Summary: Fix block_size_if_printezis_bits() so it does not expect the bits, only uses them when available. Fix block_size_no_stall() so it does not stall when the bits are missing such cases, letting the caller deal with zero size returns. Constant pool cache oops do not need to be unparsable or conc_unsafe after their klass pointer is installed. Some cosmetic clean-ups and some assertion checking for conc-usafety which, in the presence of class file redefinition, has no a-priori time boundedness, so all GCs must be able to safely deal with putatively conc-unsafe objects in a stop-world pause.
Reviewed-by: jmasa, johnc

Summary: Sometimes the gc cause was not always set. This caused JStat to print the wrong information.
Reviewed-by: tonyp, ysr
Contributed-by: suenaga.yasumasa@oss.ntt.co.jp

Summary: Initialize _sum_x_squared, _intercept and _slope in constructor.
Reviewed-by: bobv, coleenp

7007446: G1: expand the heap with a single step, not one region at a time
Summary: Changed G1CollectedHeap::expand() to expand the committed space by calling VirtualSpace::expand_by() once rather than for every region in the expansion amount. This allows the success or failure of the expansion to be determined before creating any heap regions. Introduced a develop flag G1ExitOnExpansionFailure (false by default) that, when true, will exit the VM if the expansion of the committed space fails. Finally G1CollectedHeap::expand() returns a status back to it's caller so that the caller knows whether to attempt the allocation.
Reviewed-by: brutisso, tonyp

Summary: The reference handler java thread and the GC could dead lock
Reviewed-by: never, johnc, jcoomes

Summary: Fix calculation of _desired, in free list statistics, which was missing an intended set of parentheses.
Reviewed-by: poonam, jmasa

Summary: There's a potential deadlock between the concurrent cleanup thread and the GC workers that are trying to allocate and waiting for more free regions to be made available.
Reviewed-by: iveresov, jcoomes

Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank

Summary: Update the Major and Build numbers for HS21
Reviewed-by: jcoomes

Summary: A race between the concurrent cleanup thread and the VM thread while it is processing the "expanded sparse table list" causes both threads to try to free the same sparse table entry and either causes one of the threads to fail or leaves the entry in an inconsistent state. The solution is purge all entries on the expanded list that correspond go regions that are being cleaned up.
Reviewed-by: brutisso, johnc

Summary: Use lea to compute field address in AtomicLongCSImpl::attemptUpdate() intrinsic on x86.
Reviewed-by: never, kvn

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

Summary: Restore use of stillborn flag
Reviewed-by: acorn, alanb

Reviewed-by: iveresov, twisti

Reviewed-by: iveresov, twisti

Summary: Two small fixes to deal with a guarantee failure (the marking thread should join the SuspendibleThreadSet before calling a method that does pause prediction work so that said method is never called during a pause) and an assert failure (an assert is too strong).
Reviewed-by: iveresov, johnc

Summary: Use long jumps to get from patching stubs to deopt blob
Reviewed-by: kvn, never

Summary: Currently escape analysis is turned off when EnableInvokeDynamic is true.
Reviewed-by: jrose, kvn

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: Rebuild breakpoint cache at gc_epilogue instead of during oops_do
Reviewed-by: dcubed, ysr, coleenp

Summary: With recent G1 allocation path changes, the value of StackShadowPages in fast debug builds of the JVM, is no longer large enough to prevent the JVM C++ code from touching the stack guard pages. Increase the value of StackShadowPages to a suitable value.
Reviewed-by: ysr, tonyp, coleenp

Summary: The Relocator should pass a NULL methodOop when rewriting since its resource array can never contain breakpoints.
Reviewed-by: dcubed, kvn, coleenp

Summary: Refine assertion to work before VMThread has started.
Reviewed-by: ysr, never, dholmes, acorn

Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads.
Reviewed-by: johnc, ysr