From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- xpcom/base/AvailableMemoryWatcherWin.cpp | 407 +++++++++++++++++++++++++++++++ 1 file changed, 407 insertions(+) create mode 100644 xpcom/base/AvailableMemoryWatcherWin.cpp (limited to 'xpcom/base/AvailableMemoryWatcherWin.cpp') diff --git a/xpcom/base/AvailableMemoryWatcherWin.cpp b/xpcom/base/AvailableMemoryWatcherWin.cpp new file mode 100644 index 0000000000..42e590e93a --- /dev/null +++ b/xpcom/base/AvailableMemoryWatcherWin.cpp @@ -0,0 +1,407 @@ +/* -*- 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 "AvailableMemoryWatcher.h" +#include "mozilla/Atomics.h" +#include "mozilla/Services.h" +#include "mozilla/StaticPrefs_browser.h" +#include "nsAppRunner.h" +#include "nsExceptionHandler.h" +#include "nsICrashReporter.h" +#include "nsIObserver.h" +#include "nsISupports.h" +#include "nsITimer.h" +#include "nsMemoryPressure.h" +#include "nsServiceManagerUtils.h" +#include "nsWindowsHelpers.h" + +#include + +extern mozilla::Atomic + sNumLowPhysicalMemEvents; + +namespace mozilla { + +// This class is used to monitor low memory events delivered by Windows via +// memory resource notification objects. When we enter a low memory scenario +// the LowMemoryCallback() is invoked by Windows. This initial call triggers +// an nsITimer that polls to see when the low memory condition has been lifted. +// When it has, we'll stop polling and start waiting for the next +// LowMemoryCallback(). Meanwhile, the polling may be stopped and restarted by +// user-interaction events from the observer service. +class nsAvailableMemoryWatcher final : public nsITimerCallback, + public nsINamed, + public nsAvailableMemoryWatcherBase { + public: + NS_DECL_ISUPPORTS_INHERITED + NS_DECL_NSIOBSERVER + NS_DECL_NSITIMERCALLBACK + NS_DECL_NSINAMED + + nsAvailableMemoryWatcher(); + nsresult Init() override; + + private: + static VOID CALLBACK LowMemoryCallback(PVOID aContext, BOOLEAN aIsTimer); + static void RecordLowMemoryEvent(); + static bool IsCommitSpaceLow(); + + ~nsAvailableMemoryWatcher(); + bool RegisterMemoryResourceHandler(const MutexAutoLock& aLock) + MOZ_REQUIRES(mMutex); + void UnregisterMemoryResourceHandler(const MutexAutoLock&) + MOZ_REQUIRES(mMutex); + void MaybeSaveMemoryReport(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + void Shutdown(const MutexAutoLock& aLock) MOZ_REQUIRES(mMutex); + bool ListenForLowMemory(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + void OnLowMemory(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + void OnHighMemory(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + void StartPollingIfUserInteracting(const MutexAutoLock& aLock) + MOZ_REQUIRES(mMutex); + void StopPolling(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + void StopPollingIfUserIdle(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + void OnUserInteracting(const MutexAutoLock&) MOZ_REQUIRES(mMutex); + + // The publicly available methods (::Observe() and ::Notify()) are called on + // the main thread while the ::LowMemoryCallback() method is called by an + // external thread. All functions called from those must acquire a lock on + // this mutex before accessing the object's fields to prevent races. + Mutex mMutex; + nsCOMPtr mTimer MOZ_GUARDED_BY(mMutex); + nsAutoHandle mLowMemoryHandle MOZ_GUARDED_BY(mMutex); + HANDLE mWaitHandle MOZ_GUARDED_BY(mMutex); + bool mPolling MOZ_GUARDED_BY(mMutex); + + // Indicates whether to start a timer when user interaction is notified. + // This flag is needed because the low-memory callback may be triggered when + // the user is inactive and we want to delay-start the timer. + bool mNeedToRestartTimerOnUserInteracting MOZ_GUARDED_BY(mMutex); + // Indicate that the available commit space is low. The timer handler needs + // this flag because it is triggered by the low physical memory regardless + // of the available commit space. + bool mUnderMemoryPressure MOZ_GUARDED_BY(mMutex); + + bool mSavedReport MOZ_GUARDED_BY(mMutex); + bool mIsShutdown MOZ_GUARDED_BY(mMutex); + + // Members below this line are used only in the main thread. + // No lock is needed. + + // Don't fire a low-memory notification more often than this interval. + uint32_t mPollingInterval; +}; + +NS_IMPL_ISUPPORTS_INHERITED(nsAvailableMemoryWatcher, + nsAvailableMemoryWatcherBase, nsIObserver, + nsITimerCallback, nsINamed) + +nsAvailableMemoryWatcher::nsAvailableMemoryWatcher() + : mMutex("low memory callback mutex"), + mWaitHandle(nullptr), + mPolling(false), + mNeedToRestartTimerOnUserInteracting(false), + mUnderMemoryPressure(false), + mSavedReport(false), + mIsShutdown(false), + mPollingInterval(0) {} + +nsresult nsAvailableMemoryWatcher::Init() { + nsresult rv = nsAvailableMemoryWatcherBase::Init(); + if (NS_FAILED(rv)) { + return rv; + } + + MutexAutoLock lock(mMutex); + mTimer = NS_NewTimer(); + if (!mTimer) { + return NS_ERROR_OUT_OF_MEMORY; + } + + // Use a very short interval for GTest to verify the timer's behavior. + mPollingInterval = gIsGtest ? 