RFR: 8282170: JVMTI SetBreakpoint metaspace allocation test

[Chris Plummer]

On Mon, 21 Feb 2022 10:55:42 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> There are few bugs in SetBreakpoint when it reaches for metaspace allocation, notably [JDK-8214992](https://bugs.openjdk.java.net/browse/JDK-8214992) and [JDK-8264149](https://bugs.openjdk.java.net/browse/JDK-8264149). This adds the test that exercises the metaspace allocation paths.
> 
> Additional testing:
>  - [x] New test on Linux x86_64 fastdebug
>  - [x] New test on Linux x86_64 release
>  - [x] New test with [JDK-8264149](https://bugs.openjdk.java.net/browse/JDK-8264149) reverted fails on Linux x86_64 release

So you load a class 50 times in separate ClassLoaders, and each load triggers the ClassPrepare event, and each time that happens you set a breakpoint on each of the 1000 methods, meaning a total of 5000 breakpoints. Doing this will eventually trigger calling CollectorPolicy::satisfy_failed_metadata_allocation(). Previous to the [8264149](https://bugs.openjdk.java.net/browse/JDK-8264149) fix, this used to trigger an assert. Am I understanding this properly?

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PR: https://git.openjdk.java.net/jdk/pull/7554