RFR: 8355756: G1HeapSizingPolicy::full_collection_resize_amount should consider allocation size [v3]

[Ivan Walulya]

On Mon, 5 May 2025 09:50:33 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

>> Hi,
>> 
>> Please review this change to account for pending allocations when deciding how much to shrink the heap after a full gc. Otherwise, we shrink the heap only to trigger an expansion to satisfy the allocation request that triggered the full gc.
>> 
>> Testing: Tier 1-3
>
> Ivan Walulya 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 five additional commits since the last revision:
> 
>  - use align_up_to_region_byte_size
>  - Merge remote-tracking branch 'upstream/master' into full_collection_resize_amount
>  - Thomas Review
>  - nit
>  - refactor full collection

I assumed the full-gc entry API is `do_full_collection(bool clear_all_soft_refs)`. Yes, we can probably  structure the implementation differently, but I disagree that changing `bool do_full_collection(bool clear_all_soft_refs, bool do_maximal_compaction)` is such a big price to pay.

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PR Comment: https://git.openjdk.org/jdk/pull/24944#issuecomment-2880811046