hg: jdk7/hotspot-gc/hotspot: 6722113: CMS: Incorrect overflow handling during precleaning of Reference lists

y.s.ramakrishna at sun.com y.s.ramakrishna at sun.com
Thu Nov 20 23:23:39 UTC 2008


Changeset: 00b023ae2d78
Author:    ysr
Date:      2008-11-20 12:27 -0800
URL:       http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/00b023ae2d78

6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery.
Reviewed-by: apetrusenko, jcoomes

! src/share/vm/gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp
! src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
! src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp
! src/share/vm/memory/referenceProcessor.cpp
! src/share/vm/runtime/globals.hpp




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