RFR: 8358529: GenShen: Heuristics do not respond to changes in SoftMaxHeapSize [v5]

[William Kemper]

On Tue, 8 Jul 2025 00:23:55 GMT, Rui Li <duke at openjdk.org> wrote:

>> Generational shenandoah currently doesn't pick up the changes of managed flag `SoftMaxHeapSize` when the app is running. This is because the value of `_soft_max_capacity` in `shenandoahGeneration` is never changed.
>> 
>> This change delegates the soft max heap size in `shenandoahGeneration` to `ShenandoahGenerationalHeap::heap()->soft_max_capacity()`, which does pick up the flag value changes.
>> 
>> Also, found `ShenandoahHeap:: initialize` uses `_num_regions * reg_size_bytes` rather than user input flag value. Updated to using actual flag value.
>
> Rui Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use comment style

This is a nice simplification. Thank you!

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Marked as reviewed by wkemper (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/25943#pullrequestreview-2998614615