RFR: 8246037: Shenandoah: update man pages to mention -XX:+UseShenandoahGC [v2]

[Rui Li]

On Mon, 25 Aug 2025 11:19:14 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Rui Li has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Comment for aggressive. Indent.
>
> src/java.base/share/man/java.md line 2919:
> 
>> 2917: 
>> 2918:     `static`
>> 2919:     :   Trigger GC when free heap falls below the ShenandoahMinFreeThreshold.
> 
> Same here: `ShenandoahMinFreeThreshold` is experimental, it is not worth mentioning here. In fact, there are tunables for `adaptive` and `compact` as well, yet we do not (correctly!) mention them.

True, other options respond to `ShenandoahMinFreeThreshold` as well. It's kinda hard to describe `static` option without mentioning the threshold. 
- We could make the doc vague as in the [shenandoah_globals.hpp](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp#L147): `trigger GC when free heap falls below the threshold`. 
- I now wonder why `static` is a non experimental flag - it has to be used with other experimental flags. Maybe just drop static from man page as well?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/26907#discussion_r2299344865