frameworks/base/services/java/com/android/server/SystemServer.java
public static void main(String[] args) {
new SystemServer().run();
}
private void run() {
...
Looper.prepareMainLooper();
Looper.getMainLooper().setSlowLogThresholdMs(
SLOW_DISPATCH_THRESHOLD_MS, SLOW_DELIVERY_THRESHOLD_MS);
// Start services.
try {
t.traceBegin("StartServices");
startBootstrapServices(t);
startCoreServices(t);
startOtherServices(t);
} catch (Throwable ex) {
Slog.e("System", "******************************************");
Slog.e("System", "************ Failure starting system services", ex);
throw ex;
} finally {
t.traceEnd(); // StartServices
}
...
// Loop forever.
Looper.loop();
throw new RuntimeException("Main thread loop unexpectedly exited");
}
/**
* Starts the small tangle of critical services that are needed to get the system off the
* ground. These services have complex mutual dependencies which is why we initialize them all
* in one place here. Unless your service is also entwined in these dependencies, it should be
* initialized in one of the other functions.
*/
private void startBootstrapServices(@NonNull TimingsTraceAndSlog t) {
t.traceBegin("startBootstrapServices");
...
// Activity manager runs the show.
t.traceBegin("StartActivityManager");
// TODO: Might need to move after migration to WM.
ActivityTaskManagerService atm = mSystemServiceManager.startService(
ActivityTaskManagerService.Lifecycle.class).getService();
mActivityManagerService = ActivityManagerService.Lifecycle.startService(
mSystemServiceManager, atm);
mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
mActivityManagerService.setInstaller(installer);
mWindowManagerGlobalLock = atm.getGlobalLock();
t.traceEnd();
...
// Set up the Application instance for the system process and get started.
t.traceBegin("SetSystemProcess");
mActivityManagerService.setSystemProcess();
t.traceEnd();
...
}
/**
* Starts a miscellaneous grab bag of stuff that has yet to be refactored and organized.
*/
private void startOtherServices(@NonNull TimingsTraceAndSlog t) {
t.traceBegin("startOtherServices");
...
t.traceBegin("StartInputManagerService");
inputManager = new InputManagerService(context);
t.traceEnd();
...
t.traceBegin("StartWindowManagerService");
// WMS needs sensor service ready
mSystemServiceManager.startBootPhase(t, SystemService.PHASE_WAIT_FOR_SENSOR_SERVICE);
wm = WindowManagerService.main(context, inputManager, !mFirstBoot, mOnlyCore,
new PhoneWindowManager(), mActivityManagerService.mActivityTaskManager);
ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);
ServiceManager.addService(Context.INPUT_SERVICE, inputManager,
/* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);
t.traceEnd();
t.traceBegin("SetWindowManagerService");
mActivityManagerService.setWindowManager(wm);
t.traceEnd();
t.traceBegin("WindowManagerServiceOnInitReady");
wm.onInitReady();
t.traceEnd();
}
frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java
public void setSystemProcess() {
try {
//将ActivityManagerService添加进ServiceManager
ServiceManager.addService(Context.ACTIVITY_SERVICE, this, /* allowIsolated= */ true,
DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PRIORITY_NORMAL | DUMP_FLAG_PROTO);
ServiceManager.addService(ProcessStats.SERVICE_NAME, mProcessStats);
ServiceManager.addService("meminfo", new MemBinder(this), /* allowIsolated= */ false,
DUMP_FLAG_PRIORITY_HIGH);
ServiceManager.addService("gfxinfo", new GraphicsBinder(this));
ServiceManager.addService("dbinfo", new DbBinder(this));
mAppProfiler.setCpuInfoService();
ServiceManager.addService("permission", new PermissionController(this));
ServiceManager.addService("processinfo", new ProcessInfoService(this));
ServiceManager.addService("cacheinfo", new CacheBinder(this));
...
}
frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java
public static WindowManagerService main(final Context context, final InputManagerService im,
final boolean showBootMsgs, final boolean onlyCore, WindowManagerPolicy policy,
ActivityTaskManagerService atm) {
return main(context, im, showBootMsgs, onlyCore, policy, atm,
new DisplayWindowSettingsProvider(), SurfaceControl.Transaction::new, Surface::new,
SurfaceControl.Builder::new);
}
/**
* Creates and returns an instance of the WindowManagerService. This call allows the caller
* to override factories that can be used to stub native calls during test.
*/
@VisibleForTesting
public static WindowManagerService main(final Context context, final InputManagerService im,
final boolean showBootMsgs, final boolean onlyCore, WindowManagerPolicy policy,
ActivityTaskManagerService atm, DisplayWindowSettingsProvider
displayWindowSettingsProvider, Supplier<SurfaceControl.Transaction> transactionFactory,
Supplier<Surface> surfaceFactory,
Function<SurfaceSession, SurfaceControl.Builder> surfaceControlFactory) {
DisplayThread.getHandler().runWithScissors(() ->
sInstance = new WindowManagerService(context, im, showBootMsgs, onlyCore, policy,
atm, displayWindowSettingsProvider, transactionFactory, surfaceFactory,
surfaceControlFactory), 0);
return sInstance;
}
frameworks/base/services/core/java/com/android/server/DisplayThread.java
public final class DisplayThread extends ServiceThread {
private static void ensureThreadLocked() {
if (sInstance == null) {
sInstance = new DisplayThread();
sInstance.start();
sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_SYSTEM_SERVER);
sHandler = new Handler(sInstance.getLooper());
}
}
public static Handler getHandler() {
synchronized (DisplayThread.class) {
ensureThreadLocked();
return sHandler;
}
}
}
frameworks/base/core/java/android/os/Handler.java
public class Handler {
public final boolean runWithScissors(@NonNull Runnable r, long timeout) {
if (r == null) {
throw new IllegalArgumentException("runnable must not be null");
}
if (timeout < 0) {
throw new IllegalArgumentException("timeout must be non-negative");
}
if (Looper.myLooper() == mLooper) {
r.run();
return true;
}
BlockingRunnable br = new BlockingRunnable(r);
return br.postAndWait(this, timeout);
}
}
由此可见,WindowManagerService以及ActivityManagerService等的服务的进程号都是SystemServer,但是是跑在不同的线程上