[systemd-devel] Antw: Re: Antw: Re: Antw: [EXT] Re: Memory in systemctl status

[Ulrich Windl]

>>> Benjamin Berg <benjamin at sipsolutions.net> schrieb am 30.09.2020 um 12:08 in
Nachricht <2f6a1d5b102e5dade4f578d6d704b07508d03d50.camel at sipsolutions.net>:
> On Wed, 2020-09-30 at 11:04 +0200, Ulrich Windl wrote:
>> > > > Reindl Harald <h.reindl at thelounge.net> schrieb am 30.09.2020 um 10:56 in
>> Nachricht <a4f1a092-0946-d61e-f486-3fe3e2d34086 at thelounge.net>:
>> 
>> > Am 30.09.20 um 09:06 schrieb Ulrich Windl:
>> > > > my webserver is killed because it served at monday, tuesday, thursday
>> > > > and friday 4 different files with 2 GB?
>> > > 
>> > > cgroups is for limiting resources, not for killing processes AFAIK
>> > 
>> > [Service]
>> > MemoryMax=4G
>> > 
>> > would call OOM killer
>> 
>> Are you sure? I thought OOM is called when the _system_ memory is exhausted.
>> IMHO any memory allocation request to the process will be denied, but the
>> process wouldn't be killed. But agreed, I didn't track the cgroups changes 
> in
>> the last few years.
> 
> I think you can assume that the OOM killer will kick in rather than the
> allocation request being denied.
> 
> This option does cap the amount system memory that is used for the
> cgroup. So if memory cannot be reclaimed (e.g. swapped out, file
> backed) then the OOM killer will run within the cgroup.

OK, didn't know the OOM killer is cgroup-specific

> 
> As I understand it, what Reindl is looking for is seeing and limiting
> the amount of resident anonymous pages that the cgroup has rather than
> its real memory use.
> 
> Benjamin