[systemd-devel] 11 MB cost of DefaultMemoryAccounting=yes

[Umut Tezduyar Lindskog]

Hello,

Even though this is not a systemd problem, I believe systemd mailing
list is a good place to discuss.

Our kernel has CONFIG_MEMCG enabled. As soon as we set
DefaultMemoryAccounting=yes, our system wide memory usage increased 11
MB. The increase is mostly on kmalloc-* slab memory with the peak on
kmalloc-32.

I initially thought the increase is due to systemd creating
system.slice under /sys/fs/cgroup/memory but I think I am wrong. I
have run "systemd-run -p MemoryLimit=10M /bin/sleep 5" command while
DefaultMemoryAccounting=no and there was no significant memory usage.

I am quite puzzled about where this extra cost is coming from. Does
anybody have any idea?

Umut