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From haiboc...@apache.org
Subject [06/50] [abbrv] hadoop git commit: HADOOP-15726. Create utility to limit frequency of log statements. Contributed by Erik Krogen.
Date Mon, 24 Sep 2018 19:07:28 GMT
HADOOP-15726. Create utility to limit frequency of log statements. Contributed by Erik Krogen.


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/a30b4f9e
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/a30b4f9e
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/a30b4f9e

Branch: refs/heads/YARN-1011
Commit: a30b4f9e71cf53f79c38878d6cbe5bbe79bcb277
Parents: 98c9bc4
Author: Chen Liang <cliang@apache.org>
Authored: Wed Sep 19 13:22:37 2018 -0700
Committer: Chen Liang <cliang@apache.org>
Committed: Wed Sep 19 13:22:37 2018 -0700

----------------------------------------------------------------------
 .../apache/hadoop/log/LogThrottlingHelper.java  | 358 +++++++++++++++++++
 .../hadoop/log/TestLogThrottlingHelper.java     | 172 +++++++++
 .../hdfs/server/namenode/FSNamesystemLock.java  |  46 +--
 3 files changed, 547 insertions(+), 29 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hadoop/blob/a30b4f9e/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/log/LogThrottlingHelper.java
----------------------------------------------------------------------
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/log/LogThrottlingHelper.java
b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/log/LogThrottlingHelper.java
new file mode 100644
index 0000000..aa4e61c
--- /dev/null
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/log/LogThrottlingHelper.java
@@ -0,0 +1,358 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.log;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.util.HashMap;
+import java.util.Map;
+import org.apache.commons.math3.stat.descriptive.SummaryStatistics;
+import org.apache.hadoop.util.Timer;
+
+/**
+ * This is a class to help easily throttle log statements, so that they will
+ * not be emitted more frequently than a certain rate. It is useful to help
+ * prevent flooding the application logs with redundant messages.
+ *
+ * The instantiator specifies a minimum period at which statements should be
+ * logged. When {@link #record(double...)} is called, if enough time has elapsed
+ * since the last time it was called, the return value will indicate to the
+ * caller that it should write to its actual log. Note that this class does not
+ * write to any actual log; it only records information about how many times
+ * {@code record} has been called and with what arguments, and indicates to the
+ * caller whether or not it should write to its log. If not enough time has yet
+ * elapsed, this class records the arguments and updates its summary
+ * information, and indicates to the caller that it should not log.
+ *
+ * For example, say that you want to know whenever too large of a request is
+ * received, but want to avoid flooding the logs if many such requests are
+ * received.
+ * <pre>{@code
+ *   // Helper with a minimum period of 5 seconds
+ *   private LogThrottlingHelper helper = new LogThrottlingHelper(5000);
+ *
+ *   public void receiveRequest(int requestedObjects) {
+ *     if (requestedObjects > MAXIMUM_REQUEST_SIZE) {
+ *       LogAction logAction = helper.record(requestedObjects);
+ *       if (logAction.shouldLog()) {
+ *         LOG.warn("Received {} large request(s) with a total of {} objects " +
+ *             "requested; maximum objects requested was {}",
+ *             logAction.getCount(), logAction.getStats(0).getSum(),
+ *             logAction.getStats(0).getMax());
+ *       }
+ *     }
+ *   }
+ * }</pre>
+ * The above snippet allows you to record extraneous events, but if they become
+ * frequent, to limit their presence in the log to only every 5 seconds while
+ * still maintaining overall information about how many large requests were
+ * received.
+ *
+ * <p/>This class can also be used to coordinate multiple logging points; see
+ * {@link #record(String, long, double...)} for more details.
+ *
+ * <p/>This class is not thread-safe.
+ */
+public class LogThrottlingHelper {
+
+  /**
+   * An indication of what action the caller should take. If
+   * {@link #shouldLog()} is false, no other action should be taken, and it is
+   * an error to try to access any of the summary information. If
+   * {@link #shouldLog()} is true, then the caller should write to its log, and
+   * can use the {@link #getCount()} and {@link #getStats(int)} methods to
+   * determine summary information about what has been recorded into this
+   * helper.
