RFR: 8376357: Parallel: Convert MutableSpace classes to use Atomic<T>

[Thomas Schatzl]

On Wed, 28 Jan 2026 21:15:50 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Hi all,
>> 
>>   please review these changes that convert `MutableSpace` classes to use `Atomic<T>`.
>> 
>> Testing: gha, tier1-5
>> 
>> Thanks,
>>   Thomas
>
> src/hotspot/share/runtime/vmStructs.cpp line 904:
> 
>> 902:                                                                           \
>> 903:   declare_toplevel_type(void*)                                            \
>> 904:   declare_toplevel_type(Atomic<HeapWord*>)                                \
> 
> This placement (under "C primitive pointer types ") seems inappropriate.

Since other changes also place this toplevel type at the same location to avoid future merge issues, I would like to wait finding a more appropriate place until later, filed https://bugs.openjdk.org/browse/JDK-8376664 and assigned it to me.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29427#discussion_r2740651055