X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmigrate.c;h=857a987e36904a5850a4d663c6d9e41e494ffe1f;hb=e725a9b0f5db0fa511d7667da6c4bfb1a6d3c7e4;hp=6a207e8d17ea3f74f0e20511fc726fe80ac47fb1;hpb=748c5151deb56e4b7b5a9b07a884243764933831;p=linux-2.6-omap-h63xx.git

diff --git a/mm/migrate.c b/mm/migrate.c
index 6a207e8d17e..857a987e369 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -115,11 +115,6 @@ int putback_lru_pages(struct list_head *l)
 	return count;
 }
 
-static inline int is_swap_pte(pte_t pte)
-{
-	return !pte_none(pte) && !pte_present(pte) && !pte_file(pte);
-}
-
 /*
  * Restore a potential migration pte to a working pte entry
  */
@@ -645,15 +640,33 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
 		rcu_read_lock();
 		rcu_locked = 1;
 	}
+
 	/*
-	 * 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.
+	 * Corner case handling:
+	 * 1. When a new swap-cache page is read into, it is added to the LRU
+	 * and treated as swapcache but it has no rmap yet.
+	 * Calling try_to_unmap() against a page->mapping==NULL page will
+	 * trigger a BUG.  So handle it here.
+	 * 2. An orphaned page (see truncate_complete_page) might have
+	 * fs-private metadata. The page can be picked up due to memory
+	 * offlining.  Everywhere else except page reclaim, the page is
+	 * invisible to the vm, so the page can not be migrated.  So try to
+	 * free the metadata, so the page can be freed.
 	 */
-	if (!page->mapping)
+	if (!page->mapping) {
+		if (!PageAnon(page) && PagePrivate(page)) {
+			/*
+			 * Go direct to try_to_free_buffers() here because
+			 * a) that's what try_to_release_page() would do anyway
+			 * b) we may be under rcu_read_lock() here, so we can't
+			 *    use GFP_KERNEL which is what try_to_release_page()
+			 *    needs to be effective.
+			 */
+			try_to_free_buffers(page);
+		}
 		goto rcu_unlock;
+	}
+
 	/* Establish migration ptes or remove ptes */
 	try_to_unmap(page, 1);