Method: (COLLECT-GARBAGE MARK-AND-SWEEP-HEAP)

Source

(defmethod collect-garbage ((heap mark-and-sweep-heap))
  ;; A simple test of COLLECT-SOME-GARBAGE: keep collecting 1024 bytes of
  ;; garbage until the garbage collector is ready.
  (setf (state heap) :starting)
  (loop until (eql (state heap) :ready)
        do (collect-some-garbage heap 1024)))