1. A method comprising: initiating a power-on procedure for a virtual machine on a host machine, wherein the virtual machine comprises a virtual memory space configured to be backed by a combination of physical persistent storage and physical machine memory available to the host machine; allocating, prior to completing the power-on procedure, a portion of the physical machine memory to the virtual memory space of the virtual machine, wherein a size of the allocated portion of the physical machine memory is greater than a minimum memory reservation setting of the virtual machine, the minimum memory reservation setting indicating a minimum amount of the virtual memory space that is to be backed by the physical machine memory; allocating, prior to completing the power-on procedure, a portion of the physical persistent storage to the virtual memory space of the virtual machine as a swap space, wherein a size of the allocated portion of the physical persistent storage is less than the difference between a virtual memory space size setting of the virtual memory space and the minimum memory reservation setting, the virtual memory space size setting indicating the size of the virtual memory space; completing the power-on procedure of the virtual machine; and subsequent to completing the power-on procedure of the virtual machine, iteratively increasing the size of the allocated portion of the physical persistent storage and decreasing the size of the allocated portion of the physical machine memory.