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

[Kelvin Nilsen]

On Wed, 10 Dec 2025 22:37:58 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove FRACTIONAL_DENOMINATOR constat
>
> src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp line 65:
> 
>> 63:           "(Generational mode only) If the usage within old generation "    \
>> 64:           "has grown by at least this percent of its live memory size "     \
>> 65:           "at the start of the previous old-generation marking effort, "    \
> 
> Did you intend to say "at the _end_ of the previous old-generation marking effort" above?

Actually, since we are using SATB protocol for old marking, the live data is measured as of the start of GC.  (We subtract out the allocations (promotions) that happen during concurrent GC.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28561#discussion_r2611104184