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/FgThread.java b/services/java/com/android/server/FgThread.java
new file mode 100644
index 0000000..3b655f2
--- /dev/null
+++ b/services/java/com/android/server/FgThread.java
@@ -0,0 +1,65 @@
+/*
+ * 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;
+
+/**
+ * Shared singleton foreground thread for the system. This is a thread for regular
+ * foreground service operations, which shouldn't be blocked by anything running in
+ * the background. In particular, the shared background thread could be doing
+ * relatively long-running operations like saving state to disk (in addition to
+ * simply being a background priority), which can cause operations scheduled on it
+ * to be delayed for a user-noticeable amount of time.
+ */
+public final class FgThread extends HandlerThread {
+ private static FgThread sInstance;
+ private static Handler sHandler;
+
+ private FgThread() {
+ super("android.fg", android.os.Process.THREAD_PRIORITY_DEFAULT);
+ }
+
+ private static void ensureThreadLocked() {
+ if (sInstance == null) {
+ sInstance = new FgThread();
+ sInstance.start();
+ sHandler = new Handler(sInstance.getLooper());
+ sHandler.post(new Runnable() {
+ @Override
+ public void run() {
+ android.os.Process.setCanSelfBackground(false);
+ }
+ });
+ }
+ }
+
+ public static FgThread get() {
+ synchronized (UiThread.class) {
+ ensureThreadLocked();
+ return sInstance;
+ }
+ }
+
+ public static Handler getHandler() {
+ synchronized (UiThread.class) {
+ ensureThreadLocked();
+ return sHandler;
+ }
+ }
+}