task_queue_throttler.h | Explore in Territory

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_COMMON_THROTTLING_TASK_QUEUE_THROTTLER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_COMMON_THROTTLING_TASK_QUEUE_THROTTLER_H_

#include <optional>

#include "base/memory/raw_ptr.h"
#include "base/task/sequence_manager/task_queue.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/scheduler/common/tracing_helper.h"
#include "third_party/blink/renderer/platform/wtf/hash_set.h"
#include "third_party/perfetto/include/perfetto/tracing/traced_value_forward.h"

namespace base {
class LazyNow;
namespace trace_event {
class TracedValue;
}
}  // namespace base

namespace blink {
namespace scheduler {

class BudgetPool;

// kNewTasksOnly prevents new tasks from running (old tasks can run normally),
// kAllTasks block queue completely.
// kAllTasks-type block always blocks the queue completely.
// kNewTasksOnly-type block does nothing when queue is already blocked by
// kAllTasks, and overrides previous kNewTasksOnly block if any, which may
// unblock some tasks.
enum class QueueBlockType { … };

// The job of the TaskQueueThrottler is to control when tasks posted on a
// throttled queue get to run.
//
// This is done by inserting a fence in the queue when it cannot run and
// removing or updating the fence when the next allowed wake up time is reached.
//
// TaskQueueThrottler assumes that it's the only system inserting fences in
// its associated TaskQueue.
//
// There may be more than one system that wishes to throttle a queue (e.g.
// renderer suspension vs tab level suspension) so the TaskQueueThrottler keeps
// a count of the number of systems that wish the queue to be throttled. See
// IncreaseThrottleRefCount & DecreaseThrottleRefCount.
//
// This class is main-thread only.
class PLATFORM_EXPORT TaskQueueThrottler final
    : public base::sequence_manager::TaskQueue::Throttler { … };

}  // namespace scheduler
}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_COMMON_THROTTLING_TASK_QUEUE_THROTTLER_H_
chromium/third_party/blink/renderer/platform/scheduler/common/throttling/task_queue_throttler.h
