Merge "Lower-overhead version of LockGuard." (0de9e5ca) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/AppOpsService.java

+1 −0

Original line number	Diff line number	Diff line
		@@ -235,6 +235,7 @@ public class AppOpsService extends IAppOpsService.Stub {
		}

		public AppOpsService(File storagePath, Handler handler) {
		LockGuard.installLock(this, LockGuard.INDEX_APP_OPS);
		mFile = new AtomicFile(storagePath);
		mHandler = handler;
		readState();

services/core/java/com/android/server/LockGuard.java

+63 −1

Original line number	Diff line number	Diff line
		@@ -53,10 +53,29 @@ import java.io.PrintWriter;
		* <li>A guarded synchronized block takes 50ns when disabled.
		* <li>A guarded synchronized block takes 460ns per lock checked when enabled.
		* </ul>
		* <p>
		* This class also supports a second simpler mode of operation where well-known
		* locks are explicitly registered and checked via indexes.
		*/
		public class LockGuard {
		private static final String TAG = "LockGuard";

		public static final boolean ENABLED = false;

		/**
		* Well-known locks ordered by fixed index. Locks with a specific index
		* should never be acquired while holding a lock of a lower index.
		*/
		public static final int INDEX_APP_OPS = 0;
		public static final int INDEX_POWER = 1;
		public static final int INDEX_USER = 2;
		public static final int INDEX_PACKAGES = 3;
		public static final int INDEX_STORAGE = 4;
		public static final int INDEX_WINDOW = 5;
		public static final int INDEX_ACTIVITY = 6;

		private static Object[] sKnownFixed = new Object[INDEX_ACTIVITY + 1];

		private static ArrayMap<Object, LockInfo> sKnown = new ArrayMap<>(0, true);

		private static class LockInfo {
		@@ -118,12 +137,42 @@ public class LockGuard {
		return lock;
		}

		/**
		* Yell if any lower-level locks are being held by the calling thread that
		* is about to acquire the given lock.
		*/
		public static void guard(int index) {
		for (int i = 0; i < index; i++) {
		final Object lock = sKnownFixed[i];
		if (lock != null && Thread.holdsLock(lock)) {
		Slog.w(TAG, "Calling thread " + Thread.currentThread().getName() + " is holding "
		+ lockToString(i) + " while trying to acquire "
		+ lockToString(index), new Throwable());
		}
		}
		}

		/**
		* Report the given lock with a well-known label.
		*/
		public static void installLock(Object lock, String label) {
		public static Object installLock(Object lock, String label) {
		final LockInfo info = findOrCreateLockInfo(lock);
		info.label = label;
		return lock;
		}

		/**
		* Report the given lock with a well-known index.
		*/
		public static Object installLock(Object lock, int index) {
		sKnownFixed[index] = lock;
		return lock;
		}

		public static Object installNewLock(int index) {
		final Object lock = new Object();
		installLock(lock, index);
		return lock;
		}

		private static String lockToString(Object lock) {
		@@ -135,6 +184,19 @@ public class LockGuard {
		}
		}

		private static String lockToString(int index) {
		switch (index) {
		case INDEX_APP_OPS: return "APP_OPS";
		case INDEX_POWER: return "POWER";
		case INDEX_USER: return "USER";
		case INDEX_PACKAGES: return "PACKAGES";
		case INDEX_STORAGE: return "STORAGE";
		case INDEX_WINDOW: return "WINDOW";
		case INDEX_ACTIVITY: return "ACTIVITY";
		default: return Integer.toString(index);
		}
		}

		public static void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
		for (int i = 0; i < sKnown.size(); i++) {
		final Object lock = sKnown.keyAt(i);

services/core/java/com/android/server/StorageManagerService.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -308,7 +308,7 @@ class StorageManagerService extends IStorageManager.Stub
		* <em>Never</em> hold the lock while performing downcalls into vold, since
		* unsolicited events can suddenly appear to update data structures.
		*/
		private final Object mLock = new Object();
		private final Object mLock = LockGuard.installNewLock(LockGuard.INDEX_STORAGE);

		/** Set of users that we know are unlocked. */
		@GuardedBy("mLock")

services/core/java/com/android/server/am/ActivityManagerService.java

+4 −0

Original line number	Diff line number	Diff line
		@@ -691,6 +691,9 @@ public class ActivityManagerService extends IActivityManager.Stub
		Process.setThreadPriority(tid, -2);
		}
		state.regionCounter++;
		if (LockGuard.ENABLED) {
		LockGuard.guard(LockGuard.INDEX_ACTIVITY);
		}
		}

		static void resetPriorityAfterLockedSection() {
		@@ -2657,6 +2660,7 @@ public class ActivityManagerService extends IActivityManager.Stub
		// Note: This method is invoked on the main thread but may need to attach various
		// handlers to other threads. So take care to be explicit about the looper.
		public ActivityManagerService(Context systemContext) {
		LockGuard.installLock(this, LockGuard.INDEX_ACTIVITY);
		mContext = systemContext;
		mFactoryTest = FactoryTest.getMode();
		mSystemThread = ActivityThread.currentActivityThread();

services/core/java/com/android/server/pm/PackageManagerService.java

+2 −0

Original line number	Diff line number	Diff line
		@@ -266,6 +266,7 @@ import com.android.server.EventLogTags;
		import com.android.server.FgThread;
		import com.android.server.IntentResolver;
		import com.android.server.LocalServices;
		import com.android.server.LockGuard;
		import com.android.server.ServiceThread;
		import com.android.server.SystemConfig;
		import com.android.server.SystemServerInitThreadPool;
		@@ -2212,6 +2213,7 @@ public class PackageManagerService extends IPackageManager.Stub {

		public PackageManagerService(Context context, Installer installer,
		boolean factoryTest, boolean onlyCore) {
		LockGuard.installLock(mPackages, LockGuard.INDEX_PACKAGES);
		Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "create package manager");
		EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_PMS_START,
		SystemClock.uptimeMillis());