From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- xpcom/threads/TaskController.cpp | 1098 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 1098 insertions(+) create mode 100644 xpcom/threads/TaskController.cpp (limited to 'xpcom/threads/TaskController.cpp') diff --git a/xpcom/threads/TaskController.cpp b/xpcom/threads/TaskController.cpp new file mode 100644 index 0000000000..8e3aae185a --- /dev/null +++ b/xpcom/threads/TaskController.cpp @@ -0,0 +1,1098 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "TaskController.h" +#include "nsIIdleRunnable.h" +#include "nsIRunnable.h" +#include "nsThreadUtils.h" +#include +#include "GeckoProfiler.h" +#include "mozilla/BackgroundHangMonitor.h" +#include "mozilla/EventQueue.h" +#include "mozilla/Hal.h" +#include "mozilla/InputTaskManager.h" +#include "mozilla/VsyncTaskManager.h" +#include "mozilla/IOInterposer.h" +#include "mozilla/StaticPtr.h" +#include "mozilla/SchedulerGroup.h" +#include "mozilla/ScopeExit.h" +#include "nsIThreadInternal.h" +#include "nsThread.h" +#include "prenv.h" +#include "prsystem.h" + +namespace mozilla { + +StaticAutoPtr TaskController::sSingleton; + +thread_local size_t mThreadPoolIndex = -1; +std::atomic Task::sCurrentTaskSeqNo = 0; + +const int32_t kMinimumPoolThreadCount = 2; +const int32_t kMaximumPoolThreadCount = 8; + +/* static */ +int32_t TaskController::GetPoolThreadCount() { + if (PR_GetEnv("MOZ_TASKCONTROLLER_THREADCOUNT")) { + return strtol(PR_GetEnv("MOZ_TASKCONTROLLER_THREADCOUNT"), nullptr, 0); + } + + int32_t numCores = 0; +#if defined(XP_MACOSX) && defined(__aarch64__) + if (const auto& cpuInfo = hal::GetHeterogeneousCpuInfo()) { + // -1 because of the main thread. + numCores = cpuInfo->mBigCpus.Count() + cpuInfo->mMediumCpus.Count() - 1; + } else +#endif + { + numCores = std::max(1, PR_GetNumberOfProcessors()); + } + + return std::clamp(numCores, kMinimumPoolThreadCount, + kMaximumPoolThreadCount); +} + +#if defined(MOZ_COLLECTING_RUNNABLE_TELEMETRY) + +struct TaskMarker : BaseMarkerType { + static constexpr const char* Name = "Task"; + static constexpr const char* Description = + "Marker representing a task being executed in TaskController."; + + using MS = MarkerSchema; + static constexpr MS::PayloadField PayloadFields[] = { + {"name", MS::InputType::CString, "Task Name", MS::Format::String, + MS::PayloadFlags::Searchable}, + {"priority", MS::InputType::Uint32, "Priority level", + MS::Format::Integer}, + {"priorityName", MS::InputType::CString, "Priority Name"}}; + + static constexpr MS::Location Locations[] = {MS::Location::MarkerChart, + MS::Location::MarkerTable}; + static constexpr const char* ChartLabel = "{marker.data.name}"; + static constexpr const char* TableLabel = + "{marker.name} - {marker.data.name} - priority: " + "{marker.data.priorityName} ({marker.data.priority})"; + + static constexpr MS::ETWMarkerGroup Group = MS::ETWMarkerGroup::Scheduling; + + static void TranslateMarkerInputToSchema(void* aContext, + const nsCString& aName, + uint32_t aPriority) { + ETW::OutputMarkerSchema(aContext, TaskMarker{}, aName, aPriority, + ProfilerStringView("")); + } + + static void StreamJSONMarkerData(baseprofiler::SpliceableJSONWriter& aWriter, + const nsCString& aName, uint32_t aPriority) { + aWriter.StringProperty("name", aName); + aWriter.IntProperty("priority", aPriority); + +# define EVENT_PRIORITY(NAME, VALUE) \ + if (aPriority == (VALUE)) { \ + aWriter.StringProperty("priorityName", #NAME); \ + } else + EVENT_QUEUE_PRIORITY_LIST(EVENT_PRIORITY) +# undef EVENT_PRIORITY + { + aWriter.StringProperty("priorityName", "Invalid Value"); + } + } +}; + +class MOZ_RAII AutoProfileTask { + public: + explicit AutoProfileTask(nsACString& aName, uint64_t aPriority) + : mName(aName), mPriority(aPriority) { + if (profiler_is_collecting_markers()) { + mStartTime = TimeStamp::Now(); + } + } + + ~AutoProfileTask() { + if (!profiler_thread_is_being_profiled_for_markers()) { + return; + } + + AUTO_PROFILER_LABEL("AutoProfileTask", PROFILER); + AUTO_PROFILER_STATS(AUTO_PROFILE_TASK); + profiler_add_marker("Runnable", ::mozilla::baseprofiler::category::OTHER, + mStartTime.IsNull() + ? MarkerTiming::IntervalEnd() + : MarkerTiming::IntervalUntilNowFrom(mStartTime), + TaskMarker{}, mName, mPriority); + } + + private: + TimeStamp mStartTime; + nsAutoCString mName; + uint32_t mPriority; +}; + +# define AUTO_PROFILE_FOLLOWING_TASK(task) \ + nsAutoCString name; \ + (task)->GetName(name); \ + AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING_NONSENSITIVE("Task", OTHER, name); \ + mozilla::AutoProfileTask PROFILER_RAII(name, (task)->GetPriority()); +#else +# define AUTO_PROFILE_FOLLOWING_TASK(task) +#endif + +bool TaskManager:: + UpdateCachesForCurrentIterationAndReportPriorityModifierChanged( + const MutexAutoLock& aProofOfLock, IterationType aIterationType) { + mCurrentSuspended = IsSuspended(aProofOfLock); + + if (aIterationType == IterationType::EVENT_LOOP_TURN && !mCurrentSuspended) { + int32_t oldModifier = mCurrentPriorityModifier; + mCurrentPriorityModifier = + GetPriorityModifierForEventLoopTurn(aProofOfLock); + + if (mCurrentPriorityModifier != oldModifier) { + return true; + } + } + return false; +} + +#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY +class MOZ_RAII AutoSetMainThreadRunnableName { + public: + explicit AutoSetMainThreadRunnableName(const nsCString& aName) { + MOZ_ASSERT(NS_IsMainThread()); + // We want to record our current runnable's name in a static so + // that BHR can record it. + mRestoreRunnableName = nsThread::sMainThreadRunnableName; + + // Copy the name into sMainThreadRunnableName's buffer, and append a + // terminating null. + uint32_t length = std::min((uint32_t)nsThread::kRunnableNameBufSize - 1, + (uint32_t)aName.Length()); + memcpy(nsThread::sMainThreadRunnableName.begin(), aName.BeginReading(), + length); + nsThread::sMainThreadRunnableName[length] = '\0'; + } + + ~AutoSetMainThreadRunnableName() { + nsThread::sMainThreadRunnableName = mRestoreRunnableName; + } + + private: + Array mRestoreRunnableName; +}; +#endif + +Task* Task::GetHighestPriorityDependency() { + Task* currentTask = this; + + while (!currentTask->mDependencies.empty()) { + auto iter = currentTask->mDependencies.begin(); + + while (iter != currentTask->mDependencies.end()) { + if ((*iter)->mCompleted) { + auto oldIter = iter; + iter++; + // Completed tasks are removed here to prevent needlessly keeping them + // alive or iterating over them in the future. + currentTask->mDependencies.erase(oldIter); + continue; + } + + currentTask = iter->get(); + break; + } + } + + return currentTask == this ? nullptr : currentTask; +} + +void TaskController::Initialize() { + MOZ_ASSERT(!sSingleton); + sSingleton = new TaskController(); +} + +void ThreadFuncPoolThread(void* aIndex) { + mThreadPoolIndex = *reinterpret_cast(aIndex); + delete reinterpret_cast(aIndex); + TaskController::Get()->RunPoolThread(); +} + +TaskController::TaskController() + : mGraphMutex("TaskController::mGraphMutex"), + mThreadPoolCV(mGraphMutex, "TaskController::mThreadPoolCV"), + mMainThreadCV(mGraphMutex, "TaskController::mMainThreadCV"), + mRunOutOfMTTasksCounter(0) { + InputTaskManager::Init(); + VsyncTaskManager::Init(); + mMTProcessingRunnable = NS_NewRunnableFunction( + "TaskController::ExecutePendingMTTasks()", + []() { TaskController::Get()->ProcessPendingMTTask(); }); + mMTBlockingProcessingRunnable = NS_NewRunnableFunction( + "TaskController::ExecutePendingMTTasks()", + []() { TaskController::Get()->ProcessPendingMTTask(true); }); +} + +// We want our default stack size limit to be approximately 2MB, to be safe for +// JS helper tasks that can use a lot of stack, but expect most threads to use +// much less. On Linux, however, requesting a stack of 2MB or larger risks the +// kernel allocating an entire 2MB huge page for it on first access, which we do +// not want. To avoid this possibility, we subtract 2 standard VM page sizes +// from our default. +constexpr PRUint32 sBaseStackSize = 2048 * 1024 - 2 * 4096; + +// TSan enforces a minimum stack size that's just slightly larger than our +// default helper stack size. It does this to store blobs of TSan-specific data +// on each thread's stack. Unfortunately, that means that even though we'll +// actually receive a larger stack than we requested, the effective usable space +// of that stack is significantly