RFR: 8256688: Shenandoah: Lock rank inversion after JDK-8212879

Fri Nov 20 11:28:07 UTC 2020

On Fri, 20 Nov 2020 01:02:20 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> After JDK-8212879, gc_notification() takes JvmtiTagMap_lock/24, while ShenandoahConcurrentWeakRootsEvacUpdateTask holds StringDedupQueue_lock/11, which results lock rank inversion during concurrent weak root processing.
> 
> This patch ensures that no lock is held when triggers gc notification.
> 
> Test:
> - [x] hotspot_gc_shenandoah

Looks good, thank you!

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Marked as reviewed by rkennke (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1334