+   *
+   * All summary information in this action only represents
+   * {@link #record(double...)} statements which were called <i>after</i> the
+   * last time the caller logged something; that is, since the last time a log
+   * action was returned with a true value for {@link #shouldLog()}. Information
+   * about the {@link #record(double...)} statement which created this log
+   * action is included.
+   */
+  public interface LogAction {
+
+    /**
+     * Return the number of records encapsulated in this action; that is, the
+     * number of times {@code record} was called to produce this action,
+     * including the current one.
+     */
+    int getCount();
+
+    /**
+     * Return summary information for the value that was recorded at index
+     * {@code idx}. Corresponds to the ordering of values passed to
+     * {@link #record(double...)}.
+     */
+    SummaryStatistics getStats(int idx);
+
+    /**
+     * If this is true, the caller should write to its log. Otherwise, the
+     * caller should take no action, and it is an error to call other methods
+     * on this object.
+     */
+    boolean shouldLog();
+
+  }
+
+  /**
+   * A {@link LogAction} representing a state that should not yet be logged.
+   * If any attempt is made to extract information from this, it will throw
+   * an {@link IllegalStateException}.
+   */
+  public static final LogAction DO_NOT_LOG = new NoLogAction();
+  private static final String DEFAULT_RECORDER_NAME =
+      "__DEFAULT_RECORDER_NAME__";
+
+  /**
+   * This throttler will not trigger log statements more frequently than this
+   * period.
+   */
+  private final long minLogPeriodMs;
+  /**
+   * The name of the recorder treated as the primary; this is the only one which
+   * will trigger logging. Other recorders are dependent on the state of this
+   * recorder. This may be null, in which case a primary has not yet been set.
+   */
+  private String primaryRecorderName;
+  private final Timer timer;
+  private final Map<String, LoggingAction> currentLogs;
+
+  private long lastLogTimestampMs = Long.MIN_VALUE;
+
+  /**
+   * Create a log helper without any primary recorder.
+   *
+   * @see #LogThrottlingHelper(long, String)
+   */
+  public LogThrottlingHelper(long minLogPeriodMs) {
+    this(minLogPeriodMs, null);
+  }
+
+  /**
+   * Create a log helper with a specified primary recorder name; this can be
+   * used in conjunction with {@link #record(String, long, double...)} to set up
+   * primary and dependent recorders. See
+   * {@link #record(String, long, double...)} for more details.
+   *
+   * @param minLogPeriodMs The minimum period with which to log; do not log
+   *                       more frequently than this.
+   * @param primaryRecorderName The name of the primary recorder.
+   */
+  public LogThrottlingHelper(long minLogPeriodMs, String primaryRecorderName) {
+    this(minLogPeriodMs, primaryRecorderName, new Timer());
+  }
+
+  @VisibleForTesting
+  LogThrottlingHelper(long minLogPeriodMs, String primaryRecorderName,
+      Timer timer) {
+    this.minLogPeriodMs = minLogPeriodMs;
+    this.primaryRecorderName = primaryRecorderName;
+    this.timer = timer;
+    this.currentLogs = new HashMap<>();
+  }
+
+  /**
+   * Record some set of values at the current time into this helper. Note that
+   * this does <i>not</i> actually write information to any log. Instead, this
+   * will return a LogAction indicating whether or not the caller should write
+   * to its own log. The LogAction will additionally contain summary information
+   * about the values specified since the last time the caller was expected to
+   * write to its log.
+   *
+   * <p/>Specifying multiple values will maintain separate summary statistics
+   * about each value. For example:
+   * <pre>{@code
+   *   helper.record(1, 0);
+   *   LogAction action = helper.record(3, 100);
+   *   action.getStats(0); // == 2
+   *   action.getStats(1); // == 50
+   * }</pre>
+   *
+   * @param values The values about which to maintain summary information. Every
+   *               time this method is called, the same number of values must
+   *               be specified.
+   * @return A LogAction indicating whether or not the caller should write to
+   *         its log.
