6774607: SIGSEGV or (!is_null(v),"oop value can never be zero") assertion when running with CMS and COOPs Summary: Use the more permissive set_klass_or_null() and klass_or_null() interfaces in ParNew's workqueue overflow code that manipulates the klass-word. Reviewed-by: coleenp

6684579: SoftReference processing can be made more efficient Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not. Reviewed-by: jmasa

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

Merge

6474243: suspicious jvmti code that uses oop unsafely across GC point Summary: oop stored in unsafely in Lscratch noticed by visual inspection will not be updated by GC. Reviewed-by: kamg, never, kvn

6554406: Change switch UseVMInterruptibleIO default to false (sol) Summary: The default value of UseVMInterruptibleIO is changed to false for JDK 7, but the default isn't changed for JDK 6 and earlier. Reviewed-by: never, acorn, dholmes, kamg, alanb

Merge