backport JEP 344-Abortable Mixed Collections for G1 to jdk11u

[Thomas Schatzl]

Hi Lin,

On Wed, 2019-03-27 at 10:51 +0000, 臧琳 wrote:
> Dear All, 
>      I have tried the JEP344 for a while and find it could help us to
> avoid the long Mixed GCs when the heap is large.  

It is great to hear that it helps you in your case.

I assume you tried some tuning with the options presented in the
documentation at 
https://docs.oracle.com/en/java/javase/12/gctuning/garbage-first-garbage-collector-tuning.html#GUID-D2B6ADCE-6766-4FF8-AA9D-B7F4F3D0F469
 ?

Note that in some cases this still might not result in as nice behavior
as with abortable mixed gc.

>      So I am planning to port it back to jdk11u as G1 is the default
> GC, do you think it is reasonable?

  I believe it is okay if it is useful, but it is best to ask the
maintainers of jdk11u directly in on the jdk-updates-dev mailing list.
As this would be a bit bigger change/backport, so there might be some
further concerns by the jdk11u maintainers.

Code review seems to have to occur on the jdk-updates-dev mailing list
(https://openjdk.java.net/projects/jdk-updates/codereview.html) - maybe
cc hotspot-gc-dev though.

Thanks,
  Thomas