[jdk11u-dev] RFR: 8231111: Cgroups v2: Rework Metrics in java.base so as to recognize unified hierarchy [v4]

[Zhengyu Gu]

On Fri, 11 Mar 2022 21:16:19 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

>> This is a followup backport for Cgroup v2 support.
>> 
>> The original patch does not apply cleanly, due to context differences and some of out-of-order backports, conflicts were resolved manually.
>> 
>> In additional:
>> 
>> 1) Include partial backport of JDK-8250627.
>>     - Renamed `Metrics.c` =>  `CgroupMetrics.c`
>>     - Added native method `isUseContainerSupport()` to `CgroupMetrics.java`
>>     - Return instance only if `isUseContainerSupport()` is enabled.
>>    
>> 2) Add `createTempDirectory()` method to `test/lib/jdk/test/lib/Utils.java` for `TestCgroupSubsystemController.java` test
>> 
>> 3) Add `import jdk.test.lib.process.OutputAnalyzer;` to `TestDockerMemoryMetrics.java`
>> 
>> Test:
>> 
>> - [x] jtreg containers/docker test on Ubuntu 20.04.4 LTS
>> - [x] jdk/internal/platform/cgroup on Ubuntu 20.04.4 LTS
>> - [x] jdk/internal/platform/docker on Ubuntu 20.04.4 LTS
>
> Zhengyu Gu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   More fixes

> 

@jerboaa Thanks for the review. I underestimated how many out-of-order backports that affected this backport, especially files without conflicts. I redid `CgroupV1Subsystem.java` and need to go through others.

Thanks.

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/863