Messages in this thread | | | Date | Mon, 22 Jun 2015 11:45:59 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH 3/5] vhost: support upto 509 memory regions |
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On 22/06/2015 09:10, Igor Mammedov wrote: > So far HVA is unusable even if we will make this assumption and let guest crash. > virt_net doesn't work with it anyway, > translation of GPA to HVA for descriptors works as expected (correctly) > but vhost+HVA hack backed virtio still can't send/received packets. > > That's why I prefer to merge kernel solution first as a stable and > not introducing any issues solution. And work on userspace approach on > top of that.
Also, let's do some math.
Let's assume 3 network devices per VM, one vhost device per queue, one queue per VCPU per network device. Let's assume the host is overcommitted 3:1.
Thus we have 3*3=9 times vhost devices as we have physical CPUs.
We're thus talking about 108K per physical CPU.
From a relative point of view, and assuming 1 GB of memory per physical CPU (pretty low amount if you're overcommitting CPU 3:1), this is 0.01% of the total memory.
From an absolute point of view, it takes a system with 60 physical CPUs to reach the same memory usage as the vmlinuz binary of a typical distro kernel (not counting the modules).
Paolo
> Hopefully it could be done but we still would need time > to iron out side effects/issues it causes or could cause so that > fix became stable enough for production. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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