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

[Bob Vandette]

Matthais, who reported the issue, confirmed that this patch solves the problem.

Thanks,
Bob.

> On Jul 3, 2018, at 9:38 AM, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:
> 
> 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!!!");
>>     }