less than what we expect. To offset TSan +// stealing our stack space from underneath us, double the default. +// +// Similarly, ASan requires more stack space due to red-zones. +#if defined(MOZ_TSAN) || defined(MOZ_ASAN) +constexpr PRUint32 sStackSize = 2 * sBaseStackSize; +#else +constexpr PRUint32 sStackSize = sBaseStackSize; +#endif + +void TaskController::InitializeThreadPool() { + mPoolInitializationMutex.AssertCurrentThreadOwns(); + MOZ_ASSERT(!mThreadPoolInitialized); + mThreadPoolInitialized = true; + + int32_t poolSize = GetPoolThreadCount(); + for (int32_t i = 0; i < poolSize; i++) { + int32_t* index = new int32_t(i); + mPoolThreads.push_back( + {PR_CreateThread(PR_USER_THREAD, ThreadFuncPoolThread, index, + PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD, + PR_JOINABLE_THREAD, sStackSize), + nullptr}); + } +} + +/* static */ +size_t TaskController::GetThreadStackSize() { return sStackSize; } + +void TaskController::SetPerformanceCounterState( + PerformanceCounterState* aPerformanceCounterState) { + mPerformanceCounterState = aPerformanceCounterState; +} + +/* static */ +void TaskController::Shutdown() { + InputTaskManager::Cleanup(); + VsyncTaskManager::Cleanup(); + if (sSingleton) { + sSingleton->ShutdownThreadPoolInternal(); + sSingleton = nullptr; + } + MOZ_ASSERT(!sSingleton); +} + +void TaskController::ShutdownThreadPoolInternal() { + { + // Prevent race condition on mShuttingDown and wait. + MutexAutoLock lock(mGraphMutex); + mShuttingDown = true; + mThreadPoolCV.NotifyAll(); + } + for (PoolThread& thread : mPoolThreads) { + PR_JoinThread(thread.mThread); + } +} + +void TaskController::RunPoolThread() { + IOInterposer::RegisterCurrentThread(); + + // This is used to hold on to a task to make sure it is released outside the + // lock. This is required since it's perfectly feasible for task destructors + // to post events themselves. + RefPtr lastTask; + + nsAutoCString threadName; + threadName.AppendLiteral("TaskController #"); + threadName.AppendInt(static_cast(mThreadPoolIndex)); + AUTO_PROFILER_REGISTER_THREAD(threadName.BeginReading()); + + MutexAutoLock lock(mGraphMutex); + while (true) { + bool ranTask = false; + + if (!mThreadableTasks.empty()) { + for (auto iter = mThreadableTasks.begin(); iter != mThreadableTasks.end(); + ++iter) { + // Search for the highest priority dependency of the highest priority + // task. + + // We work with rawptrs to avoid needless refcounting. All our tasks + // are always kept alive by the graph. If one is removed from the graph + // it is kept alive by mPoolThreads[mThreadPoolIndex].mCurrentTask. + Task* task = iter->get(); + + MOZ_ASSERT(!task->mTaskManager); + + mPoolThreads[mThreadPoolIndex].mEffectiveTaskPriority = + task->GetPriority(); + + Task* nextTask; + while ((nextTask = task->GetHighestPriorityDependency())) { + task = nextTask; + } + + if (task->GetKind() == Task::Kind::MainThreadOnly || + task->mInProgress) { + continue; + } + + mPoolThreads[mThreadPoolIndex].mCurrentTask = task; + mThreadableTasks.erase(task->mIterator); + task->mIterator = mThreadableTasks.end(); + task->mInProgress = true; + + if (!mThreadableTasks.empty()) { + // Ensure at least one additional thread is woken up if there are + // more threadable tasks to process. Notifying all threads at once + // isn't actually better for performance since they all need the + // GraphMutex to proceed anyway. + mThreadPoolCV.Notify(); + } + + bool taskCompleted = false; + { + MutexAutoUnlock unlock(mGraphMutex); + lastTask = nullptr; + AUTO_PROFILE_FOLLOWING_TASK(task); + taskCompleted = task->Run() == Task::TaskResult::Complete; + ranTask = true; + } + + task->mInProgress = false; + + if (!taskCompleted) { + // Presumably this task was interrupted, leave its dependencies + // unresolved and reinsert into the queue. + auto insertion = mThreadableTasks.insert( + mPoolThreads[mThreadPoolIndex].mCurrentTask); + MOZ_ASSERT(insertion.second); + task->mIterator = insertion.first; + } else { + task->mCompleted = true; +#ifdef DEBUG + task->mIsInGraph = false; +#endif + task->mDependencies.clear(); + // This may have unblocked a main thread task. We could do this only + // if there was a main