+   */
+  public LogAction record(double... values) {
+    return record(DEFAULT_RECORDER_NAME, timer.monotonicNow(), values);
+  }
+
+  /**
+   * Record some set of values at the specified time into this helper. This can
+   * be useful to avoid fetching the current time twice if the caller has
+   * already done so for other purposes. This additionally allows the caller to
+   * specify a name for this recorder. When multiple names are used, one is
+   * denoted as the primary recorder. Only recorders named as the primary
+   * will trigger logging; other names not matching the primary can <i>only</i>
+   * be triggered by following the primary. This is used to coordinate multiple
+   * logging points. A primary can be set via the
+   * {@link #LogThrottlingHelper(long, String)} constructor. If no primary
+   * is set in the constructor, then the first recorder name used becomes the
+   * primary.
+   *
+   * If multiple names are used, they maintain entirely different sets of values
+   * and summary information. For example:
+   * <pre>{@code
+   *   // Initialize "pre" as the primary recorder name
+   *   LogThrottlingHelper helper = new LogThrottlingHelper(1000, "pre");
+   *   LogAction preLog = helper.record("pre", Time.monotonicNow());
+   *   if (preLog.shouldLog()) {
+   *     // ...
+   *   }
+   *   double eventsProcessed = ... // perform some action
+   *   LogAction postLog =
+   *       helper.record("post", Time.monotonicNow(), eventsProcessed);
+   *   if (postLog.shouldLog()) {
+   *     // ...
+   *     // Can use postLog.getStats(0) to access eventsProcessed information
+   *   }
+   * }</pre>
+   * Since "pre" is the primary recorder name, logging to "pre" will trigger a
+   * log action if enough time has elapsed. This will indicate that "post"
+   * should log as well. This ensures that "post" is always logged in the same
+   * iteration as "pre", yet each one is able to maintain its own summary
+   * information.
+   *
+   * <p/>Other behavior is the same as {@link #record(double...)}.
+   *
+   * @param recorderName The name of the recorder. This is used to check if the
+   *                     current recorder is the primary. Other names are
+   *                     arbitrary and are only used to differentiate between
+   *                     distinct recorders.
+   * @param currentTimeMs The current time.
+   * @param values The values to log.
+   * @return The LogAction for the specified recorder.
+   *
+   * @see #record(double...)
+   */
+  public LogAction record(String recorderName, long currentTimeMs,
+      double... values) {
+    if (primaryRecorderName == null) {
+      primaryRecorderName = recorderName;
+    }
+    LoggingAction currentLog = currentLogs.get(recorderName);
+    if (currentLog == null || currentLog.hasLogged()) {
+      currentLog = new LoggingAction(values.length);
+      if (!currentLogs.containsKey(recorderName)) {
+        // Always log newly created loggers
+        currentLog.setShouldLog();
+      }
+      currentLogs.put(recorderName, currentLog);
+    }
+    currentLog.recordValues(values);
+    if (primaryRecorderName.equals(recorderName) &&
+        currentTimeMs - minLogPeriodMs >= lastLogTimestampMs) {
+      lastLogTimestampMs = currentTimeMs;
+      for (LoggingAction log : currentLogs.values()) {
+        log.setShouldLog();
+      }
+    }
+    if (currentLog.shouldLog()) {
+      currentLog.setHasLogged();
+      return currentLog;
+    } else {
+      return DO_NOT_LOG;
+    }
+  }
+
+  /**
+   * A standard log action which keeps track of all of the values which have
+   * been logged. This is also used for internal bookkeeping via its private
+   * fields and methods; it will maintain whether or not it is ready to be
+   * logged ({@link #shouldLog()}) as well as whether or not it has been
+   * returned for logging yet ({@link #hasLogged()}).
+   */
+  private static class LoggingAction implements LogAction {
+
+    private int count = 0;
+    private final SummaryStatistics[] stats;
+    private boolean shouldLog = false;
+    private boolean hasLogged = false;
+
+    LoggingAction(int valueCount) {
+      stats = new SummaryStatistics[valueCount];
+      for (int i = 0; i < stats.length; i++) {
+        stats[i] = new SummaryStatistics();
+      }
+    }
+
+    public int getCount() {
+      return count;
+    }
+
+    public SummaryStatistics getStats(int idx) {
+      if (idx < 0 || idx >= stats.length) {
+        throw new IllegalArgumentException("Requested stats at idx " + idx +
+            " but this log only maintains " + stats.length + " stats");
+      }
+      return stats[idx];
+    }
+
+    public boolean shouldLog() {
+      return shouldLog;
+    }
+
+    private void setShouldLog() {
+      shouldLog = true;
+    }
+
+    private boolean hasLogged() {
+      return hasLogged;
+    }
+
+    private void setHasLogged() {
+      hasLogged = true;
+    }
+
+    private void recordValues(double... values) {
+      if (values.length != stats.length) {
+        throw new IllegalArgumentException("received " + values.length +
+            " values but expected " + stats.length);
+      }
+      count++;
+      for (int i = 0; i < values.length; i++) {
+        stats[i].addValue(values[i]);
+      }
+    }
+
+  }
+
+  /**
+   * A non-logging action.
