-void push_scanned_block (bdescr *bd, step_workspace *ws);
-bdescr *grab_todo_block (step_workspace *ws);
-StgPtr todo_block_full (nat size, step_workspace *ws);
-StgPtr alloc_todo_block (step_workspace *ws, nat size);
+void push_scanned_block (bdescr *bd, gen_workspace *ws);
+StgPtr todo_block_full (nat size, gen_workspace *ws);
+StgPtr alloc_todo_block (gen_workspace *ws, nat size);
+
+bdescr *grab_local_todo_block (gen_workspace *ws);
+#if defined(THREADED_RTS)
+bdescr *steal_todo_block (nat s);
+#endif