RFR: 8361055: Serial: Inline SerialHeap::process_roots [v3]

[Kim Barrett]

On Fri, 4 Jul 2025 12:01:00 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Refactor roots processing in Serial (young-gc and full-gc) to clean up the control-flow and make is clearer what roots and closures are used in each context.
>> 
>> Test: tier1-8
>
> Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - review
>  - Merge branch 'master' into sgc-roots
>  - review
>  - sgc-roots

As is, I'm not entirely convinced this change is an improvement. We now have 3
separate places that are fairly similar (each calls some collection of
functions and maybe some additional functions). It's not at all obvious what
the reasoning for the various differences are.

Interleaving comments in each place mentioning the missing calls, and an
explanatory comment in each place about the overall task would be helpful. The
SO_xxx flags and how they were used at least provided some hints for the
latter, but now even those hints are gone.

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PR Review: https://git.openjdk.org/jdk/pull/26038#pullrequestreview-3018793377