RFR: 8375436: G1: Convert G1CardSet classes to use Atomic<T>

[Kim Barrett]

On Fri, 16 Jan 2026 09:31:59 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi all,
> 
>   please review this removal of use of the AtomicAccess class in G1 card set related classes, replacing with use of Atomic<T>.
> 
> Although a bit on the large side, it would be hard to do the card set changes separately per class. Other than that I think it is fairly straightforward, except for the addition of a copy constructor for `G1CardSetHashTableValue` because the `ConcurrentHashTable` requires it.
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Looks good, but for one trivial whitespace issue.

src/hotspot/share/gc/g1/g1CardSet.hpp line 158:

> 156: private:
> 157:   // Indices are "from" indices.
> 158:   Atomic<size_t>_coarsen_from[NumCoarsenCategories];

Missing space between type an variable.

-------------

Marked as reviewed by kbarrett (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29274#pullrequestreview-3680310484
PR Review Comment: https://git.openjdk.org/jdk/pull/29274#discussion_r2706721901