Btrfs: Add an extent buffer LRU to reduce radix tree hits

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 87456ab..67e4aca 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -443,8 +443,7 @@
 			BUG_ON(ret);
 			mutex_unlock(&tree_root->fs_info->fs_mutex);
 			btrfs_btree_balance_dirty(tree_root, nr);
-			schedule();
-
+			cond_resched();
 			mutex_lock(&tree_root->fs_info->fs_mutex);
 		}
 		BUG_ON(ret);
@@ -471,7 +470,7 @@
 		mutex_unlock(&tree_root->fs_info->fs_mutex);
 
 		btrfs_btree_balance_dirty(tree_root, nr);
-		schedule();
+		cond_resched();
 	}
 	return ret;
 }