| // Copyright 2019 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "components/memory_pressure/system_memory_pressure_evaluator_win.h" |
| |
| #include <windows.h> |
| #include <memory> |
| |
| #include "base/bind.h" |
| #include "base/metrics/histogram_functions.h" |
| #include "base/system/sys_info.h" |
| #include "base/task/single_thread_task_runner.h" |
| #include "base/threading/sequenced_task_runner_handle.h" |
| #include "base/time/time.h" |
| #include "base/win/object_watcher.h" |
| #include "components/memory_pressure/multi_source_memory_pressure_monitor.h" |
| |
| namespace memory_pressure { |
| namespace win { |
| |
| namespace { |
| |
| static const DWORDLONG kMBBytes = 1024 * 1024; |
| |
| // Implements ObjectWatcher::Delegate by forwarding to a provided callback. |
| class MemoryPressureWatcherDelegate |
| : public base::win::ObjectWatcher::Delegate { |
| public: |
| MemoryPressureWatcherDelegate(base::win::ScopedHandle handle, |
| base::OnceClosure callback); |
| ~MemoryPressureWatcherDelegate() override; |
| MemoryPressureWatcherDelegate(const MemoryPressureWatcherDelegate& other) = |
| delete; |
| MemoryPressureWatcherDelegate& operator=( |
| const MemoryPressureWatcherDelegate&) = delete; |
| |
| void ReplaceWatchedHandleForTesting(base::win::ScopedHandle handle); |
| void SetCallbackForTesting(base::OnceClosure callback) { |
| callback_ = std::move(callback); |
| } |
| |
| private: |
| void OnObjectSignaled(HANDLE handle) override; |
| |
| base::win::ScopedHandle handle_; |
| base::win::ObjectWatcher watcher_; |
| base::OnceClosure callback_; |
| }; |
| |
| MemoryPressureWatcherDelegate::MemoryPressureWatcherDelegate( |
| base::win::ScopedHandle handle, |
| base::OnceClosure callback) |
| : handle_(std::move(handle)), callback_(std::move(callback)) { |
| DCHECK(handle_.IsValid()); |
| CHECK(watcher_.StartWatchingOnce(handle_.Get(), this)); |
| } |
| |
| MemoryPressureWatcherDelegate::~MemoryPressureWatcherDelegate() = default; |
| |
| void MemoryPressureWatcherDelegate::ReplaceWatchedHandleForTesting( |
| base::win::ScopedHandle handle) { |
| if (watcher_.IsWatching()) |
| watcher_.StopWatching(); |
| handle_ = std::move(handle); |
| CHECK(watcher_.StartWatchingOnce(handle_.Get(), this)); |
| } |
| |
| void MemoryPressureWatcherDelegate::OnObjectSignaled(HANDLE handle) { |
| DCHECK_EQ(handle, handle_.Get()); |
| std::move(callback_).Run(); |
| } |
| |
| } // namespace |
| |
| // Check the amount of RAM left every 5 seconds. |
| const base::TimeDelta SystemMemoryPressureEvaluator::kMemorySamplingPeriod = |
| base::Seconds(5); |
| |
| // The following constants have been lifted from similar values in the ChromeOS |
| // memory pressure monitor. The values were determined experimentally to ensure |
| // sufficient responsiveness of the memory pressure subsystem, and minimal |
| // overhead. |
| const base::TimeDelta SystemMemoryPressureEvaluator::kModeratePressureCooldown = |
| base::Seconds(10); |
| |
| // TODO(chrisha): Explore the following constants further with an experiment. |
| |
| // A system is considered 'high memory' if it has more than 1.5GB of system |
| // memory available for use by the memory manager (not reserved for hardware |
| // and drivers). This is a fuzzy version of the ~2GB discussed below. |
| const int SystemMemoryPressureEvaluator::kLargeMemoryThresholdMb = 1536; |
| |
| // These are the default thresholds used for systems with < ~2GB of physical |
| // memory. Such systems have been observed to always maintain ~100MB of |
| // available memory, paging until that is the case. To try to avoid paging a |
| // threshold slightly above this is chosen. The moderate threshold is slightly |
| // less grounded in reality and chosen as 2.5x critical. |
| const int |
| SystemMemoryPressureEvaluator::kSmallMemoryDefaultModerateThresholdMb = 500; |
| const int |
| SystemMemoryPressureEvaluator::kSmallMemoryDefaultCriticalThresholdMb = 200; |
| |
| // These are the default thresholds used for systems with >= ~2GB of physical |
| // memory. Such systems have been observed to always maintain ~300MB of |
| // available memory, paging until that is the case. |
| const int |
| SystemMemoryPressureEvaluator::kLargeMemoryDefaultModerateThresholdMb = |
| 1000; |
| const int |
