RFR: 8339611: GenShen: Simplify ShenandoahOldHeuristics::trigger_collection_if_fragmented [v3]

[Kelvin Nilsen]

On Tue, 10 Sep 2024 23:58:58 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:
>> 
>>   Improve comments and clarify intent of old_region_span
>
> src/hotspot/share/gc/shenandoah/heuristics/shenandoahOldHeuristics.cpp line 590:
> 
>> 588:       //  old_span_percent is  60% and old_density is below 27.0%, or
>> 589:       //  old_span_percent is  50% and old_density is below 18.8%.
>> 590:       trigger_old_is_fragmented(old_density, first_old_region, last_old_region);
> 
> This method seems a bit useless, why not inline the assignment here? I realize you may be trying to make this method span fewer lines, but I think that can be easily achieved by just moving the description of its work out of line from the code into a block comment at the start that describes how fragmentation is computed and what the trigger threshold criteria are.

I'm pulled in both directions on this.  I'll go with your approach, removing both set_fragmentation_trigger() and set_growth_trigger() (renames mentioned in my responses to above comments).

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/492#discussion_r1755221778