The Tor Browser: dom/ipc/PreallocatedProcessManager.cpp@b8a032363ba2 (annotated)

dom/ipc/PreallocatedProcessManager.cpp@b8a032363ba2 (annotated)

dom/ipc/PreallocatedProcessManager.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set sw=2 ts=8 et ft=cpp : */
 /* 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 "mozilla/PreallocatedProcessManager.h"
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/dom/ContentParent.h"
 #include "nsIPropertyBag2.h"
 #include "ProcessPriorityManager.h"
 #include "nsServiceManagerUtils.h"
 #include "nsCxPusher.h"
 #ifdef MOZ_NUWA_PROCESS
 #include "ipc/Nuwa.h"
 #endif
 // This number is fairly arbitrary ... the intention is to put off
 // launching another app process until the last one has finished
 // loading its content, to reduce CPU/memory/IO contention.
 #define DEFAULT_ALLOCATE_DELAY 1000
 #define NUWA_FORK_WAIT_DURATION_MS 2000 // 2 seconds.
 using namespace mozilla;
 using namespace mozilla::hal;
 using namespace mozilla::dom;
 namespace {
 /**
  * This singleton class implements the static methods on
  * PreallocatedProcessManager.
  */
 class PreallocatedProcessManagerImpl MOZ_FINAL
   : public nsIObserver
 {
 public:
   static PreallocatedProcessManagerImpl* Singleton();
   NS_DECL_ISUPPORTS
   NS_DECL_NSIOBSERVER
   // See comments on PreallocatedProcessManager for these methods.
   void AllocateAfterDelay();
   void AllocateOnIdle();
   void AllocateNow();
   already_AddRefed<ContentParent> Take();
 #ifdef MOZ_NUWA_PROCESS
 public:
   void ScheduleDelayedNuwaFork();
   void DelayedNuwaFork();
   void PublishSpareProcess(ContentParent* aContent);
   void MaybeForgetSpare(ContentParent* aContent);
   void OnNuwaReady();
   bool PreallocatedProcessReady();
   already_AddRefed<ContentParent> GetSpareProcess();
   void RunAfterPreallocatedProcessReady(nsIRunnable* aRunnable);
 private:
   void NuwaFork();
   // initialization off the critical path of app startup.
   CancelableTask* mPreallocateAppProcessTask;
   // The array containing the preallocated processes. 4 as the inline storage size
   // should be enough so we don't need to grow the nsAutoTArray.
   nsAutoTArray<nsRefPtr<ContentParent>, 4> mSpareProcesses;
   nsTArray<nsCOMPtr<nsIRunnable> > mDelayedContentParentRequests;
   // Nuwa process is ready for creating new process.
   bool mIsNuwaReady;
 #endif
 private:
   static mozilla::StaticRefPtr<PreallocatedProcessManagerImpl> sSingleton;
   PreallocatedProcessManagerImpl();
   DISALLOW_EVIL_CONSTRUCTORS(PreallocatedProcessManagerImpl);
   void Init();
   void RereadPrefs();
   void Enable();
   void Disable();
   void ObserveProcessShutdown(nsISupports* aSubject);
   bool mEnabled;
   bool mShutdown;
   nsRefPtr<ContentParent> mPreallocatedAppProcess;
 };
 /* static */ StaticRefPtr<PreallocatedProcessManagerImpl>
 PreallocatedProcessManagerImpl::sSingleton;
 /* static */ PreallocatedProcessManagerImpl*
 PreallocatedProcessManagerImpl::Singleton()
 {
   if (!sSingleton) {
     sSingleton = new PreallocatedProcessManagerImpl();
     sSingleton->Init();
     ClearOnShutdown(&sSingleton);
   }
   return sSingleton;
 }
 NS_IMPL_ISUPPORTS(PreallocatedProcessManagerImpl, nsIObserver)
 PreallocatedProcessManagerImpl::PreallocatedProcessManagerImpl()
   : mEnabled(false)
 #ifdef MOZ_NUWA_PROCESS
   , mPreallocateAppProcessTask(nullptr)
   , mIsNuwaReady(false)
 #endif
   , mShutdown(false)
 {}
 void
 PreallocatedProcessManagerImpl::Init()
 {
   Preferences::AddStrongObserver(this, "dom.ipc.processPrelaunch.enabled");
   nsCOMPtr<nsIObserverService> os = services::GetObserverService();
   if (os) {
     os->AddObserver(this, "ipc:content-shutdown",
                     /* weakRef = */ false);
     os->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID,
                     /* weakRef = */ false);
   }
   RereadPrefs();
 }
 NS_IMETHODIMP
 PreallocatedProcessManagerImpl::Observe(nsISupports* aSubject,
                                         const char* aTopic,
                                         const char16_t* aData)
 {
   if (!strcmp("ipc:content-shutdown", aTopic)) {
     ObserveProcessShutdown(aSubject);
   } else if (!strcmp("nsPref:changed", aTopic)) {
     // The only other observer we registered was for our prefs.
