[16] RFR 8251359: Shenandoah: filter null oops before calling enqueue/SATB barrier

Aleksey Shipilev shade at redhat.com
Tue Aug 11 14:22:49 UTC 2020

On 8/11/20 4:16 PM, Zhengyu Gu wrote:
> Please review this small patch that ensures null oops are filtered out 
> before calling enqueue/SATB barrier. Enqueuing null oops create extra 
> works and only get thrown out in later phase.
> Bug: https://bugs.openjdk.java.net/browse/JDK-8251359
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8251359/webrev.00/index.html

I don't think you need CompressedOops::is_null(obj) for guaranteed "oop", and you can just use "obj
!= NULL"? That is what ShenandoahBarrierSet::storeval_barrier does (you might add parentheses there)...

1328   if (is_concurrent_mark_in_progress() && (obj != NULL))


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