What do hosts use the vmx-*.vswp swap file for?

The vmx-*.vswp swap file is utilized by hosts to manage memory for virtual machines (VMs). When a VM’s memory is overcommitted or when there is a need to free up physical memory, the hypervisor uses this swap file to temporarily store portions of the VM's memory. This mechanism allows the hypervisor to efficiently track and handle memory allocation, which can improve the performance of a VM running on constrained resources.

In environments where VMs require more physical memory than what is available (for example, in scenarios involving multiple VMs on a single host), the use of the swap file becomes critical. It helps in ensuring that the VMs can continue operating by swapping out less-used memory pages to the disk rather than causing the VMs to crash or become unresponsive.

The other choices do not accurately define the purpose of the vmx-*.vswp file. Enhancing VM disk performance and increasing CPU processing power are functions that relate more to other resources and configurations, while storing temporary files does not reflect the specific use case of the swap file in terms of memory management for VMs. Rather, the swap file is specifically focused on facilitating memory overflow situations to enhance overall VM stability and efficiency.