thread task before this one in the dependency + // chain. + mMayHaveMainThreadTask = true; + // Since this could have multiple dependencies thare are restricted + // to the main thread. Let's make sure that's awake. + EnsureMainThreadTasksScheduled(); + + MaybeInterruptTask(GetHighestPriorityMTTask()); + } + + // Store last task for release next time we release the lock or enter + // wait state. + lastTask = mPoolThreads[mThreadPoolIndex].mCurrentTask.forget(); + break; + } + } + + // Ensure the last task is released before we enter the wait state. + if (lastTask) { + MutexAutoUnlock unlock(mGraphMutex); + lastTask = nullptr; + + // Run another loop iteration, while we were unlocked there was an + // opportunity for another task to be posted or shutdown to be initiated. + continue; + } + + if (!ranTask) { + if (mShuttingDown) { + IOInterposer::UnregisterCurrentThread(); + MOZ_ASSERT(mThreadableTasks.empty()); + return; + } + + AUTO_PROFILER_LABEL("TaskController::RunPoolThread", IDLE); + mThreadPoolCV.Wait(); + } + } +} + +void TaskController::AddTask(already_AddRefed&& aTask) { + RefPtr task(aTask); + + if (task->GetKind() == Task::Kind::OffMainThreadOnly) { + MutexAutoLock lock(mPoolInitializationMutex); + if (!mThreadPoolInitialized) { + InitializeThreadPool(); + } + } + + MutexAutoLock lock(mGraphMutex); + + if (TaskManager* manager = task->GetManager()) { + if (manager->mTaskCount == 0) { + mTaskManagers.insert(manager); + } + manager->DidQueueTask(); + + // Set this here since if this manager's priority modifier doesn't change + // we will not reprioritize when iterating over the queue. + task->mPriorityModifier = manager->mCurrentPriorityModifier; + } + + if (profiler_is_active_and_unpaused()) { + task->mInsertionTime = TimeStamp::Now(); + } + +#ifdef DEBUG + task->mIsInGraph = true; + + for (const RefPtr& otherTask : task->mDependencies) { + MOZ_ASSERT(!otherTask->mTaskManager || + otherTask->mTaskManager == task->mTaskManager); + } +#endif + + LogTask::LogDispatch(task); + + std::pair, Task::PriorityCompare>::iterator, bool> + insertion; + switch (task->GetKind()) { + case Task::Kind::MainThreadOnly: + if (task->GetPriority() >= + static_cast(EventQueuePriority::Normal) && + !mMainThreadTasks.empty()) { + insertion = std::pair( + mMainThreadTasks.insert(--mMainThreadTasks.end(), std::move(task)), + true); + } else { + insertion = mMainThreadTasks.insert(std::move(task)); + } + break; + case Task::Kind::OffMainThreadOnly: + insertion = mThreadableTasks.insert(std::move(task)); + break; + } + (*insertion.first)->mIterator = insertion.first; + MOZ_ASSERT(insertion.second); + + MaybeInterruptTask(*insertion.first); +} + +void TaskController::WaitForTaskOrMessage() { + MutexAutoLock lock(mGraphMutex); + while (!mMayHaveMainThreadTask) { + AUTO_PROFILER_LABEL("TaskController::WaitForTaskOrMessage", IDLE); + mMainThreadCV.Wait(); + } +} + +void TaskController::ExecuteNextTaskOnlyMainThread() { + MOZ_ASSERT(NS_IsMainThread()); + MutexAutoLock lock(mGraphMutex); + ExecuteNextTaskOnlyMainThreadInternal(lock); +} + +void TaskController::ProcessPendingMTTask(bool aMayWait) { + MOZ_ASSERT(NS_IsMainThread()); + MutexAutoLock lock(mGraphMutex); + + for (;;) { + // We only ever process one event here. However we may sometimes + // not actually process a real event because of suspended tasks. + // This loop allows us to wait until we've processed something + // in that scenario. + + mMTTaskRunnableProcessedTask = ExecuteNextTaskOnlyMainThreadInternal(lock); + + if (mMTTaskRunnableProcessedTask || !aMayWait) { + break; + } + +#ifdef MOZ_ENABLE_BACKGROUND_HANG_MONITOR + // Unlock before calling into the BackgroundHangMonitor API as it uses + // the timer API. + { + MutexAutoUnlock unlock(mGraphMutex); + BackgroundHangMonitor().NotifyWait(); + } +#endif + + { + // ProcessNextEvent will also have attempted to wait, however we may have + // given it a Runnable when all the tasks in our task graph were suspended + // but we weren't able to cheaply determine that. + AUTO_PROFILER_LABEL("TaskController::ProcessPendingMTTask", IDLE); + mMainThreadCV.Wait(); + } + +#ifdef MOZ_ENABLE_BACKGROUND_HANG_MONITOR + { + MutexAutoUnlock