[lworld] RFR: 8376171: [lworld] Enable storing the hash code in the mark word of value objects [v3]

[Tobias Hartmann]

On Tue, 27 Jan 2026 10:17:16 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Tobias Hartmann has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Use CAS to set mark
>
> src/hotspot/share/prims/jvm.cpp line 804:
> 
>> 802:     markWord old_mark, new_mark, test;
>> 803:     do {
>> 804:       old_mark = ho->mark_acquire();
> 
> Can this be just:
> 
> Suggestion:
> 
>       old_mark = ho->mark();
> 
> I don't see why this would require an "acquire".

I took this from `ObjectSynchronizer::FastHashCode` but I can convert it back to `mark()` if you think it's not needed.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1954#discussion_r2732121275