10 : 10000; + + if (!RegisterMemoryResourceHandler(lock)) { + return NS_ERROR_FAILURE; + } + + return NS_OK; +} + +nsAvailableMemoryWatcher::~nsAvailableMemoryWatcher() { + // These handles should have been released during the shutdown phase. + MOZ_ASSERT(!mLowMemoryHandle); + MOZ_ASSERT(!mWaitHandle); +} + +// static +VOID CALLBACK nsAvailableMemoryWatcher::LowMemoryCallback(PVOID aContext, + BOOLEAN aIsTimer) { + if (aIsTimer) { + return; + } + + // The |watcher| was addref'ed when we registered the wait handle in + // ListenForLowMemory(). It is decremented when exiting the function, + // so please make sure we unregister the wait handle after this line. + RefPtr watcher = + already_AddRefed( + static_cast(aContext)); + + MutexAutoLock lock(watcher->mMutex); + if (watcher->mIsShutdown) { + // mWaitHandle should have been unregistered during shutdown + MOZ_ASSERT(!watcher->mWaitHandle); + return; + } + + ::UnregisterWait(watcher->mWaitHandle); + watcher->mWaitHandle = nullptr; + + // On Windows, memory allocations fails when the available commit space is + // not sufficient. It's possible that this callback function is invoked + // but there is still commit space enough for the application to continue + // to run. In such a case, there is no strong need to trigger the memory + // pressure event. So we trigger the event only when the available commit + // space is low. + if (IsCommitSpaceLow()) { + watcher->OnLowMemory(lock); + } else { + // Since we have unregistered the callback, we need to start a timer to + // continue watching memory. + watcher->StartPollingIfUserInteracting(lock); + } +} + +// static +void nsAvailableMemoryWatcher::RecordLowMemoryEvent() { + sNumLowPhysicalMemEvents++; + CrashReporter::AnnotateCrashReport( + CrashReporter::Annotation::LowPhysicalMemoryEvents, + sNumLowPhysicalMemEvents); +} + +bool nsAvailableMemoryWatcher::RegisterMemoryResourceHandler( + const MutexAutoLock& aLock) { + mLowMemoryHandle.own( + ::CreateMemoryResourceNotification(LowMemoryResourceNotification)); + + if (!mLowMemoryHandle) { + return false; + } + + return ListenForLowMemory(aLock); +} + +void nsAvailableMemoryWatcher::UnregisterMemoryResourceHandler( + const MutexAutoLock&) { + if (mWaitHandle) { + bool res = ::UnregisterWait(mWaitHandle); + if (res || ::GetLastError() != ERROR_IO_PENDING) { + // We decrement the refcount only when we're sure the LowMemoryCallback() + // callback won't be invoked, otherwise the callback will do it + this->Release(); + } + mWaitHandle = nullptr; + } + + mLowMemoryHandle.reset(); +} + +void nsAvailableMemoryWatcher::Shutdown(const MutexAutoLock& aLock) { + mIsShutdown = true; + mNeedToRestartTimerOnUserInteracting = false; + + if (mTimer) { + mTimer->Cancel(); + mTimer = nullptr; + } + + UnregisterMemoryResourceHandler(aLock); +} + +bool nsAvailableMemoryWatcher::ListenForLowMemory(const MutexAutoLock&) { + if (mLowMemoryHandle && !mWaitHandle) { + // We're giving ownership of this object to the LowMemoryCallback(). We + // increment the count here so that the object is kept alive until the + // callback decrements it. + this->AddRef(); + bool res = ::RegisterWaitForSingleObject( + &mWaitHandle, mLowMemoryHandle, LowMemoryCallback, this, INFINITE, + WT_EXECUTEDEFAULT | WT_EXECUTEONLYONCE); + if (!res) { + // We couldn't register the callback, decrement the count + this->Release(); + } + // Once we register the wait handle, we no longer need to start + // the timer because we can continue watching memory via callback. + mNeedToRestartTimerOnUserInteracting = false; + return res; + } + + return false; +} + +void nsAvailableMemoryWatcher::MaybeSaveMemoryReport(const MutexAutoLock&) { + if (mSavedReport) { + return; + } + + if (nsCOMPtr cr = + do_GetService("@mozilla.org/toolkit/crash-reporter;1")) { + mSavedReport = NS_SUCCEEDED(cr->SaveMemoryReport()); + } +} + +void nsAvailableMemoryWatcher::OnLowMemory(const