RFR (11u, XXL): Upstream/backport Shenandoah to JDK11u - the review thread

[Roman Kennke]

On Wed, 2020-07-29 at 14:56 +0100, Andrew Haley wrote:
> On 27/07/2020 16:59, Roman Kennke wrote:> Indeed! That mess of ifdefs
> is indeed a little complicated, it is so
> > much nicer in JDK12+ where we have proper GC interfaces for that
> > stuff.
> > But that would be too much to backport now. (And who disables G1
> > and
> > enables Shenandoah from their builds anyway? :-P )
> > 
> > Here comes webrev12, I only added the #if-block around G1-code:
> > 
> > Shared-only:
> > http://cr.openjdk.java.net/~rkennke/shenandoah-jdk11u-upstream/webrev.12-shared/
> > Full:
> > http://cr.openjdk.java.net/~rkennke/shenandoah-jdk11u-upstream/webrev.12-all/
> 
> Thanks.
> 
> I think I may say without reasonable fear of successful contradiction
> that you've done enough to show that this patch does no harm. Also,
> by
> demonstrating that it's possible to add a feature in such a way that
> it has no effect (on the generated binary) unless enabled you've
> shown
> a way to solve a difficult problem.
> 
> I don't wish to encourage more feature backports to JDK 11, and I
> don't want to see the source code turn into an unmaintainable mess of
> #ifdefs. However, in a few rare cases this technique well the closest
> thing to satisfying both the proponents and the opponents of a
> backport.
> 
> You're good to go. Thank you for your hard work and patience.

Thank you!
For the record, the final patch/webrev that I'll be pushing is this:
http://cr.openjdk.java.net/~rkennke/shenandoah-jdk11u-upstream/webrev.13/

I only adjusted the synopsis to reflect the bug-ID that I created for
this backport:
https://bugs.openjdk.java.net/browse/JDK-8250784

Thanks & cheers!
Roman