Adding am send-trim-memory command

This patch adds a send-trim-memory command to the ActivityManager to allow
for better debugging&testing.

The command is
adb shell am send-trim-memory [--user <USER_ID>] <PROCESS> <LEVEL>
whereas LEVEL can be one of the following:
[HIDDEN|RUNNING_MODERATE|BACKGROUND|RUNNING_LOW|MODERATE|
 RUNNING_CRITICAL|COMPLETE]

Bug: 21633189
Change-Id: I7a41ce02c3c9043ffd3e5aaa791f7b7306a9de49

5 files changed, 224 insertions, 98 deletions

diff --git a/cmds/am/src/com/android/commands/am/Am.java b/cmds/am/src/com/android/commands/am/Am.java
index 808e124..b0a7dc7 100644
--- a/cmds/am/src/com/android/commands/am/Am.java
+++ b/cmds/am/src/com/android/commands/am/Am.java
@@ -31,6 +31,7 @@ import android.app.UiAutomationConnection;
 import android.app.usage.ConfigurationStats;
 import android.app.usage.IUsageStatsManager;
 import android.app.usage.UsageStatsManager;
+import android.content.ComponentCallbacks2;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.IIntentReceiver;
@@ -144,6 +145,8 @@ public class Am extends BaseCommand {
                 "       am get-config\n" +
                 "       am set-inactive [--user <USER_ID>] <PACKAGE> true|false\n" +
                 "       am get-inactive [--user <USER_ID>] <PACKAGE>\n" +
+                "       am send-trim-memory [--user <USER_ID>] <PROCESS>\n" +
+                "               [HIDDEN|RUNNING_MODERATE|BACKGROUND|RUNNING_LOW|MODERATE|RUNNING_CRITICAL|COMPLETE]\n" +
                 "\n" +
                 "am start: start an Activity.  Options are:\n" +
                 "    -D: enable debugging\n" +
@@ -271,9 +274,9 @@ public class Am extends BaseCommand {
                 "\n" +
                 "am stack info: display the information about activity stack <STACK_ID>.\n" +
                 "\n" +
-                "am task lock: bring <TASK_ID> to the front and don't allow other tasks to run\n" +
+                "am task lock: bring <TASK_ID> to the front and don't allow other tasks to run.\n" +
                 "\n" +
-                "am task lock stop: end the current task lock\n" +
+                "am task lock stop: end the current task lock.\n" +
                 "\n" +
                 "am task resizeable: change if <TASK_ID> is resizeable (true) or not (false).\n" +
                 "\n" +
@@ -282,12 +285,13 @@ public class Am extends BaseCommand {
                 "   has the specified bounds.\n" +
                 "\n" +
                 "am get-config: retrieve the configuration and any recent configurations\n" +
-                "  of the device\n" +
+                "  of the device.\n" +
                 "\n" +
-                "am set-inactive: sets the inactive state of an app\n" +
+                "am set-inactive: sets the inactive state of an app.\n" +
                 "\n" +
-                "am get-inactive: returns the inactive state of an app\n" +
+                "am get-inactive: returns the inactive state of an app.\n" +
                 "\n" +
+                " am send-trim-memory: Send a memory trim event to a <PROCESS>.\n" +
                 "\n" +
                 "<INTENT> specifications include these flags and arguments:\n" +
                 "    [-a <ACTION>] [-d <DATA_URI>] [-t <MIME_TYPE>]\n" +
@@ -399,6 +403,8 @@ public class Am extends BaseCommand {
             runSetInactive();
         } else if (op.equals("get-inactive")) {
             runGetInactive();
+        } else if (op.equals("send-trim-memory")) {
+            runSendTrimMemory();
         } else {
             showError("Error: unknown command '" + op + "'");
         }
@@ -2070,6 +2076,57 @@ public class Am extends BaseCommand {
         System.out.println("Idle=" + isIdle);
     }
 