     RereadPrefs();
   } else if (!strcmp(NS_XPCOM_SHUTDOWN_OBSERVER_ID, aTopic)) {
     mShutdown = true;
   } else {
     MOZ_ASSERT(false);
   }
   return NS_OK;
 }
 void
 PreallocatedProcessManagerImpl::RereadPrefs()
 {
   if (Preferences::GetBool("dom.ipc.processPrelaunch.enabled")) {
     Enable();
   } else {
     Disable();
   }
 }
 already_AddRefed<ContentParent>
 PreallocatedProcessManagerImpl::Take()
 {
   return mPreallocatedAppProcess.forget();
 }
 void
 PreallocatedProcessManagerImpl::Enable()
 {
   if (mEnabled) {
     return;
   }
   mEnabled = true;
 #ifdef MOZ_NUWA_PROCESS
   ScheduleDelayedNuwaFork();
 #else
   AllocateAfterDelay();
 #endif
 }
 void
 PreallocatedProcessManagerImpl::AllocateAfterDelay()
 {
   if (!mEnabled || mPreallocatedAppProcess) {
     return;
   }
   MessageLoop::current()->PostDelayedTask(
     FROM_HERE,
     NewRunnableMethod(this, &PreallocatedProcessManagerImpl::AllocateOnIdle),
     Preferences::GetUint("dom.ipc.processPrelaunch.delayMs",
                          DEFAULT_ALLOCATE_DELAY));
 }
 void
 PreallocatedProcessManagerImpl::AllocateOnIdle()
 {
   if (!mEnabled || mPreallocatedAppProcess) {
     return;
   }
   MessageLoop::current()->PostIdleTask(
     FROM_HERE,
     NewRunnableMethod(this, &PreallocatedProcessManagerImpl::AllocateNow));
 }
 void
 PreallocatedProcessManagerImpl::AllocateNow()
 {
   if (!mEnabled || mPreallocatedAppProcess) {
     return;
   }
   mPreallocatedAppProcess = ContentParent::PreallocateAppProcess();
 }
 #ifdef MOZ_NUWA_PROCESS
 void
 PreallocatedProcessManagerImpl::RunAfterPreallocatedProcessReady(nsIRunnable* aRequest)
 {
   MOZ_ASSERT(NS_IsMainThread());
   mDelayedContentParentRequests.AppendElement(aRequest);
   // This is an urgent NuwaFork() request. Request to fork at once.
   DelayedNuwaFork();
 }
 void
 PreallocatedProcessManagerImpl::ScheduleDelayedNuwaFork()
 {
   MOZ_ASSERT(NS_IsMainThread());
   if (mPreallocateAppProcessTask) {
     // Make sure there is only one request running.
     return;
   }
   mPreallocateAppProcessTask = NewRunnableMethod(
     this, &PreallocatedProcessManagerImpl::DelayedNuwaFork);
   MessageLoop::current()->PostDelayedTask(
     FROM_HERE, mPreallocateAppProcessTask,
     Preferences::GetUint("dom.ipc.processPrelaunch.delayMs",
                          DEFAULT_ALLOCATE_DELAY));
 }
 void
 PreallocatedProcessManagerImpl::DelayedNuwaFork()
 {
   MOZ_ASSERT(NS_IsMainThread());
   mPreallocateAppProcessTask = nullptr;
   if (!mIsNuwaReady) {
     if (!mPreallocatedAppProcess && !mShutdown && mEnabled) {
       mPreallocatedAppProcess = ContentParent::RunNuwaProcess();
     }
     // else mPreallocatedAppProcess is starting. It will NuwaFork() when ready.
