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

[Andrew Haley]

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.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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