Re: slabinfo shows incorrect active_objs ???

[Vasily Averin <vvs@virtuozzo.com>]

On 22.02.2022 19:47, Roman Gushchin wrote:
>> On Feb 22, 2022, at 4:10 AM, Vasily Averin <vvs@virtuozzo.com> wrote:
>> I'm preparing new set of memcg accounting patches, with reparired tools/cgroup/memcg_slapinfo.py
>> I can get numbers of accounted resources, but I need to understand how may resources was NOT
>> accounted to memcg but allocated on host. I expected get these numbers from host's slabinfo but
>> it does not show correct numbers.
> 
> I’m really curious what these patches are. Are you looking to enable accounting for more slab caches?

I think I can announce it right now:

- Terminal accounting patch was lost in previous iteration,
- nft replaced iptables but still lacks an accounting,
- in openvz, we have a limit for each container for network interfaces, but upstream lacks it.  As a result, you can create many network interfaces, allocate a lot of non-memcg-accounted memory, and easily run OOM from a memcg-limited container. When creating a network device, various objects are allocated: queues, sysctl tables, kernfs_node, hash tables with dynamically resizable size using hashtable_init() and some others. I expect accounting for some of them can be quickly approved, but others may meet resistance. Moreover, I tested only veth devices, others may consume some other specific resources.
  In any case, I'm going to pay attention to this problem and find some acceptable solution.

Thank you,
	Vasily Averin