[jdk11u-dev] RFR: 8228609: G1 copy cost prediction uses used vs. actual copied bytes [v7]

[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 updated the pull request incrementally with one additional commit since the last revision:

  remove unused variables and their dependency

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk11u-dev/pull/927/files
  - new: https://git.openjdk.java.net/jdk11u-dev/pull/927/files/b3d5f41c..e552fdbd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=927&range=06
 - incr: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=927&range=05-06

  Stats: 8 lines in 3 files changed: 0 ins; 5 del; 3 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