[HBASE-10116] SlabCache metrics improvements

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.98.0, 0.96.2, 0.99.0
• Component/s: metrics, regionserver
• Hadoop Flags: Reviewed

Release Note

This change introduces DirectMemory reporting to the RegionServer status page. Oracle JDK6 (1.6.0_31 in my test) doesn't expose "java.nio:type=BufferPool,name=direct", so DirectMemoryUtils#getDirectMemoryUsage (and thus the change to rs-status#memoryStats) reports 0 on that environment, even when DirectMemory is being consumed.

• Assignee: Nick Dimiduk
• Reporter: Nick Dimiduk
• Created: 10/Dec/13 01:10
• Updated: 21/Feb/15 23:32
• Resolved: 12/Dec/13 20:51

Description

SlabCache incorrectly reports block count and could do a better job reporting free size. MetricsRegionServerWrapperImpl incorrectly reports block cache count. Expose Direct Memory stats on RegionServer WebUI.

Also clean up javadoc on BlockCache interface methods, and whitespace in cache-related classes.