diff --git a/cmds/system_server/library/system_init.cpp b/cmds/system_server/library/system_init.cpp
index 745c34a..3e52d30 100644
--- a/cmds/system_server/library/system_init.cpp
+++ b/cmds/system_server/library/system_init.cpp
@@ -94,12 +94,12 @@
     if (methodId == NULL) {
         return UNKNOWN_ERROR;
     }
-    env->CallStaticVoidMethod(clazz, methodId);
 
-    ALOGI("System server: entering thread pool.\n");
+    ALOGI("System server: entering thread pool.");
     ProcessState::self()->startThreadPool();
-    IPCThreadState::self()->joinThreadPool();
-    ALOGI("System server: exiting thread pool.\n");
+
+    // This is the main thread of the system server, and will never exit.
+    env->CallStaticVoidMethod(clazz, methodId);
 
     return NO_ERROR;
 }
diff --git a/core/java/android/os/Looper.java b/core/java/android/os/Looper.java
index d5cf771..78c859e 100644
--- a/core/java/android/os/Looper.java
+++ b/core/java/android/os/Looper.java
@@ -289,6 +289,16 @@
         return mQueue;
     }
 
+    /**
+     * Return whether this looper's thread is currently idle, waiting for new work
+     * to do.  This is intrinsically racy, since its state can change before you get
+     * the result back.
+     * @hide
+     */
+    public boolean isIdling() {
+        return mQueue.isIdling();
+    }
+
     public void dump(Printer pw, String prefix) {
         pw = PrefixPrinter.create(pw, prefix);
         pw.println(this.toString());
diff --git a/core/java/android/os/MessageQueue.java b/core/java/android/os/MessageQueue.java
index bf7e5ca..1e8983e 100644
--- a/core/java/android/os/MessageQueue.java
+++ b/core/java/android/os/MessageQueue.java
@@ -52,6 +52,7 @@
     private native static void nativeDestroy(int ptr);
     private native static void nativePollOnce(int ptr, int timeoutMillis);
     private native static void nativeWake(int ptr);
+    private native static boolean nativeIsIdling(int ptr);
 
     /**
      * Callback interface for discovering when a thread is going to block
@@ -379,6 +380,10 @@
         }
     }
 
+    boolean isIdling() {
+        return nativeIsIdling(mPtr);
+    }
+
     void removeMessages(Handler h, int what, Object object) {
         if (h == null) {
             return;
diff --git a/core/jni/android_os_MessageQueue.cpp b/core/jni/android_os_MessageQueue.cpp
index 7540645..c9c3720 100644
--- a/core/jni/android_os_MessageQueue.cpp
+++ b/core/jni/android_os_MessageQueue.cpp
@@ -141,6 +141,11 @@
     return nativeMessageQueue->wake();
 }
 
+static jboolean android_os_MessageQueue_nativeIsIdling(JNIEnv* env, jclass clazz, jint ptr) {
+    NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
+    return nativeMessageQueue->getLooper()->isIdling();
+}
+
 // ----------------------------------------------------------------------------
 
 static JNINativeMethod gMessageQueueMethods[] = {
@@ -148,7 +153,8 @@
     { "nativeInit", "()I", (void*)android_os_MessageQueue_nativeInit },
     { "nativeDestroy", "(I)V", (void*)android_os_MessageQueue_nativeDestroy },
     { "nativePollOnce", "(II)V", (void*)android_os_MessageQueue_nativePollOnce },
-    { "nativeWake", "(I)V", (void*)android_os_MessageQueue_nativeWake }
+    { "nativeWake", "(I)V", (void*)android_os_MessageQueue_nativeWake },
+    { "nativeIsIdling", "(I)Z", (void*)android_os_MessageQueue_nativeIsIdling }
 };
 
