On Fri, Jun 29, 2018 at 7:55 AM Michal Hocko mhocko@kernel.org wrote:
On Fri 29-06-18 16:40:23, Paolo Bonzini wrote:
On 29/06/2018 16:30, Michal Hocko wrote:
I am not familiar wtih kvm to judge but if we are going to account this memory we will probably want to let oom_badness know how much memory to account to a specific process. Is this something that we can do? We will probably need a new MM_KERNEL rss_stat stat for that purpose.
Just to make it clear. I am not opposing to this patch but considering that shadow page tables might consume a lot of memory it would be good to know who is responsible for it from the OOM perspective. Something to solve on top of this.
The amount of memory is generally proportional to the size of the virtual machine memory, which is reflected directly into RSS. Because KVM processes are usually huge, and will probably dwarf everything else in the system (except firefox and chromium of course :)), the general order of magnitude of the oom_badness should be okay.
I think we will need MM_KERNEL longterm anyway. As I've said this is not a must for this patch to go. But it is better to have a fair comparision and kill larger processes if at all possible. It seems this should be the case here.
I will look more into MM_KERNEL counter. I still have couple more kmem allocations in kvm (like dirty bitmap) which I want to be accounted. I will bundle them together.
thanks, Shakeel