Backport cgroups v2 to 8u

[Severin Gehwolf]

Hi Poonam,

On Tue, 2022-10-04 at 20:52 +0000, Poonam Parhar wrote:
> Hello Severin, Andrew,
> 
> We, Oracle, are in the process of backporting a bunch of cgroups v2 fixes to Oracle jdk8u. We have started with backporting the following 6 issues first.
> 
> 1. JDK-8230305: Cgroups v2: Container awareness
> 2. JDK-8231111: Cgroups v2: Rework Metrics in java.base so as to recognize unified hierarchy
> 3. JDK-8253714: [cgroups v2] Soft memory limit incorrectly using memory.high
> 4. JDK-8237479: 8230305 causes slowdebug build failure
> 5. JDK-8253727: [cgroups v2] Memory and swap limits reported incorrectly
> 6. JDK-8278951: containers/cgroup/PlainRead.java fails on Ubuntu 21.10 
> 
> I see that Jonathan Dowland has already submitted PRs to jdk8u-dev
> for the first 2 issues. 
> 
> I think we can collaborate our efforts here. In a few days, we will
> be completing our work on backporting the above fixes to Oracle
> jdk8u. After that, we can contribute the changes for the remaining
> four issues to jdk8u-dev. Please let me know your thoughts.

Thanks for reaching out. We welcome contributions of course! I think 1,
2, 4 are already covered by Jon's PRs.

In order to reduce the risk of regressions in 8u, we have 22 bugs on
our list to do (in no particular order):

JDK-8284102: [TESTBUG] Retroactively add regression test for JDK-8272124
JDK-8284756: [11u] Remove unused isUseContainerSupport in CgroupV1Subsystem     
JDK-8266391: Replace use of reflection in jdk.internal.platform.Metrics
JDK-8254997: Remove unimplemented OSContainer::read_memory_limit_in_bytes
JDK-8252957: Wrong comment in CgroupV1Subsystem::cpu_quota      
JDK-8262379: Add regression test for JDK-8257746
JDK-8253727: [cgroups v2] Memory and swap limits reported incorrectly   
JDK-8240189: [TESTBUG] Some cgroup tests are failing after JDK-8231111  
JDK-8253797: [cgroups v2] Account for the fact that swap accounting is disabled on some systems
JDK-8244500: jtreg test error in test/hotspot/jtreg/containers/docker/TestMemoryAwareness.java  
JDK-8245543: Cgroups: Incorrect detection logic on some systems (still reproducible)    
JDK-8253435: Cgroup: 'stomping of _mount_path' crash if manually mounted cpusets exist  
JDK-8254001: [Metrics] Enhance parsing of cgroup interface files for version detection  
JDK-8252359: HotSpot Not Identifying it is Running in a Container
JDK-8239785: Cgroups: Incorrect detection logic on old systems in hotspot
JDK-8239559: Cgroups: Incorrect detection logic on some systems
JDK-8253939: [TESTBUG] Increase coverage of the cgroups detection code  
JDK-8278951: containers/cgroup/PlainRead.java fails on Ubuntu 21.10     
JDK-8230305: Cgroups v2: Container awareness    
JDK-8231111: Cgroups v2: Rework Metrics in java.base so as to recognize unified hierarchy
JDK-8237479: 8230305 causes slowdebug build failure     
JDK-8253714: [cgroups v2] Soft memory limit incorrectly using memory.high

Feel free to help with any of those. If you do, please add a comment on
the bug so that we know who's working on what.

Thanks,
Severin