diff --git a/src/hotspot/share/gc/parallel/gcTaskManager.hpp b/src/hotspot/share/gc/parallel/gcTaskManager.hpp
deleted file mode 100644
index c29bfa028b0..00000000000
--- a/src/hotspot/share/gc/parallel/gcTaskManager.hpp
+++ /dev/null
@@ -1,668 +0,0 @@
-/*
- * Copyright (c) 2002, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- *
- */
-
-#ifndef SHARE_GC_PARALLEL_GCTASKMANAGER_HPP
-#define SHARE_GC_PARALLEL_GCTASKMANAGER_HPP
-
-#include "runtime/mutex.hpp"
-#include "utilities/growableArray.hpp"
-
-//
-// The GCTaskManager is a queue of GCTasks, and accessors
-// to allow the queue to be accessed from many threads.
-//
-
-// Forward declarations of types defined in this file.
-class GCTask;
-class GCTaskQueue;
-class SynchronizedGCTaskQueue;
-class GCTaskManager;
-// Some useful subclasses of GCTask.  You can also make up your own.
-class NoopGCTask;
-class WaitForBarrierGCTask;
-class IdleGCTask;
-// A free list of Monitor*'s.
-class MonitorSupply;
-
-// Forward declarations of classes referenced in this file via pointer.
-class GCTaskThread;
-class Mutex;
-class Monitor;
-class ThreadClosure;
-
-// The abstract base GCTask.
-class GCTask : public ResourceObj {
-public:
-  // Known kinds of GCTasks, for predicates.
-  class Kind : AllStatic {
-  public:
-    enum kind {
-      unknown_task,
-      ordinary_task,
-      wait_for_barrier_task,
-      noop_task,
-      idle_task
-    };
-    static const char* to_string(kind value);
-  };
-private:
-  // Instance state.
-  Kind::kind       _kind;               // For runtime type checking.
-  uint             _affinity;           // Which worker should run task.
-  GCTask*          _newer;              // Tasks are on doubly-linked ...
-  GCTask*          _older;              // ... lists.
-  uint             _gc_id;              // GC Id to use for the thread that executes this task
-public:
-  virtual char* name() { return (char *)"task"; }
-
-  uint gc_id() { return _gc_id; }
-
-  // Abstract do_it method
-  virtual void do_it(GCTaskManager* manager, uint which) = 0;
-  // Accessors
-  Kind::kind kind() const {
-    return _kind;
-  }
-  uint affinity() const {
-    return _affinity;
-  }
-  GCTask* newer() const {
-    return _newer;
-  }
-  void set_newer(GCTask* n) {
-    _newer = n;
-  }
-  GCTask* older() const {
-    return _older;
-  }
-  void set_older(GCTask* p) {
-    _older = p;
-  }
-  // Predicates.
-  bool is_ordinary_task() const {
-    return kind()==Kind::ordinary_task;
-  }
-  bool is_barrier_task() const {
-    return kind()==Kind::wait_for_barrier_task;
-  }
-  bool is_noop_task() const {
-    return kind()==Kind::noop_task;
-  }
-  bool is_idle_task() const {
-    return kind()==Kind::idle_task;
-  }
-  void print(const char* message) const PRODUCT_RETURN;
-protected:
-  // Constructors: Only create subclasses.
-  //     An ordinary GCTask.
-  GCTask();
-  //     A GCTask of a particular kind, usually barrier or noop.
-  GCTask(Kind::kind kind);
-  GCTask(Kind::kind kind, uint gc_id);
-  // We want a virtual destructor because virtual methods,
-  // but since ResourceObj's don't have their destructors
-  // called, we don't have one at all.  Instead we have
-  // this method, which gets called by subclasses to clean up.
-  virtual void destruct();
-  // Methods.
-  void initialize(Kind::kind kind, uint gc_id);
-};
-
-// A doubly-linked list of GCTasks.
