Bug 970307: Part 2: Let Nuwa wait for all tasks of preload slow things to finish. r=cyu

dom/ipc/ContentChild.cpp

@@ -1243,7 +1243,6 @@ ContentChild::RecvPBrowserConstructor(PBrowserChild* aActor,
 {
     // This runs after AllocPBrowserChild() returns and the IPC machinery for this
     // PBrowserChild has been set up.
-
     nsCOMPtr<nsIObserverService> os = services::GetObserverService();
     if (os) {
         nsITabChild* tc =
@@ -1991,8 +1990,11 @@ bool
 ContentChild::RecvFlushMemory(const nsString& reason)
 {
 #ifdef MOZ_NUWA_PROCESS
-    if (IsNuwaProcess()) {
+    if (IsNuwaProcess() || ManagedPBrowserChild().Length() == 0) {
         // Don't flush memory in the nuwa process: the GC thread could be frozen.
+        // If there's no PBrowser child, don't flush memory, either. GC writes
+        // to copy-on-write pages and makes preallocated process take more memory
+        // before it actually becomes an app.
         return true;
     }
 #endif
@@ -2080,12 +2082,25 @@ ContentChild::RecvAppInfo(const nsCString& version, const nsCString& buildID,
     // BrowserElementChild.js.
     if ((mIsForApp || mIsForBrowser)
 #ifdef MOZ_NUWA_PROCESS
-        && !IsNuwaProcess()
+        && IsNuwaProcess()
 #endif
        ) {
         PreloadSlowThings();
     }
 
+#ifdef MOZ_NUWA_PROCESS
+    // Some modules are initialized in preloading. We need to wait until the
+    // tasks they dispatched to chrome process are done.
+    if (IsNuwaProcess()) {
+        SendNuwaWaitForFreeze();
+    }
+#endif
+    return true;
+}
+
+bool
+ContentChild::RecvNuwaFreeze()
+{
 #ifdef MOZ_NUWA_PROCESS
     if (IsNuwaProcess()) {
         ContentChild::GetSingleton()->RecvGarbageCollect();
@@ -2093,7 +2108,6 @@ ContentChild::RecvAppInfo(const nsCString& version, const nsCString& buildID,
             FROM_HERE, NewRunnableFunction(OnFinishNuwaPreparation));
     }
 #endif
-
     return true;
 }
 
@@ -2344,6 +2358,36 @@ RunNuwaFork()
       DoNuwaFork();
     }
 }
+
+class NuwaForkCaller: public nsRunnable
+{
+public:
+    NS_IMETHODIMP
+    Run() {
+        // We want to ensure that the PBackground actor gets cloned in the Nuwa
+        // process before we freeze. Also, we have to do this to avoid deadlock.
+        // Protocols that are "opened" (e.g. PBackground, PCompositor) block the
+        // main thread to wait for the IPC thread during the open operation.
+        // NuwaSpawnWait() blocks the IPC thread to wait for the main thread when
+        // the Nuwa process is forked. Unless we ensure that the two cannot happen
+        // at the same time then we risk deadlock. Spinning the event loop here
+        // guarantees the ordering is safe for PBackground.
+        if (!BackgroundChild::GetForCurrentThread()) {
+            // Dispatch ourself again.
+            NS_DispatchToMainThread(this, NS_DISPATCH_NORMAL);
+        } else {
+            MessageLoop* ioloop = XRE_GetIOMessageLoop();
+            ioloop->PostTask(FROM_HERE, NewRunnableFunction(RunNuwaFork));
+        }
+        return NS_OK;
+    }
+private:
+    virtual
+    ~NuwaForkCaller()
+    {
+    }
+};
+
 #endif
 
 bool
@@ -2355,22 +2399,9 @@ ContentChild::RecvNuwaFork()
     }
     sNuwaForking = true;
 
-    // We want to ensure that the PBackground actor gets cloned in the Nuwa
-    // process before we freeze. Also, we have to do this to avoid deadlock.
-    // Protocols that are "opened" (e.g. PBackground, PCompositor) block the
-    // main thread to wait for the IPC thread during the open operation.
-    // NuwaSpawnWait() blocks the IPC thread to wait for the main thread when
-    // the Nuwa process is forked. Unless we ensure that the two cannot happen
-    // at the same time then we risk deadlock. Spinning the event loop here
-    // guarantees the ordering is safe for PBackground.
-    while (!BackgroundChild::GetForCurrentThread()) {
-        if (NS_WARN_IF(!NS_ProcessNextEvent())) {
-            return false;
-        }
-    }
+    nsRefPtr<NuwaForkCaller> runnable = new NuwaForkCaller();
+    NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL);
 
-    MessageLoop* ioloop = XRE_GetIOMessageLoop();
-    ioloop->PostTask(FROM_HERE, NewRunnableFunction(RunNuwaFork));
     return true;
 #else
     return false; // Makes the underlying IPC channel abort.

dom/ipc/ContentChild.h

@@ -350,6 +350,8 @@ public:
 
     virtual bool RecvNotifyPhoneStateChange(const nsString& state) MOZ_OVERRIDE;
 
