RFR 8215299: Remove G1CMTask::should_exit_termination()'s undesirable side-effect

[zgu at redhat.com]

Ping! Could I have reviews for this RFR?

New webrev updated copyright year:
http://cr.openjdk.java.net/~zgu/JDK-8215299/webrev.01/

It also passed submit tests.

Thanks,

-Zhengyu

On Wed, 2019-01-02 at 12:49 -0500, zgu at redhat.com wrote:
> TerminatorTerminator::should_exit_termination() might return true to
> abort ongoing termination, due to external events. However, it should
> not introduce side-effect that may conflict with termination result,
> because the current termination may have completed, even
> TerminatorTerminator::should_exit_termination() returns true.
> 
> This undesirable side-effect is a blocker of JDK-8215047. With JDK-
> 8215047, termination protocol should complete in one of two
> consistent
> state. The side-effect of setting abort flag in this particular case,
> G1CMTask may re-enter termination protocol with completed terminator.
> 
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8215299
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8215299/webrev.00/
> 
> Test:
> 
>   hotspot_gc on Linux 64 (fastdebug and releas)
> 
> Thanks,
> 
> -Zhengyu