主存回收函数实现：有上邻空闲区和下邻空闲区，它们与回收区的合并；有上邻空闲区，无下邻空闲区，回收区与上邻空闲区的合并；无上邻空闲区，有下邻空闲区，回收区与下邻空闲区的合并。-Main memory to achieve recovery of function: there are o-free zones and free zones under the neighborhood, which combined with the recovery area　have on adjacent free zone free zone free of o, the recovery area and on the merger of adjacent free zone　supreme o free area, there is under the free zone adjacent to recover under the adjacent areas and free zones combined.