RFR: 8369913: Parallel: Refactor PSAdjustTask

[Albert Mingkun Yang]

On Wed, 15 Oct 2025 13:53:14 GMT, Francesco Andreuzzi <fandreuzzi at openjdk.org> wrote:

>> Cleanup roots processing (adjusting/remapping) during the adjust-phase of full-gc, so that relevant roots are grouped together with some documentations. Also, the use of `SubTasksDone` is replaced with a `volatile bool`, which is more transparent in the context.
>> 
>> Test: tier1-5
>
> src/hotspot/share/gc/parallel/psParallelCompact.cpp line 1408:
> 
>> 1406:       ResourceMark rm;
>> 1407:       Threads::possibly_parallel_oops_do(_nworkers > 1, &pc_adjust_pointer_closure, nullptr);
>> 1408:       if (try_claim_code_cache_task()) {
> 
> Can `worker_id = 0` always do it?

I did consider use the same technique in `PSParallelCleaningTask` here, but I wanna keep this semantic grouping instead of placing serial-task at the beginning of this method. Therefore, I chose this way.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27822#discussion_r2432689750