Memory swapper for virtualized environments

Prof. Assaf Schuster | Computer Science


Information and Computer Science

The Technology

The main enabling technology for cloud computing is machine virtualization, which abstracts the rigid physical infrastructure and turns it into soft components that may be easily managed and used. Clouds and virtualization are driven by strong economical incentives, notably the ability to consolidate multiple VM guest servers on one physical host. The number of VM guests that can be consolidated and supported on one physical host is typically limited by the size of the host’s physical memory, motivating hosts to overcommit their memory to increase their capacity.

Overcommitment of memory requires memory management to guarantee proper operation of all VM guests consolidated on the host. Memory overcommit using host-swapping mechanism suffers severe overheads of common workload. Other memory overcommitment solutions that may perform better are imperfect and cannot always be applied.

The technology suggested here, offers a method for reducing disk read rate by managing dataset mapping of virtual machine (VM) guest memory, comprising: monitoring a plurality of disk read write operations of a VM guest; updating a dataset mapping between disk blocks allocated to the VM guest and corresponding physical addresses of memory pages of the VM guest containing replica of data stored in the disk blocks, based on the plurality of disk read write operations; when identifying writing to one of the memory pages removing a mapping of corresponding disk block and corresponding physical address of memory page; when reclaiming a mapped memory page of the VM guest by a host of the VM guest, discarding data contained in the memory page; and when the data is requested by the VM guest after it was reclaimed by said host, retrieving the data from corresponding disk block according to the mapping.


  • Faster than existing host-swapping solution
  • System preforms without enduring other memory-overcommitment mechanism drawbacks

Applications and Opportunities

  • The system can be embodied in existing VMMs to improve their performance: VMM vendors, cloud providers
arrow Business Development Contacts
Ofer Shneyour
Director of Business Development, ICT