concurrent-marker.h

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// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef V8_HEAP_CPPGC_CONCURRENT_MARKER_H_
#define V8_HEAP_CPPGC_CONCURRENT_MARKER_H_
 
#include "include/cppgc/platform.h"
#include "src/heap/base/incremental-marking-schedule.h"
#include "src/heap/cppgc/marking-state.h"
#include "src/heap/cppgc/marking-visitor.h"
#include "src/heap/cppgc/marking-worklists.h"
 
namespace cppgc {
namespace internal {
 
class V8_EXPORT_PRIVATE ConcurrentMarkerBase {
 public:
  ConcurrentMarkerBase(HeapBase&, MarkingWorklists&,
                       heap::base::IncrementalMarkingSchedule&,
                       cppgc::Platform*);
  virtual ~ConcurrentMarkerBase();
 
  ConcurrentMarkerBase(const ConcurrentMarkerBase&) = delete;
  ConcurrentMarkerBase& operator=(const ConcurrentMarkerBase&) = delete;
 
  void Start();
  // Returns whether the job has been joined.
  bool Join();
  // Returns whether the job has been cancelled.
  bool Cancel();
 
  void NotifyIncrementalMutatorStepCompleted();
  void NotifyOfWorkIfNeeded(cppgc::TaskPriority priority);
 
  bool IsActive() const;
 
  HeapBase& heap() const { return heap_; }
  MarkingWorklists& marking_worklists() const { return marking_worklists_; }
  heap::base::IncrementalMarkingSchedule& incremental_marking_schedule() const {
    return incremental_marking_schedule_;
  }
 
  void AddConcurrentlyMarkedBytes(size_t marked_bytes);
  size_t concurrently_marked_bytes() const {
    return concurrently_marked_bytes_.load(std::memory_order_relaxed);
  }
 
  virtual std::unique_ptr<Visitor> CreateConcurrentMarkingVisitor(
      ConcurrentMarkingState&) const = 0;
 
 protected:
  void IncreaseMarkingPriorityIfNeeded();
 
 private:
  HeapBase& heap_;
  MarkingWorklists& marking_worklists_;
  heap::base::IncrementalMarkingSchedule& incremental_marking_schedule_;
  cppgc::Platform* const platform_;
 
  // The job handle doubles as flag to denote concurrent marking was started.
  std::unique_ptr<JobHandle> concurrent_marking_handle_{nullptr};
 
  std::atomic<size_t> concurrently_marked_bytes_ = 0;
  bool concurrent_marking_priority_increased_{false};
};
 
class V8_EXPORT_PRIVATE ConcurrentMarker : public ConcurrentMarkerBase {
 public:
  ConcurrentMarker(
      HeapBase& heap, MarkingWorklists& marking_worklists,
      heap::base::IncrementalMarkingSchedule& incremental_marking_schedule,
      cppgc::Platform* platform)
      : ConcurrentMarkerBase(heap, marking_worklists,
                             incremental_marking_schedule, platform) {}
 
  std::unique_ptr<Visitor> CreateConcurrentMarkingVisitor(
      ConcurrentMarkingState&) const final;
};
 
}  // namespace internal
}  // namespace cppgc
 
#endif  // V8_HEAP_CPPGC_CONCURRENT_MARKER_H_