RFR: JDK-8260282: Add option to compress heap dumps created by -XX:+HeapDumpOnOutOfMemoryError [v3]

[Chris Plummer]

On Tue, 26 Jan 2021 08:09:22 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> Ralf Schmelter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
>> 
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8260282
>>  - Limit memory of heap dumping VM
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8260282
>>  - Fixed maximum supported compression level.
>>  - Fixed trailing whitespace.
>>  - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8260282
>>  - Change allowed levels. 0 now means disabled.#
>>  - Added option to compress the heap dump created by -XX:+HeapDumpOnOutOfMemoryError
>
> Marked as reviewed by cjplummer (Reviewer).

> > I've added a -Xmx128M. This should probably also done to TestHeapDumpOnOutOfMemoryError, which uses the same code.
> 
> Yes, it should. Probably it hasn't caused failures because my recollection is that it usually takes 2 or more such heap exhaustion tests running in parallel to result in unexpected failures in our testing, but it really depends on the test host and available memory. Also, the metaspace version of the test does use `-XX:MaxMetaspaceSize=16m`, so it doesn't use that much memory.

Looks like this was just addressed today by [JDK-8252545](https://bugs.openjdk.java.net/browse/JDK-8252545).

-------------

PR: https://git.openjdk.java.net/jdk/pull/2222