2 files changed, 34 insertions, 16 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 7d2983f3783e..89e5c3fe8bbc 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -564,7 +564,7 @@ static int fallback_migrate_page(struct address_space *mapping,
  *  == 0 - success
  */
 static int move_to_new_page(struct page *newpage, struct page *page,
-                                                int remap_swapcache)
+                                        int remap_swapcache, bool sync)
 {
         struct address_space *mapping;
         int rc;
@@ -586,18 +586,28 @@ static int move_to_new_page(struct page *newpage, struct page *page,
         mapping = page_mapping(page);
         if (!mapping)
                 rc = migrate_page(mapping, newpage, page);
-        else if (mapping->a_ops->migratepage)
+        else {
                 /*
-                 * Most pages have a mapping and most filesystems
-                 * should provide a migration function. Anonymous
-                 * pages are part of swap space which also has its
-                 * own migration function. This is the most common
-                 * path for page migration.
+                 * Do not writeback pages if !sync and migratepage is
+                 * not pointing to migrate_page() which is nonblocking
+                 * (swapcache/tmpfs uses migratepage = migrate_page).
                  */
-                rc = mapping->a_ops->migratepage(mapping,
-                                                newpage, page);
-        else
-                rc = fallback_migrate_page(mapping, newpage, page);
+                if (PageDirty(page) && !sync &&
+                    mapping->a_ops->migratepage != migrate_page)
+                        rc = -EBUSY;
+                else if (mapping->a_ops->migratepage)
+                        /*
+                         * Most pages have a mapping and most filesystems
+                         * should provide a migration function. Anonymous
+                         * pages are part of swap space which also has its
+                         * own migration function. This is the most common
+                         * path for page migration.
+                         */
+                        rc = mapping->a_ops->migratepage(mapping,
+                                                        newpage, page);
+                else
+                        rc = fallback_migrate_page(mapping, newpage, page);
+        }
 
         if (rc) {
                 newpage->mapping = NULL;
@@ -641,7 +651,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
         rc = -EAGAIN;
 
         if (!trylock_page(page)) {
-                if (!force)
+                if (!force || !sync)
                         goto move_newpage;
 
                 /*
@@ -686,7 +696,15 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
         BUG_ON(charge);
 
         if (PageWriteback(page)) {
-                if (!force || !sync)
+                /*
+                 * For !sync, there is no point retrying as the retry loop
+                 * is expected to be too short for PageWriteback to be cleared
+                 */
+                if (!sync) {
+                        rc = -EBUSY;
+                        goto uncharge;
+                }
+                if (!force)
                         goto uncharge;
                 wait_on_page_writeback(page);
         }
@@ -757,7 +775,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
 
 skip_unmap:
         if (!page_mapped(page))
-                rc = move_to_new_page(newpage, page, remap_swapcache);
+                rc = move_to_new_page(newpage, page, remap_swapcache, sync);
 
         if (rc && remap_swapcache)
                 remove_migration_ptes(page, page);
@@ -850,7 +868,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
         try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
 
         if (!page_mapped(hpage))
-                rc = move_to_new_page(new_hpage, hpage, 1);
+                rc = move_to_new_page(new_hpage, hpage, 1, sync);
 
         if (rc)
                 remove_migration_ptes(hpage, hpage);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 426056aff12a..6d0032bdb5d8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2103,7 +2103,7 @@ rebalance:
                                         sync_migration);
         if (page)
                 goto got_pg;
-        sync_migration = true;
+        sync_migration = !(gfp_mask & __GFP_NO_KSWAPD);
 
         /* Try direct reclaim and then allocating */
         page = __alloc_pages_direct_reclaim(gfp_mask, order,