diff --git a/core/java/com/android/internal/os/BinderInternal.java b/core/java/com/android/internal/os/BinderInternal.java
index eacf0ce..ba0bf0d 100644
--- a/core/java/com/android/internal/os/BinderInternal.java
+++ b/core/java/com/android/internal/os/BinderInternal.java
@@ -76,6 +76,13 @@
      */
     public static final native IBinder getContextObject();
     
+    /**
+     * Special for system process to not allow incoming calls to run at
+     * background scheduling priority.
+     * @hide
+     */
+    public static final native void disableBackgroundScheduling(boolean disable);
+    
     static native final void handleGc();
     
     public static void forceGc(String reason) {
diff --git a/core/jni/android_util_Binder.cpp b/core/jni/android_util_Binder.cpp
index f0885fd..627fcbf 100644
--- a/core/jni/android_util_Binder.cpp
+++ b/core/jni/android_util_Binder.cpp
@@ -670,6 +670,12 @@
     android::IPCThreadState::self()->joinThreadPool();
 }
 
+static void android_os_BinderInternal_disableBackgroundScheduling(JNIEnv* env,
+        jobject clazz, jboolean disable)
+{
+    IPCThreadState::disableBackgroundScheduling(disable ? true : false);
+}
+
 static void android_os_BinderInternal_handleGc(JNIEnv* env, jobject clazz)
 {
     LOGV("Gc has executed, clearing binder ops");
@@ -682,6 +688,7 @@
      /* name, signature, funcPtr */
     { "getContextObject", "()Landroid/os/IBinder;", (void*)android_os_BinderInternal_getContextObject },
     { "joinThreadPool", "()V", (void*)android_os_BinderInternal_joinThreadPool },
+    { "disableBackgroundScheduling", "(Z)V", (void*)android_os_BinderInternal_disableBackgroundScheduling },
     { "handleGc", "()V", (void*)android_os_BinderInternal_handleGc }
 };
 
diff --git a/core/jni/android_util_Process.cpp b/core/jni/android_util_Process.cpp
index 094b02d..e84f2e5 100644
--- a/core/jni/android_util_Process.cpp
+++ b/core/jni/android_util_Process.cpp
@@ -120,11 +120,7 @@
 
 jint android_os_Process_myTid(JNIEnv* env, jobject clazz)
 {
-#ifdef HAVE_GETTID
-    return gettid();
-#else
-    return getpid();
-#endif
+    return androidGetTid();
 }
 
 jint android_os_Process_getUidForName(JNIEnv* env, jobject clazz, jstring name)
@@ -191,15 +187,11 @@
 
 void android_os_Process_setThreadGroup(JNIEnv* env, jobject clazz, int pid, jint grp)
 {
-    if (grp > ANDROID_TGROUP_MAX || grp < 0) { 
-        signalExceptionForGroupError(env, clazz, EINVAL);
+    int res = androidSetThreadSchedulingGroup(pid, grp);
+    if (res != NO_ERROR) {
+        signalExceptionForGroupError(env, clazz, res == BAD_VALUE ? EINVAL : errno);
         return;
     }
-
-    if (set_sched_policy(pid, (grp == ANDROID_TGROUP_BG_NONINTERACT) ?
-                                      SP_BACKGROUND : SP_FOREGROUND)) {
-        signalExceptionForGroupError(env, clazz, errno);
-    }
 }
 
 void android_os_Process_setProcessGroup(JNIEnv* env, jobject clazz, int pid, jint grp) 
@@ -275,22 +267,15 @@
 void android_os_Process_setThreadPriority(JNIEnv* env, jobject clazz,
                                               jint pid, jint pri)
 {
-    int rc = 0;
-
-    if (pri >= ANDROID_PRIORITY_BACKGROUND) {
-        rc = set_sched_policy(pid, SP_BACKGROUND);
-    } else if (getpriority(PRIO_PROCESS, pid) >= ANDROID_PRIORITY_BACKGROUND) {
-        rc = set_sched_policy(pid, SP_FOREGROUND);
+    int rc = androidSetThreadPriority(pid, pri);
+    if (rc != 0) {
+        if (rc == INVALID_OPERATION) {
+            signalExceptionForPriorityError(env, clazz, errno);
+        } else {
+            signalExceptionForGroupError(env, clazz, errno);
+        }
     }
-
-    if (rc) {
-        signalExceptionForGroupError(env, clazz, errno);
-        return;
-    }
-
-    if (setpriority(PRIO_PROCESS, pid, pri) < 0) {
-        signalExceptionForPriorityError(env, clazz, errno);
-    }
+    
     //LOGI("Setting priority of %d: %d, getpriority returns %d\n",
     //     pid, pri, getpriority(PRIO_PROCESS, pid));
 }
diff --git a/include/binder/IBinder.h b/include/binder/IBinder.h
index 884b5c1..749a977 100644
--- a/include/binder/IBinder.h
+++ b/include/binder/IBinder.h
@@ -52,7 +52,7 @@
         DUMP_TRANSACTION        = B_PACK_CHARS('_','D','M','P'),
         INTERFACE_TRANSACTION   = B_PACK_CHARS('_', 'N', 'T', 'F'),
 
