Integrated: 8352765: G1CollectedHeap::expand_and_allocate() may fail to allocate even after heap expansion succeeds

[Ivan Walulya]

On Wed, 26 Mar 2025 15:05:46 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

> Hi,
> 
> Please review this change to ensure that G1 provisions for at least one Eden region after a GC when computing the young length target.
> 
> The issue reported in the CR occurs at the end of a GC, after successfully expanding the heap, an allocation fails because `policy()->should_allocate_mutator_region()` returns false. This happens because the computation did not properly account for young regions already allocated as survivor regions, leading to an Eden region target of zero.
> 
> With this change, we factor in the young regions that have already been allocated as survivor regions and ensure that at least one region is targeted for Eden.
> 
> Testing: Tier 1-3
>               Reproducer in the CR.

This pull request has now been integrated.

Changeset: 804a8fa4
Author:    Ivan Walulya <iwalulya at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/804a8fa4e96a32be2b38c2d0906dc5861a292007
Stats:     23 lines in 1 file changed: 7 ins; 1 del; 15 mod

8352765: G1CollectedHeap::expand_and_allocate() may fail to allocate even after heap expansion succeeds

Reviewed-by: tschatzl, manc

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PR: https://git.openjdk.org/jdk/pull/24257