RFR: JDK-8322237: Heap dump contains duplicate thread records for mounted virtual threads [v4]

[Serguei Spitsyn]

On Fri, 22 Dec 2023 20:52:48 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> HeapDumper dumps virtual threads in 2 places:
>> - dumping platform threads (mounted virtual threads are dumped as separate thread object);
>> - dumping heap objects when the object is `java.lang.VirtualThread`.
>> 
>> In the 2nd case mounted virtual threads should be skipped (as they are already dumped with correct stack traces/stack references)
>> Check that a virtual thread is mounted is non-trivial, method from JvmtiEnvBase was used for this.
>> 
>> Testing: tier1..3, heapdump-related tests: open/test/hotspot/jtreg/serviceability,open/test/hotspot/jtreg/runtime/ErrorHandling,open/test/hotspot/jtreg/gc/epsilon,open/test/jdk/sun/tools/jhsdb
>
> Alex Menkov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   feedback: extended comment

Thank you for the update!

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

Marked as reviewed by sspitsyn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17134#pullrequestreview-1795555865