Mitigating eviction of the memory pages of virtualized machines. Upon detecting that a request to perform an I/O operation has been issued against a block stored a disk, a determination is made as to whether a pristine copy of the contents of the block is stored in memory. If a pristine copy of the contents of the block is stored in memory, then the request may be performed by updating mapping data that maps a page of memory to a location in memory at which the pristine copy is stored. In this way, the request is performed without performing the I/O operation against the block stored on disk. Various approaches for resharing memory, including memory of a template virtual machine, are discussed.