今天查了一下msdn，有如下一段话：
MaximumSize [in, optional]
Specifies the maximum size, in bytes, of the section. ZwCreateSection rounds this value up to the nearest multiple of PAGE_SIZE. If the section is backed by the paging file, MaximumSize specifies the actual size of the section. If the section is backed by an ordinary file, MaximumSize specifies the maximum size that the file can be extended or mapped to.
