arm32 status

[Peter Johnson]

On Tue, Feb 2, 2021 at 11:36 AM Doerr, Martin <martin.doerr at sap.com> wrote:

> Hi,
>
> note that Shenandoah has similar prerequisites as zGC with JDK17 which
> include at least:
>
> Load barriers in interpreter:
> OopHandle should use Access API:
> https://bugs.openjdk.java.net/browse/JDK-8260369
>
> Concurrent Class Unloading:
> nmethod entry barriers:
> https://bugs.openjdk.java.net/browse/JDK-8260372
>
> And very recently: Concurrent Thread-Stack Processing
> ZGC: Implementation of JEP 376: ZGC: Concurrent Thread-Stack Processing:
> https://bugs.openjdk.java.net/browse/JDK-8253180
>
> These ones are currently missing on PPC64, too.


It seems like HEAD is a moving target, both for these types of changes and
maybe overall ARM32 stability?  I’m sure the general preference is to
develop against HEAD, but is there an argument here that it might be more
efficient to do the initial port on a more stable branch (16?) to get it
working, and then bring it forward?  It might be just trading one set of
challenges for a different set though.  Is the Shenandoah backport to
earlier versions kept fairly up to date?

-Peter

>