RFR: 8373225: GenShen: More adaptive old-generation growth heuristics [v5]

[Kelvin Nilsen]

On Wed, 10 Dec 2025 23:43:16 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/heuristics/shenandoahOldHeuristics.hpp line 105:
>> 
>>> 103:   size_t _fragmentation_last_old_region;
>>> 104: 
>>> 105:   // adapted value of ShenandoahOldGarbageThreshold
>> 
>> May be reword to:
>> 
>> // a dynamic threshold of garbage for an old
>> // region to be deemed eligible for evacuation.
>> 
>> since `ShenandoahOldGarbageThreshold` is a constant parameter to the JVM.
>
> As I write this, I realize "Old region" may not be the right term here. It should be "an Old or otherwise tenurable region" because it seems regions that are Young but tenurable are filtered through this check, not just Old regions?

Thanks for your review and suggestions.  I'll make a pass over this code and try to improve the comments.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28561#discussion_r2611248131