+    private void runSendTrimMemory() throws Exception {
+        int userId = UserHandle.USER_CURRENT;
+        String opt;
+        while ((opt = nextOption()) != null) {
+            if (opt.equals("--user")) {
+                userId = parseUserArg(nextArgRequired());
+                if (userId == UserHandle.USER_ALL) {
+                    System.err.println("Error: Can't use user 'all'");
+                    return;
+                }
+            } else {
+                System.err.println("Error: Unknown option: " + opt);
+                return;
+            }
+        }
+
+        String proc = nextArgRequired();
+        String levelArg = nextArgRequired();
+        int level;
+        switch (levelArg) {
+            case "HIDDEN":
+                level = ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN;
+                break;
+            case "RUNNING_MODERATE":
+                level = ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE;
+                break;
+            case "BACKGROUND":
+                level = ComponentCallbacks2.TRIM_MEMORY_BACKGROUND;
+                break;
+            case "RUNNING_LOW":
+                level = ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW;
+                break;
+            case "MODERATE":
+                level = ComponentCallbacks2.TRIM_MEMORY_MODERATE;
+                break;
+            case "RUNNING_CRITICAL":
+                level = ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL;
+                break;
+            case "COMPLETE":
+                level = ComponentCallbacks2.TRIM_MEMORY_COMPLETE;
+                break;
+            default:
+                System.err.println("Error: Unknown level option: " + levelArg);
+                return;
+        }
+        if (!mAm.setProcessMemoryTrimLevel(proc, userId, level)) {
+            System.err.println("Error: Failure to set the level - probably Unknown Process: " +
+                               proc);
+        }
+    }
+
     /**
      * Open the given file for sending into the system process. This verifies
      * with SELinux that the system will have access to the file.
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index edebc28..3892dd9 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -462,7 +462,7 @@ public class ActivityManager {
     public int getMemoryClass() {
         return staticGetMemoryClass();
     }
-    
+
     /** @hide */
     static public int staticGetMemoryClass() {
         // Really brain dead right now -- just take this from the configured
@@ -473,7 +473,7 @@ public class ActivityManager {
         }
         return staticGetLargeMemoryClass();
     }
-    
+
     /**
      * Return the approximate per-application memory class of the current
      * device when an application is running with a large heap.  This is the
@@ -490,7 +490,7 @@ public class ActivityManager {
     public int getLargeMemoryClass() {
         return staticGetLargeMemoryClass();
     }
-    
+
     /** @hide */
     static public int staticGetLargeMemoryClass() {
         // Really brain dead right now -- just take this from the configured
@@ -809,7 +809,7 @@ public class ActivityManager {
          * The true identifier of this task, valid even if it is not running.
          */
         public int persistentId;
-        
+
         /**
          * The original Intent used to launch the task.  You can use this
          * Intent to re-launch the task (if it is no longer running) or bring
@@ -1014,7 +1014,7 @@ public class ActivityManager {
      * user has started and the maximum number the system can remember.
      * @param flags Information about what to return.  May be any combination
      * of {@link #RECENT_WITH_EXCLUDED} and {@link #RECENT_IGNORE_UNAVAILABLE}.
-     * 
+     *
      * @return Returns a list of RecentTaskInfo records describing each of
      * the recent tasks.
      */
@@ -1146,7 +1146,7 @@ public class ActivityManager {
             numActivities = source.readInt();
             numRunning = source.readInt();
         }
-        
+
         public static final Creator<RunningTaskInfo> CREATOR = new Creator<RunningTaskInfo>() {
             public RunningTaskInfo createFromParcel(Parcel source) {
                 return new RunningTaskInfo(source);
@@ -1469,100 +1469,100 @@ public class ActivityManager {
          * If non-zero, this is the process the service is running in.
          */
         public int pid;
-        
+
         /**
          * The UID that owns this service.
          */
         public int uid;
-        
+
         /**
          * The name of the process this service runs in.
          */
         public String process;
-        
+
         /**
          * Set to true if the service has asked to run as a foreground process.
          */
         public boolean foreground;
-        
+
         /**
          * The time when the service was first made active, either by someone
          * starting or binding to it.  This
          * is in units of {@link android.os.SystemClock#elapsedRealtime()}.
          */
         public long activeSince;
-        
+
         /**
          * Set to true if this service has been explicitly started.
          */
         public boolean started;
-        
+
         /**
          * Number of clients connected to the service.
          */
         public int clientCount;
-        
+
         /**
          * Number of times the service's process has crashed while the service
          * is running.
          */
         public int crashCount;
-        
+
         /**
          * The time when there was last activity in the service (either
          * explicit requests to start it or clients binding to it).  This
          * is in units of {@link android.os.SystemClock#uptimeMillis()}.
          */
         public long lastActivityTime;
-        
+
         /**
          * If non-zero, this service is not currently running, but scheduled to
          * restart at the given time.
          */
         public long restarting;
-        
+
         /**
          * Bit for {@link #flags}: set if this service has been
          * explicitly started.
          */
         public static final int FLAG_STARTED = 1<<0;
-        
+
         /**
          * Bit for {@link #flags}: set if the service has asked to
          * run as a foreground process.
          */
         public static final int FLAG_FOREGROUND = 1<<1;
-        
+
         /**
          * Bit for {@link #flags): set if the service is running in a
          * core system process.
          */
         public static final int FLAG_SYSTEM_PROCESS = 1<<2;
-        
+
         /**
          * Bit for {@link #flags): set if the service is running in a
          * persistent process.
          */
         public static final int FLAG_PERSISTENT_PROCESS = 1<<3;
-        
+
         /**
          * Running flags.
          */
         public int flags;
-        
+
         /**
          * For special services that are bound to by system code, this is
          * the package that holds the binding.
          */
         public String clientPackage;
-        
+
         /**
          * For special services that are bound to by system code, this is
          * a string resource providing a user-visible label for who the
          * client is.
          */
         public int clientLabel;
-        
+
         public RunningServiceInfo() {
         }
 
