Rate limit dropbox entries in ActivityManagerService per process and add (b4167cca) · Commits · e / os / android_frameworks_base

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

+3 −18

Original line number	Diff line number	Diff line
		@@ -310,7 +310,6 @@ import android.sysprop.InitProperties;
		import android.sysprop.VoldProperties;
		import android.telephony.TelephonyManager;
		import android.text.TextUtils;
		import android.text.format.DateUtils;
		import android.text.style.SuggestionSpan;
		import android.util.ArrayMap;
		import android.util.ArraySet;
		@@ -8693,7 +8692,7 @@ public class ActivityManagerService extends IActivityManager.Stub
		}
		}

		private final ArrayMap<String, long[]> mErrorClusterRecords = new ArrayMap<>();
		private final DropboxRateLimiter mDropboxRateLimiter = new DropboxRateLimiter();

		/**
		* Write a description of an error (crash, WTF, ANR) to the drop box.
		@@ -8728,22 +8727,8 @@ public class ActivityManagerService extends IActivityManager.Stub
		final String dropboxTag = processClass(process) + "_" + eventType;
		if (dbox == null \|\| !dbox.isTagEnabled(dropboxTag)) return;

		// Rate-limit how often we're willing to do the heavy lifting below to
		// collect and record logs; currently 5 logs per 10 second period per eventType.
		final long now = SystemClock.elapsedRealtime();
		synchronized (mErrorClusterRecords) {
		long[] errRecord = mErrorClusterRecords.get(eventType);
		if (errRecord == null) {
		errRecord = new long[2]; // [0]: startTime, [1]: count
		mErrorClusterRecords.put(eventType, errRecord);
		}
		if (now - errRecord[0] > 10 * DateUtils.SECOND_IN_MILLIS) {
		errRecord[0] = now;
		errRecord[1] = 1L;
		} else {
		if (errRecord[1]++ >= 5) return;
		}
		}
		// Check if we should rate limit and abort early if needed.
		if (mDropboxRateLimiter.shouldRateLimit(eventType, processName)) return;

		final StringBuilder sb = new StringBuilder(1024);
		appendDropBoxProcessHeaders(process, processName, sb);

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

0 → 100644

+125 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2022 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.am;

		import android.os.SystemClock;
		import android.text.format.DateUtils;
		import android.util.ArrayMap;

		import com.android.internal.annotations.GuardedBy;

		/** Rate limiter for adding errors into dropbox. */
		public class DropboxRateLimiter {
		private static final long RATE_LIMIT_BUFFER_EXPIRY = 15 * DateUtils.SECOND_IN_MILLIS;
		private static final long RATE_LIMIT_BUFFER_DURATION = 10 * DateUtils.SECOND_IN_MILLIS;
		private static final int RATE_LIMIT_ALLOWED_ENTRIES = 5;

		@GuardedBy("mErrorClusterRecords")
		private final ArrayMap<String, ErrorRecord> mErrorClusterRecords = new ArrayMap<>();
		private final Clock mClock;

		private long mLastMapCleanUp = 0L;

		public DropboxRateLimiter() {
		this(new DefaultClock());
		}

		public DropboxRateLimiter(Clock clock) {
		mClock = clock;
		}

		/** The interface clock to use for tracking the time elapsed. */
		public interface Clock {
		/** How long in millis has passed since the device came online. */
		long uptimeMillis();
		}

		/** Determines whether dropbox entries of a specific tag and process should be rate limited. */
		public boolean shouldRateLimit(String eventType, String processName) {
		// Rate-limit how often we're willing to do the heavy lifting to collect and record logs.
		final long now = mClock.uptimeMillis();
		synchronized (mErrorClusterRecords) {
		// Remove expired records if enough time has passed since the last cleanup.
		maybeRemoveExpiredRecords(now);

		ErrorRecord errRecord = mErrorClusterRecords.get(errorKey(eventType, processName));
		if (errRecord == null) {
		errRecord = new ErrorRecord(now, 1);
		mErrorClusterRecords.put(errorKey(eventType, processName), errRecord);
		} else if (now - errRecord.getStartTime() > RATE_LIMIT_BUFFER_DURATION) {
		errRecord.setStartTime(now);
		errRecord.setCount(1);
		} else {
		errRecord.incrementCount();
		if (errRecord.getCount() > RATE_LIMIT_ALLOWED_ENTRIES) return true;
		}
		}
		return false;
		}

		private void maybeRemoveExpiredRecords(long now) {
		if (now - mLastMapCleanUp <= RATE_LIMIT_BUFFER_EXPIRY) return;

		for (int i = mErrorClusterRecords.size() - 1; i >= 0; i--) {
		if (now - mErrorClusterRecords.valueAt(i).getStartTime() > RATE_LIMIT_BUFFER_EXPIRY) {
		mErrorClusterRecords.removeAt(i);
		}
		}

		mLastMapCleanUp = now;
		}

		String errorKey(String eventType, String processName) {
		return eventType + processName;
		}

		private class ErrorRecord {
		long mStartTime;
		int mCount;

		ErrorRecord(long startTime, int count) {
		mStartTime = startTime;
		mCount = count;
		}

		public void setStartTime(long startTime) {
		mStartTime = startTime;
		}

		public void setCount(int count) {
		mCount = count;
		}

		public void incrementCount() {
		mCount++;
		}

		public long getStartTime() {
		return mStartTime;
		}

		public int getCount() {
		return mCount;
		}
		}

		private static class DefaultClock implements Clock {
		public long uptimeMillis() {
		return SystemClock.uptimeMillis();
		}
		}
		}

services/tests/servicestests/src/com/android/server/am/DropboxRateLimiterTest.java

0 → 100644

+87 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2022 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.am;

		import static org.junit.Assert.assertFalse;
		import static org.junit.Assert.assertTrue;

		import android.os.SystemClock;

		import org.junit.Before;
		import org.junit.Test;

		/**
		* Test class for {@link DropboxRateLimiter}.
		*
		* Build/Install/Run:
		* atest DropboxRateLimiterTest
		*/
		public class DropboxRateLimiterTest {
		private DropboxRateLimiter mRateLimiter;
		private TestClock mClock;

		@Before
		public void setUp() {
		mClock = new TestClock();
		mRateLimiter = new DropboxRateLimiter(mClock);
		}

		@Test
		public void testMultipleProcesses() {
		// The first 5 entries should not be rate limited.
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		// Different processes and tags should not get rate limited either.
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process2"));
		assertFalse(mRateLimiter.shouldRateLimit("tag2", "process"));
		// The 6th entry of the same process should be rate limited.
		assertTrue(mRateLimiter.shouldRateLimit("tag", "process"));
		}

		@Test
		public void testBufferClearing() throws Exception {
		// The first 5 entries should not be rate limited.
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		// The 6th entry of the same process should be rate limited.
		assertTrue(mRateLimiter.shouldRateLimit("tag", "process"));

		// After 11 seconds there should be nothing left in the buffer and the same type of entry
		// should not get rate limited anymore.
		mClock.setOffsetMillis(11000);

		assertFalse(mRateLimiter.shouldRateLimit("tag", "process"));
		}

		private static class TestClock implements DropboxRateLimiter.Clock {
		long mOffsetMillis = 0L;

		public long uptimeMillis() {
		return mOffsetMillis + SystemClock.uptimeMillis();
		}

		public void setOffsetMillis(long millis) {
		mOffsetMillis = millis;
		}
		}
		}