RFR: 8338977: Parallel: Improve heap resizing heuristics [v13]

[Zhengyu Gu]

On Sun, 6 Jul 2025 20:47:20 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> src/hotspot/share/gc/parallel/parallelArguments.cpp line 71:
>> 
>>> 69:   // True in product build, since tests using debug build often stress GC
>>> 70:   if (FLAG_IS_DEFAULT(UseGCOverheadLimit)) {
>>> 71:     FLAG_SET_DEFAULT(UseGCOverheadLimit, trueInProduct);
>> 
>> Given only Parallel honors `UseGCOverheadLimit`, you may want to set the default to `trueInProduct` in `gc_globals.hpp`
>
> It's indeed that only Parallel implements this flag. However, if we decide to change the default value of this flag globally, I feel we should do that in its own PR for better visibility. Currently, this changes the default value only for Parallel, as one expects in a PR titled "Parallel: ...".

Okay.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25000#discussion_r2190120397