RFR: 8332516: Serial: Refactor how promoted bytes are sampled

Mon May 20 09:09:09 UTC 2024

Simple heuristic update around how promoted-bytes are tracked. The real change is in `TenuredGeneration::update_promote_stats`, which uses `used-old-gen` before/after gc to derived promoted-bytes.

The metric is imprecise in the cases of promotion-failure, because those should be rare. Also, after full-gc, used-old-gen an be decreased; in this case, we'd set promoted bytes as the min value (zero), the best-effort estimate.

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Commit messages:
 - s1-promote-stat

Changes: https://git.openjdk.org/jdk/pull/19306/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19306&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332516
  Stats: 31 lines in 4 files changed: 6 ins; 16 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/19306.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19306/head:pull/19306

PR: https://git.openjdk.org/jdk/pull/19306