Summary: Some optimizations to improve the concurrent marking phase: specialize the main oop closure, make sure a few methods in the fast path are properly inlined, a few more bits and pieces, and some cosmetic fixes.
Reviewed-by: stefank, johnc

7042285: G1: native memory leak during humongous object allocation
6804436: G1: heap region indices should be size_t
Summary: A series of fixes and improvements to the HeapRegionSeq class: a) replace the _regions growable array with a standard C array, b) avoid de-allocating / re-allocating HeapRegion instances when the heap shrinks / grows (fix for 7042285), c) introduce fast method to map address to HeapRegion via a "biased" array pointer, d) embed the _hrs object in G1CollectedHeap, instead of pointing to it via an indirection, e) assume that all the regions added to the HeapRegionSeq instance are contiguous, f) replace int's with size_t's for indexes (and expand that to HeapRegion as part of 6804436), g) remove unnecessary / unused methods, h) rename a couple of fields (_alloc_search_start and _seq_bottom), i) fix iterate_from() not to always start from index 0 irrespective of the region passed to it, j) add a verification method to check the HeapRegionSeq assumptions, k) always call the wrappers for _hrs.iterate(), _hrs_length(), and _hrs.at() from G1CollectedHeap, not those methods directly, and l) unify the code that expands the sequence (by either re-using or creating a new HeapRegion) and make it robust wrt to a HeapRegion allocation failing.
Reviewed-by: stefank, johnc, brutisso

Summary: make the method non-virtual, remove five unused closures, and fix a couple of copyright typos.
Reviewed-by: stefank, johnc, poonam

Summary: This changeset extends the logging information generated by +PrintGCDetails to also print out separate size transitions for the eden, survivors, and old regions.
Reviewed-by: ysr, brutisso

Summary: During an evacuation pause clear the region fields of any concurrent marking task whose local finger points into the collection set as the values in the region fields will become stale. Clearing these fields causes the concurrent mark task to claim a new region when marking restarts after the pause.
Reviewed-by: tonyp, iveresov

Summary: Add a notification to the GarbageCollectorMXBeans
Reviewed-by: acorn, mchung

7040450: G1: assert((_g1->evacuation_failed()) || (!_g1->obj_in_cs(obj))) failed: shouldn't still be in ...
Summary: There is a race in the evac failure handling code that causes the condition the assert checks not to be true. The fix is to replace the too-strong assert with a more targeted one.
Reviewed-by: johnc, ysr, jcoomes

Summary: Implement a more accurate is_scavengable()
Reviewed-by: stefank, jcoomes, ysr

7035144: G1: nightly failure: Non-dirty cards in region that should be dirty (failures still exist...)
Summary: We should only undirty cards after we decide that they are not on a young region, not before. The fix also includes improvements to the verify_dirty_region() method which print out which cards were not found dirty.
Reviewed-by: johnc, brutisso

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: In G1 heap verification, we no longer scan perm to G1-collected heap refs as part of process_strong_roots() but rather in a separate explicit oop iteration over the perm gen. This preserves the original perm card-marks. Added a new assertion in younger_refs_iterate() to catch a simple subcase where the user may have forgotten a prior save_marks() call, as happened in the case of G1's attempt to iterate perm to G1 refs when verifying the heap before exit. The assert was deliberately weakened for ParNew+CMS and will be fixed for that combination in a future CR. Also made some (non-G1) cleanups related to code and comments obsoleted by the migration of Symbols to the native heap.
Reviewed-by: iveresov, jmasa, tonyp

Summary: Added counters for jstat
Reviewed-by: tonyp, jwilhelm, stefank, ysr, johnc

Summary: It introduces non-product cmd line parameter G1DummyRegionsPerGC which indicates how many "dummy" regions to allocate at the end of each GC. This allows the G1 heap to grow artificially and makes concurrent marking cycles more frequent irrespective of what the application that is running is doing. The dummy regions will be found totally empty during cleanup so this parameter can also be used to stress the concurrent cleanup operation.
Reviewed-by: brutisso, johnc

Summary: Missing parentheses around a casted expression and some missing casts were causing build failures with the jdk6 build tools.
Reviewed-by: kvn, brutisso

Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes

7010070: Update all 2010 Oracle-changed OpenJDK files to have the proper copyright dates - second pass
Summary: Update the copyright to be 2010 on all changed files in OpenJDK
Reviewed-by: ohair

Summary: Use _max_num_q = max(discovery_degree, processing_degree), and let balance_queues() redistribute from discovery_degree to processing_degree of queues. This should also allow a more dynamic and flexible parallelism policy in the future.
Reviewed-by: jmasa, johnc

7023747: G1: too strict assert in RefineRecordRefsIntoCSCardTableEntryClosure::do_card_ptr in g1RemSet.cpp
Summary: Made sure that the assert looks at ParallelGCThreads.
Reviewed-by: stefank, tonyp, jwilhelm, johnc

Summary: Introduced buffered loggging to make sure that log lines are logged one line at a time
Reviewed-by: stefank, johnc, dsamersoff

Summary: Some G1 code cleanup.
Reviewed-by: johnc, jcoomes, jwilhelm

Summary: Bulk zeroing reduction didn't work with G1, because arraycopy would call pre-barriers on uninitialized oops. The solution is to have version of arraycopy stubs that don't have pre-barriers. Also refactored arraycopy stubs generation on SPARC to be more readable and reduced the number of stubs necessary in some cases.
Reviewed-by: jrose, kvn, never

Summary: Make the G1 specific version of is_in_closed_subset() available in all builds.
Reviewed-by: tonyp, jcoomes

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

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: 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

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

Summary: What the synopsis says.
Reviewed-by: jwilhelm, iveresov, johnc

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

Summary: Changed default value of WorkStealingYieldsBeforeSleep from 1000 to 5000. Added more information to G1 pause logging.
Reviewed-by: jwilhelm, tonyp, jmasa

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

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

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: 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: 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

Summary: Pass the value of UseLargePages instead of false as the "large" parameter when reserving the G1 heap.
Reviewed-by: tonyp, johnc, phh