| SystemMemoryPressureEvaluator::kLargeMemoryDefaultCriticalThresholdMb = 400; |
| |
| // A memory pressure evaluator that receives memory pressure notifications from |
| // the OS and forwards them to the memory pressure monitor. |
| class SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator { |
| public: |
| using MemoryPressureLevel = base::MemoryPressureListener::MemoryPressureLevel; |
| |
| explicit OSSignalsMemoryPressureEvaluator( |
| std::unique_ptr<MemoryPressureVoter> voter); |
| ~OSSignalsMemoryPressureEvaluator(); |
| OSSignalsMemoryPressureEvaluator( |
| const OSSignalsMemoryPressureEvaluator& other) = delete; |
| OSSignalsMemoryPressureEvaluator& operator=( |
| const OSSignalsMemoryPressureEvaluator&) = delete; |
| |
| // Creates the watcher used to receive the low and high memory notifications. |
| void Start(); |
| |
| MemoryPressureWatcherDelegate* GetWatcherForTesting() const { |
| return memory_notification_watcher_.get(); |
| } |
| void WaitForHighMemoryNotificationForTesting(base::OnceClosure closure); |
| |
| private: |
| // Called when receiving a low/high memory notification. |
| void OnLowMemoryNotification(); |
| void OnHighMemoryNotification(); |
| |
| void StartLowMemoryNotificationWatcher(); |
| void StartHighMemoryNotificationWatcher(); |
| |
| // The period of the critical pressure notification timer. |
| static constexpr base::TimeDelta kHighPressureNotificationInterval = |
| base::Seconds(2); |
| |
| // The voter used to cast the votes. |
| std::unique_ptr<MemoryPressureVoter> voter_; |
| |
| // The memory notification watcher. |
| std::unique_ptr<MemoryPressureWatcherDelegate> memory_notification_watcher_; |
| |
| // Timer that will re-emit the critical memory pressure signal until the |
| // memory gets high again. |
| base::RepeatingTimer critical_pressure_notification_timer_; |
| |
| // Beginning of the critical memory pressure session. |
| base::TimeTicks critical_pressure_session_begin_; |
| |
| // Ensures that this object is used from a single sequence. |
| SEQUENCE_CHECKER(sequence_checker_); |
| }; |
| |
| SystemMemoryPressureEvaluator::SystemMemoryPressureEvaluator( |
| std::unique_ptr<MemoryPressureVoter> voter) |
| : memory_pressure::SystemMemoryPressureEvaluator(std::move(voter)), |
| moderate_threshold_mb_(0), |
| critical_threshold_mb_(0), |
| moderate_pressure_repeat_count_(0) { |
| InferThresholds(); |
| StartObserving(); |
| } |
| |
| SystemMemoryPressureEvaluator::SystemMemoryPressureEvaluator( |
| int moderate_threshold_mb, |
| int critical_threshold_mb, |
| std::unique_ptr<MemoryPressureVoter> voter) |
| : memory_pressure::SystemMemoryPressureEvaluator(std::move(voter)), |
| moderate_threshold_mb_(moderate_threshold_mb), |
| critical_threshold_mb_(critical_threshold_mb), |
| moderate_pressure_repeat_count_(0) { |
| DCHECK_GE(moderate_threshold_mb_, critical_threshold_mb_); |
| DCHECK_LE(0, critical_threshold_mb_); |
| StartObserving(); |
| } |
| |
| SystemMemoryPressureEvaluator::~SystemMemoryPressureEvaluator() { |
| StopObserving(); |
| } |
| |
| void SystemMemoryPressureEvaluator::CheckMemoryPressureSoon() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| base::SequencedTaskRunnerHandle::Get()->PostTask( |
| FROM_HERE, BindOnce(&SystemMemoryPressureEvaluator::CheckMemoryPressure, |
| weak_ptr_factory_.GetWeakPtr())); |
| } |
| |
| void SystemMemoryPressureEvaluator::CreateOSSignalPressureEvaluator( |
| std::unique_ptr<MemoryPressureVoter> voter) { |
| os_signals_evaluator_ = |
| std::make_unique<OSSignalsMemoryPressureEvaluator>(std::move(voter)); |
| os_signals_evaluator_->Start(); |
| } |
| |
| void SystemMemoryPressureEvaluator::ReplaceWatchedHandleForTesting( |
| base::win::ScopedHandle handle) { |
| os_signals_evaluator_->GetWatcherForTesting()->ReplaceWatchedHandleForTesting( |
| std::move(handle)); |
| } |
| |
| void SystemMemoryPressureEvaluator::WaitForHighMemoryNotificationForTesting( |
| base::OnceClosure closure) { |
| os_signals_evaluator_->WaitForHighMemoryNotificationForTesting( |
| std::move(closure)); |
| } |
| |
| void SystemMemoryPressureEvaluator::InferThresholds() { |
| // Default to a 'high' memory situation, which uses more conservative |
| // thresholds. |
| bool high_memory = true; |
| MEMORYSTATUSEX mem_status = {}; |
| if (GetSystemMemoryStatus(&mem_status)) { |
