Summary:
- Port fix D2553 to Dragonwell
- Change default GC policy to UseConcMarkSweepGC

Test Plan: hotspot/test/gc/TestDefaultGC.sh

Reviewers: 井桐

Reviewed By: 井桐

Subscribers:

Differential Revision: https://aone.alibaba-inc.com/code/D849276

Reviewed-by: tschatzl

Reviewed-by: coleenp, sla

Reviewed-by: coleenp, sla

Reviewed-by: kbarrett, stefank

Reviewed-by: kbarrett, stefank

Summary: Putting a comma after the year in GPL header.
Reviewed-by: dholmes, tschatzl

8076995: gc/ergonomics/TestDynamicNumberOfGCThreads.java failed with java.lang.RuntimeException: 'new_active_workers' missing from stdout/stderr
Reviewed-by: jmasa, drwhite

Reviewed-by: jmasa, kbarrett, tschatzl

Reviewed-by: coffeys
Contributed-by: NAlexander Vorobyev <alexander.vorobyev@oracle.com>

Summary: Add a WhiteBox callback to the VM to start a concurrent mark cycle in G1.
Reviewed-by: tschatzl, sjohanss
Contributed-by: NLeonid Mesnik <leonid.mesnik@oracle.com>

Summary: Fix up GPL headers so that the RE script works.
Reviewed-by: stefank, dholmes, coleenp

8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before
Summary: added WhiteBox methods to count regions and exact aux data sizes
Reviewed-by: jwilhelm, brutisso

Summary: Prevent eager reclaim of objects that might be on mark stack.
Reviewed-by: brutisso, tschatzl

Reviewed-by: tschatzl, ecaspole

Reviewed-by: jmasa, jwilhelm

Reviewed-by: tschatzl, jwilhelm

Summary: Allow use of large pages for auxiliary data structures in G1. Clean up existing interfaces.
Reviewed-by: jmasa, pliden, stefank

Summary: Push the remembered sets of large objects with few referenced into the dirty card queue at the beginning of the evacuation so that they may end up with zero remembered set entries at the end of the collection, and are potentially reclaimed. Also improve timing measurements of the early reclaim mechanism, and shorten flag names.
Reviewed-by: brutisso, jmasa, dfazunen

Reviewed-by: jmasa

Reviewed-by: jmasa, dfazunen

8062957: Heap is not shrunk when deallocating under memory pressure
Summary: Added explicit -XX:-ExplicitGCInvokesConcurrent to invocations
Reviewed-by: brutisso, tschatzl

8060467: CMS: small OldPLABSize and -XX:-ResizePLAB cause assert(ResizePLAB || n_blks == OldPLABSize) failed: Error
Reviewed-by: tschatzl, jmasa, kbarrett

8052172: Evacuation failure handling in G1 does not evacuate all objects if -XX:-G1DeferredRSUpdate is set
Summary: Remove -XX:-G1DeferredRSUpdate functionality as it is racy. During evacuation failure handling, threads where evacuation failure handling occurred may try to add remembered sets to regions which remembered sets are currently being scanned. The iterator to handle the remembered set scan does not support addition of entries during scan and so may skip valid references.
Reviewed-by: iveresov, brutisso, mgerdin

Summary: Ergonomics updates flags for number of GC threads
Reviewed-by: tschatzl, jwilhelm
Contributed-by: sangheon.kim@oracle.com

Reviewed-by: jmasa

Reviewed-by: jmasa, dfazunen

8058475: TestCMSClassUnloadingEnabledHWM.java fails with '.*CMS Initial Mark.*' missing from stdout/stderr
Reviewed-by: mgerdin, tschatzl, brutisso

Reviewed-by: jmasa, tamao

Summary: Add option VerifySubSet to selectively verify the memory sub-systems
Reviewed-by: kevinw, jmasa

Reviewed-by: coffeys
Contributed-by: NAlexander Vorobyev <alexander.vorobyev@oracle.com>

Summary: Enable shrinking within the heap by removing some code added for JDK-8054818. Enable the test case that checks that again too.
Reviewed-by: jwilhelm, jmasa

8037925: CMM Testing: an allocated humongous object at the end of the heap should not prevents shrinking the heap
Summary: New test added.
Reviewed-by: ehelin, tschatzl, jwilhelm
Contributed-by: andrey.x.zakharov@oracle.com

Summary: Add missing unit test.
Reviewed-by: tschatzl
Contributed-by: NLeonid Mesnik <leonid.mesnik@oracle.com>

8058801: G1TraceReclaimDeadHumongousObjectsAtYoungGC only prints humongous object liveness output when there is at least one candidate humongous object
Summary: If G1TraceReclaimDeadHumongousObjectsAtYoungGC is enabled, always print humongous object liveness output.
Reviewed-by: tschatzl
Contributed-by: sangheon.kim@oracle.com

Reviewed-by: stefank, jmasa

Summary: Do not try to verify timing measures for the redirty logged cards phase when it is not executed.
Reviewed-by: brutisso, jmasa

Summary: Do not try to verify timing measures for the redirty logged cards phase when it is not executed.
Reviewed-by: brutisso, jmasa

Summary: Eager reclaim also needs to clear marks of eagerly reclaimed regions if they have already been marked during concurrent mark.
Reviewed-by: jmasa

Summary: Eager reclaim also needs to clear marks of eagerly reclaimed regions if they have already been marked during concurrent mark.
Reviewed-by: jmasa