-// The list is not synchronized, because sometimes we want to
-// build up a list and then make it available to other threads.
-// See also: SynchronizedGCTaskQueue.
-class GCTaskQueue : public ResourceObj {
-private:
-  // Instance state.
-  GCTask*    _insert_end;               // Tasks are enqueued at this end.
-  GCTask*    _remove_end;               // Tasks are dequeued from this end.
-  uint       _length;                   // The current length of the queue.
-  const bool _is_c_heap_obj;            // Is this a CHeapObj?
-public:
-  // Factory create and destroy methods.
-  //     Create as ResourceObj.
-  static GCTaskQueue* create();
-  //     Create as CHeapObj.
-  static GCTaskQueue* create_on_c_heap();
-  //     Destroyer.
-  static void destroy(GCTaskQueue* that);
-  // Accessors.
-  //     These just examine the state of the queue.
-  bool is_empty() const {
-    assert(((insert_end() == NULL && remove_end() == NULL) ||
-            (insert_end() != NULL && remove_end() != NULL)),
-           "insert_end and remove_end don't match");
-    assert((insert_end() != NULL) || (_length == 0), "Not empty");
-    return insert_end() == NULL;
-  }
-  uint length() const {
-    return _length;
-  }
-  // Methods.
-  //     Enqueue one task.
-  void enqueue(GCTask* task);
-  //     Enqueue a list of tasks.  Empties the argument list.
-  void enqueue(GCTaskQueue* list);
-  //     Dequeue one task.
-  GCTask* dequeue();
-  //     Dequeue one task, preferring one with affinity.
-  GCTask* dequeue(uint affinity);
-protected:
-  // Constructor. Clients use factory, but there might be subclasses.
-  GCTaskQueue(bool on_c_heap);
-  // Destructor-like method.
-  // Because ResourceMark doesn't call destructors.
-  // This method cleans up like one.
-  virtual void destruct();
-  // Accessors.
-  GCTask* insert_end() const {
-    return _insert_end;
-  }
-  void set_insert_end(GCTask* value) {
-    _insert_end = value;
-  }
-  GCTask* remove_end() const {
-    return _remove_end;
-  }
-  void set_remove_end(GCTask* value) {
-    _remove_end = value;
-  }
-  void increment_length() {
-    _length += 1;
-  }
-  void decrement_length() {
-    _length -= 1;
-  }
-  void set_length(uint value) {
-    _length = value;
-  }
-  bool is_c_heap_obj() const {
-    return _is_c_heap_obj;
-  }
-  // Methods.
-  void initialize();
-  GCTask* remove();                     // Remove from remove end.
-  GCTask* remove(GCTask* task);         // Remove from the middle.
-  void print(const char* message) const PRODUCT_RETURN;
-  // Debug support
-  void verify_length() const PRODUCT_RETURN;
-};
-
-// A GCTaskQueue that can be synchronized.
-// This "has-a" GCTaskQueue and a mutex to do the exclusion.
-class SynchronizedGCTaskQueue : public CHeapObj<mtGC> {
-private:
-  // Instance state.
-  GCTaskQueue* _unsynchronized_queue;   // Has-a unsynchronized queue.
-  Monitor *    _lock;                   // Lock to control access.
-public:
-  // Factory create and destroy methods.
-  static SynchronizedGCTaskQueue* create(GCTaskQueue* queue, Monitor * lock) {
-    return new SynchronizedGCTaskQueue(queue, lock);
-  }
-  static void destroy(SynchronizedGCTaskQueue* that) {
-    if (that != NULL) {
-      delete that;
-    }
-  }
-  // Accessors
-  GCTaskQueue* unsynchronized_queue() const {
-    return _unsynchronized_queue;
-  }
-  Monitor * lock() const {
-    return _lock;
-  }
-  // GCTaskQueue wrapper methods.
-  // These check that you hold the lock
-  // and then call the method on the queue.
