RFR: 8302744: Refactor Hotspot container detection code [v3]

[Johan Sjölen]

On Mon, 27 May 2024 12:50:16 GMT, Johan Sjölen <jsjolen 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 16 additional commits since the last revision:
>> 
>>  - Add proper comments for parsing utility functions
>>  - Add a test for a large string read
>>  - Add convenience function for 'max' handling
>>    
>>    This now makes limit_from_str a private method
>>  - Fix general read string cases.
>>  - Get rid of the templated function
>>  - Use enum class for TupleValue
>>  - Merge branch 'master' into jdk-8302744-cleanup-getcontainer-info
>>  - Fix TestMemoryAwareness for cgroup v2
>>    
>>    It only reads the swap value, thus doesn't print:
>>    "Memory and Swap Limit is" but rather prints:
>>    "Swap Limit is". This is fine, since for cg v2
>>    the memory limit and the swap limits are in different
>>    files.
>>  - Fix whitespace
>>  - Handle cpu quota for cgroups v1 specially
>>  - ... and 6 more: https://git.openjdk.org/jdk/compare/60138569...c41d3183
>
> src/hotspot/os/linux/cgroupV2Subsystem_linux.cpp line 152:
> 
>> 150:   bool is_ok = _memory->controller()->
>> 151:                     read_numerical_key_value("/memory.stat", "anon", &rss);
>> 152:   if (!is_ok) {
> 
> Style, nit: A bit unconventional (for Hotspot) to line break after `->`, maybe this is preferable:
> 
> ```c++
> bool is_ok =
>   _memory->controller()->read_numerical_key_value("/memory.stat", "anon", &rss);

Or each argument can be line-separated, just a couple of ideas.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19060#discussion_r1616012371