1. A method for monitoring a data structure maintained by guest software within a virtual machine, the virtual machine being supported by virtualization logic in a virtualized computer system, the method comprising: monitoring said data structure and detecting changes to said data structure; determining either that one or more memory pages containing said data structure are swapped into guest physical memory by guest software or that one or more memory pages containing said data structure are swapped out of guest physical memory by guest software; and based on the determination that one or more memory pages are swapped into or out of guest physical memory, retaining information about the contents of the data structure contained in at least one memory page that is swapped out of guest physical memory so that said contents are available after the at least one memory page has been swapped out of guest physical memory.