[systemd-devel] Antw: [EXT] Re: version bump of minimal kernel version supported by systemd?

[Ulrich Windl]

>>> Greg KH <gregkh at linuxfoundation.org> schrieb am 24.03.2022 um 14:22 in
Nachricht <YjxwsAe3WZHt/36h at kroah.com>:
> On Thu, Mar 24, 2022 at 02:05:09PM +0100, Zbigniew Jędrzejewski-Szmek
wrote:
>> On Thu, Mar 24, 2022 at 10:28:39AM +0000, Luca Boccassi wrote:
>> > On Thu, 2022-03-24 at 09:38 +0100, Lennart Poettering wrote:
>> > > On Mi, 23.03.22 11:28, Luca Boccassi (bluca at debian.org) wrote:
>> > >
>> > > > At least according to our documentation it wouldn't save us much
>> > > > anyway, as the biggest leap is taking cgroupv2 for granted, which
>> > > > requires 4.1, so it's included regardless. Unless there's something
>> > > > undocumented that would make a big difference, in practical terms of
>> > > > maintainability?
>> > >
>> > > Note that "cgroupv2 exists" and "cgroupv2 works well" are two distinct
>> > > things. Initially too few controllers supported cgroupv2 for cgroupv2
>> > > to be actually useful.
>> > >
>> > > What I am trying to say is that it would actually help us a lot if
>> > > we'd not just be able to take croupv2 for granted but to take a
>> > > reasonably complete cgroupv2 for granted.
>> >
>> > Yes, that does sound like worth exploring - our README doesn't document
>> > it though, do we have a list of required controllers and when they were
>> > introduced?
>> 
>> In the README:
>>   Linux kernel >= 4.2 for unified cgroup hierarchy support
>>   Linux kernel >= 4.10 for cgroup-bpf egress and ingress hooks
>>   Linux kernel >= 4.15 for cgroup-bpf device hook
>>   Linux kernel >= 4.17 for cgroup-bpf socket address hooks
>> 
>> In this light, 4.19 is better than 4.4 or 4.9 ;)
> 
> Then move to 4.19.  I strongly doubt that any distro that is using older
> kernels would ever be willing to update systemd.

SLES12 SP5 is running at 4.12, but right: Even with significant rest support
time they won't change the systemd major version, I guess.

> 
> thanks,
> 
> greg k-h