JDK-8027746 : Remove do_gen_barrier template parameter in G1ParCopyClosure
- Type: Enhancement
- Component: hotspot
- Sub-Component: gc
- Affected Version: hs25,8
- Priority: P5
- Status: Resolved
- Resolution: Fixed
- Submitted: 2013-11-02
- Updated: 2014-07-29
- Resolved: 2014-01-20
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| JDK 8 | JDK 9 |
|---|---|
8u20Fixed  |
9 b03Fixed |
Description
The do_gen_barrier template parameter is set to false in all closures that are used in G1. Further, the code added by this template parameter in G1ParCopyClosure::do_oop_work is conceptually flawed anyway: it calls ParScanClosure::par_do_barrier(), which does not work in G1. In particular, it uses OopsInGenClosure::gen_boundary() which cannot be used in G1. Also remove the G1ParScanAndMarkClosure typedef which is the only one that sets this do_gen_barrier template parameter to true, but is otherwise unreferenced. I also think OopsInHeapRegionClosure should inherit from ExtendedOopClosure, not OopsInGenClosure, as G1 does not have such a simple view on generations as other collectors (i.e. a simple address boundary). This would also decrease memory footprint of closures, possibly increasing locality of access of other members that are actually accessed in the oop closures.
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