+   *
+   * @see #DO_NOT_LOG
+   */
+  private static class NoLogAction implements LogAction {
+
+    public int getCount() {
+      throw new IllegalStateException("Cannot be logged yet!");
+    }
+
+    public SummaryStatistics getStats(int idx) {
+      throw new IllegalStateException("Cannot be logged yet!");
+    }
+
+    public boolean shouldLog() {
+      return false;
+    }
+
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/a30b4f9e/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/log/TestLogThrottlingHelper.java
----------------------------------------------------------------------
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/log/TestLogThrottlingHelper.java
b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/log/TestLogThrottlingHelper.java
new file mode 100644
index 0000000..a675d0a
--- /dev/null
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/log/TestLogThrottlingHelper.java
@@ -0,0 +1,172 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.log;
+
+import org.apache.hadoop.log.LogThrottlingHelper.LogAction;
+import org.apache.hadoop.util.FakeTimer;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Tests for {@link LogThrottlingHelper}.
+ */
+public class TestLogThrottlingHelper {
+
+  private static final int LOG_PERIOD = 100;
+
+  private LogThrottlingHelper helper;
+  private FakeTimer timer;
+
+  @Before
+  public void setup() {
+    timer = new FakeTimer();
+    helper = new LogThrottlingHelper(LOG_PERIOD, null, timer);
+  }
+
+  @Test
+  public void testBasicLogging() {
+    assertTrue(helper.record().shouldLog());
+
+    for (int i = 0; i < 5; i++) {
+      timer.advance(LOG_PERIOD / 10);
+      assertFalse(helper.record().shouldLog());
+    }
+    timer.advance(LOG_PERIOD);
+    assertTrue(helper.record().shouldLog());
+  }
+
+  @Test
+  public void testLoggingWithValue() {
+    assertTrue(helper.record(1).shouldLog());
+
+    for (int i = 0; i < 4; i++) {
+      timer.advance(LOG_PERIOD / 5);
+      assertFalse(helper.record(i % 2 == 0 ? 0 : 1).shouldLog());
+    }
+
+    timer.advance(LOG_PERIOD);
+    LogAction action = helper.record(0.5);
+    assertTrue(action.shouldLog());
+    assertEquals(5, action.getCount());
+    assertEquals(0.5, action.getStats(0).getMean(), 0.01);
+    assertEquals(1.0, action.getStats(0).getMax(), 0.01);
+    assertEquals(0.0, action.getStats(0).getMin(), 0.01);
+  }
+
+  @Test
+  public void testLoggingWithMultipleValues() {
+    assertTrue(helper.record(1).shouldLog());
+
+    for (int i = 0; i < 4; i++) {
+      timer.advance(LOG_PERIOD / 5);
+      int base = i % 2 == 0 ? 0 : 1;
+      assertFalse(helper.record(base, base * 2).shouldLog());
+    }
+
+    timer.advance(LOG_PERIOD);
+    LogAction action = helper.record(0.5, 1.0);
+    assertTrue(action.shouldLog());
+    assertEquals(5, action.getCount());
+    for (int i = 1; i <= 2; i++) {
+      assertEquals(0.5 * i, action.getStats(i - 1).getMean(), 0.01);
+      assertEquals(1.0 * i, action.getStats(i - 1).getMax(), 0.01);
+      assertEquals(0.0, action.getStats(i - 1).getMin(), 0.01);
+    }
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testLoggingWithInconsistentValues() {
+    assertTrue(helper.record(1, 2).shouldLog());
+    helper.record(1, 2);
+    helper.record(1, 2, 3);
+  }
+
+  @Test
+  public void testNamedLoggersWithoutSpecifiedPrimary() {
+    assertTrue(helper.record("foo", 0).shouldLog());
+    assertTrue(helper.record("bar", 0).shouldLog());
+
+    assertFalse(helper.record("foo", LOG_PERIOD / 2).shouldLog());
+    assertFalse(helper.record("bar", LOG_PERIOD / 2).shouldLog());
+
