RFR: 8333446: Add tests for hierarchical container support [v6]

[Severin Gehwolf]

On Fri, 30 Aug 2024 11:02:52 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> 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 10 additional commits since the last revision:
>> 
>>  - Add root check for SystemdMemoryAwarenessTest.java
>>  - Merge branch 'master' into jdk-8333446-systemd-slice-tests
>>  - Merge branch 'master' into jdk-8333446-systemd-slice-tests
>>  - Merge branch 'master' into jdk-8333446-systemd-slice-tests
>>  - Add Whitebox check for host cpu
>>  - Merge branch 'master' into jdk-8333446-systemd-slice-tests
>>  - 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
>
> src/hotspot/share/prims/whitebox.cpp line 2507:
> 
>> 2505: WB_END
>> 2506: 
>> 2507: // Physical cpus of the host machine (including containers), Linux only.
> 
> Isn't the comment a bit misleading ?  From what I see , ` os::Linux::active_processor_count()` can use various mechanisms to get number of processor info, if it uses https://linux.die.net/man/2/sched_getaffinity it gives the 'set of CPUs on which it is eligible to run.'   That might be different from what the host has.

Yes. See #20768 for an attempt to unify it. I'll change the comment with the update that I have for nested hierarchies. Thanks!

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PR Review Comment: https://git.openjdk.org/jdk/pull/19530#discussion_r1738475745