RFR: 8205928 - [TESTBUG]: jdk/internal/platform/docker/TestDockerMemoryMetrics.java fails depending on kernel config

[Thomas Stüfe]

Hi Bob,

It does look fine from the outside. I did not test it though, since I
have no suitable kernel.

Best Regards, Thomas

On Tue, Jul 3, 2018 at 3:13 PM, Bob Vandette <bob.vandette at oracle.com> wrote:
> Please review this small fix to correct a test failure when the Linux system kernel is
> not configured with the CONFIG_MEMCG_KMEM option.
>
> The Container Metric tests are dependent on docker which allow us to assume a certain minimum
> Linux kernel configuration level. However, the kernel memory resource limiting feature is not a hard
> requirement for docker. This test will need to be updated to allow for running on kernels without this
> option.  A 0 return from the getKernelMemoryLimit is defined to indicate that this API is not available.
>
> BUG: https://bugs.openjdk.java.net/browse/JDK-8205928
>
> PROPOSED FIX:
>
> diff --git a/test/jdk/jdk/internal/platform/docker/MetricsMemoryTester.java b/test/jdk/jdk/internal/platform/docker/MetricsMemoryTester.java
> --- a/test/jdk/jdk/internal/platform/docker/MetricsMemoryTester.java
> +++ b/test/jdk/jdk/internal/platform/docker/MetricsMemoryTester.java
> @@ -95,10 +95,11 @@
>
>      private static void testKernelMemoryLimit(String value) {
>          long limit = getMemoryValue(value);
> -        if (limit != Metrics.systemMetrics().getKernelMemoryLimit()) {
> +        long kmemlimit = Metrics.systemMetrics().getKernelMemoryLimit();
> +        if (kmemlimit != 0 && limit != kmemlimit) {
>              throw new RuntimeException("Kernel Memory limit not equal, expected : ["
>                      + limit + "]" + ", got : ["
> -                    + Metrics.systemMetrics().getKernelMemoryLimit() + "]");
> +                    + kmemlimit + "]");
>          }
>          System.out.println("TEST PASSED!!!");
>      }