Allow pausing Watchdog on the current thread (2a05039b) · Commits · e / os / android_frameworks_base

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

+74 −5

Original line number	Diff line number	Diff line
		@@ -140,6 +140,7 @@ public class Watchdog extends Thread {
		private boolean mCompleted;
		private Monitor mCurrentMonitor;
		private long mStartTime;
		private int mPauseCount;

		HandlerChecker(Handler handler, String name, long waitMaxMillis) {
		mHandler = handler;
		@@ -160,17 +161,18 @@ public class Watchdog extends Thread {
		mMonitors.addAll(mMonitorQueue);
		mMonitorQueue.clear();
		}
		if (mMonitors.size() == 0 && mHandler.getLooper().getQueue().isPolling()) {
		if ((mMonitors.size() == 0 && mHandler.getLooper().getQueue().isPolling())
		\|\| (mPauseCount > 0)) {
		// Don't schedule until after resume OR
		// If the target looper has recently been polling, then
		// there is no reason to enqueue our checker on it since that
		// is as good as it not being deadlocked. This avoid having
		// to do a context switch to check the thread. Note that we
		// only do this if mCheckReboot is false and we have no
		// monitors, since those would need to be executed at this point.
		// only do this if we have no monitors since those would need to
		// be executed at this point.
		mCompleted = true;
		return;
		}

		if (!mCompleted) {
		// we already have a check in flight, so no need
		return;
		@@ -236,6 +238,28 @@ public class Watchdog extends Thread {
		mCurrentMonitor = null;
		}
		}

		/** Pause the HandlerChecker. */
		public void pauseLocked(String reason) {
		mPauseCount++;
		// Mark as completed, because there's a chance we called this after the watchog
		// thread loop called Object#wait after 'WAITED_HALF'. In that case we want to ensure
		// the next call to #getCompletionStateLocked for this checker returns 'COMPLETED'
		mCompleted = true;
		Slog.i(TAG, "Pausing HandlerChecker: " + mName + " for reason: "
		+ reason + ". Pause count: " + mPauseCount);
		}

		/** Resume the HandlerChecker from the last {@link #pauseLocked}. */
		public void resumeLocked(String reason) {
		if (mPauseCount > 0) {
		mPauseCount--;
		Slog.i(TAG, "Resuming HandlerChecker: " + mName + " for reason: "
		+ reason + ". Pause count: " + mPauseCount);
		} else {
		Slog.wtf(TAG, "Already resumed HandlerChecker: " + mName);
		}
		}
		}

		final class RebootRequestReceiver extends BroadcastReceiver {
		@@ -363,6 +387,51 @@ public class Watchdog extends Thread {
		}
		}

		/**
		* Pauses Watchdog action for the currently running thread. Useful before executing long running
		* operations that could falsely trigger the watchdog. Each call to this will require a matching
		* call to {@link #resumeWatchingCurrentThread}.
		*
		* <p>If the current thread has not been added to the Watchdog, this call is a no-op.
		*
		* <p>If the Watchdog is already paused for the current thread, this call adds
		* adds another pause and will require an additional {@link #resumeCurrentThread} to resume.
		*
		* <p>Note: Use with care, as any deadlocks on the current thread will be undetected until all
		* pauses have been resumed.
		*/
		public void pauseWatchingCurrentThread(String reason) {
		synchronized (this) {
		for (HandlerChecker hc : mHandlerCheckers) {
		if (Thread.currentThread().equals(hc.getThread())) {
		hc.pauseLocked(reason);
		}
		}
		}
		}

		/**
		* Resumes the last pause from {@link #pauseWatchingCurrentThread} for the currently running
		* thread.
		*
		* <p>If the current thread has not been added to the Watchdog, this call is a no-op.
		*
		* <p>If the Watchdog action for the current thread is already resumed, this call logs a wtf.
		*
		* <p>If all pauses have been resumed, the Watchdog action is finally resumed, otherwise,
		* the Watchdog action for the current thread remains paused until resume is called at least
		* as many times as the calls to pause.
		*/
		public void resumeWatchingCurrentThread(String reason) {
		synchronized (this) {
		for (HandlerChecker hc : mHandlerCheckers) {
		if (Thread.currentThread().equals(hc.getThread())) {
		hc.resumeLocked(reason);
		}
		}
		}
		}

		/**
		* Perform a full reboot of the system.
		*/

services/java/com/android/server/SystemServer.java

+3 −0

Original line number	Diff line number	Diff line
		@@ -1174,9 +1174,12 @@ public final class SystemServer {
		if (!mOnlyCore) {
		traceBeginAndSlog("UpdatePackagesIfNeeded");
		try {
		Watchdog.getInstance().pauseWatchingCurrentThread("dexopt");
		mPackageManagerService.updatePackagesIfNeeded();
		} catch (Throwable e) {
		reportWtf("update packages", e);
		} finally {
		Watchdog.getInstance().resumeWatchingCurrentThread("dexopt");
		}
		traceEnd();
		}