@@ -1603,7 +1603,7 @@ public class ActivityManager {
             clientPackage = source.readString();
             clientLabel = source.readInt();
         }
-        
+
         public static final Creator<RunningServiceInfo> CREATOR = new Creator<RunningServiceInfo>() {
             public RunningServiceInfo createFromParcel(Parcel source) {
                 return new RunningServiceInfo(source);
@@ -1627,7 +1627,7 @@ public class ActivityManager {
      * @param maxNum The maximum number of entries to return in the list.  The
      * actual number returned may be smaller, depending on how many services
      * are running.
-     * 
+     *
      * @return Returns a list of RunningServiceInfo records describing each of
      * the running tasks.
      */
@@ -1641,7 +1641,7 @@ public class ActivityManager {
             return null;
         }
     }
-    
+
     /**
      * Returns a PendingIntent you can start to show a control panel for the
      * given running service.  If the service does not have a control panel,
@@ -1657,7 +1657,7 @@ public class ActivityManager {
             return null;
         }
     }
-    
+
     /**
      * Information you can retrieve about the available memory through
      * {@link ActivityManager#getMemoryInfo}.
@@ -1684,7 +1684,7 @@ public class ActivityManager {
          * processes.
          */
         public long threshold;
-        
+
         /**
          * Set to true if the system considers itself to currently be in a low
          * memory situation.
@@ -1717,7 +1717,7 @@ public class ActivityManager {
             dest.writeLong(visibleAppThreshold);
             dest.writeLong(foregroundAppThreshold);
         }
-        
+
         public void readFromParcel(Parcel source) {
             availMem = source.readLong();
             totalMem = source.readLong();
@@ -1841,7 +1841,7 @@ public class ActivityManager {
      */
     public boolean clearApplicationUserData(String packageName, IPackageDataObserver observer) {
         try {
-            return ActivityManagerNative.getDefault().clearApplicationUserData(packageName, 
+            return ActivityManagerNative.getDefault().clearApplicationUserData(packageName,
                     observer, UserHandle.myUserId());
         } catch (RemoteException e) {
             return false;
@@ -1882,7 +1882,7 @@ public class ActivityManager {
          * The process name in which the crash or error occurred.
          */
         public String processName;
-        
+
         /**
          * The pid of this process; 0 if none
          */
@@ -1894,7 +1894,7 @@ public class ActivityManager {
          * the same uid).
          */
         public int uid;
-        
+
         /**
          * The activity name associated with the error, if known.  May be null.
          */
@@ -1950,8 +1950,8 @@ public class ActivityManager {
             longMsg = source.readString();
             stackTrace = source.readString();
         }
-        
-        public static final Creator<ProcessErrorStateInfo> CREATOR = 
+
+        public static final Creator<ProcessErrorStateInfo> CREATOR =
                 new Creator<ProcessErrorStateInfo>() {
             public ProcessErrorStateInfo createFromParcel(Parcel source) {
                 return new ProcessErrorStateInfo(source);
@@ -1965,11 +1965,11 @@ public class ActivityManager {
             readFromParcel(source);
         }
     }
-    
+
     /**
-     * Returns a list of any processes that are currently in an error condition.  The result 
+     * Returns a list of any processes that are currently in an error condition.  The result
      * will be null if all processes are running properly at this time.
-     * 
+     *
      * @return Returns a list of ProcessErrorStateInfo records, or null if there are no
      * current error conditions (it will not return an empty list).  This list ordering is not
      * specified.
@@ -1985,7 +1985,7 @@ public class ActivityManager {
     /**
      * Information you can retrieve about a running process.
      */
-    public static class RunningAppProcessInfo implements Parcelable {        
+    public static class RunningAppProcessInfo implements Parcelable {
         /**
          * The name of the process that this object is associated with
          */
@@ -1995,17 +1995,17 @@ public class ActivityManager {
          * The pid of this process; 0 if none
          */
         public int pid;
-        
+
         /**
          * The user id of this process.
          */
         public int uid;
-        
+
         /**
          * All packages that have been loaded into the process.
          */
         public String pkgList[];
-        
+
         /**
          * Constant for {@link #flags}: this is an app that is unable to
