[HDFS-14863] Remove Synchronization From BlockPlacementPolicyDefault

• Type: Improvement
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.2.0
• Component/s: block placement
• Flags: Patch
• Assignee: David Mollitor
• Reporter: David Mollitor
• Created: 20/Sep/19 16:44
• Updated: 25/Sep/19 19:48

Description

https://github.com/apache/hadoop/blob/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java#L1010

The clusterMap has its own internal synchronization. Also, these are only read operations so any changes applied to the clusterMap from another thread will be applied since no other thread synchronizes on the clusterMap itself (that I could find).