-  bool is_empty() const {
-    guarantee(own_lock(), "don't own the lock");
-    return unsynchronized_queue()->is_empty();
-  }
-  void enqueue(GCTask* task) {
-    guarantee(own_lock(), "don't own the lock");
-    unsynchronized_queue()->enqueue(task);
-  }
-  void enqueue(GCTaskQueue* list) {
-    guarantee(own_lock(), "don't own the lock");
-    unsynchronized_queue()->enqueue(list);
-  }
-  GCTask* dequeue() {
-    guarantee(own_lock(), "don't own the lock");
-    return unsynchronized_queue()->dequeue();
-  }
-  GCTask* dequeue(uint affinity) {
-    guarantee(own_lock(), "don't own the lock");
-    return unsynchronized_queue()->dequeue(affinity);
-  }
-  uint length() const {
-    guarantee(own_lock(), "don't own the lock");
-    return unsynchronized_queue()->length();
-  }
-  // For guarantees.
-  bool own_lock() const {
-    return lock()->owned_by_self();
-  }
-protected:
-  // Constructor.  Clients use factory, but there might be subclasses.
-  SynchronizedGCTaskQueue(GCTaskQueue* queue, Monitor * lock);
-  // Destructor.  Not virtual because no virtuals.
-  ~SynchronizedGCTaskQueue();
-};
-
-class WaitHelper {
- private:
-  Monitor*      _monitor;
-  volatile bool _should_wait;
- public:
-  WaitHelper();
-  ~WaitHelper();
-  void wait_for(bool reset);
-  void notify();
-  void set_should_wait(bool value) {
-    _should_wait = value;
-  }
-
-  Monitor* monitor() const {
-    return _monitor;
-  }
-  bool should_wait() const {
-    return _should_wait;
-  }
-  void release_monitor();
-};
-
-// Dynamic number of GC threads
-//
-//  GC threads wait in get_task() for work (i.e., a task) to perform.
-// When the number of GC threads was static, the number of tasks
-// created to do a job was equal to or greater than the maximum
-// number of GC threads (ParallelGCThreads).  The job might be divided
-// into a number of tasks greater than the number of GC threads for
-// load balancing (i.e., over partitioning).  The last task to be
-// executed by a GC thread in a job is a work stealing task.  A
-// GC  thread that gets a work stealing task continues to execute
-// that task until the job is done.  In the static number of GC threads
-// case, tasks are added to a queue (FIFO).  The work stealing tasks are
-// the last to be added.  Once the tasks are added, the GC threads grab
-// a task and go.  A single thread can do all the non-work stealing tasks
-// and then execute a work stealing and wait for all the other GC threads
-// to execute their work stealing task.
-//  In the dynamic number of GC threads implementation, idle-tasks are
-// created to occupy the non-participating or "inactive" threads.  An
-// idle-task makes the GC thread wait on a barrier that is part of the
-// GCTaskManager.  The GC threads that have been "idled" in a IdleGCTask
-// are released once all the active GC threads have finished their work
-// stealing tasks.  The GCTaskManager does not wait for all the "idled"
-// GC threads to resume execution. When those GC threads do resume
-// execution in the course of the thread scheduling, they call get_tasks()
-// as all the other GC threads do.  Because all the "idled" threads are
-// not required to execute in order to finish a job, it is possible for
-// a GC thread to still be "idled" when the next job is started.  Such
-// a thread stays "idled" for the next job.  This can result in a new
-// job not having all the expected active workers.  For example if on
-// job requests 4 active workers out of a total of 10 workers so the
-// remaining 6 are "idled", if the next job requests 6 active workers
-// but all 6 of the "idled" workers are still idle, then the next job
-// will only get 4 active workers.
