7034139: G1: assert(Thread::current()->is_ConcurrentGC_thread()) failed: only a conc GC thread can call this.
Summary: We were calling STS join and leave during a STW pause and we are not suppoesed to. I now only call those during  concurrent phase. I also added stress code in the non-product builds to force an overflows (the condition that ws uncovering the bug) to make sure it does not happen again.
Reviewed-by: johnc, brutisso

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

Summary: Implement support for ParallelRefProcEnabled in the reference processing that takes place at the end of G1 concurrent marking.
Reviewed-by: tonyp, ysr

Summary: This changeset removes the zero-filling thread from G1 and collapses the two free region lists we had before (the "free" and "unclean" lists) into one. The new free list uses the new heap region sets / lists abstractions that we'll ultimately use it to keep track of all regions in the heap. A heap region set was also introduced for the humongous regions. Finally, this change increases the concurrency between the thread that completes freeing regions (after a cleanup pause) and the rest of the system (before we'd have to wait for said thread to complete before allocating a new region). The changest also includes a lot of refactoring and code simplification.
Reviewed-by: jcoomes, johnc

Summary: Initialize the _is_alive_non_header field of G1's reference processor with an instance of the G1CMIsAliveClosure. This will stop adding reference objects with live referents to the discovered reference lists unnecessarily.
Reviewed-by: tonyp, ysr, jwilhelm, brutisso

Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

Summary: Re-enable use of the lock-free versions of region stack push() and pop() by recording aborted regions in a thread-local structure, which are then processed when scanning of the region stack restarts. The previous locking versions of these routines are retained for diagnostic purposes.
Reviewed-by: tonyp, ysr

Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

6871109: G1: remove the concept of the scan only prefix
Summary: Removed scan only regions and associated code. The young portion of the collection set is now constructed incrementally - when a young region is retired as the current allocation region it is added to the collection set.
Reviewed-by: apetrusenko, iveresov, tonyp

Summary: Calling the methods region_stack_push() and region_stack_pop() concurrent is not MT-safe. The assumption is that we will only call region_stack_push() during a GC pause and region_stack_pop() during marking. Unfortunately, we also call region_stack_push() during marking which seems to be introducing subtle marking failures. This change introduces lock-based methods for pushing / popping to be called during marking.
Reviewed-by: iveresov, johnc

Summary: Various fixes to the G1 debugging output.
Reviewed-by: johnc, iveresov

Summary: Use an explicit stack for object arrays and process them in chunks.
Reviewed-by: iveresov, apetrusenko

Summary: change more guarantees in concurrent marking into asserts.
Reviewed-by: apetrusenko, iveresov

Summary: When G1 is enabled, thread dumps are inconsistent as the info for some of the G1 threads is not formatted properly.
Reviewed-by: ysr, johnc

Summary: Revamp the reachable object dump debugging facility.
Reviewed-by: jmasa, apetrusenko

Summary: Removing the concurrent overhead tracker from G1, along with the GC overhead reporter and the G1AccountConcurrentOverhead (both of which rely on the the concurrent overhead tracker).
Reviewed-by: iveresov, johnc

Summary: Modifications to G1 so as to allow the use of compressed oops.
Reviewed-by: apetrusenko, coleenp, jmasa, kvn, never, phh, tonyp

Summary: Update copyright for files that have been modified in 2009, up to 03/09
Reviewed-by: katleman, tbell, ohair

Reviewed-by: tonyp

Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr