RFR: 8355756: G1HeapSizingPolicy::full_collection_resize_amount should consider allocation size

[Thomas Schatzl]

On Tue, 29 Apr 2025 09:02:43 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

Changes requested by tschatzl (Reviewer).

src/hotspot/share/gc/g1/g1CollectedHeap.cpp line 860:

> 858:   do_full_collection(clear_all_soft_refs,
> 859:                      false /* do_maximal_compaction */,
> 860:                      size_t(0) /* allocation_word_size*/);

Suggestion:

                     size_t(0) /* allocation_word_size */);

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PR Review: https://git.openjdk.org/jdk/pull/24944#pullrequestreview-2802899902
PR Review Comment: https://git.openjdk.org/jdk/pull/24944#discussion_r2066019574