incremental-marking-job.h

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// Copyright 2012 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_INCREMENTAL_MARKING_JOB_H_
#define V8_HEAP_INCREMENTAL_MARKING_JOB_H_
 
#include <optional>
 
#include "include/v8-platform.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/time.h"
 
namespace v8::internal {
 
class Heap;
class Isolate;
 
// The incremental marking job uses platform tasks to perform incremental
// marking actions (start, step, finalize). The job posts regular foreground
// tasks or delayed foreground tasks if marking progress allows.
class IncrementalMarkingJob final {
 public:
  explicit IncrementalMarkingJob(Heap* heap);
 
  IncrementalMarkingJob(const IncrementalMarkingJob&) = delete;
  IncrementalMarkingJob& operator=(const IncrementalMarkingJob&) = delete;
 
  // Schedules a task with the given `priority`. Safe to be called from any
  // thread.
  void ScheduleTask(TaskPriority priority = TaskPriority::kUserBlocking);
 
  // Returns a weighted average of time to task. For delayed tasks the time to
  // task is only recorded after the initial delay. In case a task is currently
  // running, it is added to the average.
  std::optional<v8::base::TimeDelta> AverageTimeToTask() const;
 
  std::optional<v8::base::TimeDelta> CurrentTimeToTask() const;
 
 private:
  class Task;
 
  Heap* const heap_;
  const std::shared_ptr<v8::TaskRunner> user_blocking_task_runner_;
  const std::shared_ptr<v8::TaskRunner> user_visible_task_runner_;
  mutable base::Mutex mutex_;
  v8::base::TimeTicks scheduled_time_;
  bool pending_task_ = false;
};
 
}  // namespace v8::internal
 
#endif  // V8_HEAP_INCREMENTAL_MARKING_JOB_H_