RFR: 8298730: Refactor subsystem_file_line_contents and add docs and tests [v3]

[Johan Sjölen]

On Thu, 15 Dec 2022 18:58:57 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add two more test cases
>
> src/hotspot/os/linux/cgroupSubsystem_linux.hpp line 93:
> 
>> 91:                                               T returnval) {
>> 92:   if (c == nullptr) {
>> 93:     log_debug(os, container)("subsystem_file_line_contents: CgroupController* is nullptr");
> 
> The function name `subsystem_file_line_contents` is a bit vague. Maybe it should be changed to something like `parse_subsystem_file()`?

I'd like for a future RFE to split this function into two (with more reasonable names), separating the two parsing cases.

-------------

PR: https://git.openjdk.org/jdk/pull/11667