 #define FIND_CLASS(var, className) \
diff --git a/services/java/com/android/server/IoThread.java b/services/java/com/android/server/IoThread.java
index b443578..09f2af7 100644
--- a/services/java/com/android/server/IoThread.java
+++ b/services/java/com/android/server/IoThread.java
@@ -47,14 +47,14 @@
     }
 
     public static IoThread get() {
-        synchronized (UiThread.class) {
+        synchronized (IoThread.class) {
             ensureThreadLocked();
             return sInstance;
         }
     }
 
     public static Handler getHandler() {
-        synchronized (UiThread.class) {
+        synchronized (IoThread.class) {
             ensureThreadLocked();
             return sHandler;
         }
diff --git a/services/java/com/android/server/MountService.java b/services/java/com/android/server/MountService.java
index 1d1b6b9..7857d6c 100644
--- a/services/java/com/android/server/MountService.java
+++ b/services/java/com/android/server/MountService.java
@@ -37,6 +37,7 @@
 import android.os.Environment;
 import android.os.Environment.UserEnvironment;
 import android.os.Handler;
+import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.Looper;
 import android.os.Message;
@@ -1311,7 +1312,9 @@
         // XXX: This will go away soon in favor of IMountServiceObserver
         mPms = (PackageManagerService) ServiceManager.getService("package");
 
-        mHandler = new MountServiceHandler(IoThread.get().getLooper());
+        HandlerThread hthread = new HandlerThread(TAG);
+        hthread.start();
+        mHandler = new MountServiceHandler(hthread.getLooper());
 
         // Watch for user changes
         final IntentFilter userFilter = new IntentFilter();
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 89a6f60..7d7aeec 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -75,7 +75,7 @@
 import java.util.Timer;
 import java.util.TimerTask;
 
-class ServerThread extends Thread {
+class ServerThread {
     private static final String TAG = "SystemServer";
     private static final String ENCRYPTING_STATE = "trigger_restart_min_framework";
     private static final String ENCRYPTED_STATE = "1";
@@ -87,8 +87,7 @@
         Log.wtf(TAG, "BOOT FAILURE " + msg, e);
     }
 
-    @Override
-    public void run() {
+    public void initAndLoop() {
         EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_SYSTEM_RUN,
             SystemClock.uptimeMillis());
 
@@ -1119,8 +1118,10 @@
 
     public static final void init2() {
         Slog.i(TAG, "Entered the Android system server!");
-        Thread thr = new ServerThread();
-        thr.setName("android.server.ServerThread");
-        thr.start();
+
+        // This used to be its own separate thread, but now it is
+        // just the loop we run on the main thread.
+        ServerThread thr = new ServerThread();
+        thr.initAndLoop();
     }
 }
diff --git a/services/java/com/android/server/Watchdog.java b/services/java/com/android/server/Watchdog.java
index 551d9f6c7..7eedc2a 100644
--- a/services/java/com/android/server/Watchdog.java
+++ b/services/java/com/android/server/Watchdog.java
@@ -33,7 +33,6 @@
 import android.os.Debug;
 import android.os.Handler;
 import android.os.Looper;
-import android.os.Message;
 import android.os.Process;
 import android.os.ServiceManager;
 import android.os.SystemClock;
@@ -135,6 +134,16 @@
         }
 
         public void scheduleCheckLocked() {
+            if (!mCheckReboot && mMonitors.size() == 0 && mHandler.getLooper().isIdling()) {
+                // If the target looper is or just recently was idling, then
+                // there is no reason to enqueue our checker on it since that
+                // is as good as it not being deadlocked.  This avoid having
+                // to do a context switch to check the thread.  Note that we
+                // only do this if mCheckReboot is false and we have no
+                // monitors, since those would need to be executed at this point.
+                mCompleted = true;
+                return;
+            }
             mCompleted = false;
             mCurrentMonitor = null;
             mHandler.postAtFrontOfQueue(this);
diff --git a/services/java/com/android/server/usb/UsbDebuggingManager.java b/services/java/com/android/server/usb/UsbDebuggingManager.java
index ba3f1d1..ce953a4 100644
--- a/services/java/com/android/server/usb/UsbDebuggingManager.java
+++ b/services/java/com/android/server/usb/UsbDebuggingManager.java
@@ -161,7 +161,7 @@
 
                     mAdbEnabled = true;
 
-                    mThread = new Thread(UsbDebuggingManager.this, "UsbDebuggingManager");
+                    mThread = new Thread(UsbDebuggingManager.this, TAG);
                     mThread.start();
 
                     break;