if (!page_mapped(page))
-                        rc = move_to_new_page(newpage, page);
-        } else
-                /* A vma has VM_LOCKED set -> permanent failure */
-                rc = -EPERM;
+        try_to_unmap(page, 1);
+        if (!page_mapped(page))
+                rc = move_to_new_page(newpage, page);
 
         if (rc)
                 remove_migration_ptes(page, page);
+
 unlock:
         unlock_page(page);