unlock(mGraphMutex); + BackgroundHangMonitor().NotifyActivity(); + } +#endif + } + + if (mMayHaveMainThreadTask) { + EnsureMainThreadTasksScheduled(); + } +} + +void TaskController::ReprioritizeTask(Task* aTask, uint32_t aPriority) { + MutexAutoLock lock(mGraphMutex); + std::set, Task::PriorityCompare>* queue = &mMainThreadTasks; + if (aTask->GetKind() == Task::Kind::OffMainThreadOnly) { + queue = &mThreadableTasks; + } + + MOZ_ASSERT(aTask->mIterator != queue->end()); + queue->erase(aTask->mIterator); + + aTask->mPriority = aPriority; + + auto insertion = queue->insert(aTask); + MOZ_ASSERT(insertion.second); + aTask->mIterator = insertion.first; + + MaybeInterruptTask(aTask); +} + +// Code supporting runnable compatibility. +// Task that wraps a runnable. +class RunnableTask : public Task { + public: + RunnableTask(already_AddRefed&& aRunnable, int32_t aPriority, + Kind aKind) + : Task(aKind, aPriority), mRunnable(aRunnable) {} + + virtual TaskResult Run() override { + mRunnable->Run(); + mRunnable = nullptr; + return TaskResult::Complete; + } + + void SetIdleDeadline(TimeStamp aDeadline) override { + nsCOMPtr idleRunnable = do_QueryInterface(mRunnable); + if (idleRunnable) { + idleRunnable->SetDeadline(aDeadline); + } + } + + virtual bool GetName(nsACString& aName) override { +#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY + if (nsCOMPtr named = do_QueryInterface(mRunnable)) { + MOZ_ALWAYS_TRUE(NS_SUCCEEDED(named->GetName(aName))); + } else { + aName.AssignLiteral("non-nsINamed runnable"); + } + if (aName.IsEmpty()) { + aName.AssignLiteral("anonymous runnable"); + } + return true; +#else + return false; +#endif + } + + private: + RefPtr mRunnable; +}; + +void TaskController::DispatchRunnable(already_AddRefed&& aRunnable, + uint32_t aPriority, + TaskManager* aManager) { + RefPtr task = new RunnableTask(std::move(aRunnable), aPriority, + Task::Kind::MainThreadOnly); + + task->SetManager(aManager); + TaskController::Get()->AddTask(task.forget()); +} + +nsIRunnable* TaskController::GetRunnableForMTTask(bool aReallyWait) { + MutexAutoLock lock(mGraphMutex); + + while (mMainThreadTasks.empty()) { + if (!aReallyWait) { + return nullptr; + } + + AUTO_PROFILER_LABEL("TaskController::GetRunnableForMTTask::Wait", IDLE); + mMainThreadCV.Wait(); + } + + return aReallyWait ? mMTBlockingProcessingRunnable : mMTProcessingRunnable; +} + +bool TaskController::HasMainThreadPendingTasks() { + MOZ_ASSERT(NS_IsMainThread()); + auto resetIdleState = MakeScopeExit([&idleManager = mIdleTaskManager] { + if (idleManager) { + idleManager->State().ClearCachedIdleDeadline(); + } + }); + + for (bool considerIdle : {false, true}) { + if (considerIdle && !mIdleTaskManager) { + continue; + } + + MutexAutoLock lock(mGraphMutex); + + if (considerIdle) { + mIdleTaskManager->State().ForgetPendingTaskGuarantee(); + // Temporarily unlock so we can peek our idle deadline. + // XXX We could do this _before_ we take the lock if the API would let us. + // We do want to do this before looking at mMainThreadTasks, in case + // someone adds one while we're unlocked. + { + MutexAutoUnlock unlock(mGraphMutex); + mIdleTaskManager->State().CachePeekedIdleDeadline(unlock); + } + } + + // Return early if there's no tasks at all. + if (mMainThreadTasks.empty()) { + return false; + } + + // We can cheaply count how many tasks are suspended. + uint64_t totalSuspended = 0; + for (TaskManager* manager : mTaskManagers) { + DebugOnly modifierChanged = + manager + ->UpdateCachesForCurrentIterationAndReportPriorityModifierChanged( + lock, TaskManager::IterationType::NOT_EVENT_LOOP_TURN); + MOZ_ASSERT(!modifierChanged); + + // The idle manager should be suspended unless we're doing the idle pass. + MOZ_ASSERT(manager != mIdleTaskManager || manager->mCurrentSuspended || + considerIdle, + "Why are idle tasks not suspended here?"); + + if (manager->mCurrentSuspended) { + // XXX - If managers manage off-main-thread tasks this breaks! This + // scenario is explicitly not supported. + // + // This is only incremented inside the lock -or- decremented on the main + // thread so this is safe. + totalSuspended += manager->mTaskCount; + } + } + + // This would break down if we have