Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

[pandora-kernel.git] / mm / migrate.c

diff --git a/mm/migrate.c b/mm/migrate.c
index a91ca00..37c73b9 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -49,9 +49,8 @@ int isolate_lru_page(struct page *page, struct list_head *pagelist)
                struct zone *zone = page_zone(page);
 
                spin_lock_irq(&zone->lru_lock);
-               if (PageLRU(page)) {
+               if (PageLRU(page) && get_page_unless_zero(page)) {
                        ret = 0;
-                       get_page(page);
                        ClearPageLRU(page);
                        if (PageActive(page))
                                del_page_from_active_list(zone, page);
@@ -632,18 +631,35 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
                        goto unlock;
                wait_on_page_writeback(page);
        }
-
        /*
-        * Establish migration ptes or remove ptes
+        * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
+        * we cannot notice that anon_vma is freed while we migrates a page.
+        * This rcu_read_lock() delays freeing anon_vma pointer until the end
+        * of migration. File cache pages are no problem because of page_lock()
+        */
+       rcu_read_lock();
+       /*
+        * This is a corner case handling.
+        * When a new swap-cache is read into, it is linked to LRU
+        * and treated as swapcache but has no rmap yet.
+        * Calling try_to_unmap() against a page->mapping==NULL page is
+        * BUG. So handle it here.
         */
+       if (!page->mapping)
+               goto rcu_unlock;
+       /* Establish migration ptes or remove ptes */
        try_to_unmap(page, 1);
+
        if (!page_mapped(page))
                rc = move_to_new_page(newpage, page);
 
        if (rc)
                remove_migration_ptes(page, page);
+rcu_unlock:
+       rcu_read_unlock();
 
 unlock:
+
        unlock_page(page);
 
        if (rc != -EAGAIN) {
@@ -761,7 +777,8 @@ static struct page *new_page_node(struct page *p, unsigned long private,
 
        *result = &pm->status;
 
-       return alloc_pages_node(pm->node, GFP_HIGHUSER | GFP_THISNODE, 0);
+       return alloc_pages_node(pm->node,
+                               GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0);
 }
 
 /*