| static const DWORDLONG kLargeMemoryThresholdBytes = |
| static_cast<DWORDLONG>(kLargeMemoryThresholdMb) * kMBBytes; |
| high_memory = mem_status.ullTotalPhys >= kLargeMemoryThresholdBytes; |
| } |
| |
| if (high_memory) { |
| moderate_threshold_mb_ = kLargeMemoryDefaultModerateThresholdMb; |
| critical_threshold_mb_ = kLargeMemoryDefaultCriticalThresholdMb; |
| } else { |
| moderate_threshold_mb_ = kSmallMemoryDefaultModerateThresholdMb; |
| critical_threshold_mb_ = kSmallMemoryDefaultCriticalThresholdMb; |
| } |
| } |
| |
| void SystemMemoryPressureEvaluator::StartObserving() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| timer_.Start( |
| FROM_HERE, kMemorySamplingPeriod, |
| BindRepeating(&SystemMemoryPressureEvaluator::CheckMemoryPressure, |
| weak_ptr_factory_.GetWeakPtr())); |
| } |
| |
| void SystemMemoryPressureEvaluator::StopObserving() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| // If StartObserving failed, StopObserving will still get called. |
| timer_.Stop(); |
| weak_ptr_factory_.InvalidateWeakPtrs(); |
| } |
| |
| void SystemMemoryPressureEvaluator::CheckMemoryPressure() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| // Get the previous pressure level and update the current one. |
| MemoryPressureLevel old_vote = current_vote(); |
| SetCurrentVote(CalculateCurrentPressureLevel()); |
| |
| // |notify| will be set to true if MemoryPressureListeners need to be |
| // notified of a memory pressure level state change. |
| bool notify = false; |
| switch (current_vote()) { |
| case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE: |
| break; |
| |
| case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE: |
| if (old_vote != current_vote()) { |
| // This is a new transition to moderate pressure so notify. |
| moderate_pressure_repeat_count_ = 0; |
| notify = true; |
| } else { |
| // Already in moderate pressure, only notify if sustained over the |
| // cooldown period. |
| const int kModeratePressureCooldownCycles = |
| kModeratePressureCooldown / kMemorySamplingPeriod; |
| if (++moderate_pressure_repeat_count_ == |
| kModeratePressureCooldownCycles) { |
| moderate_pressure_repeat_count_ = 0; |
| notify = true; |
| } |
| } |
| break; |
| |
| case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL: |
| // Always notify of critical pressure levels. |
| notify = true; |
| break; |
| } |
| |
| SendCurrentVote(notify); |
| } |
| |
| base::MemoryPressureListener::MemoryPressureLevel |
| SystemMemoryPressureEvaluator::CalculateCurrentPressureLevel() { |
| MEMORYSTATUSEX mem_status = {}; |
| if (!GetSystemMemoryStatus(&mem_status)) |
| return base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE; |
| |
| // How much system memory is actively available for use right now, in MBs. |
| int phys_free = static_cast<int>(mem_status.ullAvailPhys / kMBBytes); |
| |
| // TODO(chrisha): This should eventually care about address space pressure, |
| // but the browser process (where this is running) effectively never runs out |
| // of address space. Renderers occasionally do, but it does them no good to |
| // have the browser process monitor address space pressure. Long term, |
| // renderers should run their own address space pressure monitors and act |
| // accordingly, with the browser making cross-process decisions based on |
| // system memory pressure. |
| |
| // Determine if the physical memory is under critical memory pressure. |
| if (phys_free <= critical_threshold_mb_) |
| return base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL; |
| |
| // Determine if the physical memory is under moderate memory pressure. |
| if (phys_free <= moderate_threshold_mb_) |
| return base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE; |
| |
| // No memory pressure was detected. |
| return base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE; |
| } |
| |
| bool SystemMemoryPressureEvaluator::GetSystemMemoryStatus( |
| MEMORYSTATUSEX* mem_status) { |
| DCHECK(mem_status); |
| mem_status->dwLength = sizeof(*mem_status); |
| if (!::GlobalMemoryStatusEx(mem_status)) |
| return false; |
| return true; |
| } |
| |
| SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| OSSignalsMemoryPressureEvaluator(std::unique_ptr<MemoryPressureVoter> voter) |
