[HDFS-14260] Replace synchronized method in BlockReceiver with atomic value

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.2.0
• Fix Version/s: 3.3.0
• Component/s: datanode
• Hadoop Flags: Reviewed
• Assignee: David Mollitor
• Reporter: David Mollitor
• Created: 07/Feb/19 21:51
• Updated: 08/Aug/19 04:21
• Resolved: 11/Feb/19 18:10

Description

This synchronized block is protecting lastSentTime which is a native long. Can use AtomicLong and remove this synchronization.

  synchronized boolean packetSentInTime() {
    long diff = Time.monotonicNow() - lastSentTime;
    if (diff > maxSendIdleTime) {
      LOG.info("A packet was last sent " + diff + " milliseconds ago.");
      return false;
    }
    return true;
  }

https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockReceiver.java#L392-L399

Issue Links

• links to: GitHub Pull Request #483