Summary: Make sure that two marking cycles do not overlap, i.e., a new one can only start after the concurrent marking thread finishes all its work. In the fix I piggy-back a couple of minor extra fixes: some general code reformatting for consistency (only around the code I modified), the removal of a field (G1CollectorPolicy::_should_initiate_conc_mark) which doesn't seem to be used at all (it's only set but never read), as well as moving the "is GC locker active" test earlier into the G1 pause / Full GC and using a more appropriate method for it.
Reviewed-by: johnc, jmasa, jcoomes, ysr

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: Enable parallel RSet updating and scanning.
Reviewed-by: iveresov, jmasa

Summary: Remove the G1GCPercent parameter, that specifies the desired GC overhead percentage in G1, and observe the GCTimeRatio parameter instead.
Reviewed-by: jmasa, johnc

Summary: Update the HS18 build number to 02
Reviewed-by: jcoomes

Summary: Fix build.bat so invoking command shell doesn't exit on error. Fix dirname assumptions. Document some MKS environment dependencies.
Reviewed-by: coleenp

Summary: Remove assert to decouple JDK and HotSpot additions of known types.
Reviewed-by: mchung

Summary: Update the Major and build numbers for HS18 fork
Reviewed-by: jcoomes

Summary: Add close to returns (fix for 6929067 also contributed by aph)
Reviewed-by: aph, dcubed, andrew, acorn
Contributed-by: aph@redhat.com, andreas.kohn@fredhopper.com

Summary: process one item at a time from the objarray stack/queue
Reviewed-by: apetrusenko, tonyp

Summary: Newly-created threads always had the active field of their SATB queue initialized to false, even if they were created during marking. As a result, updates from threads created during a marking cycle were never enqueued and never processed. The fix includes remaining a method from active() to is_active() for readability and naming consistency.
Reviewed-by: ysr, johnc

Summary: Some code cleanups found during the JSR 292 SPARC port.
Reviewed-by: kvn, never

Summary: If CM task was aborted while scanning the last object of the specified region and the size of that object is equal to bitmap's granularity then the next offset would be equal or over the region limit which is exactly what the assertion states.
Reviewed-by: ysr, tonyp, jmasa

Reviewed-by: kvn

Summary: Added missing counter decrement when substring search restarted.
Reviewed-by: twisti

Summary: Adding probes related to thread scheduling and class initialization
Reviewed-by: kamg, never

Summary: The logic for x86 C1 to save the SP over MH calls is pretty straight forward but SPARC handles that differently.
Reviewed-by: never, jrose

Summary: Clean up get_msc_ver, build.bat and build.make in general and for Cygwin.
Reviewed-by: ohair

Summary: Add missing guard.
Reviewed-by: never

Summary: Passing a null pointer to an InvokeDynamic function call should lead to a NullPointerException.
Reviewed-by: kvn, never

Summary: Use -XX:+TraceSafepointCleanupTime to print out the details of each clean up tasks.
Reviewed-by: dholmes, ysr

Summary: Add code to unmap stack guard area when thread is detached.
Reviewed-by: coleenp, kamg

Summary: A TLAB became large enough to be considered a humongous object allowing multiple objects to be allocated in a humongous region, which violates a basic assumption about humongous regions. The changes ensure that TLABs cannot be regarded as humongous.
Reviewed-by: iveresov, tonyp

Summary: The fix for 6927165 increased the number of shadow pages for 32-bit platforms and this causes a problem on systems with 64kb pages.
Reviewed-by: twisti
Contributed-by: NGary Benson <gbenson@redhat.com>