a non-suspended task depending on a + // suspended task. This is why for the moment we do not allow tasks + // to be dependent on tasks managed by another taskmanager. + if (mMainThreadTasks.size() > totalSuspended) { + // If mIdleTaskManager->mTaskCount is 0, we never updated the suspended + // state of mIdleTaskManager above, hence shouldn't even check it here. + // But in that case idle tasks are not contributing to our suspended task + // count anyway. + if (mIdleTaskManager && mIdleTaskManager->mTaskCount && + !mIdleTaskManager->mCurrentSuspended) { + MOZ_ASSERT(considerIdle, "Why is mIdleTaskManager not suspended?"); + // Check whether the idle tasks were really needed to make our "we have + // an unsuspended task" decision. If they were, we need to force-enable + // idle tasks until we run our next task. + if (mMainThreadTasks.size() - mIdleTaskManager->mTaskCount <= + totalSuspended) { + mIdleTaskManager->State().EnforcePendingTaskGuarantee(); + } + } + return true; + } + } + return false; +} + +uint64_t TaskController::PendingMainthreadTaskCountIncludingSuspended() { + MutexAutoLock lock(mGraphMutex); + return mMainThreadTasks.size(); +} + +bool TaskController::ExecuteNextTaskOnlyMainThreadInternal( + const MutexAutoLock& aProofOfLock) { + MOZ_ASSERT(NS_IsMainThread()); + mGraphMutex.AssertCurrentThreadOwns(); + // Block to make it easier to jump to our cleanup. + bool taskRan = false; + do { + taskRan = DoExecuteNextTaskOnlyMainThreadInternal(aProofOfLock); + if (taskRan) { + if (mIdleTaskManager && mIdleTaskManager->mTaskCount && + mIdleTaskManager->IsSuspended(aProofOfLock)) { + uint32_t activeTasks = mMainThreadTasks.size(); + for (TaskManager* manager : mTaskManagers) { + if (manager->IsSuspended(aProofOfLock)) { + activeTasks -= manager->mTaskCount; + } else { + break; + } + } + + if (!activeTasks) { + // We have only idle (and maybe other suspended) tasks left, so need + // to update the idle state. We need to temporarily release the lock + // while we do that. + MutexAutoUnlock unlock(mGraphMutex); + mIdleTaskManager->State().RequestIdleDeadlineIfNeeded(unlock); + } + } + break; + } + + if (!mIdleTaskManager) { + break; + } + + if (mIdleTaskManager->mTaskCount) { + // We have idle tasks that we may not have gotten above because + // our idle state is not up to date. We need to update the idle state + // and try again. We need to temporarily release the lock while we do + // that. + MutexAutoUnlock unlock(mGraphMutex); + mIdleTaskManager->State().UpdateCachedIdleDeadline(unlock); + } else { + MutexAutoUnlock unlock(mGraphMutex); + mIdleTaskManager->State().RanOutOfTasks(unlock); + } + + // When we unlocked, someone may have queued a new task on us. So try to + // see whether we can run things again. + taskRan = DoExecuteNextTaskOnlyMainThreadInternal(aProofOfLock); + } while (false); + + if (mIdleTaskManager) { + // The pending task guarantee is not needed anymore, since we just tried + // running a task + mIdleTaskManager->State().ForgetPendingTaskGuarantee(); + + if (mMainThreadTasks.empty()) { + ++mRunOutOfMTTasksCounter; + + // XXX the IdlePeriodState API demands we have a MutexAutoUnlock for it. + // Otherwise we could perhaps just do this after we exit the locked block, + // by pushing the lock down into this method. Though it's not clear that + // we could check mMainThreadTasks.size() once we unlock, and whether we + // could maybe substitute mMayHaveMainThreadTask for that check. + MutexAutoUnlock unlock(mGraphMutex); + mIdleTaskManager->State().RanOutOfTasks(unlock); + } + } + + return taskRan; +} + +bool TaskController::DoExecuteNextTaskOnlyMainThreadInternal( + const MutexAutoLock& aProofOfLock) { + mGraphMutex.AssertCurrentThreadOwns(); + + nsCOMPtr mainIThread; + NS_GetMainThread(getter_AddRefs(mainIThread)); + + nsThread* mainThread = static_cast(mainIThread.get()); + if (mainThread) { + mainThread->SetRunningEventDelay(TimeDuration(), TimeStamp()); + } + + uint32_t totalSuspended = 0; + for (TaskManager* manager : mTaskManagers) { + bool modifierChanged = + manager + ->UpdateCachesForCurrentIterationAndReportPriorityModifierChanged( + aProofOfLock, TaskManager::IterationType::EVENT_LOOP_TURN); + if (modifierChanged) { + ProcessUpdatedPriorityModifier(manager); + } + if (manager->mCurrentSuspended) { + totalSuspended += manager->mTaskCount; + } + } + + MOZ_ASSERT(mMainThreadTasks.size() >= totalSuspended); + + // This would break down if we have a non-suspended task depending on a + // suspended task. This is why for the moment we do not allow tasks + // to be dependent on tasks managed by another taskmanager. + if (mMainThreadTasks.size() > totalSuspended) { + for (auto iter = mMainThreadTasks.begin(); iter != mMainThreadTasks.end(); + iter++) { + Task* task = iter->get(); + + if (task->mTaskManager && task->mTaskManager->mCurrentSuspended) { + // Even though we may want to run some dependencies of this task, we + // will run them at their own priority level and not the priority + // level of their dependents. + continue; + } + + task = GetFinalDependency(task); + + if (task->GetKind() == Task::Kind::OffMainThreadOnly || + task->mInProgress || + (task->mTaskManager && task->mTaskManager->mCurrentSuspended)) { + continue; + } + + mCurrentTasksMT.push(task); + mMainThreadTasks.erase(task->mIterator); + task->mIterator = mMainThreadTasks.end(); + task->mInProgress = true; + TaskManager* manager = task->GetManager(); + bool result = false; + + { + MutexAutoUnlock unlock(mGraphMutex); + if (manager) { + manager->WillRunTask(); + if (manager != mIdleTaskManager) { + // Notify the idle period state that we're running a non-idle task. + // This needs to happen while our mutex is not locked! + mIdleTaskManager->State().FlagNotIdle(); + } else { + TimeStamp idleDeadline = + mIdleTaskManager->State().GetCachedIdleDeadline(); + MOZ_ASSERT( + idleDeadline, + "How can we not have a deadline if our manager is enabled?"); + task->SetIdleDeadline(idleDeadline); + } + } + if (mIdleTaskManager) { + // We found a task to run; we can clear the idle deadline on our idle + // task manager. This _must_ be done before we actually run the task, + // because running the task could reenter via spinning the event loop + // and we want to make sure there's no cached idle deadline at that + // point. But we have to make sure we do it after out SetIdleDeadline + // call above, in the case when the task is actually an idle task. + mIdleTaskManager->State().ClearCachedIdleDeadline(); + } + + TimeStamp now = TimeStamp::Now(); + + if (mainThread) { + if (task->GetPriority() < uint32_t(EventQueuePriority::InputHigh) || + task->mInsertionTime.IsNull()) { + mainThread->SetRunningEventDelay(TimeDuration(), now); + } else { + mainThread->SetRunningEventDelay(now - task->mInsertionTime, now); + } + } + + nsAutoCString name; +#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY + task->GetName(name); +#endif + + PerformanceCounterState::Snapshot snapshot = + mPerformanceCounterState->RunnableWillRun( + now, manager == mIdleTaskManager); + + { + LogTask::Run log(task); +#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY + AutoSetMainThreadRunnableName nameGuard(name); +#endif + AUTO_PROFILE_FOLLOWING_TASK(task); + result = task->Run() == Task::TaskResult::Complete; + } + + // Task itself should keep manager alive. + if (manager) { + manager->DidRunTask(); + } + + mPerformanceCounterState->RunnableDidRun(name, std::move(snapshot)); + } + + // Task itself should keep manager alive. + if (manager && result && manager->mTaskCount == 0) { + mTaskManagers.erase(manager); + } + + task->mInProgress = false; + + if (!result) { + // Presumably this task was interrupted, leave its dependencies + // unresolved and reinsert into the queue. + auto insertion = + mMainThreadTasks.insert(std::move(mCurrentTasksMT.top())); + MOZ_ASSERT(insertion.second); + task->mIterator = insertion.first; + manager->WillRunTask(); + } else { + task->mCompleted = true; +#ifdef DEBUG + task->mIsInGraph = false; +#endif + // Clear dependencies to release references. + task->mDependencies.clear(); + + if (!mThreadableTasks.empty()) { + // We're going to wake up a single thread in our pool. This thread + // is responsible for waking up additional threads in the situation + // where more than one task became available. + mThreadPoolCV.Notify(); + } + } + + mCurrentTasksMT.pop(); + return