          * correctly save its state when going to the background,
@@ -2013,7 +2013,7 @@ public class ActivityManager {
          * @hide
          */
         public static final int FLAG_CANT_SAVE_STATE = 1<<0;
-        
+
         /**
          * Constant for {@link #flags}: this process is associated with a
          * persistent system app.
@@ -2048,7 +2048,7 @@ public class ActivityManager {
          * that the user is interacting with.
          */
         public static final int IMPORTANCE_FOREGROUND = 100;
-        
+
         /**
          * Constant for {@link #importance}: This process is running a foreground
          * service, for example to perform music playback even while the user is
@@ -2075,13 +2075,13 @@ public class ActivityManager {
          * other services under the system's control that it inconsiders important.
          */
         public static final int IMPORTANCE_VISIBLE = 200;
-        
+
         /**
          * Constant for {@link #importance}: This process is not something the user
          * is directly aware of, but is otherwise perceptable to them to some degree.
          */
         public static final int IMPORTANCE_PERCEPTIBLE = 130;
-        
+
         /**
          * Constant for {@link #importance}: This process is running an
          * application that can not save its state, and thus can't be killed
@@ -2089,7 +2089,7 @@ public class ActivityManager {
          * @hide
          */
         public static final int IMPORTANCE_CANT_SAVE_STATE = 170;
-        
+
         /**
          * Constant for {@link #importance}: This process is contains services
          * that should remain running.  These are background services apps have
@@ -2098,13 +2098,13 @@ public class ActivityManager {
          * stay running as long as they want to).
          */
         public static final int IMPORTANCE_SERVICE = 300;
-        
+
         /**
          * Constant for {@link #importance}: This process process contains
          * background code that is expendable.
          */
         public static final int IMPORTANCE_BACKGROUND = 400;
-        
+
         /**
          * Constant for {@link #importance}: This process is empty of any
          * actively running code.
@@ -2148,7 +2148,7 @@ public class ActivityManager {
          * smaller than "less important" values.
          */
         public int importance;
-        
+
         /**
          * An additional ordering within a particular {@link #importance}
          * category, providing finer-grained information about the relative
@@ -2165,7 +2165,7 @@ public class ActivityManager {
          * been specified for the reason for this level.
          */
         public static final int REASON_UNKNOWN = 0;
-        
+
         /**
          * Constant for {@link #importanceReasonCode}: one of the application's
          * content providers is being used by another process.  The pid of
@@ -2174,7 +2174,7 @@ public class ActivityManager {
          * {@link #importanceReasonComponent}.
          */
         public static final int REASON_PROVIDER_IN_USE = 1;
-        
+
         /**
          * Constant for {@link #importanceReasonCode}: one of the application's
          * content providers is being used by another process.  The pid of
@@ -2183,25 +2183,25 @@ public class ActivityManager {
          * {@link #importanceReasonComponent}.
          */
         public static final int REASON_SERVICE_IN_USE = 2;
-        
+
         /**
          * The reason for {@link #importance}, if any.
          */
         public int importanceReasonCode;
-        
+
         /**
          * For the specified values of {@link #importanceReasonCode}, this
          * is the process ID of the other process that is a client of this
          * process.  This will be 0 if no other process is using this one.
          */
         public int importanceReasonPid;
-        
+
         /**
          * For the specified values of {@link #importanceReasonCode}, this
          * is the name of the component that is being used in this process.
          */
         public ComponentName importanceReasonComponent;
-        
+
         /**
          * When {@link #importanceReasonPid} is non-0, this is the importance
          * of the other pid. @hide
@@ -2219,7 +2219,7 @@ public class ActivityManager {
             importanceReasonCode = REASON_UNKNOWN;
             processState = PROCESS_STATE_IMPORTANT_FOREGROUND;
         }
-        
+
         public RunningAppProcessInfo(String pProcessName, int pPid, String pArr[]) {
             processName = pProcessName;
             pid = pPid;
@@ -2262,7 +2262,7 @@ public class ActivityManager {
             processState = source.readInt();
         }
 
