RFR: 8371284: GenShen: Avoid unnecessary card marking [v2]

[Nityanand Rai]

On Fri, 7 Nov 2025 21:40:38 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> Nityanand Rai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   early return of oop is null
>
> src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.inline.hpp line 200:
> 
>> 198:   // Exclude old-old
>> 199:   T heap_oop = RawAccess<>::oop_load(field);
>> 200:   if (!CompressedOops::is_null(heap_oop)) {
> 
> We can return early if `CompressedOops::is_null` (we don't need to remember old pointers that are null).

Good point, fixed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28204#discussion_r2505799473