Should meminfo-writer be on or off for service DispVMs with PCI devices?

User Support
1

I was reading Disposable customization — Qubes OS Documentation and noticed that the section on “Named disposable for service qubes with PCI devices via GUI” says to Add the meminfo-writer service, while the next section describing how to do it via command line says to issue qvm-service <SERVICE_QUBE> meminfo-writer off, which has the opposite effect.

Which one is correct? And what is the goal here in turning meminfo-writer on/off?

1 Like
2

Thanks for reporting, it should be: “Add and uncheck”. Because it is “on” by default, you have to add it to the list to be able to disable it.

2 Likes
3
3 Likes
4

Thanks for confirming! By the way, what is the goal of turning it off in this case?

5

so… why I dont have it by default in my sys-usb and sys-net???
what could happen if it’s on?

6

These qubes have a constant memory assignment:

[user@dom0 ~]$ qvm-prefs sys-usb maxmem
0
[user@dom0 ~]$ qvm-prefs sys-net maxmem
0

So they don’t need their memory assignment to be managed by qmemmand in dom0. Therefore they don’t need to send updates about their memory usage upstream to dom0, which is what meminfo-writer does.

I think there is no harm if it’s on, but it’s not useful.

1 Like