-//  The implementation for the parallel old compaction phase has an
-// added complication.  In the static case parold partitions the chunks
-// ready to be filled into stacks, one for each GC thread.  A GC thread
-// executing a draining task (drains the stack of ready chunks)
-// claims a stack according to it's id (the unique ordinal value assigned
-// to each GC thread).  In the dynamic case not all GC threads will
-// actively participate so stacks with ready to fill chunks can only be
-// given to the active threads.  An initial implementation chose stacks
-// number 1-n to get the ready chunks and required that GC threads
-// 1-n be the active workers.  This was undesirable because it required
-// certain threads to participate.  In the final implementation a
-// list of stacks equal in number to the active workers are filled
-// with ready chunks.  GC threads that participate get a stack from
-// the task (DrainStacksCompactionTask), empty the stack, and then add it to a
-// recycling list at the end of the task.  If the same GC thread gets
-// a second task, it gets a second stack to drain and returns it.  The
-// stacks are added to a recycling list so that later stealing tasks
-// for this tasks can get a stack from the recycling list.  Stealing tasks
-// use the stacks in its work in a way similar to the draining tasks.
-// A thread is not guaranteed to get anything but a stealing task and
-// a thread that only gets a stealing task has to get a stack. A failed
-// implementation tried to have the GC threads keep the stack they used
-// during a draining task for later use in the stealing task but that didn't
-// work because as noted a thread is not guaranteed to get a draining task.
-//
-// For PSScavenge and ParCompactionManager the GC threads are
-// held in the GCTaskThread** _thread array in GCTaskManager.
-
-
-class GCTaskManager : public CHeapObj<mtGC> {
- friend class ParCompactionManager;
- friend class PSParallelCompact;
- friend class PSScavenge;
- friend class PSRefProcTaskExecutor;
- friend class RefProcTaskExecutor;
- friend class GCTaskThread;
- friend class IdleGCTask;
-private:
-  // Instance state.
-  const uint                _workers;           // Number of workers.
-  Monitor*                  _monitor;           // Notification of changes.
-  SynchronizedGCTaskQueue*  _queue;             // Queue of tasks.
-  GCTaskThread**            _thread;            // Array of worker threads.
-  uint                      _created_workers;   // Number of workers created.
-  uint                      _active_workers;    // Number of active workers.
-  uint                      _busy_workers;      // Number of busy workers.
-  uint                      _blocking_worker;   // The worker that's blocking.
-  bool*                     _resource_flag;     // Array of flag per threads.
-  uint                      _delivered_tasks;   // Count of delivered tasks.
-  uint                      _completed_tasks;   // Count of completed tasks.
-  uint                      _barriers;          // Count of barrier tasks.
-  uint                      _emptied_queue;     // Times we emptied the queue.
-  NoopGCTask*               _noop_task;         // The NoopGCTask instance.
-  WaitHelper                _wait_helper;       // Used by inactive worker
-  volatile uint             _idle_workers;      // Number of idled workers
-  uint*                     _processor_assignment; // Worker to cpu mappings. May
-                                                   // be used lazily
-public:
-  // Factory create and destroy methods.
-  static GCTaskManager* create(uint workers) {
-    return new GCTaskManager(workers);
-  }
-  static void destroy(GCTaskManager* that) {
-    if (that != NULL) {
-      delete that;
-    }
-  }
-  // Accessors.
-  uint busy_workers() const {
-    return _busy_workers;
-  }
-  volatile uint idle_workers() const {
-    return _idle_workers;
-  }
-  //     Pun between Monitor* and Mutex*
-  Monitor* monitor() const {
-    return _monitor;
-  }
-  Monitor * lock() const {
-    return _monitor;
-  }
-  WaitHelper* wait_helper() {
-    return &_wait_helper;
-  }
-  // Methods.
-  //     Add the argument task to be run.
-  void add_task(GCTask* task);
-  //     Add a list of tasks.  Removes task from the argument list.
-  void add_list(GCTaskQueue* list);
-  //     Claim a task for argument worker.
-  GCTask* get_task(uint which);
-  //     Note the completion of a task by the argument worker.
