[PATCH 5/5]memhp: migrate swap cache page

[Shaohua Li <shaohua.li@intel.com>]

In test, some pages in swap-cache can't be migrated, as they aren't rmap.

unmap_and_move() ignores swap-cache page which is just read in and hasn't
rmap (see the comments in the code), but swap_aops provides .migratepage.
Better to migrate such pages instead of ignore them.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
---
 mm/migrate.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: linux/mm/migrate.c
===================================================================
--- linux.orig/mm/migrate.c	2009-06-26 09:41:05.000000000 +0800
+++ linux/mm/migrate.c	2009-06-26 10:00:49.000000000 +0800
@@ -147,7 +147,7 @@ out:
 static void remove_file_migration_ptes(struct page *old, struct page *new)
 {
 	struct vm_area_struct *vma;
-	struct address_space *mapping = page_mapping(new);
+	struct address_space *mapping = new->mapping;
 	struct prio_tree_iter iter;
 	pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
 
@@ -664,13 +664,15 @@ static int unmap_and_move(new_page_t get
 			 *    needs to be effective.
 			 */
 			try_to_free_buffers(page);
+			goto rcu_unlock;
 		}
-		goto rcu_unlock;
+		goto skip_unmap;
 	}
 
 	/* Establish migration ptes or remove ptes */
 	try_to_unmap(page, 1);
 
+skip_unmap:
 	if (!page_mapped(page))
 		rc = move_to_new_page(newpage, page);
 


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