Start combining threads in system process.
This introduces four generic thread that services can
use in the system process:
- Background: part of the framework for all processes, for
work that is purely background (no timing constraint).
- UI: for time-critical display of UI.
- Foreground: normal foreground work.
- IO: performing IO operations.
I went through and moved services into these threads in the
places I felt relatively comfortable about understanding what
they are doing. There are still a bunch more we need to look
at -- lots of networking stuff left, 3 or so different native
daemon connectors which I didn't know how much would block,
audio stuff, etc.
Also updated Watchdog to be aware of and check these new
threads, with a new API for other threads to also participate
in this checking.
Change-Id: Ie2f11061cebde5f018d7383b3a910fbbd11d5e11
diff --git a/services/java/com/android/server/UiThread.java b/services/java/com/android/server/UiThread.java
new file mode 100644
index 0000000..60d73aa
--- /dev/null
+++ b/services/java/com/android/server/UiThread.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.StrictMode;
+import android.util.Slog;
+
+/**
+ * Shared singleton thread for showing UI. This is a foreground thread, and in
+ * additional should not have operations that can take more than a few ms scheduled
+ * on it to avoid UI jank.
+ */
+public final class UiThread extends HandlerThread {
+ private static UiThread sInstance;
+ private static Handler sHandler;
+
+ private UiThread() {
+ super("android.ui", android.os.Process.THREAD_PRIORITY_FOREGROUND);
+ }
+
+ private static void ensureThreadLocked() {
+ if (sInstance == null) {
+ sInstance = new UiThread();
+ sInstance.start();
+ sHandler = new Handler(sInstance.getLooper());
+ sHandler.post(new Runnable() {
+ @Override
+ public void run() {
+ //Looper.myLooper().setMessageLogging(new LogPrinter(
+ // Log.VERBOSE, "WindowManagerPolicy", Log.LOG_ID_SYSTEM));
+ android.os.Process.setCanSelfBackground(false);
+
+ // For debug builds, log event loop stalls to dropbox for analysis.
+ if (StrictMode.conditionallyEnableDebugLogging()) {
+ Slog.i("UiThread", "Enabled StrictMode logging for UI thread");
+ }
+ }
+ });
+ }
+ }
+
+ public static UiThread get() {
+ synchronized (UiThread.class) {
+ ensureThreadLocked();
+ return sInstance;
+ }
+ }
+
+ public static Handler getHandler() {
+ synchronized (UiThread.class) {
+ ensureThreadLocked();
+ return sHandler;
+ }
+ }
+}