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

Zhengyu Gu zgu at redhat.com
Tue Aug 11 15:53:30 UTC 2020



On 8/11/20 10:22 AM, Aleksey Shipilev wrote:
> 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))

Updated: http://cr.openjdk.java.net/~zgu/JDK-8251359/webrev.01/

Okay now?

Thanks,

-Zhengyu
> 



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