Patent ID: 7433951

Claim:
A computer system comprising: a host system, which includes a host operating system (OS) and a hardware memory that is addressable in a hardware memory address space; at least one virtual computer, each of which includes at least one virtual processor, guest physical memory, and a guest OS operable to address, allocate and deallocate the guest physical memory in a guest physical address space, and is operatively connected to the host system; and a memory reservation software module located within the virtual computer for receiving a memory quantity request from the host system and for changing the allocation of the guest physical memory from within the respective guest OS according to the memory quantity request, thereby changing the amount of the hardware memory available for arbitrary use by the host system, wherein the memory reservation software module, in response to the memory quantity request, changes the allocation of the guest physical memory from within the respective guest OS at a controlled rate, said controlled rate being adjusted up or down between a predetermined maximum rate and a predetermined minimum rate as the memory reservation software changes the allocation of the guest physical memory from within the respective guest OS, said controlled rate being increased if said memory reservation software module is successful in changing the allocation of the guest physical memory from within the respective guest OS at the controlled rate, and said controlled rate being decreased if said memory reservation software module is not successful in changing the allocation of the guest physical memory from within the respective guest OS at the controlled rate.