RFR: 8041626: [Event Request] Shutdown reason

[David Holmes]

Hi Robin,

Adding in hotspot-runtime-dev as all the hotspot changes belong to runtime.

I had an initial look through this.

To be honest I don't like it. We seem to have to record little bits of 
information all over the place just so they can be reported by the 
shutdown event. It seems untidy. :(

Can you rename _starting_thread to _main_thread please. The use of 
"starting" in thread.hpp/cpp is really a naming anomaly. The main thread 
is the thread that loads the JVM. And that would be consistent with 
set_exception_in_main_thread.

Though why do we care if the main thread exited with an unhandled 
exception? And if we do care, why do we only care when the shutdown 
reason is ""No remaining non-daemon Java threads"?

I don't like the need to add os::get_abort_exit_code. Do we really need 
it? What useful information does it convey?

It is unfortunate that you need to add beforeHalt to deal with the event 
mechanism itself being turned off (?) by a shutdown hook. That would 
seem to potentially lose a lot of event information given hooks can run 
in arbitrary order and execute arbitrary Java code. And essentially you 
end up recording the initial reason shutdown started, though potentially 
it could end up terminating for a different reason.

Let's see what others think ...

Thanks,
David

On 8/02/2018 1:18 AM, Robin Westberg wrote:
> Hi all,
> 
> Please review the following change that adds an event-based tracing 
> event that is generated when the VM shuts down. The intent is to capture 
> shutdowns that occur after the VM has been properly initialized (as 
> initialization problems would most likely mean that the tracing 
> framework hasn’t been properly started either).
> 
> Issue: https://bugs.openjdk.java.net/browse/JDK-8041626
> Webrev: http://cr.openjdk.java.net/~rwestberg/8041626/webrev.00/
> Testing: hs-tier1,hs-tier2,jdk-tier1,jdk-tier2
> 
> Best regards,
> Robin