RFR: 8367709: GenShen: Dirty cards for objects that get promoted by safepoint that intervenes between allocation and stores

[William Kemper]

On Wed, 15 Oct 2025 22:55:47 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp line 106:
>> 
>>> 104:   }
>>> 105: #endif // COMPILER2_OR_JVMCI
>>> 106:   assert(thread->deferred_card_mark().is_empty(), "We don't use this");
>> 
>> This is rare, so probably not worth the extra work, but there is an existing mechanism to defer this until the safepoint (or until another such deferment arises). Not sure if it's worth using it.
>
> Probably not worth the trouble, because that mechanism might require wiring in some other stuff which may not be wired in for GenShen.

Yeah, I thought it looked like a lot of complexity to bring in.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27832#discussion_r2434169557