Add ServiceThread to WallpaperManagerService.

During a user switch, binding the WallpaperService was done on
the system_server's main handler, and was being delayed unnecessarily
when the system_server was busy. With this CL, we are giving the
WallpaperManagerService its own thread handler and do the binding of
the target user's wallpaper service on that handler. This improves
user switch duration by 17%, and reduces spikiness 10 times.

Bug: 300421828
Test: Manual control of Perfetto traces
Change-Id: Ib8514d3cdc7a69359866b1e3d0c8ffcb32c9a4aa

1 files changed, 16 insertions, 1 deletions

diff --git a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
index 4c525e902b88..01ea33f1aecd 100644
--- a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
+++ b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
@@ -28,6 +28,7 @@ import static android.os.ParcelFileDescriptor.MODE_CREATE;
 import static android.os.ParcelFileDescriptor.MODE_READ_ONLY;
 import static android.os.ParcelFileDescriptor.MODE_READ_WRITE;
 import static android.os.ParcelFileDescriptor.MODE_TRUNCATE;
+import static android.os.Process.THREAD_PRIORITY_FOREGROUND;
 import static android.view.Display.DEFAULT_DISPLAY;
 import static android.view.WindowManager.LayoutParams.TYPE_WALLPAPER;
 
@@ -74,6 +75,7 @@ import android.graphics.BitmapFactory;
 import android.graphics.Rect;
 import android.graphics.RectF;
 import android.hardware.display.DisplayManager;
+import android.multiuser.Flags;
 import android.os.Binder;
 import android.os.Bundle;
 import android.os.FileObserver;
@@ -114,6 +116,7 @@ import com.android.internal.util.DumpUtils;
 import com.android.server.EventLogTags;
 import com.android.server.FgThread;
 import com.android.server.LocalServices;
+import com.android.server.ServiceThread;
 import com.android.server.SystemService;
 import com.android.server.pm.UserManagerInternal;
 import com.android.server.utils.TimingsTraceAndSlog;
@@ -132,6 +135,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
 
@@ -746,6 +750,8 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
     }
 
     private final Context mContext;
+    private final AtomicBoolean mIsInitialBinding = new AtomicBoolean(true);
+    private final ServiceThread mHandlerThread;
     private final WindowManagerInternal mWindowManagerInternal;
     private final PackageManagerInternal mPackageManagerInternal;
     private final IPackageManager mIPackageManager;
@@ -1619,6 +1625,12 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
     public WallpaperManagerService(Context context) {
         if (DEBUG) Slog.v(TAG, "WallpaperService startup");
         mContext = context;
+        if (Flags.bindWallpaperServiceOnItsOwnThreadDuringAUserSwitch()) {
+            mHandlerThread = new ServiceThread(TAG, THREAD_PRIORITY_FOREGROUND, true /*allowIo*/);
+            mHandlerThread.start();
+        } else {
+            mHandlerThread = null;
+        }
         mShuttingDown = false;
         mImageWallpaper = ComponentName.unflattenFromString(
                 context.getResources().getString(R.string.image_wallpaper_component));
@@ -3652,7 +3664,10 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                     com.android.internal.R.bool.config_wallpaperTopApp)) {
                 bindFlags |= Context.BIND_SCHEDULE_LIKE_TOP_APP;
             }
-            boolean bindSuccess = mContext.bindServiceAsUser(intent, newConn, bindFlags,
+            Handler handler = Flags.bindWallpaperServiceOnItsOwnThreadDuringAUserSwitch()
+                    && !mIsInitialBinding.compareAndSet(true, false)
+                    ? mHandlerThread.getThreadHandler() : mContext.getMainThreadHandler();
+            boolean bindSuccess = mContext.bindServiceAsUser(intent, newConn, bindFlags, handler,
                     new UserHandle(serviceUserId));
             if (!bindSuccess) {
                 String msg = "Unable to bind service: " + componentName;