Hi Severin, I'll put your patch into our internal build/test queue .
Additionally I can confirm that the error I reported last week when running
jtreg tests :
>
> > ./jtregojdk.sh tools/jpackage
>
>
> java.lang.InternalError: java.lang.reflect.InvocationTargetException
> at
> java.base/jdk.internal.platform.Metrics.systemMetrics(Metrics.java:65)
> at
> java.base/jdk.internal.platform.Container.metrics(Container.java:43)
> at
> jdk.management/com.sun.management.internal.OperatingSystemImpl.<init>(OperatingSystemImpl.java:48)
> at
> jdk.management/com.sun.management.internal.PlatformMBeanProviderImpl.getOperatingSystemMXBean(PlatformMBeanProviderImpl.java:281)
> at
> jdk.management/com.sun.management.internal.PlatformMBeanProviderImpl$3.nameToMBeanMap(PlatformMBeanProviderImpl.java:198)
> at
> java.management/sun.management.spi.PlatformMBeanProvider$PlatformComponent.getMBeans(PlatformMBeanProvider.java:195)
> at
> java.management/java.lang.management.ManagementFactory.getPlatformMXBean(ManagementFactory.java:686)
> at
> java.management/java.lang.management.ManagementFactory.getOperatingSystemMXBean(ManagementFactory.java:388)
...
Is gone with the patch.
Best regards, Matthias
>
> Could I please get a review of this fix to the detection heuristic of
> cgroup v1 vs cgroup v2? Matthias (in CC) discovered that on some old
> systems the JDK Metrics code throws InternalError caused by wrong
> detection logic when Metrics are being created on Linux.
>
> The reason for this is that hierarchy IDs of 0 in /proc/cgroups is
> being used as a heuristic to detect cgroups v2 systems. Apparently some
> old systems like RHEL 6 and SLES 11 have no cgroups controllers
> mounted, thus, triggering a false positive.
>
> The fix is to also look at /proc/self/mountinfo and correct logic in
> this case.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8239559
> webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-
> 8239559/01/webrev/
>
> Testing: docker/cgroups tests on hybrid (cgroups v1) and unified
> hierarchy (cgroups v2). New regression test. Looks good here.
>
> Unfortunately, I wasn't able to reproduce this on an actual affected
> system. I somewhat reproduced via the derived regression test based on
> data from reporters. I'd appreciate any testing on systems where this
> reproduces.
>
> Thanks,
> Severin