+    assertTrue(helper.record("foo", LOG_PERIOD).shouldLog());
+    assertTrue(helper.record("bar", LOG_PERIOD).shouldLog());
+
+    assertFalse(helper.record("foo", (LOG_PERIOD * 3) / 2).shouldLog());
+    assertFalse(helper.record("bar", (LOG_PERIOD * 3) / 2).shouldLog());
+
+    assertFalse(helper.record("bar", LOG_PERIOD * 2).shouldLog());
+    assertTrue(helper.record("foo", LOG_PERIOD * 2).shouldLog());
+    assertTrue(helper.record("bar", LOG_PERIOD * 2).shouldLog());
+  }
+
+  @Test
+  public void testPrimaryAndDependentLoggers() {
+    helper = new LogThrottlingHelper(LOG_PERIOD, "foo", timer);
+
+    assertTrue(helper.record("foo", 0).shouldLog());
+    assertTrue(helper.record("bar", 0).shouldLog());
+    assertFalse(helper.record("bar", 0).shouldLog());
+    assertFalse(helper.record("foo", 0).shouldLog());
+
+    assertFalse(helper.record("foo", LOG_PERIOD / 2).shouldLog());
+    assertFalse(helper.record("bar", LOG_PERIOD / 2).shouldLog());
+
+    // Both should log once the period has elapsed
+    assertTrue(helper.record("foo", LOG_PERIOD).shouldLog());
+    assertTrue(helper.record("bar", LOG_PERIOD).shouldLog());
+
+    // "bar" should not log yet because "foo" hasn't been triggered
+    assertFalse(helper.record("bar", LOG_PERIOD * 2).shouldLog());
+    assertTrue(helper.record("foo", LOG_PERIOD * 2).shouldLog());
+    // The timing of "bar" shouldn't matter as it is dependent on "foo"
+    assertTrue(helper.record("bar", 0).shouldLog());
+  }
+
+  @Test
+  public void testMultipleLoggersWithValues() {
+    helper = new LogThrottlingHelper(LOG_PERIOD, "foo", timer);
+
+    assertTrue(helper.record("foo", 0).shouldLog());
+    assertTrue(helper.record("bar", 0, 2).shouldLog());
+    assertTrue(helper.record("baz", 0, 3, 3).shouldLog());
+
+    // "bar"/"baz" should not log yet because "foo" hasn't been triggered
+    assertFalse(helper.record("bar", LOG_PERIOD, 2).shouldLog());
+    assertFalse(helper.record("baz", LOG_PERIOD, 3, 3).shouldLog());
+
+    // All should log once the period has elapsed
+    LogAction foo = helper.record("foo", LOG_PERIOD);
+    LogAction bar = helper.record("bar", LOG_PERIOD, 2);
+    LogAction baz = helper.record("baz", LOG_PERIOD, 3, 3);
+    assertTrue(foo.shouldLog());
+    assertTrue(bar.shouldLog());
+    assertTrue(baz.shouldLog());
+    assertEquals(1, foo.getCount());
+    assertEquals(2, bar.getCount());
+    assertEquals(2, baz.getCount());
+    assertEquals(2.0, bar.getStats(0).getMean(), 0.01);
+    assertEquals(3.0, baz.getStats(0).getMean(), 0.01);
+    assertEquals(3.0, baz.getStats(1).getMean(), 0.01);
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/a30b4f9e/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystemLock.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystemLock.java
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystemLock.java
index 5992e54..7c28465 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystemLock.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystemLock.java
@@ -26,6 +26,7 @@ import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.log.LogThrottlingHelper;
 import org.apache.hadoop.metrics2.lib.MutableRatesWithAggregation;
 import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.util.Timer;
@@ -40,6 +41,7 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_READ_LOCK_REPORT
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_READ_LOCK_REPORTING_THRESHOLD_MS_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_WRITE_LOCK_REPORTING_THRESHOLD_MS_DEFAULT;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_WRITE_LOCK_REPORTING_THRESHOLD_MS_KEY;
