RFR: 8364090: Dump JFR recording on CrashOnOutOfMemoryError

[Erik Gahlin]

On Fri, 25 Jul 2025 00:52:29 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

> JFR emergency dump would happen when OOM was thrown. However it would not contain most recent `OldObjectSample` events emitted by LeakProfiler.
> 
> I [reported this issue in past](https://mail.openjdk.org/pipermail/hotspot-jfr-dev/2019-January/000381.html), and it seems to be difficult to fix soon, and also JDK codebase has been updated in several years. It brings us to fix this issue easier than past.
> 
> So I propose again to emit the events from LeakProfiler when OOM happened.
> This change passed `jdk_jfr` tests on Linux x64 (excepts TestHeapSummaryEventPSParOld.java reported in [JDK-8364082](https://bugs.openjdk.org/browse/JDK-8364082))
> 
> Related email thread: https://mail.openjdk.org/pipermail/hotspot-jfr-dev/2025-July/008007.html

src/hotspot/share/runtime/java.cpp line 466:

> 464:   }
> 465: 
> 466:   JFR_ONLY(Jfr::on_vm_shutdown(true, halt);)

You set oom to true here, why?

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PR Review Comment: https://git.openjdk.org/jdk/pull/26468#discussion_r2230419356