RFR: 8333446: Add tests for hierarchical container support [v3]

[Jan Kratochvil]

On Mon, 1 Jul 2024 14:43:58 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> Please review this PR which adds test support for systemd slices so that bugs like [JDK-8217338](https://bugs.openjdk.org/browse/JDK-8217338) can be verified. The added test, `SystemdMemoryAwarenessTest` currently passes on cgroups v1 and fails on cgroups v2 due to the way how [JDK-8217338](https://bugs.openjdk.org/browse/JDK-8217338) was implemented when JDK 13 was a thing. Therefore immediately problem-listed. It should get unlisted once [JDK-8322420](https://bugs.openjdk.org/browse/JDK-8322420) merges.
>> 
>> I'm adding those tests in order to not regress another time.
>> 
>> Testing:
>> - [x] Container tests on Linux x86_64 cgroups v2 and Linux x86_64 cgroups v1.
>> - [x] New systemd test on cg v1 (passes). Fails on cg v2 (due to  JDK-8322420)
>> - [x] GHA
>
> Severin Gehwolf has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Merge branch 'master' into jdk-8333446-systemd-slice-tests
>  - Merge branch 'master' into jdk-8333446-systemd-slice-tests
>  - Fix comments
>  - 8333446: Add tests for hierarchical container support

[test.patch.txt](https://github.com/user-attachments/files/16171122/test.patch.txt)
* `CPUQuota` (changed it to `AllowedCPUs`) does not work for me - it properly distributes the load but JDK still sees all available CPU cores (4 of my VM).
* the change 2 -> 1 cores: // We could check 2 cores ("0-1") but then it would fail on single-core nodes / virtual machines.

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PR Comment: https://git.openjdk.org/jdk/pull/19530#issuecomment-2221959393