зеркало из https://github.com/mozilla/gecko-dev.git
116 строки
3.7 KiB
C++
116 строки
3.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_Scheduler_h
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#define mozilla_Scheduler_h
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#include "mozilla/Attributes.h"
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#include "mozilla/EventQueue.h"
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#include "mozilla/RefPtr.h"
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#include "mozilla/ThreadLocal.h"
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#include "mozilla/UniquePtr.h"
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#include "nsTArray.h"
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#include "nsILabelableRunnable.h"
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// Windows silliness. winbase.h defines an empty no-argument Yield macro.
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#undef Yield
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class nsIBlockThreadedExecutionCallback;
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class nsIIdlePeriod;
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class nsThread;
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namespace mozilla {
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class SchedulerGroup;
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class SchedulerImpl;
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class SynchronizedEventQueue;
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// This is the central class for scheduling work on the "main" thread. It starts
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// a pool of cooperatively scheduled threads (using CooperativeThreadPool) and
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// controls them using a single, main-thread event queue
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// (SchedulerEventQueue). Even if cooperative scheduling is not enabled,
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// Scheduler can schedule work on the main thread. Its behavior is controlled by
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// a number of preferences:
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//
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// "dom.ipc.scheduler": If this pref is false, Scheduler is not used at all.
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//
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// "dom.ipc.scheduler.useMultipleQueues": When this pref is true, a
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// LabeledEventQueue is used for the main thread event queue. This divides the
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// event queue into multiple queues, one per SchedulerGroup. If the pref is
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// false, a normal EventQueue is used. Either way, event prioritization via
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// PrioritizedEventQueue still happens.
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//
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// "dom.ipc.scheduler.preemption": If this pref is true, then cooperative
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// threads can be preempted before they have finished. This might happen if a
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// different cooperative thread is running an event for a higher priority
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// SchedulerGroup.
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//
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// "dom.ipc.scheduler.threadCount": The number of cooperative threads to start.
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//
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// "dom.ipc.scheduler.chaoticScheduling": When this pref is set, we make an
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// effort to switch between threads even when it is not necessary to do
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// this. This is useful for debugging.
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class Scheduler
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{
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public:
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static already_AddRefed<nsThread> Init(nsIIdlePeriod* aIdlePeriod);
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static void Start();
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static void Shutdown();
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// Scheduler prefs need to be handled differently because the scheduler needs
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// to start up in the content process before the normal preferences service.
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static nsCString GetPrefs();
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static void SetPrefs(const char* aPrefs);
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static bool IsSchedulerEnabled();
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static bool UseMultipleQueues();
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static bool IsCooperativeThread();
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static void Yield();
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static bool UnlabeledEventRunning();
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static bool AnyEventRunning();
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static void BlockThreadedExecution(nsIBlockThreadedExecutionCallback* aCallback);
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static void UnblockThreadedExecution();
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class MOZ_RAII EventLoopActivation
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{
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public:
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using EventGroups = nsILabelableRunnable::SchedulerGroupSet;
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EventLoopActivation();
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~EventLoopActivation();
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static void Init();
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bool IsNested() const { return !!mPrev; }
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void SetEvent(nsIRunnable* aEvent, EventPriority aPriority);
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EventPriority Priority() const { return mPriority; }
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bool IsLabeled() { return mIsLabeled; }
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EventGroups& EventGroupsAffected() { return mEventGroups; }
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private:
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EventLoopActivation* mPrev;
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bool mProcessingEvent;
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bool mIsLabeled;
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EventGroups mEventGroups;
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EventPriority mPriority;
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static MOZ_THREAD_LOCAL(EventLoopActivation*) sTopActivation;
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};
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private:
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friend class SchedulerImpl;
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static UniquePtr<SchedulerImpl> sScheduler;
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};
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} // namespace mozilla
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#endif // mozilla_Scheduler_h
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