[HADOOP-10593] Concurrency Improvements

• Type: Improvement
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Assignee: Benoy Antony
• Reporter: Benoy Antony
• Created: 09/May/14 16:11
• Updated: 09/May/14 16:19

Description

This is an umbrella jira to improve the concurrency of a few classes by making use of safe publication idioms. Most of the improvements are based on the following:

To publish an object safely, both the reference to the object and the object's state must be made visible to other threads at the same time. A properly constructed object can be safely published by:

• Initializing an object reference from a static initializer;
• Storing a reference to it into a volatile field or AtomicReference;
• Storing a reference to it into a final field of a properly constructed object; or
• Storing a reference to it into a field that is properly guarded by a lock.

Issue Links

• is related to: HADOOP-10448 Support pluggable mechanism to specify proxy user settings
• is related to: HADOOP-10590 ServiceAuthorizationManager is not threadsafe
• is related to: HDFS-6363 Improve concurrency while checking inclusion and exclusion of datanodes

Sub-Tasks

• Improve Concurrency in Groups: Patch Available
• Improve concurrency in HostFileReader: Open