[systemd-devel] MemoryLimit for user unit

[WaLyong Cho]

On 2017년 11월 13일 09:53, Kai Krakow wrote:
> Am Sun, 12 Nov 2017 18:14:38 +0100
> schrieb Stefan Schweter <stefan at schweter.it>:
> 
>> Hi systemd-users,
>>
>> I tried to add a memory limit for a user service unit (inspired by
>> [1]), it looks like:
>>
>> [Service]
>> # ....
>> MemoryAccounting=true
>> MemoryLimit=1G
>>
>> Now the problem is that the (user) service consumes more than 1G
>> without being terminated.
> 
> As far as I could see, this limits the amount of RAM occupied. It
> doesn't stop the memory from being swapped out. You need to limit swap
> memory, too. Take note that swap accounting may have noticeable
> overheads and as such is not enabled by default on many systems.
> 
By this reason, MemorySwapMax= option is introduced.

https://github.com/systemd/systemd/pull/3659

Note, MemorySwapLimit= does not exist. Lennard does not want to add more
options for legacy cgroup. Further, the swap limit operations different
between legacy and unified cgroup. So adding MemorySwapLimit= was not
good idea.

> 
>> htop shows a memory consumption of 1.4 GB. The output of
>> `systemd-cgtop` is:
>>
>> Control Group                             Tasks   %CPU   Memory
>> Input/s Output/s
>> /                                             -    1.5
>> 1.7G        -
>>
>> /user.slice                                  46    0.4
>> 14.3M        -
>>
>> /user.slice/user-1001.slice                  46    0.4
>> 14.2M        -
>>
>> /init.scope                                   1      -
>> 1.4M        -
>>
>> /system.slice
>>
>>
>> So my question is how would MemoryLimit= work for a user unit?
> 
> Maybe you want to apply the limit to a slice? Your output of cgtop
> doesn't show any service units...
> 
>