   } else if (mSpareProcesses.IsEmpty()) {
     NuwaFork();
   }
 }
 /**
  * Get a spare ContentParent from mSpareProcesses list.
  */
 already_AddRefed<ContentParent>
 PreallocatedProcessManagerImpl::GetSpareProcess()
 {
   MOZ_ASSERT(NS_IsMainThread());
   if (mSpareProcesses.IsEmpty()) {
     return nullptr;
   }
   nsRefPtr<ContentParent> process = mSpareProcesses.LastElement();
   mSpareProcesses.RemoveElementAt(mSpareProcesses.Length() - 1);
   if (mSpareProcesses.IsEmpty() && mIsNuwaReady) {
     NS_ASSERTION(mPreallocatedAppProcess != nullptr,
                  "Nuwa process is not present!");
     ScheduleDelayedNuwaFork();
   }
   return process.forget();
 }
 /**
  * Publish a ContentParent to spare process list.
  */
 void
 PreallocatedProcessManagerImpl::PublishSpareProcess(ContentParent* aContent)
 {
   MOZ_ASSERT(NS_IsMainThread());
   if (Preferences::GetBool("dom.ipc.processPriorityManager.testMode")) {
     AutoJSContext cx;
     nsCOMPtr<nsIMessageBroadcaster> ppmm =
       do_GetService("@mozilla.org/parentprocessmessagemanager;1");
     nsresult rv = ppmm->BroadcastAsyncMessage(
       NS_LITERAL_STRING("TEST-ONLY:nuwa-add-new-process"),
       JS::NullHandleValue, JS::NullHandleValue, cx, 1);
   }
   mSpareProcesses.AppendElement(aContent);
   if (!mDelayedContentParentRequests.IsEmpty()) {
     nsCOMPtr<nsIRunnable> runnable = mDelayedContentParentRequests[0];
     mDelayedContentParentRequests.RemoveElementAt(0);
     NS_DispatchToMainThread(runnable);
   }
 }
 void
 PreallocatedProcessManagerImpl::MaybeForgetSpare(ContentParent* aContent)
 {
   MOZ_ASSERT(NS_IsMainThread());
   if (!mDelayedContentParentRequests.IsEmpty()) {
     if (!mPreallocateAppProcessTask) {
       // This NuwaFork request is urgent. Don't delay it.
       DelayedNuwaFork();
     }
   }
   if (mSpareProcesses.RemoveElement(aContent)) {
     return;
   }
   if (aContent == mPreallocatedAppProcess) {
     mPreallocatedAppProcess = nullptr;
     mIsNuwaReady = false;
     ScheduleDelayedNuwaFork();
   }
 }
 void
 PreallocatedProcessManagerImpl::OnNuwaReady()
 {
   NS_ASSERTION(!mIsNuwaReady, "Multiple Nuwa processes created!");
   ProcessPriorityManager::SetProcessPriority(mPreallocatedAppProcess,
                                              hal::PROCESS_PRIORITY_MASTER);
   mIsNuwaReady = true;
   if (Preferences::GetBool("dom.ipc.processPriorityManager.testMode")) {
     AutoJSContext cx;
     nsCOMPtr<nsIMessageBroadcaster> ppmm =
       do_GetService("@mozilla.org/parentprocessmessagemanager;1");
     nsresult rv = ppmm->BroadcastAsyncMessage(
       NS_LITERAL_STRING("TEST-ONLY:nuwa-ready"),
       JS::NullHandleValue, JS::NullHandleValue, cx, 1);
   }
   NuwaFork();
 }
 bool
 PreallocatedProcessManagerImpl::PreallocatedProcessReady()
 {
   return !mSpareProcesses.IsEmpty();
 }
 void
 PreallocatedProcessManagerImpl::NuwaFork()
 {
   mPreallocatedAppProcess->SendNuwaFork();
 }
 #endif
 void
 PreallocatedProcessManagerImpl::Disable()
 {
   if (!mEnabled) {
     return;
   }
   mEnabled = false;
 #ifdef MOZ_NUWA_PROCESS
   // Cancel pending fork.