-        // Corresponds to tfOneWay -- an asynchronous call.
+        // Corresponds to TF_ONE_WAY -- an asynchronous call.
         FLAG_ONEWAY             = 0x00000001
     };
 
diff --git a/include/binder/IPCThreadState.h b/include/binder/IPCThreadState.h
index 78306b2..3ab985d 100644
--- a/include/binder/IPCThreadState.h
+++ b/include/binder/IPCThreadState.h
@@ -68,6 +68,13 @@
 
     static  void                shutdown();
     
+    // Call this to disable switching threads to background scheduling when
+    // receiving incoming IPC calls.  This is specifically here for the
+    // Android system process, since it expects to have background apps calling
+    // in to it but doesn't want to acquire locks in its services while in
+    // the background.
+    static  void                disableBackgroundScheduling(bool disable);
+    
 private:
                                 IPCThreadState();
                                 ~IPCThreadState();
@@ -93,9 +100,10 @@
                                            void* cookie);
     
     const   sp<ProcessState>    mProcess;
+    const   pid_t               mMyThreadId;
             Vector<BBinder*>    mPendingStrongDerefs;
             Vector<RefBase::weakref_type*> mPendingWeakDerefs;
-                                
+            
             Parcel              mIn;
             Parcel              mOut;
             status_t            mLastError;
diff --git a/include/utils/threads.h b/include/utils/threads.h
index 0fc533f..130d83c 100644
--- a/include/utils/threads.h
+++ b/include/utils/threads.h
@@ -124,6 +124,24 @@
 
 extern void androidSetCreateThreadFunc(android_create_thread_fn func);
 
+// ------------------------------------------------------------------
+// Extra functions working with raw pids.
+
+// Get pid for the current thread.
+extern pid_t androidGetTid();
+
+// Change the scheduling group of a particular thread.  The group
+// should be one of the ANDROID_TGROUP constants.  Returns BAD_VALUE if
+// grp is out of range, else another non-zero value with errno set if
+// the operation failed.
+extern int androidSetThreadSchedulingGroup(pid_t tid, int grp);
+
+// Change the priority AND scheduling group of a particular thread.  The priority
+// should be one of the ANDROID_PRIORITY constants.  Returns INVALID_OPERATION
+// if the priority set failed, else another value if just the group set failed;
+// in either case errno is set.
+extern int androidSetThreadPriority(pid_t tid, int prio);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index b2a7db8..473f580 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -292,6 +292,7 @@
 static bool gHaveTLS = false;
 static pthread_key_t gTLS = 0;
 static bool gShutdown = false;
+static bool gDisableBackgroundScheduling = false;
 
 IPCThreadState* IPCThreadState::self()
 {
@@ -332,6 +333,11 @@
     }
 }
 
+void IPCThreadState::disableBackgroundScheduling(bool disable)
+{
+    gDisableBackgroundScheduling = disable;
+}
+
 sp<ProcessState> IPCThreadState::process()
 {
     return mProcess;
@@ -386,6 +392,11 @@
 
     mOut.writeInt32(isMain ? BC_ENTER_LOOPER : BC_REGISTER_LOOPER);
     
+    // This thread may have been spawned by a thread that was in the background
+    // scheduling group, so first we will make sure it is in the default/foreground
+    // one to avoid performing an initial transaction in the background.
+    androidSetThreadSchedulingGroup(mMyThreadId, ANDROID_TGROUP_DEFAULT);
+        
     status_t result;
     do {
         int32_t cmd;
@@ -427,19 +438,13 @@
         }
         
         // After executing the command, ensure that the thread is returned to the
-        // default cgroup and priority before rejoining the pool.  This is a failsafe
-        // in case the command implementation failed to properly restore the thread's
-        // scheduling parameters upon completion.
-        int my_id;
-#ifdef HAVE_GETTID
-        my_id = gettid();
-#else
-        my_id = getpid();
-#endif
-        if (!set_sched_policy(my_id, SP_FOREGROUND)) {
-            // success; reset the priority as well
-            setpriority(PRIO_PROCESS, my_id, ANDROID_PRIORITY_NORMAL);
-        }
+        // default cgroup before rejoining the pool.  The driver takes care of
+        // restoring the priority, but doesn't do anything with cgroups so we
+        // need to take care of that here in userspace.  Note that we do make
+        // sure to go in the foreground after executing a transaction, but
+        // there are other callbacks into user code that could have changed
+        // our group so we want to make absolutely sure it is put back.
+        androidSetThreadSchedulingGroup(mMyThreadId, ANDROID_TGROUP_DEFAULT);
 