-        public static final Creator<RunningAppProcessInfo> CREATOR = 
+        public static final Creator<RunningAppProcessInfo> CREATOR =
             new Creator<RunningAppProcessInfo>() {
             public RunningAppProcessInfo createFromParcel(Parcel source) {
                 return new RunningAppProcessInfo(source);
@@ -2276,7 +2276,7 @@ public class ActivityManager {
             readFromParcel(source);
         }
     }
-    
+
     /**
      * Returns a list of application processes installed on external media
      * that are running on the device.
@@ -2297,6 +2297,23 @@ public class ActivityManager {
     }
 
     /**
+     * Sets the memory trim mode for a process and schedules a memory trim operation.
+     *
+     * <p><b>Note: this method is only intended for testing framework.</b></p>
+     *
+     * @return Returns true if successful.
+     * @hide
+     */
+    public boolean setProcessMemoryTrimLevel(String process, int userId, int level) {
+        try {
+            return ActivityManagerNative.getDefault().setProcessMemoryTrimLevel(process, userId,
+                    level);
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
+
+    /**
      * Returns a list of application processes that are running on the device.
      *
      * <p><b>Note: this method is only intended for debugging or building
@@ -2368,7 +2385,7 @@ public class ActivityManager {
             return null;
         }
     }
-    
+
     /**
      * @deprecated This is now just a wrapper for
      * {@link #killBackgroundProcesses(String)}; the previous behavior here
@@ -2380,17 +2397,17 @@ public class ActivityManager {
     public void restartPackage(String packageName) {
         killBackgroundProcesses(packageName);
     }
-    
+
     /**
      * Have the system immediately kill all background processes associated
      * with the given package.  This is the same as the kernel killing those
      * processes to reclaim memory; the system will take care of restarting
      * these processes in the future as needed.
-     * 
+     *
      * <p>You must hold the permission
      * {@link android.Manifest.permission#KILL_BACKGROUND_PROCESSES} to be able to
      * call this method.
-     * 
+     *
      * @param packageName The name of the package whose processes are to
      * be killed.
      */
@@ -2426,14 +2443,14 @@ public class ActivityManager {
      * removed, etc.  In addition, a {@link Intent#ACTION_PACKAGE_RESTARTED}
      * broadcast will be sent, so that any of its registered alarms can
      * be stopped, notifications removed, etc.
-     * 
+     *
      * <p>You must hold the permission
      * {@link android.Manifest.permission#FORCE_STOP_PACKAGES} to be able to
      * call this method.
-     * 
+     *
      * @param packageName The name of the package to be stopped.
      * @param userId The user for which the running package is to be stopped.
-     * 
+     *
      * @hide This is not available to third party applications due to
      * it allowing them to break other applications by stopping their
      * services, removing their alarms, etc.
@@ -2697,7 +2714,7 @@ public class ActivityManager {
     }
 
