RFR: 8255235: ZGC: Allocate and initialize forwarding data structures in parallel

Thu Oct 22 14:27:26 UTC 2020

As a continuation of JDK-8255234, we can speed things up even more by allocating/initializing forwarding data structures in parallel. For example, testing using BigRamTester shows the time for "Concurrent Select Relocation Set" phase drop by ~50% when using 4 threads.

This PR depends on "8255234: ZGC: Bulk allocate forwarding data structures", which is a separate PR (https://github.com/openjdk/jdk/pull/804).

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Commit messages:
 - 8255235: ZGC: Allocate and initialize forwarding data structures in parallel
 - 8255234: ZGC: Bulk allocate forwarding data structures

Changes: https://git.openjdk.java.net/jdk/pull/805/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=805&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255235
  Stats: 502 lines in 21 files changed: 333 ins; 105 del; 64 mod
  Patch: https://git.openjdk.java.net/jdk/pull/805.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/805/head:pull/805

PR: https://git.openjdk.java.net/jdk/pull/805