RFR: 8231627: ThreadsListHandleInErrorHandlingTest.java fails in printing all threads

[Daniel D.Daugherty]

On Tue, 5 Jan 2021 09:48:11 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> A small robustness fix in ThreadsSMRSupport::print_info_on() to reduce the
>> likelihood of crashes during error reporting. Uses Threads_lock->try_lock()
>> for safety and restricts some reporting to when the Threads_lock has been
>> acquired (depends on JDK-8256383). Uses a ThreadsListHandle to make
>> the current ThreadsList safe for reporting (depends on JDK-8258284). Also
>> detects when the system ThreadsList (_java_thread_list) has changed and
>> will warn that some of the reported info may now be stale.
>> 
>> Two existing tests have been updated to reflect the use of a ThreadsListHandle
>> in ThreadsSMRSupport::print_info_on(). Mach5 Tier[1-6] testing has no regressions.
>
> Hi Dan,
> 
> It looks good modulo a couple of suggestions from Patricio.
> 
> Thanks,
> Serguei

Made copyright changes based on comments from coleenp,
code changes based on comments from pchilano, and changed
the title based on comments from iklam.
Thanks to coleenp, pchilano and sspitsyn for the code reviews.
Re-testing now...

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PR: https://git.openjdk.java.net/jdk/pull/1891