     /**
-     * @param userid the user's id. Zero indicates the default user 
+     * @param userid the user's id. Zero indicates the default user.
      * @hide
      */
     public boolean switchUser(int userid) {
diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index e4def1e..ff52e67 100644
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -1546,21 +1546,21 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeInt(res ? 1 : 0);
             return true;
         }
-        
+
         case STOP_APP_SWITCHES_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             stopAppSwitches();
             reply.writeNoException();
             return true;
         }
-        
+
         case RESUME_APP_SWITCHES_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             resumeAppSwitches();
             reply.writeNoException();
             return true;
         }
-        
+
         case PEEK_SERVICE_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             Intent service = Intent.CREATOR.createFromParcel(data);
@@ -1570,7 +1570,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeStrongBinder(binder);
             return true;
         }
-        
+
         case START_BACKUP_AGENT_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             ApplicationInfo info = ApplicationInfo.CREATOR.createFromParcel(data);
@@ -1623,7 +1623,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeNoException();
             return true;
         }
-        
+
         case GET_PROCESS_MEMORY_INFO_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             int[] pids = data.createIntArray();
@@ -1641,7 +1641,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeNoException();
             return true;
         }
-        
+
         case OVERRIDE_PENDING_TRANSITION_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             IBinder token = data.readStrongBinder();
@@ -1652,7 +1652,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeNoException();
             return true;
         }
-        
+
         case IS_USER_A_MONKEY_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             boolean areThey = isUserAMonkey();
@@ -1660,7 +1660,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeInt(areThey ? 1 : 0);
             return true;
         }
-        
+
         case SET_USER_IS_MONKEY_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             final boolean monkey = (data.readInt() == 1);
@@ -1736,7 +1736,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeNoException();
             return true;
         }
-        
+
         case IS_TOP_ACTIVITY_IMMERSIVE_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             boolean isit = isTopActivityImmersive();
@@ -1888,7 +1888,7 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeNoException();
             return true;
         }
-        
+
         case SWITCH_USER_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             int userid = data.readInt();
@@ -2548,6 +2548,17 @@ public abstract class ActivityManagerNative extends Binder implements IActivityM
             reply.writeInt(res);
             return true;
         }
+
+        case SET_PROCESS_MEMORY_TRIM_TRANSACTION: {
+            data.enforceInterface(IActivityManager.descriptor);
+            String process = data.readString();
+            int userId = data.readInt();
+            int level = data.readInt();
+            boolean res = setProcessMemoryTrimLevel(process, userId, level);
+            reply.writeNoException();
+            reply.writeInt(res ? 1 : 0);
+            return true;
+        }
         }
 
         return super.onTransact(code, data, reply, flags);
@@ -3619,7 +3630,7 @@ class ActivityManagerProxy implements IActivityManager
         reply.recycle();
         return res;
     }
-    
+
     public ComponentName startService(IApplicationThread caller, Intent service,
             String resolvedType, int userId) throws RemoteException
     {
@@ -3722,7 +3733,7 @@ class ActivityManagerProxy implements IActivityManager
         reply.recycle();
         return res;
     }
-    
+
     public void publishService(IBinder token,
             Intent intent, IBinder service) throws RemoteException {
         Parcel data = Parcel.obtain();
@@ -3765,7 +3776,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         reply.recycle();
     }
-    
+
     public IBinder peekService(Intent service, String resolvedType) throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
@@ -4455,7 +4466,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         reply.recycle();
     }
-    
+
     public void getMyMemoryState(ActivityManager.RunningAppProcessInfo outInfo)
             throws RemoteException
     {
@@ -4519,7 +4530,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         return res;
     }
-    
+
     public void stopAppSwitches() throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
@@ -4529,7 +4540,7 @@ class ActivityManagerProxy implements IActivityManager
         reply.recycle();
         data.recycle();
     }
-    
+
     public void resumeAppSwitches() throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
@@ -4564,7 +4575,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         reply.recycle();
     }
-    
+
     public void closeSystemDialogs(String reason) throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
@@ -4575,7 +4586,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         reply.recycle();
     }
-    
+
     public Debug.MemoryInfo[] getProcessMemoryInfo(int[] pids)
             throws RemoteException {
         Parcel data = Parcel.obtain();
@@ -4601,7 +4612,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         reply.recycle();
     }
-        
+
     public void overridePendingTransition(IBinder token, String packageName,
             int enterAnim, int exitAnim) throws RemoteException {
         Parcel data = Parcel.obtain();
@@ -4616,7 +4627,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         reply.recycle();
     }
-    
+
     public boolean isUserAMonkey() throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
@@ -4872,7 +4883,7 @@ class ActivityManagerProxy implements IActivityManager
         data.recycle();
         return res;
     }
-    
+
     public int startActivities(IApplicationThread caller, String callingPackage,
             Intent[] intents, String[] resolvedTypes, IBinder resultTo,
             Bundle options, int userId) throws RemoteException {
@@ -5880,5 +5891,22 @@ class ActivityManagerProxy implements IActivityManager
         return res;
     }
 
