[Qemu-discuss] Arbitrarily high VIRT?

[Christian Theune]

Hi,

I’m currently analyzing a potential Linux (host) kernel memory issue that is 
causing relatively frequent BUG/Oops on our hosts. Something that I haven’t 
found much documentation on is the amount of virtual memory (VIRT) that Qemu 
allocates. Besides the guest memory I guess it depends a lot on what 
devices/backends we’re running.

I currently see VMs with 1GiB guest memory allocated showing 14GiB VIRT but 
correctly using less than 1GiB RES. In general allocating arbitrary amounts of 
VIRT isn’t a problem at all (e.g. for memory mapping files) but I’m still 
curious whether this is typical and assumed or whether VIRT should be much 
closer to the guest memory size.

Thanks and cheers,
Christian

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