If the size of the reallocated block is smaller than the original block, the block is split and the extrablock is returned to the free tree with the required size block being returned to the caller.
如果重新分配的块小于原来的块,那么把它分割开,多余的块返回给空闲树,请求的块返回给调用者。
3
Extra classrooms were built out from the main block.