Merge

7020042: G1: Partially remove fix for 6994628 Summary: Disable reference discovery and processing during concurrent marking by disabling fix for 6994628. Reviewed-by: tonyp, ysr

7027766: G1: introduce flag to dump the liveness information per region at the end of marking Summary: Repurpose the existing flag G1PrintRegionLivenessInfo to print out the liveness distribution across the regions in the heap at the end of marking. Reviewed-by: iveresov, jwilhelm

7033292: G1: nightly failure: Non-dirty cards in region that should be dirty Summary: The epochs on the card cache array are initialized to 0 and our initial epoch also starts at 0. So, until the first GC, it might be possible to successfully "claim" a card which was in fact never initialized. Reviewed-by: johnc, iveresov, ysr

7023069: G1: Introduce symmetric locking in the slow allocation path 7023151: G1: refactor the code that operates on _cur_alloc_region to be re-used for allocs by the GC threads 7018286: G1: humongous allocation attempts should take the GC locker into account Summary: First, this change replaces the asymmetric locking scheme in the G1 slow alloc path by a summetric one. Second, it factors out the code that operates on _cur_alloc_region so that it can be re-used for allocations by the GC threads in the future. Reviewed-by: stefank, brutisso, johnc

7029458: G1: Add newly-reclaimed regions to the beginning of the region free list, not the end Summary: What the synopsis says. Reviewed-by: jwilhelm, iveresov, johnc

7026932: G1: No need to abort VM when card count cache expansion fails Summary: Manage allocation/freeing of the card cache counts and epochs arrays directly so that an allocation failure while attempting to expand these arrays does not abort the JVM. Failure to expand these arrays is not fatal. Reviewed-by: iveresov, tonyp