JDK-8151386 : Extract card live data out of G1ConcurrentMark
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 9
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2016-03-07
  • Updated: 2018-06-21
  • Resolved: 2016-04-06
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JDK 9
9 b116Fixed
Related Reports
Blocks :  
JDK-8077144 - Concurrent mark initialization takes too long
Blocks :  
JDK-8153170 - Card Live Data does not correctly handle eager reclaim
Blocks :  
JDK-8151846 - Record the number of live cards per region while creating live data
Relates :  
JDK-8154838 - G1CardLiveData::free_large_bitmap() uses wrong calculation to determine the number of words
Relates :  
JDK-8017163 - G1: Refactor remembered sets
Relates :  
JDK-8153843 - G1CardLiveDataHelper incorrectly sets next_live_bytes on dead humongous regions
Relates :  
JDK-8152932 - Investigate optimal method to set bits in card live data
Description
G1ConcurrentMark provides information about the liveness in cards on a per-region basis.

This information will be crucial for improving remembered set scanning performance. It is prudent to extract this information into a separate data holder class so that we do not need to pass around G1ConcurrentMark everywhere.

Extract this information (per-card liveness, per-region liveness, and a new per-region live number of cards map) into a separate class to be owned by G1RemSet and passed around instead of multiple parameters.

Also clean up the code a little, adding basic logging and memory deallocation.