[jdk21u-dev] RFR: 8322420: [Linux] cgroup v2: Limits in parent nested control groups are not detected

[Severin Gehwolf]

On Thu, 16 Jan 2025 14:48:12 GMT, Jan Kratochvil <jkratochvil at openjdk.org> wrote:

>> The goal is to backport: [8322420](https://bugs.openjdk.org/browse/JDK-8322420): [Linux] cgroup v2: Limits in parent nested control groups are not detected
>> 
>> There are included some pre-/post-requisite patches to be squashed as a single commit. Or should I submit 14 separate github pull requests / backports?
>> 
>> In a chronological order (the reverse of `git log`):
>> 
>> - [c96cbe481c86800b76e220374b24b6671984adb7](https://github.com/openjdk/jdk/commit/c96cbe481c86800b76e220374b24b6671984adb7)
>>     [8313083](https://bugs.openjdk.org/browse/JDK-8313083) Print 'rss' and 'cache' as part of the container information
>> - [cab74b075e4572529a21bf8ac652ec2f1ab4fcaf](https://github.com/openjdk/jdk/commit/cab74b075e4572529a21bf8ac652ec2f1ab4fcaf)
>>     [8324287](https://bugs.openjdk.org/browse/JDK-8324287) Record total and free swap space in JFR
>>   patch reduced only to files:
>>    - src/hotspot/os/linux/os_linux.cpp
>>    - src/hotspot/share/runtime/os.hpp
>> - [3d106cb091de6b6ef2a9bf483fb0f5c98c28263c](https://github.com/openjdk/jdk/commit/3d106cb091de6b6ef2a9bf483fb0f5c98c28263c)
>>     [8325139](https://bugs.openjdk.org/browse/JDK-8325139) JFR SwapSpace event - add free swap space information on Linux when running in a container environment
>> - [c1281e6b45ed167df69d29a6039d81854c145ae6](https://github.com/openjdk/jdk/commit/c1281e6b45ed167df69d29a6039d81854c145ae6)
>>     [8324678](https://bugs.openjdk.org/browse/JDK-8324678) Replace NULL with nullptr in HotSpot gtests
>>   patch reduced only to files:
>>    - test/hotspot/gtest/runtime/test_os_linux_cgroups.cpp
>> - [09d4936657a0bdc122a4ab80735bd9c8c109839c](https://github.com/openjdk/jdk/commit/09d4936657a0bdc122a4ab80735bd9c8c109839c)
>>     [8252136](https://bugs.openjdk.org/browse/JDK-8252136) Several methods in hotspot are missing "static"
>>   patch reduced only to files:
>>    - test/hotspot/gtest/os/linux/test_cgroupSubsystem_linux.cpp
>> - [e889b460c03b3887ec5477fa734c430d3c3a41c8](https://github.com/openjdk/jdk/commit/e889b460c03b3887ec5477fa734c430d3c3a41c8)
>>     [8327071](https://bugs.openjdk.org/browse/JDK-8327071) [Testbug] g-tests for cgroup leave files in /tmp on linux
>> - [3d4eb159e6d597f37081faf21b7e3f0f1af299e5](https://github.com/openjdk/jdk/commit/3d4eb159e6d597f37081faf21b7e3f0f1af299e5)
>>     [8302744](https://bugs.openjdk.org/browse/JDK-8302744) Refactor Hotspot container detection code
>> - [d0052c032cc1927e7e92f04cfedab20e0c4e0293](https://github.com/openjdk/jdk/commit/d0052c032cc1927e7e92f...
>
> I expect I should rather do separate backports of each of the commits.

@jankratochvil This seems a rather large backport. In order to determine if we really want to backport all of the bugs listed there should be a) an agreement in principle from JDK 21 maintainers and developers b) provided there is agreement in principle, there needs to be a plan to actually carry out the work so that all requirements will be done in a specific release that we'd target. Ideally early in a release so that it receives as much test as possible.

For b) I'd suggest to start a discussion on jdk-updates-dev with the suggested backport, argument why it's needed and why it justifies the risk of backporting all the dependencies and how you plan to go about this.

Thank you!

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

PR Comment: https://git.openjdk.org/jdk21u-dev/pull/1330#issuecomment-2596057664