Re: Some more basic questions..

["Zhang Haoyu" <zhanghy@sangfor.com>]

> Hello,
> Some more basic questions..
> 
> 1. How can I ensure that memory for the a guest is available and
> reserved? In other words, I bring up a Linux VM which has 4G
> allocated, I want to make sure it has all the 4G available right away.
> I saw references to balloon driver, it seemed like that was more for
> dynamic memory exchange between host and guest. In my case, it is a
> Linux guest with a Linux VM.
> 
Try -realtime mlock=on, this option ensure that all the memory allocated for VM  is available right away.

> 2. Does the host reclaim pages from guest if it needs it without a
>balloon driver?
> 
Yes, just consider the memory of VM as that of QEMU(user-process).

> 3. This might be a very basic question, please bear with me:) If I use
> virtio for say network and block, does network and block traffic still
> go through QEMU? Is the host part of virtio basically QEMU or is it
> something that runs in the host kernel. If QEMU, does every IO still
> pass through it? Found some conflicting information, so not a 100%
> sure. Found this, not sure if it is 100% accurate? Trying to
> understand the flow through different layers, and what the layers are.
> http://events.linuxfoundation.org/sites/events/files/slides/MasakiKimura_LinuxConNorthAmerica2013_1.pdf
> 
> 
It depends on whether you enable the vhost or something.
 
> Thank you in Advance:)
> --