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 ------------- Commit messages: - Fix comments - 8333446: Add tests for hierarchical container support Changes: https://git.openjdk.org/jdk/pull/19530/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19530&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8333446 Stats: 489 lines in 8 files changed: 482 ins; 0 del; 7 mod Patch: https://git.openjdk.org/jdk/pull/19530.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/19530/head:pull/19530 PR: https://git.openjdk.org/jdk/pull/19530