true; + } + } + + mMayHaveMainThreadTask = false; + if (mIdleTaskManager) { + // We did not find a task to run. We still need to clear the cached idle + // deadline on our idle state, because that deadline was only relevant to + // the execution of this function. Had we found a task, we would have + // cleared the deadline before running that task. + mIdleTaskManager->State().ClearCachedIdleDeadline(); + } + return false; +} + +Task* TaskController::GetFinalDependency(Task* aTask) { + Task* nextTask; + + while ((nextTask = aTask->GetHighestPriorityDependency())) { + aTask = nextTask; + } + + return aTask; +} + +void TaskController::MaybeInterruptTask(Task* aTask) { + mGraphMutex.AssertCurrentThreadOwns(); + + if (!aTask) { + return; + } + + // This optimization prevents many slow lookups in long chains of similar + // priority. + if (!aTask->mDependencies.empty()) { + Task* firstDependency = aTask->mDependencies.begin()->get(); + if (aTask->GetPriority() <= firstDependency->GetPriority() && + !firstDependency->mCompleted && + aTask->GetKind() == firstDependency->GetKind()) { + // This task has the same or a higher priority as one of its dependencies, + // never any need to interrupt. + return; + } + } + + Task* finalDependency = GetFinalDependency(aTask); + + if (finalDependency->mInProgress) { + // No need to wake anything, we can't schedule this task right now anyway. + return; + } + + if (aTask->GetKind() == Task::Kind::MainThreadOnly) { + mMayHaveMainThreadTask = true; + + EnsureMainThreadTasksScheduled(); + + if (mCurrentTasksMT.empty()) { + return; + } + + // We could go through the steps above here and interrupt an off main + // thread task in case it has a lower priority. + if (finalDependency->GetKind() == Task::Kind::OffMainThreadOnly) { + return; + } + + if (mCurrentTasksMT.top()->GetPriority() < aTask->GetPriority()) { + mCurrentTasksMT.top()->RequestInterrupt(aTask->GetPriority()); + } + } else { + Task* lowestPriorityTask = nullptr; + for (PoolThread& thread : mPoolThreads) { + if (!thread.mCurrentTask) { + mThreadPoolCV.Notify(); + // There's a free thread, no need to interrupt anything. + return; + } + + if (!lowestPriorityTask) { + lowestPriorityTask = thread.mCurrentTask.get(); + continue; + } + + // This should possibly select the lowest priority task which was started + // the latest. But for now we ignore that optimization. + // This also doesn't guarantee a task is interruptable, so that's an + // avenue for improvements as well. + if (lowestPriorityTask->GetPriority() > thread.mEffectiveTaskPriority) { + lowestPriorityTask = thread.mCurrentTask.get(); + } + } + + if (lowestPriorityTask->GetPriority() < aTask->GetPriority()) { + lowestPriorityTask->RequestInterrupt(aTask->GetPriority()); + } + + // We choose not to interrupt main thread tasks for tasks which may be + // executed off the main thread. + } +} + +Task* TaskController::GetHighestPriorityMTTask() { + mGraphMutex.AssertCurrentThreadOwns(); + + if (!mMainThreadTasks.empty()) { + return mMainThreadTasks.begin()->get(); + } + return nullptr; +} + +void TaskController::EnsureMainThreadTasksScheduled() { + if (mObserver) { + mObserver->OnDispatchedEvent(); + } + if (mExternalCondVar) { + mExternalCondVar->Notify(); + } + mMainThreadCV.Notify(); +} + +void TaskController::ProcessUpdatedPriorityModifier(TaskManager* aManager) { + mGraphMutex.AssertCurrentThreadOwns(); + + MOZ_ASSERT(NS_IsMainThread()); + + int32_t modifier = aManager->mCurrentPriorityModifier; + + std::vector> storedTasks; + // Find all relevant tasks. + for (auto iter = mMainThreadTasks.begin(); iter != mMainThreadTasks.end();) { + if ((*iter)->mTaskManager == aManager) { + storedTasks.push_back(*iter); + iter = mMainThreadTasks.erase(iter); + } else { + iter++; + } + } + + // Reinsert found tasks with their new priorities. + for (RefPtr& ref : storedTasks) { + // Kept alive at first by the vector and then by mMainThreadTasks. + Task* task = ref; + task->mPriorityModifier = modifier; + auto insertion = mMainThreadTasks.insert(std::move(ref)); + MOZ_ASSERT(insertion.second); + task->mIterator = insertion.first; + } +} + +} // namespace mozilla -- cgit v1.2.3