JDK-6995781 : RFE: Native Memory Tracking (Phase 1)
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 8-pool
  • Priority: P2
  • Status: Closed
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2010-10-28
  • Updated: 2017-05-16
  • Resolved: 2012-07-14
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JDK 7 JDK 8 Other
7u40Fixed 8Fixed hs24Fixed
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Description
NMT = Native Memory Tracking

NMT Phase 1 tracks native memory allocations by the JVM itself

An initial approach to NMT Phase 1 includes:
1. Import Doug Lea's malloc to hotspot
2. Utilize mspace to "group" different types of objects
3. Further marking object types using spare bits in malloc header
4. Implement callsite statistics and per chunk callsite tracking (JRockit memory tracking feature)
5. Disable/Enable locking
6. mspace cleanup
Phrase 1 only tracks VM native memory usage. There are a few design changes vs. documented in description section:

1. No malloc library is imported, contine using platform's malloc implementation.
2. Native memory tracking is implemented on top of all current VM memory management systems.

Comments
Feature verified by NMT tests developed according to test plan
12-06-2013

EVALUATION http://hg.openjdk.java.net/hsx/hotspot-emb/hotspot/rev/d2a62e0f25eb
14-07-2012

EVALUATION http://hg.openjdk.java.net/hsx/hotspot-rt/hotspot/rev/d2a62e0f25eb
28-06-2012