[jdk11u-dev] RFR: 8228609: G1 copy cost prediction uses used vs. actual copied bytes [v4]

[Yude Lin]

> I would like to backport 8228609 which fixes a prediction error regarding cost per bytes copied.
> 
> The patch does not apply cleanly, so this backport is basically changing the calculation of copied bytes.
> 
> https://bugs.openjdk.java.net/browse/JDK-8227442 is not in 11u. So this patch also uses G1ParScanThreadState::surviving_young_words() in place of _surviving_young_words to adjust for the correct cset index.

Yude Lin has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  8228609: G1 copy cost prediction uses used vs. actual copied bytes

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Changes:
  - all: https://git.openjdk.java.net/jdk11u-dev/pull/927/files
  - new: https://git.openjdk.java.net/jdk11u-dev/pull/927/files/be565894..c30b074f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=927&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=927&range=02-03

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/927.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/927/head:pull/927

PR: https://git.openjdk.java.net/jdk11u-dev/pull/927