   if (mPreallocateAppProcessTask) {
     mPreallocateAppProcessTask->Cancel();
     mPreallocateAppProcessTask = nullptr;
   }
 #endif
   if (mPreallocatedAppProcess) {
 #ifdef MOZ_NUWA_PROCESS
     while (mSpareProcesses.Length() > 0){
       nsRefPtr<ContentParent> process = mSpareProcesses[0];
       process->Close();
       mSpareProcesses.RemoveElementAt(0);
     }
     mIsNuwaReady = false;
 #endif
     mPreallocatedAppProcess->Close();
     mPreallocatedAppProcess = nullptr;
   }
 }
 void
 PreallocatedProcessManagerImpl::ObserveProcessShutdown(nsISupports* aSubject)
 {
   if (!mPreallocatedAppProcess) {
     return;
   }
   nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aSubject);
   NS_ENSURE_TRUE_VOID(props);
   uint64_t childID = CONTENT_PROCESS_ID_UNKNOWN;
   props->GetPropertyAsUint64(NS_LITERAL_STRING("childID"), &childID);
   NS_ENSURE_TRUE_VOID(childID != CONTENT_PROCESS_ID_UNKNOWN);
   if (childID == mPreallocatedAppProcess->ChildID()) {
     mPreallocatedAppProcess = nullptr;
   }
 }
 inline PreallocatedProcessManagerImpl* GetPPMImpl()
 {
   return PreallocatedProcessManagerImpl::Singleton();
 }
 } // anonymous namespace
 namespace mozilla {
 /* static */ void
 PreallocatedProcessManager::AllocateAfterDelay()
 {
 #ifdef MOZ_NUWA_PROCESS
   GetPPMImpl()->ScheduleDelayedNuwaFork();
 #else
   GetPPMImpl()->AllocateAfterDelay();
 #endif
 }
 /* static */ void
 PreallocatedProcessManager::AllocateOnIdle()
 {
   GetPPMImpl()->AllocateOnIdle();
 }
 /* static */ void
 PreallocatedProcessManager::AllocateNow()
 {
   GetPPMImpl()->AllocateNow();
 }
 /* static */ already_AddRefed<ContentParent>
 PreallocatedProcessManager::Take()
 {
 #ifdef MOZ_NUWA_PROCESS
   return GetPPMImpl()->GetSpareProcess();
 #else
   return GetPPMImpl()->Take();
 #endif
 }
 #ifdef MOZ_NUWA_PROCESS
 /* static */ void
 PreallocatedProcessManager::PublishSpareProcess(ContentParent* aContent)
 {
   GetPPMImpl()->PublishSpareProcess(aContent);
 }
 /* static */ void
 PreallocatedProcessManager::MaybeForgetSpare(ContentParent* aContent)
 {
   GetPPMImpl()->MaybeForgetSpare(aContent);
 }
 /* static */ void
 PreallocatedProcessManager::OnNuwaReady()
 {
   GetPPMImpl()->OnNuwaReady();
 }
 /*static */ bool
 PreallocatedProcessManager::PreallocatedProcessReady()
 {
   return GetPPMImpl()->PreallocatedProcessReady();
 }
 /* static */ void
 PreallocatedProcessManager::RunAfterPreallocatedProcessReady(nsIRunnable* aRequest)
 {
   GetPPMImpl()->RunAfterPreallocatedProcessReady(aRequest);
 }
 #endif
 } // namespace mozilla

The Tor Browser / annotate

dom/ipc/PreallocatedProcessManager.cpp@b8a032363ba2 (annotated)

dom/ipc/PreallocatedProcessManager.cpp