Is it possible to detect from within a Linux VM that memory is being reclaimed by the memory balloon? I don't think any information about the host is propagated to the VM, so connecting to the host and asking is not an option. I would prefer not to rely on heuristic approach either.
Edit: The reason why I want to know about it from the VM is to raise an alert to the VM's admin, who may not have access to the host, but should nevertheless know about the potential performance degradation.