Memory over-commit support for live migration of virtual machines

A system comprising:

• a memory;
• and
• a processing device of a source host computer system operatively coupled to the memory, the processing device to:
• allocate a host page cache and a backing store to a virtual machine (VM), the VM undergoing live migration from the source host computer system to a destination host computer system;
• transmit, from the source host computer system to the destination host computer system, in a priority order, at least a part of the host page cache, wherein the transmission of the part of the host page cache causes an instruction to start the VM on the destination host computer system following the transmission of the part of the host page cache;
• discard the part of the host page cache;
• read, into the host page cache, from the backing store, one or more memory pages of a second plurality of memory pages associated with the VM;
• and
• transmit, from the source host computer system to the destination host computer system, the one or more memory pages stored by the host page cache.

A non-transitory computer-readable media storing instructions that, when executed, cause a processing device to:

• allocate, by a source host computer system, a host page cache and a backing store to a virtual machine (VM), the VM undergoing live migration from the source host computer system to a destination host computer system;
• transmit, from the source host computer system to the destination host computer system, in a priority order, at least a part of the host page cache, wherein the transmission of the part of the host page cache causes an instruction to start the VM on the destination host computer system following the transmission of the part of the host page cache;
• discard the part of the host page cache;
• read, into the host page cache, from the backing store, one or more memory pages of a second plurality of memory pages associated with the VM;
• and
• transmit, from the source host computer system to the destination host computer system, the one or more memory pages stored by the host page cache.