RFR: 8302744: Refactor Hotspot container detection code [v5]

[Severin Gehwolf]

On Tue, 28 May 2024 12:51:20 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> Please review this container detection code refactoring in hotspot. The main point of this is to
>> 
>> - get rid of the `GET_CONTAINER_INFO` macros which hide too many things under the hood
>> - prevent refactoring of the code (since `GET_CONTAINER_INFO` macros short-return and are therefore not portable; at least not without some risk)
>> - make the code easier to understand
>> - allow for better testing via `gtest`
>> - separate multi-line parsing from single line parsing for clarity.
>> 
>> Testing:
>> - [x] GHA
>> - [x] `gtest:cgroupTest` tests
>> - [x] Container tests on Linux with cgroup v1 (legacy) and cgroup v2. All pass.
>> 
>> Thoughts?
>
> Severin Gehwolf has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review feedback for the test

Thanks for the reviews! I'll do a final testing round and merge tomorrow.

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PR Comment: https://git.openjdk.org/jdk/pull/19060#issuecomment-2135500563