RFR: 8370492: [Linux] Update cpu shares to cpu.weight mapping function [v4]

[Severin Gehwolf]

On Wed, 12 Nov 2025 15:36:29 GMT, Casper Norrbin <cnorrbin 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 seven additional commits since the last revision:
>> 
>>  - Merge branch 'master' into jdk-8370492-fix-cpushares-mapping
>>  - Remove SkippedException import
>>  - Merge branch 'master' into jdk-8370492-fix-cpushares-mapping
>>  - Fix include
>>  - Add asserts/checks for input domain
>>  - Add regression test for jdk-8370492
>>  - 8370492: [Linux] Update cpu shares to cpu.weight mapping function
>
> test/hotspot/jtreg/containers/docker/TestMisc.java line 107:
> 
>> 105:         // Don't use 1024 exactly so as to avoid mapping to the unlimited/uset case.
>> 106:         // Use a value > 100 post-mapping so as to hit the non-default branch: 1052 => 103
>> 107:         printContainerInfo(1052, 1024, true);
> 
> These tests fail in rootless Podman containers using cgroup v1, because that configuration does not support resource limits. We get the following error to stderr:
> `Resource limits are not supported and ignored on cgroups V1 rootless systems`
> and the cpu shares value is reset to 1024. `cpu_shares: no shares` is then in the output, leading to the first test failing. Then, `1024 != 1052` which leads to the second test failing.

OK. Thanks for the heads-up. I'll test it. We have infra to check for rootless and can skip it there.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28157#discussion_r2519021505