RFR: cli options for young/old ShenandoahMinFreeThreshold [v2]

[Joshua Cao]

On Wed, 6 Jul 2022 00:20:14 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Joshua Cao has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update docs for Shenandoah minimum thresholds
>
> src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp line 122:
> 
>> 120:   product(uintx, ShenandoahOldMinFreeThreshold, 5, EXPERIMENTAL,            \
>> 121:           "Percentage of free heap memory below which most heuristics "     \
>> 122:           "old generation trigger collection independent of other   "       \
> 
> "Percentage of free old generation memory below which most heuristics will trigger its collection independent of other ..."
> 
> Similarly, I'd modify the documentation of "ShenandoahMinFreeThreshold" to state:
> "Percentage of free heap memory (or young generation memory, in
>  generational mode) below which most heuristics trigger its collection independent of ..."
> 
> ASIDE: I was thinking that these may be worth making "manageable" in the future, but I realize now that there is not precedent for that, e.g. in the case of InitiatingHeapOccupancyPercent. I do wonder why not though, since it can allow for some flexibility and external dynamic adaptation of the VM's settings.

Updating docs based on @ysramakrishna's suggestions. Its not exactly word for word.

> Percentage of free old generation memory below which most heuristics will trigger its collection independent of other ..

I did not include the `will`.

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PR: https://git.openjdk.org/shenandoah/pull/150