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What is memory page sharing?
Shared memory allows one or more processes to communicate via memory that appears in all of their virtual address spaces. The pages of the virtual memory is referenced by page table entries in each of the sharing processes page tables. Each newly created shared memory area is represented by a shmid_ds data structure.
10 shares per megabyte of configured virtual machine memory. 5 shares per megabyte of configured virtual machine memory. For example, an SMP virtual machine with two virtual CPUs and 1GB RAM with CPU and memory shares set to Normal has 2×1000=2000 shares of CPU and 10×1024=10240 shares of memory.
Can a virtual machine share memory with another OS?
Shared memory, as you’ve been using it, is an OS-level concept; you can’t use it to share memory with something that’s outside the control of the (guest) OS. In principle, the virtual machine technology could offer some way to share memory between the guest and the host.
Why does a virtual machine need memory on the host?
Some memory must be kept available on the host to ensure the host is able to operate properly while virtual machines are running. The amount of memory reserved for the host depends on the host operating system and the size of the host computer’s memory. Many workloads present opportunities for sharing memory across virtual machines.
How does memory sharing work in VMware Workstation?
VMware Workstation memory sharing runs as a background activity that scans for sharing opportunities over time. The amount of memory saved may vary over time; for a fairly constant workload, the amount generally increases slowly until all sharing opportunities are exploited.
How is memory reserved for the host computer?
The amount of memory reserved for the host depends on the host operating system and the size of the host computer’s memory. Many workloads present opportunities for sharing memory across virtual machines.