[HADOOP-18740] s3a prefetch cache blocks should be accessed by RW locks

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.6
• Fix Version/s: 3.3.6
• Labels: pull-request-available
• Assignee: Viraj Jasani
• Reporter: Viraj Jasani
• Created: 11/May/23 21:24
• Updated: 21/Jan/24 01:11
• Resolved: 09/Jun/23 17:05

Description

In order to implement LRU or LFU based cache removal policies for s3a prefetched cache blocks, it is important for all cache reader threads to acquire read lock and similarly cache file removal mechanism (fs close or cache eviction) to acquire write lock before accessing the files.

As we maintain the block entries in an in-memory map, we should be able to introduce read-write lock per cache file entry, we don't need coarse-grained lock shared by all entries.

 

This is a prerequisite to HADOOP-18291.

Issue Links

• is related to: HADOOP-18756 CachingBlockManager to use AtomicBoolean for closed flag
• links to: GitHub Pull Request #5675
• links to: https://github.com/apache/hadoop/pull/5675