-  void note_completion(uint which);
-  //     Is the queue blocked from handing out new tasks?
-  bool is_blocked() const {
-    return (blocking_worker() != sentinel_worker());
-  }
-  //     Request that all workers release their resources.
-  void release_all_resources();
-  //     Ask if a particular worker should release its resources.
-  bool should_release_resources(uint which); // Predicate.
-  //     Note the release of resources by the argument worker.
-  void note_release(uint which);
-  //     Create IdleGCTasks for inactive workers and start workers
-  void task_idle_workers();
-  //     Release the workers in IdleGCTasks
-  void release_idle_workers();
-  // Constants.
-  //     A sentinel worker identifier.
-  static uint sentinel_worker() {
-    return (uint) -1;                   // Why isn't there a max_uint?
-  }
-
-  //     Execute the task queue and wait for the completion.
-  void execute_and_wait(GCTaskQueue* list);
-
-  void print_task_time_stamps();
-  void print_threads_on(outputStream* st);
-  void threads_do(ThreadClosure* tc);
-
-protected:
-  // Constructors.  Clients use factory, but there might be subclasses.
-  //     Create a GCTaskManager with the appropriate number of workers.
-  GCTaskManager(uint workers);
-  //     Make virtual if necessary.
-  ~GCTaskManager();
-  // Accessors.
-  uint workers() const {
-    return _workers;
-  }
-  uint update_active_workers(uint v) {
-    assert(v <= _workers, "Trying to set more workers active than there are");
-    _active_workers = MIN2(v, _workers);
-    assert(v != 0, "Trying to set active workers to 0");
-    _active_workers = MAX2(1U, _active_workers);
-    return _active_workers;
-  }
-  // Sets the number of threads that will be used in a collection
-  void set_active_gang();
-
-  SynchronizedGCTaskQueue* queue() const {
-    return _queue;
-  }
-  NoopGCTask* noop_task() const {
-    return _noop_task;
-  }
-  //     Bounds-checking per-thread data accessors.
-  GCTaskThread* thread(uint which);
-  void set_thread(uint which, GCTaskThread* value);
-  bool resource_flag(uint which);
-  void set_resource_flag(uint which, bool value);
-  // Modifier methods with some semantics.
-  //     Is any worker blocking handing out new tasks?
-  uint blocking_worker() const {
-    return _blocking_worker;
-  }
-  void set_blocking_worker(uint value) {
-    _blocking_worker = value;
-  }
-  void set_unblocked() {
-    set_blocking_worker(sentinel_worker());
-  }
-  //     Count of busy workers.
-  void reset_busy_workers() {
-    _busy_workers = 0;
-  }
-  uint increment_busy_workers();
-  uint decrement_busy_workers();
-  //     Count of tasks delivered to workers.
-  uint delivered_tasks() const {
-    return _delivered_tasks;
-  }
-  void increment_delivered_tasks() {
-    _delivered_tasks += 1;
-  }
-  void reset_delivered_tasks() {
-    _delivered_tasks = 0;
-  }
-  //     Count of tasks completed by workers.
-  uint completed_tasks() const {
-    return _completed_tasks;
-  }
-  void increment_completed_tasks() {
-    _completed_tasks += 1;
-  }
-  void reset_completed_tasks() {
-    _completed_tasks = 0;
-  }
-  //     Count of barrier tasks completed.
-  uint barriers() const {
-    return _barriers;
-  }
-  void increment_barriers() {
-    _barriers += 1;
-  }
-  void reset_barriers() {
-    _barriers = 0;
-  }
-  //     Count of how many times the queue has emptied.
-  uint emptied_queue() const {
-    return _emptied_queue;
-  }
-  void increment_emptied_queue() {
-    _emptied_queue += 1;
-  }
-  void reset_emptied_queue() {
-    _emptied_queue = 0;
-  }
-  void increment_idle_workers() {
-    _idle_workers++;
-  }
-  void decrement_idle_workers() {
-    _idle_workers--;
-  }
-  // Other methods.