| : voter_(std::move(voter)) {} |
| |
| SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| ~OSSignalsMemoryPressureEvaluator() = default; |
| |
| void SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator::Start() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| // Start by observing the low memory notifications. If the system is already |
| // under pressure this will run the |OnLowMemoryNotification| callback and |
| // automatically switch to waiting for the high memory notification/ |
| StartLowMemoryNotificationWatcher(); |
| } |
| |
| void SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| OnLowMemoryNotification() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| critical_pressure_session_begin_ = base::TimeTicks::Now(); |
| |
| base::UmaHistogramEnumeration( |
| "Discarding.WinOSPressureSignals.PressureLevelOnLowMemoryNotification", |
| base::MemoryPressureMonitor::Get()->GetCurrentPressureLevel()); |
| |
| base::UmaHistogramMemoryMB( |
| "Discarding.WinOSPressureSignals." |
| "AvailableMemoryMbOnLowMemoryNotification", |
| base::SysInfo::AmountOfAvailablePhysicalMemory() / 1024 / 1024); |
| |
| voter_->SetVote(base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL, |
| /* notify = */ true); |
| |
| // Start a timer to repeat the notification at regular interval until |
| // OnHighMemoryNotification gets called. |
| critical_pressure_notification_timer_.Start( |
| FROM_HERE, kHighPressureNotificationInterval, |
| base::BindRepeating( |
| &MemoryPressureVoter::SetVote, base::Unretained(voter_.get()), |
| base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL, |
| /* notify = */ true)); |
| |
| // Start the high memory notification watcher to be notified when the system |
| // exits memory pressure. |
| StartHighMemoryNotificationWatcher(); |
| } |
| |
| void SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| OnHighMemoryNotification() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| base::UmaHistogramMediumTimes( |
| "Discarding.WinOSPressureSignals.LowMemorySessionLength", |
| base::TimeTicks::Now() - critical_pressure_session_begin_); |
| critical_pressure_session_begin_ = base::TimeTicks(); |
| |
| critical_pressure_notification_timer_.Stop(); |
| voter_->SetVote(base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE, |
| /* notify = */ false); |
| |
| // Start the low memory notification watcher to be notified the next time the |
| // system hits memory pressure. |
| StartLowMemoryNotificationWatcher(); |
| } |
| |
| void SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| StartLowMemoryNotificationWatcher() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| DCHECK(base::SequencedTaskRunnerHandle::IsSet()); |
| memory_notification_watcher_ = |
| std::make_unique<MemoryPressureWatcherDelegate>( |
| base::win::ScopedHandle(::CreateMemoryResourceNotification( |
| ::LowMemoryResourceNotification)), |
| base::BindOnce( |
| &SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| OnLowMemoryNotification, |
| base::Unretained(this))); |
| } |
| |
| void SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| StartHighMemoryNotificationWatcher() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| memory_notification_watcher_ = |
| std::make_unique<MemoryPressureWatcherDelegate>( |
| base::win::ScopedHandle(::CreateMemoryResourceNotification( |
| ::HighMemoryResourceNotification)), |
| base::BindOnce( |
| &SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| OnHighMemoryNotification, |
| base::Unretained(this))); |
| } |
| |
| void SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator:: |
| WaitForHighMemoryNotificationForTesting(base::OnceClosure closure) { |
| // If the timer isn't running then it means that the high memory notification |
| // has already been received. |
| if (!critical_pressure_notification_timer_.IsRunning()) { |
| std::move(closure).Run(); |
| return; |
| } |
| |
| memory_notification_watcher_->SetCallbackForTesting(base::BindOnce( |
| [](SystemMemoryPressureEvaluator::OSSignalsMemoryPressureEvaluator* |
| evaluator, |
| base::OnceClosure closure) { |
| evaluator->OnHighMemoryNotification(); |
| std::move(closure).Run(); |
| }, |
| base::Unretained(this), std::move(closure))); |
| } |
| |
| } // namespace win |
| } // namespace memory_pressure |