RFR: 8366328: G1: Crash on reading os::thread_cpu_time

[Thomas Schatzl]

On Thu, 4 Sep 2025 09:28:11 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

> > Did you consider the alternative to prevent the GC from starting a GC pause if the JVM is shutting down?
> 
> I have filed [JDK-8366865](https://bugs.openjdk.org/browse/JDK-8366865) to continue with that investigation.

Ivan and me talked about this briefly, but the difference in how the STW collectors request GCs does not allow simple blocking like for ZGC and Shenandoah.

In these collectors, Java threads send a request to a director thread that can delay the completion of these (GC) requests easily. In the other collectors, the allocating threads directly enqueue the VM operations which means blocking is not possible as is.

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PR Comment: https://git.openjdk.org/jdk/pull/27087#issuecomment-3252827916