RFR: 8365823: Revert storing abstract and interface Klasses to non-class metaspace [v2]

[Coleen Phillimore]

On Mon, 15 Sep 2025 13:33:47 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Coleen Phillimore has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - Update src/hotspot/share/memory/metaspace.cpp
>>    
>>    Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>
>>  - Update src/hotspot/share/memory/metaspace.cpp
>>    
>>    Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>
>>  - Restore comment.
>
> src/hotspot/share/oops/klass.cpp line 281:
> 
>> 279: #ifdef _LP64
>> 280:   if (UseCompactObjectHeaders) {
>> 281:     precond(CompressedKlassPointers::is_encodable(kls));
> 
> Sounds like we want to leave this comment in:
> 
> 
> // With compact object headers, the narrow Klass ID is part of the mark word.
> // We therefore seed the mark word with the narrow Klass ID.

Little too aggressive with the delete button.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27295#discussion_r2349206231