Usage Stats: don't block writing stats to disk. (389a9167) · Commits · e / os / android_frameworks_base

services/java/com/android/server/am/UsageStatsService.java

+81 −40

Original line number	Diff line number	Diff line
		@@ -44,6 +44,9 @@ import java.util.List;
		import java.util.Map;
		import java.util.Set;
		import java.util.TimeZone;
		import java.util.concurrent.atomic.AtomicBoolean;
		import java.util.concurrent.atomic.AtomicInteger;
		import java.util.concurrent.atomic.AtomicLong;

		/**
		* This service collects the statistics associated with usage
		@@ -88,11 +91,13 @@ public final class UsageStatsService extends IUsageStats.Stub {
		private boolean mIsResumed;
		private File mFile;
		private String mFileLeaf;
		//private File mBackupFile;
		private long mLastWriteElapsedTime;
		private File mDir;
		private Calendar mCal;
		private int mLastWriteDay;

		private Calendar mCal; // guarded by itself

		private final AtomicInteger mLastWriteDay = new AtomicInteger(-1);
		private final AtomicLong mLastWriteElapsedTime = new AtomicLong(0);
		private final AtomicBoolean mUnforcedDiskWriteRunning = new AtomicBoolean(false);

		static class TimeStats {
		int count;
		@@ -241,17 +246,18 @@ public final class UsageStatsService extends IUsageStats.Stub {
		mFileLeaf = getCurrentDateStr(FILE_PREFIX);
		mFile = new File(mDir, mFileLeaf);
		readStatsFromFile();
		mLastWriteElapsedTime = SystemClock.elapsedRealtime();
		mLastWriteElapsedTime.set(SystemClock.elapsedRealtime());
		// mCal was set by getCurrentDateStr(), want to use that same time.
		mLastWriteDay = mCal.get(Calendar.DAY_OF_YEAR);
		mLastWriteDay.set(mCal.get(Calendar.DAY_OF_YEAR));
		}

		/*
		* Utility method to convert date into string.
		*/
		private String getCurrentDateStr(String prefix) {
		mCal.setTimeInMillis(System.currentTimeMillis());
		StringBuilder sb = new StringBuilder();
		synchronized (mCal) {
		mCal.setTimeInMillis(System.currentTimeMillis());
		if (prefix != null) {
		sb.append(prefix);
		}
		@@ -266,6 +272,7 @@ public final class UsageStatsService extends IUsageStats.Stub {
		sb.append("0");
		}
		sb.append(dd);
		}
		return sb.toString();
		}

		@@ -361,22 +368,55 @@ public final class UsageStatsService extends IUsageStats.Stub {
		}
		}

		private void writeStatsToFile(boolean force) {
		synchronized (mFileLock) {
		/**
		* Conditionally start up a disk write if it's been awhile, or the
		* day has rolled over.
		*
		* This is called indirectly from user-facing actions (when
		* 'force' is false) so it tries to be quick, without writing to
		* disk directly or acquiring heavy locks.
		*
		* @params force do an unconditional, synchronous stats flush
		* to disk on the current thread.
		*/
		private void writeStatsToFile(final boolean force) {
		int curDay;
		synchronized (mCal) {
		mCal.setTimeInMillis(System.currentTimeMillis());
		final int curDay = mCal.get(Calendar.DAY_OF_YEAR);
		curDay = mCal.get(Calendar.DAY_OF_YEAR);
		}
		final boolean dayChanged = curDay != mLastWriteDay.get();

		// Determine if the day changed... note that this will be wrong
		// if the year has changed but we are in the same day of year...
		// we can probably live with this.
		final boolean dayChanged = curDay != mLastWriteDay;
		long currElapsedTime = SystemClock.elapsedRealtime();
		final long currElapsedTime = SystemClock.elapsedRealtime();

		// Fast common path, without taking the often-contentious
		// mFileLock.
		if (!force) {
		if (((currElapsedTime-mLastWriteElapsedTime) < FILE_WRITE_INTERVAL) &&
		(!dayChanged)) {
		if (!dayChanged &&
		(currElapsedTime - mLastWriteElapsedTime.get()) < FILE_WRITE_INTERVAL) {
		// wait till the next update
		return;
		}
		if (mUnforcedDiskWriteRunning.compareAndSet(false, true)) {
		new Thread("UsageStatsService_DiskWriter") {
		public void run() {
		try {
		Slog.d(TAG, "Disk writer thread starting.");
		writeStatsToFile(true);
		} finally {
		mUnforcedDiskWriteRunning.set(false);
		Slog.d(TAG, "Disk writer thread ending.");
		}
		}
		}.start();
		}
		return;
		}

		synchronized (mFileLock) {
		// Get the most recent file
		mFileLeaf = getCurrentDateStr(FILE_PREFIX);
		// Copy current file to back up
		@@ -395,10 +435,10 @@ public final class UsageStatsService extends IUsageStats.Stub {

		try {
		// Write mStats to file
		writeStatsFLOCK();
		mLastWriteElapsedTime = currElapsedTime;
		writeStatsFLOCK(mFile);
		mLastWriteElapsedTime.set(currElapsedTime);
		if (dayChanged) {
		mLastWriteDay = curDay;
		mLastWriteDay.set(curDay);
		// clear stats
		synchronized (mStats) {
		mStats.clear();
		@@ -418,10 +458,11 @@ public final class UsageStatsService extends IUsageStats.Stub {
		}
		}
		}
		Slog.d(TAG, "Dumped usage stats.");
		}

		private void writeStatsFLOCK() throws IOException {
		FileOutputStream stream = new FileOutputStream(mFile);
		private void writeStatsFLOCK(File file) throws IOException {
		FileOutputStream stream = new FileOutputStream(file);
		try {
		Parcel out = Parcel.obtain();
		writeStatsToParcelFLOCK(out);