Method: (MAKE-ROOM-IN-CACHE STANDARD-CACHE)

Source

(defmethod make-room-in-cache ((cache standard-cache))
  ;; We need to remove some objects from the in-memory cache (both
  ;; from the hash table and from the queue).
  ;; We do this by removing the objects that have been used least
  ;; recently.  We don't do anything with dirty objects, because
  ;; they contain changes that must still be committed to disk.
  (let ((queue (queue cache))
        (nr-objects-to-remove (* (- 1.0 (cache-shrink-ratio cache))
                                 (cache-size cache)))
        (nr-objects-removed 0))
    (loop until (or (= nr-objects-removed nr-objects-to-remove)
                    (queue-empty-p queue))
          do (let ((id (queue-remove queue)))
               (when (remhash id (objects cache))
                 (incf nr-objects-removed))))))