MutexAutoLock& aLock) { + mUnderMemoryPressure = true; + RecordLowMemoryEvent(); + + if (NS_IsMainThread()) { + MaybeSaveMemoryReport(aLock); + UpdateLowMemoryTimeStamp(); + { + // Don't invoke UnloadTabAsync() with the lock to avoid deadlock + // because nsAvailableMemoryWatcher::Notify may be invoked while + // running the method. + MutexAutoUnlock unlock(mMutex); + mTabUnloader->UnloadTabAsync(); + } + } else { + // SaveMemoryReport and mTabUnloader needs to be run in the main thread + // (See nsMemoryReporterManager::GetReportsForThisProcessExtended) + NS_DispatchToMainThread(NS_NewRunnableFunction( + "nsAvailableMemoryWatcher::OnLowMemory", [self = RefPtr{this}]() { + { + MutexAutoLock lock(self->mMutex); + self->MaybeSaveMemoryReport(lock); + self->UpdateLowMemoryTimeStamp(); + } + self->mTabUnloader->UnloadTabAsync(); + })); + } + + StartPollingIfUserInteracting(aLock); +} + +void nsAvailableMemoryWatcher::OnHighMemory(const MutexAutoLock& aLock) { + MOZ_ASSERT(NS_IsMainThread()); + + if (mUnderMemoryPressure) { + RecordTelemetryEventOnHighMemory(); + NS_NotifyOfEventualMemoryPressure(MemoryPressureState::NoPressure); + } + + mUnderMemoryPressure = false; + mSavedReport = false; // Will save a new report if memory gets low again + StopPolling(aLock); + ListenForLowMemory(aLock); +} + +// static +bool nsAvailableMemoryWatcher::IsCommitSpaceLow() { + // Other options to get the available page file size: + // - GetPerformanceInfo + // Too slow, don't use it. + // - PdhCollectQueryData and PdhGetRawCounterValue + // Faster than GetPerformanceInfo, but slower than GlobalMemoryStatusEx. + // - NtQuerySystemInformation(SystemMemoryUsageInformation) + // Faster than GlobalMemoryStatusEx, but undocumented. + MEMORYSTATUSEX memStatus = {sizeof(memStatus)}; + if (!::GlobalMemoryStatusEx(&memStatus)) { + return false; + } + + constexpr size_t kBytesPerMB = 1024 * 1024; + return (memStatus.ullAvailPageFile / kBytesPerMB) < + StaticPrefs::browser_low_commit_space_threshold_mb(); +} + +void nsAvailableMemoryWatcher::StartPollingIfUserInteracting( + const MutexAutoLock&) { + // When the user is inactive, we mark the flag to delay-start + // the timer when the user becomes active later. + mNeedToRestartTimerOnUserInteracting = true; + + if (mInteracting && !mPolling) { + if (NS_SUCCEEDED(mTimer->InitWithCallback( + this, mPollingInterval, nsITimer::TYPE_REPEATING_SLACK))) { + mPolling = true; + } + } +} + +void nsAvailableMemoryWatcher::StopPolling(const MutexAutoLock&) { + mTimer->Cancel(); + mPolling = false; +} + +void nsAvailableMemoryWatcher::StopPollingIfUserIdle( + const MutexAutoLock& aLock) { + if (!mInteracting) { + StopPolling(aLock); + } +} + +void nsAvailableMemoryWatcher::OnUserInteracting(const MutexAutoLock& aLock) { + if (mNeedToRestartTimerOnUserInteracting) { + StartPollingIfUserInteracting(aLock); + } +} + +// Timer callback, polls the low memory resource notification to detect when +// we've freed enough memory or if we have to send more memory pressure events. +// Polling stops automatically when the user is not interacting with the UI. +NS_IMETHODIMP +nsAvailableMemoryWatcher::Notify(nsITimer* aTimer) { + MutexAutoLock lock(mMutex); + StopPollingIfUserIdle(lock); + + if (IsCommitSpaceLow()) { + OnLowMemory(lock); + } else { + OnHighMemory(lock); + } + + return NS_OK; +} + +NS_IMETHODIMP +nsAvailableMemoryWatcher::GetName(nsACString& aName) { + aName.AssignLiteral("nsAvailableMemoryWatcher"); + return NS_OK; +} + +// Observer service callback, used to stop the polling timer when the user +// stops interacting with Firefox and resuming it when they interact again. +// Also used to shut down the service if the application is quitting. +NS_IMETHODIMP +nsAvailableMemoryWatcher::Observe(nsISupports* aSubject, const char* aTopic, + const char16_t* aData) { + nsresult rv = nsAvailableMemoryWatcherBase::Observe(aSubject, aTopic, aData); + if (NS_FAILED(rv)) { + return rv; + } + + MutexAutoLock lock(mMutex); + + if (strcmp(aTopic, "xpcom-shutdown") == 0) { + Shutdown(lock); + } else if (strcmp(aTopic, "user-interaction-active") == 0) { + OnUserInteracting(lock); + } + + return NS_OK; +} + +already_AddRefed CreateAvailableMemoryWatcher() { + RefPtr watcher(new nsAvailableMemoryWatcher); + if (NS_FAILED(watcher->Init())) { + return do_AddRef(new nsAvailableMemoryWatcherBase); // fallback + } + return watcher.forget(); +} + +} // namespace mozilla -- cgit v1.2.3