RFR: 8309403: Serial: Remove the useless adaptive size policy in GenCollectedHeap [v2]

[Albert Mingkun Yang]

On Wed, 7 Jun 2023 15:05:54 GMT, Guoxiong Li <gli at openjdk.org> wrote:

>> Hi all,
>> 
>> This patch removes the useless code related to the `AdaptiveSizePolicy` in `GenCollectedHeap`.
>> As a result, the `SoftRefGenPolicy` is unnecessary too, use `SoftRefPolicy` instead.
>> 
>> Thanks for the review.
>> 
>> Best Regards,
>> -- Guoxiong
>
> Guoxiong Li has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Restore the _should_clear_all_soft_refs in WB_FullGC.
>  - Merge branch 'master' into JDK-8309403
>  - JDK-8309403

src/hotspot/share/prims/whitebox.cpp line 1449:

> 1447:   Universe::heap()->collect(GCCause::_wb_full_gc);
> 1448: #if defined(INCLUDE_G1GC) || defined(INCLUDE_PARALLELGC) || defined(INCLUDE_SERIALGC)
> 1449:   if (UseG1GC || UseParallelGC || UseSerialGC) {

I don't think you can do the same for Parallel due to the presence of `GCOverheadChecker`, which also updates the global var.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14296#discussion_r1222121791