RFR: 8258252: Move PtrQueue enqueue to PtrQueueSet subclasses

[Thomas Schatzl]

On Tue, 15 Dec 2020 05:32:07 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this refactoring in the PtrQueue/PtrQueueSet hierarchy.
> 
> The functions PtrQueue::enqueue and PtrQueue::enqueue_known_active are
> removed, along with the helper virtual function PtrQueue::handle_completed_buffer.
> 
> Instead we now have G1{Dirty,Redirty}CardQueueSet::enqueue and SATBMarkQueueSet::enqueue/enqueue_known_active, each tailored to the corresponding specific behavior. They use some shared helper routines from PtrQueueSet, and the PtrQueue buffer and index have been made accessible to clients.
> 
> Testing:
> mach5 tier1-3, 5 (stress tests)
> Local (linux-x64) tier1 with -XX:+UseShenandoahGC

Lgtm.

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1776