+    virtual bool RecvNuwaFreeze() MOZ_OVERRIDE;
+
     void AddIdleObserver(nsIObserver* aObserver, uint32_t aIdleTimeInS);
     void RemoveIdleObserver(nsIObserver* aObserver, uint32_t aIdleTimeInS);
     virtual bool RecvNotifyIdleObserver(const uint64_t& aObserver,

dom/ipc/ContentParent.cpp

@@ -124,6 +124,7 @@
 #include "nsServiceManagerUtils.h"
 #include "nsStyleSheetService.h"
 #include "nsThreadUtils.h"
+#include "nsThreadManager.h"
 #include "nsToolkitCompsCID.h"
 #include "nsWidgetsCID.h"
 #include "PreallocatedProcessManager.h"
@@ -1372,6 +1373,28 @@ StaticAutoPtr<LinkedList<SystemMessageHandledListener> >
 NS_IMPL_ISUPPORTS(SystemMessageHandledListener,
                   nsITimerCallback)
 
+#ifdef MOZ_NUWA_PROCESS
+class NuwaFreezeListener : public nsThreadManager::AllThreadsWereIdleListener
+{
+public:
+    NuwaFreezeListener(ContentParent* parent)
+        : mParent(parent)
+    {
+    }
+
+    void OnAllThreadsWereIdle()
+    {
+        unused << mParent->SendNuwaFreeze();
+        nsThreadManager::get()->RemoveAllThreadsWereIdleListener(this);
+    }
+private:
+    nsRefPtr<ContentParent> mParent;
+    virtual ~NuwaFreezeListener()
+    {
+    }
+};
+#endif // MOZ_NUWA_PROCESS
+
 } // anonymous namespace
 
 void
@@ -2062,6 +2085,8 @@ ContentParent::ContentParent(ContentParent* aTemplate,
         priority = PROCESS_PRIORITY_FOREGROUND;
     }
 
+    mSendPermissionUpdates = aTemplate->mSendPermissionUpdates;
+
     InitInternal(priority,
                  false, /* Setup Off-main thread compositing */
                  false  /* Send registered chrome */);
@@ -2219,7 +2244,7 @@ ContentParent::IsForApp()
 
 #ifdef MOZ_NUWA_PROCESS
 bool
-ContentParent::IsNuwaProcess()
+ContentParent::IsNuwaProcess() const
 {
     return mIsNuwaProcess;
 }
@@ -2568,6 +2593,19 @@ ContentParent::RecvNuwaReady()
 #endif
 }
 
+bool
+ContentParent::RecvNuwaWaitForFreeze()
+{
+#ifdef MOZ_NUWA_PROCESS
+    nsRefPtr<NuwaFreezeListener> listener = new NuwaFreezeListener(this);
+    nsThreadManager::get()->AddAllThreadsWereIdleListener(listener);
+    return true;
+#else // MOZ_NUWA_PROCESS
+    NS_ERROR("ContentParent::RecvNuwaWaitForFreeze() not implemented!");
+    return false;
+#endif // MOZ_NUWA_PROCESS
+}
+
 bool
 ContentParent::RecvAddNewProcess(const uint32_t& aPid,
                                  const InfallibleTArray<ProtocolFdMapping>& aFds)

dom/ipc/ContentParent.h

@@ -206,7 +206,7 @@ public:
       return mIsForBrowser;
     }
 #ifdef MOZ_NUWA_PROCESS
-    bool IsNuwaProcess();
+    bool IsNuwaProcess() const;
 #endif
 
     GeckoChildProcessHost* Process() {
@@ -220,7 +220,11 @@ public:
     }
 
     bool NeedsPermissionsUpdate() const {
+#ifdef MOZ_NUWA_PROCESS
+        return !IsNuwaProcess() && mSendPermissionUpdates;
+#else
         return mSendPermissionUpdates;
+#endif
     }
 
     bool NeedsDataStoreInfos() const {
@@ -680,6 +684,8 @@ private:
 
     virtual bool RecvNuwaReady() MOZ_OVERRIDE;
 
+    virtual bool RecvNuwaWaitForFreeze() MOZ_OVERRIDE;
+
     virtual bool RecvAddNewProcess(const uint32_t& aPid,
                                    const InfallibleTArray<ProtocolFdMapping>& aFds) MOZ_OVERRIDE;
 

dom/ipc/PContent.ipdl

@@ -524,6 +524,7 @@ child:
     intr GetProfile()
       returns (nsCString aProfile);
 
+    NuwaFreeze();
 parent:
     /**
      * Tell the parent process a new accessible document has been created.
@@ -735,6 +736,9 @@ parent:
     async SystemMessageHandled();
 
     NuwaReady();
+    // Sent when nuwa finished its initialization process and is waiting for
+    // parent's signal to make it freeze.
+    NuwaWaitForFreeze();
 
     sync AddNewProcess(uint32_t pid, ProtocolFdMapping[] aFds);
 

dom/ipc/tests/test_NuwaProcessCreation.html

@@ -77,7 +77,7 @@ function runTest()
   let timeout = setTimeout(function() {
     ok(false, "Nuwa process is not launched");
     testEnd();
-  }, 60000);
+  }, 240000);
 
   function testEnd() {
     cpmm.removeMessageListener("TEST-ONLY:nuwa-ready", msgHandler);

dom/ipc/tests/test_NuwaProcessDeadlock.html

@@ -78,7 +78,7 @@ function runTest()
   let timeout = setTimeout(function() {
     ok(false, "Nuwa process is not launched");
     testEnd();
-  }, 90000);
+  }, 240000);
 
   function testEnd() {
     cpmm.removeMessageListener("TEST-ONLY:nuwa-ready", msgHandler);