RFR: 8376126: G1: Convert remaining volatiles in G1ConcurrentMark to Atomic<T> [v2]

[Stefan Karlsson]

On Mon, 26 Jan 2026 10:03:18 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi all,
>> 
>>   please convert remaining volatile declarations in `G1ConcurrentMark` to use `Atomic<T>`. These volatiles are used to indicate concurrent phased access (like changing the variable in thread A, then reading the variable in thread B while A is dormant, or only ever updating it in one direction) where concurrency safety is provided by barriers between these phases. But there are also other cases)
>> 
>> The exception is `G1ConcurrentMark::_finger` that has apparently been overlooked in an earlier changes.
>> 
>> Testing: gha
>> 
>> Thanks,
>>   Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   * reviews

Clearing "Request changes"

Marked as reviewed by stefank (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/29368#pullrequestreview-3711503253
PR Review: https://git.openjdk.org/jdk/pull/29368#pullrequestreview-3711506378