[jdk11u-dev] RFR: 8239785: Cgroups: Incorrect detection logic on old systems in hotspot [v2]

[Severin Gehwolf]

On Fri, 25 Mar 2022 11:09:26 GMT, Jonathan Dowland <jdowland at openjdk.org> wrote:

>> This is a backport of 8239785 for jdk11u. The dependent backports have now all been integrated.
>> 
>> This PR replaces #881 which was stuck with a dependency on a superseded dependent PR.
>> 
>> It's not clean, but the only conflict was the copyright line in the
>> comment header for src/hotspot/share/prims/whitebox.hpp.
>> 
>> I'm checking jtreg tests in test/hotspot/jtreg/containers on a mixture of cgroup v1 and v2 systems now.
>> 
>> ---------
>> ### Progress
>> - [x] Change must not contain extraneous whitespace
>> - [x] Commit message must refer to an issue
>> - [ ] Change must be properly reviewed
>> 
>> ### Error
>>  ⚠️ The pull request body must not be empty.
>> 
>> 
>> 
>> ### Reviewing
>> <details><summary>Using <code>git</code></summary>
>> 
>> Checkout this PR locally: \
>> `$ git fetch https://git.openjdk.java.net/jdk11u-dev pull/946/head:pull/946` \
>> `$ git checkout pull/946`
>> 
>> Update a local copy of the PR: \
>> `$ git checkout pull/946` \
>> `$ git pull https://git.openjdk.java.net/jdk11u-dev pull/946/head`
>> 
>> </details>
>> <details><summary>Using Skara CLI tools</summary>
>> 
>> Checkout this PR locally: \
>> `$ git pr checkout 946`
>> 
>> View PR using the GUI difftool: \
>> `$ git pr show -t 946`
>> 
>> </details>
>> <details><summary>Using diff file</summary>
>> 
>> Download this PR as a diff file: \
>> <a href="https://git.openjdk.java.net/jdk11u-dev/pull/946.diff">https://git.openjdk.java.net/jdk11u-dev/pull/946.diff</a>
>> 
>> </details>
>
> Jonathan Dowland has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:
> 
>   8239785: Cgroups: Incorrect detection logic on old systems in hotspot
>   
>   Return NULL subsystem if no cgroup controllers are mounted.
>   
>   Reviewed-by: bobv, mbaesken

Marked as reviewed by sgehwolf (Reviewer).

I'm marking this one clean as the only change is the copyright line in `whitebox.hpp` which has been fixed manually.

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/946