A method and an apparatus for performing memory space reservation and management are provided, wherein the method is applied to a server system. The method includes: providing a mount point at a file system of a server in the server system, and creating a file at the mount point to occupy partial memory space of a physical memory; mapping the file to a section of virtual memory addresses to prevent any swap operation from being applied to the partial memory space; and updating file information of the file into a memory space management list to dynamically manage the partial memory space.