[8] RFR: Shenandoah: JNI weak roots are always cleared before Full GC mark

[Roman Kennke]

Looks good.

Minor nit: "Work that around" -> "Work around that" I believe sounds
better.

Roman


On Mon, 2020-06-22 at 19:39 +0200, Aleksey Shipilev wrote:
> Amir found the crash with Cassandra that started to happen recently
> with Shenandoah 8u. It
> reproduces more or less reliably with starting Cassandra 3.11.4 with
> fastdebug build and
> -XX:ShenandoahGCMode=passive -XX:-ShenandoahDegeneratedGC.
> 
> This is a symptom of a larger problem (see JDK-8248041), but 8u it is
> catastrophic due to clearing
> of the weak roots.
> 
> Fix:
>   
> https://cr.openjdk.java.net/~shade/shenandoah/8u-fullgc-jni-weak/webrev.01/
> 
> Testing: hotspot_gc_shenandoah; Cassandra tests
>