RFR: 8343191: Cgroup v1 subsystem fails to set subsystem path [v3]

[Severin Gehwolf]

On Mon, 11 Nov 2024 18:28:11 GMT, Sergey Chernyshev <schernyshev at openjdk.org> wrote:

> > So on cg v1 you start out and end with a `subsystem_path() == null` and on cg v2 you start out and end with a `subsystem_path() == /../../../../../../test`. In both cases the memory limit of 400m won't be detected.
> 
> Only when docker fails to mount the cgroup while moving process to an outer group or a sibling group. It's probably not the case with CloudFoundry.

The bug suggests it's a cg v1 only problem, but I'm able to reproduce in cg v2 too. We should handle both cases more gracefully.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/21808#issuecomment-2470033800