+import static org.apache.hadoop.log.LogThrottlingHelper.LogAction;
 
 /**
  * Mimics a ReentrantReadWriteLock but does not directly implement the interface
@@ -74,11 +76,8 @@ class FSNamesystemLock {
   private final long writeLockReportingThresholdMs;
   /** Last time stamp for write lock. Keep the longest one for multi-entrance.*/
   private long writeLockHeldTimeStampNanos;
-  private int numWriteLockWarningsSuppressed = 0;
-  /** Time stamp (ms) of the last time a write lock report was written. */
-  private long timeStampOfLastWriteLockReportMs = 0;
-  /** Longest time (ms) a write lock was held since the last report. */
-  private long longestWriteLockHeldIntervalMs = 0;
+  /** Frequency limiter used for reporting long write lock hold times. */
+  private final LogThrottlingHelper writeLockReportLogger;
 
   /** Threshold (ms) for long holding read lock report. */
   private final long readLockReportingThresholdMs;
@@ -132,6 +131,8 @@ class FSNamesystemLock {
     this.lockSuppressWarningIntervalMs = conf.getTimeDuration(
         DFS_LOCK_SUPPRESS_WARNING_INTERVAL_KEY,
         DFS_LOCK_SUPPRESS_WARNING_INTERVAL_DEFAULT, TimeUnit.MILLISECONDS);
+    this.writeLockReportLogger =
+        new LogThrottlingHelper(lockSuppressWarningIntervalMs);
     this.metricsEnabled = conf.getBoolean(
         DFS_NAMENODE_LOCK_DETAILED_METRICS_KEY,
         DFS_NAMENODE_LOCK_DETAILED_METRICS_DEFAULT);
@@ -251,25 +252,11 @@ class FSNamesystemLock {
     final long writeLockIntervalMs =
         TimeUnit.NANOSECONDS.toMillis(writeLockIntervalNanos);
 
-    boolean logReport = false;
-    int numSuppressedWarnings = 0;
-    long longestLockHeldIntervalMs = 0;
+    LogAction logAction = LogThrottlingHelper.DO_NOT_LOG;
     if (needReport &&
         writeLockIntervalMs >= this.writeLockReportingThresholdMs) {
-      if (writeLockIntervalMs > longestWriteLockHeldIntervalMs) {
-        longestWriteLockHeldIntervalMs = writeLockIntervalMs;
-      }
-      if (currentTimeMs - timeStampOfLastWriteLockReportMs >
-          this.lockSuppressWarningIntervalMs) {
-        logReport = true;
-        numSuppressedWarnings = numWriteLockWarningsSuppressed;
-        numWriteLockWarningsSuppressed = 0;
-        longestLockHeldIntervalMs = longestWriteLockHeldIntervalMs;
-        longestWriteLockHeldIntervalMs = 0;
-        timeStampOfLastWriteLockReportMs = currentTimeMs;
-      } else {
-        numWriteLockWarningsSuppressed++;
-      }
+      logAction = writeLockReportLogger
+          .record("write", currentTimeMs, writeLockIntervalMs);
     }
 
     coarseLock.writeLock().unlock();
@@ -278,13 +265,14 @@ class FSNamesystemLock {
       addMetric(opName, writeLockIntervalNanos, true);
     }
 
-    if (logReport) {
-      FSNamesystem.LOG.info("FSNamesystem write lock held for " +
-          writeLockIntervalMs + " ms via\n" +
-          StringUtils.getStackTrace(Thread.currentThread()) +
-          "\tNumber of suppressed write-lock reports: " +
-          numSuppressedWarnings + "\n\tLongest write-lock held interval: " +
-          longestLockHeldIntervalMs);
+    if (logAction.shouldLog()) {
+      FSNamesystem.LOG.info("FSNamesystem write lock held for {} ms via {}\t" +
+          "Number of suppressed write-lock reports: {}\n\tLongest write-lock " +
+          "held interval: {} \n\tTotal suppressed write-lock held time: {}",
+          writeLockIntervalMs,
+          StringUtils.getStackTrace(Thread.currentThread()),
+          logAction.getCount() - 1, logAction.getStats(0).getMax(),
+          logAction.getStats(0).getSum() - writeLockIntervalMs);
     }
   }
 


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