RFR: 8258742: Move PtrQueue reset to PtrQueueSet subclasses

[Ivan Walulya]

On Sun, 17 Jan 2021 13:17:20 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please remove this change to the PtrQueue hierarchy, changing queue reset
> from an intrinsic operation of the queue to an operation the qset performs
> on a queue.  This is another piece of the refactoring being done under
> JDK-8258251, separated out for easier review.
> 
> After the refactoring of queue reset, PtrQueue::is_empty and PtrQueue::size
> are no longer used, so are removed.  Further, PtrQueue::{set_}index_in_bytes
> are removed, directly using _index instead.
> 
> A less obvious part of the change is in the G1 remark task and Shenandoah
> final marking task.  The threads walk performed by these no longer directly
> processes the partial per-thread SATB buffers.  Instead they just flush the
> queues for later completed buffer processing.
> 
> Testing:
> mach5 tier1
> local (linux-x64) hotspot:tier1 with -XX:+UseShenandoahGC

Looks good!

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Marked as reviewed by iwalulya (Committer).

PR: https://git.openjdk.java.net/jdk/pull/2115