JDK-8200545 : Improve filter for enqueued deferred cards
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 11
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2018-03-30
  • Updated: 2019-07-16
  • Resolved: 2019-05-14
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JDK 13
13 b21Fixed
Related Reports
Duplicate :  
JDK-8067920 - Rename InCSetState to something more understandable
Relates :  
JDK-8227739 - Merge cost predictions for scanning cards and log buffer entries
Relates :  
JDK-8213108 - Improve work distribution during remembered set scan
Relates :  
JDK-8197928 - Only enqueue deferred cards with references into regions that have a tracked remembered set during GC
Relates :  
JDK-8225418 - G1: region attribute remembered set state disagrees with actual remembered set state
Description
In JDK-8197928 we introduced a filter to not enqueue deferred cards for regions we do not track the remembered sets for during gc based on whether the target region. This has been a very simple and presumably slow filter.

Do some more improvements / tests to see whether this can and should be improved.

One suggestion is to use a per-region array with flags indicating whether this region has a remembered set.