8.3.2.2. Memory Backing

The optional <memoryBacking> element may contain several elements that influence how virtual memory pages are backed by host pages.

Red Hat Enterprise Linux 6.6 and later includes support for locking a virtual machine's memory pages in the host memory with the locked parameter.

Setting locked prevents the host from swapping out memory pages belonging to the guest, which can cause latency. Add the following to the guest XML using the virsh edit command to lock the virtual memory pages in the host's memory:

<memoryBacking>
        <locked/>
</memoryBacking>

Setting nosharepages prevents the host from merging the same memory used among guests. To instruct the hypervisor to disable share pages for a guest, add the following to the guest's XML using the virsh edit command:

<memoryBacking>
         <nosharepages/>
</memoryBacking>