RFR: 8271579: G1: Move copy before CAS in do_copy_to_survivor_space [v3]

Fri Aug 6 02:15:55 UTC 2021

> Propose to move copy before CAS in do_copy_to_survivor_space, as we found this will improve G1 performance. Specjbb shows 3.7% in critical on aarch64, no change in max.
> 
> After this change copy_to_survivor in G1 is also aligned with PS's copy_to_survivor.

Hamlin Li 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.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4983/files
  - new: https://git.openjdk.java.net/jdk/pull/4983/files/91601879..997fdc19

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4983&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4983&range=01-02

  Stats: 11 lines in 1 file changed: 10 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4983.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4983/head:pull/4983

PR: https://git.openjdk.java.net/jdk/pull/4983