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

[Aleksey Shipilev]

On 8/11/20 5:53 PM, Zhengyu Gu wrote:
> 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/

Sorry, I was not clear. shenandoahBarrierSet.inline.hpp can do the same != check. No need for
another review, consider changing it before pushing.

-- 
Thanks,
-Aleksey