RFR: 8369097: Parallel: Support allocation in from space when heap is too full

Fri Oct 3 08:38:58 UTC 2025

Support allocation in from-space of young-gen in extreme cases (heap is almost full), so that gc-log shows used-heap is almost at max-heap when OOM is thrown.

Test: tier1-5

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Commit messages:
 - pgc-allocate-in-from-space

Changes: https://git.openjdk.org/jdk/pull/27620/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27620&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369097
  Stats: 16 lines in 1 file changed: 14 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/27620.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27620/head:pull/27620

PR: https://git.openjdk.org/jdk/pull/27620