RFR(xs): 8202073: MetaspaceAllocationTest gtest shall lock during space creation

[coleen.phillimore at oracle.com]

Looks good.
Coleen

On 4/20/18 3:11 AM, Thomas Stüfe wrote:
> May I please have reviews for this small fix to the
> metaspace-allocate-stresstest-gtest:
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8202073
>
> webrev: http://cr.openjdk.java.net/~stuefe/webrevs/8202073-MetaspaceAllocationTest-gtest-shall-lock-during-space-creation/webrev.00/webrev/
>
> MetaspaceAllocationTest mimicks ClassLoaderMetaspace creation,
> allocation and destruction to stress metaspace allocation.
>
> So it runs outside the normal create-allocate-delete cycle in the VM.
> For instance, there are no associated ClassLoaderData. So, the test
> needs to mimick the surroundings of the VM.
>
> This means, when creating ClassLoaderMetaspace objects, the test needs
> to lock its associated lock. In the VM, this happens in
> ClassLoaderData::metaspace_non_null(), and there the associated lock
> is pulled before allocation too.
>
> Thanks, Thomas