         // Let this thread exit the thread pool if it is no longer
         // needed and it is not the main process thread.
@@ -583,10 +588,10 @@
 }
 
 IPCThreadState::IPCThreadState()
-    : mProcess(ProcessState::self())
+    : mProcess(ProcessState::self()), mMyThreadId(androidGetTid())
 {
     pthread_setspecific(gTLS, this);
-        clearCaller();
+    clearCaller();
     mIn.setDataCapacity(256);
     mOut.setDataCapacity(256);
 }
@@ -930,6 +935,17 @@
             mCallingPid = tr.sender_pid;
             mCallingUid = tr.sender_euid;
             
+            bool doBackground = !gDisableBackgroundScheduling &&
+                    getpriority(PRIO_PROCESS, mMyThreadId)
+                            >= ANDROID_PRIORITY_BACKGROUND;
+            if (doBackground) {
+                // We have inherited a background priority from the caller.
+                // Ensure this thread is in the background scheduling class,
+                // since the driver won't modify scheduling classes for us.
+                androidSetThreadSchedulingGroup(mMyThreadId,
+                        ANDROID_TGROUP_BG_NONINTERACT);
+            }
+            
             //LOGI(">>>> TRANSACT from pid %d uid %d\n", mCallingPid, mCallingUid);
             
             Parcel reply;
@@ -967,6 +983,13 @@
             mCallingPid = origPid;
             mCallingUid = origUid;
             
+            if (doBackground) {
+                // We moved to the background scheduling group to execute
+                // this transaction, so now that we are done go back in the
+                // foreground.
+                androidSetThreadSchedulingGroup(mMyThreadId, ANDROID_TGROUP_DEFAULT);
+            }
+            
             IF_LOG_TRANSACTIONS() {
                 TextOutput::Bundle _b(alog);
                 alog << "BC_REPLY thr " << (void*)pthread_self() << " / obj "
diff --git a/libs/utils/Threads.cpp b/libs/utils/Threads.cpp
index ec3db09..6ca2603 100644
--- a/libs/utils/Threads.cpp
+++ b/libs/utils/Threads.cpp
@@ -20,6 +20,8 @@
 #include <utils/threads.h>
 #include <utils/Log.h>
 
+#include <cutils/sched_policy.h>
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <memory.h>
@@ -269,6 +271,53 @@
     gCreateThreadFn = func;
 }
 
+pid_t androidGetTid()
+{
+#ifdef HAVE_GETTID
+    return gettid();
+#else
+    return getpid();
+#endif
+}
+
+int androidSetThreadSchedulingGroup(pid_t tid, int grp)
+{
+    if (grp > ANDROID_TGROUP_MAX || grp < 0) { 
+        return BAD_VALUE;
+    }
+
+    if (set_sched_policy(tid, (grp == ANDROID_TGROUP_BG_NONINTERACT) ?
+                                      SP_BACKGROUND : SP_FOREGROUND)) {
+        return PERMISSION_DENIED;
+    }
+    
+    return NO_ERROR;
+}
+
+int androidSetThreadPriority(pid_t tid, int pri)
+{
+    int rc = 0;
+    int lasterr = 0;
+
+    if (pri >= ANDROID_PRIORITY_BACKGROUND) {
+        rc = set_sched_policy(tid, SP_BACKGROUND);
+    } else if (getpriority(PRIO_PROCESS, tid) >= ANDROID_PRIORITY_BACKGROUND) {
+        rc = set_sched_policy(tid, SP_FOREGROUND);
+    }
+
+    if (rc) {
+        lasterr = errno;
+    }
+
+    if (setpriority(PRIO_PROCESS, tid, pri) < 0) {
+        rc = INVALID_OPERATION;
+    } else {
+        errno = lasterr;
+    }
+    
+    return rc;
+}
+
 namespace android {
 
 /*
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 73f930d..214ecc1 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -18,6 +18,7 @@
 
 import com.android.server.am.ActivityManagerService;
 import com.android.server.status.StatusBarService;
+import com.android.internal.os.BinderInternal;
 import com.android.internal.os.SamplingProfilerIntegration;
 
 import dalvik.system.VMRuntime;
@@ -80,6 +81,8 @@
         android.os.Process.setThreadPriority(
                 android.os.Process.THREAD_PRIORITY_FOREGROUND);
 
+        BinderInternal.disableBackgroundScheduling(true);
+        
         String factoryTestStr = SystemProperties.get("ro.factorytest");
         int factoryTest = "".equals(factoryTestStr) ? SystemServer.FACTORY_TEST_OFF
                 : Integer.parseInt(factoryTestStr);