Re: Scheduling of VCPUs and allocation of Guest Physical Memory

[Sukanto Ghosh <sukanto@cse.iitb.ac.in>]

Anthony Liguori wrote:
> Sukanto Ghosh wrote:
>> Hi all,
>>
>> I have two questions regarding KVM:
>>
>> i) Is a VCPU scheduled like a normal Linux process
>
> A normal process.
>
>> or there is some mechanism by which performance guarantees can be 
>> provided to the VCPUs ?
>
> FWIW, there are various mechanisms to do scheduler tuning in Linux.  
> cpusets and cgroups both provide mechanisms to ensure "performance 
> guarantees".
are any of these mechanisms currently being used in kvm ?

>> ii) Who does the allocation of host physical memory to the guest, is 
>> it KVM module or the associated QEmu process ?
>
> The QEMU process allocates the memory via malloc().
Doesn't the QEMU process and the guest have different address-spaces ? 
So, how can it malloc for the guest ? I thought the QEMU process 
requests for the memory allocation to the kvm module via the /dev/kvm 
device node.


Thanks and regards
Sukanto