+    @Override
+    public boolean setProcessMemoryTrimLevel(String process, int userId, int level)
+            throws RemoteException {
+        Parcel data = Parcel.obtain();
+        Parcel reply = Parcel.obtain();
+        data.writeInterfaceToken(IActivityManager.descriptor);
+        data.writeString(process);
+        data.writeInt(userId);
+        data.writeInt(level);
+        mRemote.transact(SET_PROCESS_MEMORY_TRIM_TRANSACTION, data, reply, 0);
+        reply.readException();
+        int res = reply.readInt();
+        data.recycle();
+        reply.recycle();
+        return res != 0;
+    }
+
     private IBinder mRemote;
 }
diff --git a/core/java/android/app/IActivityManager.java b/core/java/android/app/IActivityManager.java
index 0a425ae..7fa4c40 100644
--- a/core/java/android/app/IActivityManager.java
+++ b/core/java/android/app/IActivityManager.java
@@ -240,14 +240,14 @@ public interface IActivityManager extends IInterface {
 
     public void showWaitingForDebugger(IApplicationThread who, boolean waiting)
             throws RemoteException;
-    
+
     public void getMemoryInfo(ActivityManager.MemoryInfo outInfo) throws RemoteException;
-    
+
     public void killBackgroundProcesses(final String packageName, int userId)
             throws RemoteException;
     public void killAllBackgroundProcesses() throws RemoteException;
     public void forceStopPackage(final String packageName, int userId) throws RemoteException;
-    
+
     // Note: probably don't want to allow applications access to these.
     public void setLockScreenShown(boolean shown) throws RemoteException;
 
@@ -261,7 +261,7 @@ public interface IActivityManager extends IInterface {
         throws RemoteException;
 
     public void enterSafeMode() throws RemoteException;
-    
+
     public void noteWakeupAlarm(IIntentSender sender, int sourceUid, String sourcePkg, String tag)
             throws RemoteException;
     public void noteAlarmStart(IIntentSender sender, int sourceUid, String tag)
@@ -316,9 +316,9 @@ public interface IActivityManager extends IInterface {
 
     public void killApplicationWithAppId(String pkg, int appid, String reason)
             throws RemoteException;
-    
+
     public void closeSystemDialogs(String reason) throws RemoteException;
-    
+
     public Debug.MemoryInfo[] getProcessMemoryInfo(int[] pids)
             throws RemoteException;
 
@@ -505,6 +505,9 @@ public interface IActivityManager extends IInterface {
 
     public int getPackageProcessState(String packageName) throws RemoteException;
 
+    public boolean setProcessMemoryTrimLevel(String process, int uid, int level)
+            throws RemoteException;
+
     /*
      * Private non-Binder interfaces
      */
@@ -790,6 +793,7 @@ public interface IActivityManager extends IInterface {
     // Available
     int GET_ACTIVITY_DISPLAY_ID_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+184;
     int DELETE_ACTIVITY_CONTAINER_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+185;
+    int SET_PROCESS_MEMORY_TRIM_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+186;
 
 
     // Start of L transactions
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 81b8457..754bb1d 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -3613,6 +3613,26 @@ public final class ActivityManagerService extends ActivityManagerNative
         return procState;
     }
 
+    @Override
+    public boolean setProcessMemoryTrimLevel(String process, int userId, int level) {
+        ProcessRecord app = getProcessRecordLocked(process, userId, true);
+        if (app == null) {
+            return false;
+        }
+        if (app.trimMemoryLevel < level && app.thread != null &&
+                (level < ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN ||
+                        app.trimMemoryLevel >= ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN)) {
+            try {
+                app.thread.scheduleTrimMemory(level);
+                app.trimMemoryLevel = level;
+                return true;
+            } catch (RemoteException e) {
+                // Fallthrough to failure case.
+            }
+        }
+        return false;
+    }
+
     private void dispatchProcessesChanged() {
         int N;
         synchronized (this) {