US Patent 10474359 Write minimization for de-allocated memory

Disclosed herein are techniques for reducing the number of write operations performed to a storage-class memory in a virtualized environment. In one embodiment, when a memory page is de-allocated from a virtual machine, the memory page and/or the subpages of the memory page are marked as “trimmed” in a control table such that any read to the memory page or subpages is denied, and no physical memory initialization is performed to the memory page or subpages. A de-allocated memory page or subpage is only initialized when it is reallocated and is to be written to by the virtual machine to which the memory page is reallocated.