RFR: JDK-8266490: Extend the OSContainer API to support the pids controller of cgroups [v5]

[Matthias Baesken]

On Fri, 16 Jul 2021 06:14:07 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> Hello, please review this PR; it extend the OSContainer API in order to also support the pids controller of cgroups.
>> 
>> I noticed that unlike the other controllers "cpu", "cpuset", "cpuacct", "memory"  on some older Linux distros (SLES 12.1, RHEL 7.1) the pids controller might not be there (or not fully supported) so it was added as optional  , see the coding
>> 
>> 
>>   if (!cg_infos[PIDS_IDX]._data_complete) {
>>     log_debug(os, container)("Optional cgroup v1 pids subsystem not found");
>>     // keep the other controller info, pids is optional
>>   }
>
> Matthias Baesken has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into JDK-8266490
>  - Add hotspot tests
>  - test and small adjustments suggested by Severin
>  - Adjustments following Severins comments
>  - JDK-8266490

Hi Severin, thanks for the comments. I added a commit with a number of adjustments 

src/hotspot/os/linux/cgroupSubsystem_linux.cpp
adjusted log_info to log_debug

src/java.base/share/classes/sun/launcher/LauncherHelper.java
adjusted the output to "Maximum Processes Limit:"

test/hotspot/jtreg/containers/docker/CheckOperatingSystemMXBean.java
removed the getPidsMax related line (I think I inserted it while running some tests and forgot previously to remove it)

test/hotspot/jtreg/containers/docker/TestPids.java
added testing of "Unlimited"; added  --pids-limit=-1  for  Unlimited procs like you suggested

test/jdk/jdk/internal/platform/docker/TestPidsLimit.java
adjusted output; added  --pids-limit=-1  for  Unlimited procs like you suggested

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PR: https://git.openjdk.java.net/jdk/pull/4518