-  void initialize();
-
- public:
-  // Return true if all workers are currently active.
-  bool all_workers_active() { return workers() == active_workers(); }
-  uint active_workers() const {
-    return _active_workers;
-  }
-  uint created_workers() const {
-    return _created_workers;
-  }
-  // Create a GC worker and install into GCTaskManager
-  GCTaskThread* install_worker(uint worker_id);
-  // Add GC workers as needed.
-  void add_workers(bool initializing);
-  // Base name (without worker id #) of threads.
-  const char* group_name();
-};
-
-//
-// Some exemplary GCTasks.
-//
-
-// A noop task that does nothing,
-// except take us around the GCTaskThread loop.
-class NoopGCTask : public GCTask {
-public:
-  // Factory create and destroy methods.
-  static NoopGCTask* create_on_c_heap();
-  static void destroy(NoopGCTask* that);
-
-  virtual char* name() { return (char *)"noop task"; }
-  // Methods from GCTask.
-  void do_it(GCTaskManager* manager, uint which) {
-    // Nothing to do.
-  }
-protected:
-  // Constructor.
-  NoopGCTask();
-  // Destructor-like method.
-  void destruct();
-};
-
-// A WaitForBarrierGCTask is a GCTask
-// with a method you can call to wait until
-// the BarrierGCTask is done.
-class WaitForBarrierGCTask : public GCTask {
-  friend class GCTaskManager;
-  friend class IdleGCTask;
-private:
-  // Instance state.
-  WaitHelper    _wait_helper;
-  WaitForBarrierGCTask();
-public:
-  virtual char* name() { return (char *) "waitfor-barrier-task"; }
-
-  // Factory create and destroy methods.
-  static WaitForBarrierGCTask* create();
-  static void destroy(WaitForBarrierGCTask* that);
-  // Methods.
-  void     do_it(GCTaskManager* manager, uint which);
-protected:
-  // Destructor-like method.
-  void destruct();
-
-  // Methods.
-  //     Wait for this to be the only task running.
-  void do_it_internal(GCTaskManager* manager, uint which);
-
-  void wait_for(bool reset) {
-    _wait_helper.wait_for(reset);
-  }
-};
-
-// Task that is used to idle a GC task when fewer than
-// the maximum workers are wanted.
-class IdleGCTask : public GCTask {
-  const bool    _is_c_heap_obj;            // Was allocated on the heap.
- public:
-  bool is_c_heap_obj() {
-    return _is_c_heap_obj;
-  }
-  // Factory create and destroy methods.
-  static IdleGCTask* create();
-  static IdleGCTask* create_on_c_heap();
-  static void destroy(IdleGCTask* that);
-
-  virtual char* name() { return (char *)"idle task"; }
-  // Methods from GCTask.
-  virtual void do_it(GCTaskManager* manager, uint which);
-protected:
-  // Constructor.
-  IdleGCTask(bool on_c_heap) :
-    GCTask(GCTask::Kind::idle_task),
-    _is_c_heap_obj(on_c_heap) {
-    // Nothing to do.
-  }
-  // Destructor-like method.
-  void destruct();
-};
-
-class MonitorSupply : public AllStatic {
-private:
-  // State.
-  //     Control multi-threaded access.
-  static Mutex*                   _lock;
-  //     The list of available Monitor*'s.
-  static GrowableArray<Monitor*>* _freelist;
-public:
-  // Reserve a Monitor*.
-  static Monitor* reserve();
-  // Release a Monitor*.
-  static void release(Monitor* instance);
-private:
-  // Accessors.
-  static Mutex* lock() {
-    return _lock;
-  }
-  static GrowableArray<Monitor*>* freelist() {
-    return _freelist;
-  }
-};
-
-#endif // SHARE_GC_PARALLEL_GCTASKMANAGER_HPP