Summary: Some parts of the G1 heap can only be walked during a safepoint. Skip verifying these parts of the heap when verifying during JVM startup.
Reviewed-by: brutisso, tschatzl

Summary: Keep a counter of how many times we were stalled by the GC locker, add a diagnostic flag which sets the limit.
Reviewed-by: brutisso, ehelin, johnc

Summary: If the marking stack overflows while the marking tasks are draining the SATB buffers, remark will exit with some SATB buffers left unprocessed. Relax the guarantee to allow for overflow.
Reviewed-by: jmasa, brutisso

Summary: Skip reference processing if the global marking stack overflows during remark. Refactor and rename set_phase(); move code that sets the concurrency level into its own routine. Do not call set_phase() from within parallel reference processing; use the concurrency level routine instead. The marking state should only set reset by CMTask[0] during the concurrent phase of the marking cycle; if an overflow occurs at any stage during the remark, the marking state will be reset after reference processing.
Reviewed-by: brutisso, jmasa

Summary: In CMTask::do_marking_step(), Skip offering termination and entering the first and second synchronization barriers if called from a serial context, i.e. the VM thread.
Reviewed-by: brutisso, tschatzl

Summary: ASSERT and other symbols used incorrectly with #if are supposed to be defined or not.
Reviewed-by: dholmes, mikael

Summary: Update the task local finger to the start of the next object when marking aborts, in order to avoid the redundant scanning of all 0's when the marking task restarts, if otherwise updating to the next word. In addition, reuse the routine nextObject() in routine iterate().
Reviewed-by: johnc, ysr
Contributed-by: Ntamao <tao.mao@oracle.com>

Summary: Stop adding old regions to collection set when the remaining reclaimable bytes reaches, or goes below, G1HeapWastePercent. Changes were also reviewed by Vitaly Davidovich <vitalyd@gmail.com>.
Reviewed-by: brutisso

Summary: Add timer units to concurrent marking phases where the units were missing.
Reviewed-by: jmasa, ysr

Reviewed-by: brutisso, johnc
Contributed-by: vladimir.kempik@oracle.com

Summary: Reuse the parallel reference processing oop closures during serial reference processing.
Reviewed-by: brutisso

Summary: Set ConcGCThreads to the calculated number of marking threads.
Reviewed-by: jmasa, ysr

Summary: Check that the concurrent marking worker gang exists in ConcurrentMark::print_worker_threads_on(). Changes were also reviewed by Vitaly Davidovich <vitalyd@gmail.com>.
Reviewed-by: brutisso

8007772: G1: assert(!hr->isHumongous() || mr.start() == hr->bottom()) failed: the start of HeapRegion and MemRegion should be consistent for humongous regions
Summary: In do_marking_step(), we should always give up current region after scanning the object, if the region is humongous.
Reviewed-by: brutisso, jwilhelm, tamao

Summary: Use Stack<> instead of GrowableArray to keep track of preserved marks. Also reviewed by vitalyd@gmail.com.
Reviewed-by: johnc, jcoomes

Summary: Flags changed to be of uintx type
Reviewed-by: johnc, tamao

Summary: Skip unnecessary scanning of bitmap for unmarked humongous objects/regions.
Reviewed-by: jwilhelm, johnc
Contributed-by: NTao Mao <tao.mao@oracle.com>

Summary: Rename INCLUDE_ALTERNATE_GCS to INCLUDE_ALL_GCS and replace SERIALGC with INCLUDE_ALL_GCS.
Reviewed-by: coleenp, stefank

Summary: Also reviewed by vitalyd@gmail.com.
Reviewed-by: johnc, mgerdin

Summary: Changes to default and ergonomic flag values recommended by performance team. Changes were also reviewed by Monica Beckwith <monica.beckwith@oracle.com>.
Reviewed-by: brutisso, huntch

Reviewed-by: johnc, ysr

Summary: Reset the marking state, including the mark stack overflow flag, in the event of a marking stack overflow during serial reference processing.
Reviewed-by: jmasa

Summary: Rename G1DefaultMinNewGenPercent, G1DefaultMaxNewGenPercent, and G1OldCSetRegionLiveThresholdPercent to G1NewSizePercent, G1MaxNewSizePercent, and G1MixedGCLiveThresholdPercent respectively. The previous names are no longer accepted.
Reviewed-by: brutisso, ysr

Summary: Remove bit-rotten ValidateMarkSweep functionality and flag.
Reviewed-by: johnc, jmasa
Contributed-by: Ntamao <tao.mao@oracle.com>

Summary: Add flushes to G1CollectedHeap::log_gc_footer() and TraceCPUTime destructor.
Reviewed-by: jwilhelm, azeemj, brutisso

Summary: Add detailed error messages to assertions and guarantees in G1's block offset table.
Reviewed-by: ysr, brutisso

Reviewed-by: dholmes, rbackman, coleenp

Summary: Restore non-silent output of heap verification.
Reviewed-by: ysr, brutisso, jmasa

Summary: Update copyright year to 2012 for relevant files
Reviewed-by: dholmes, coleenp

Summary: Missing call to MetaspaceAux::print_on() in G1CollectedHeap::print_on().
Reviewed-by: azeemj, jmasa
Contributed-by: NMikael Gerdin <mikael.gerdin@oracle.com>

Summary: Change the type of various task num fields, parameters etc to unsigned and rename them to be more consistent with the other collectors. Code changes were also reviewed by Vitaly Davidovich.
Reviewed-by: johnc
Contributed-by: NKaushik Srenevasan <kaushik@twitter.com>

Summary: Divide by zero error, if ParallelGCThreads is 0, when adjusting the PLAB size.
Reviewed-by: jmasa, jcoomes

Summary: Change the flags and variables related to tenuring threshold to be unsigned
Reviewed-by: jmasa, johnc

Summary: Set the value of MarkStackSize to a value based on the number of parallel marking threads with a reasonable minimum. Expand the marking stack if we have to restart marking due to an overflow up to a reasonable maximum. Allocate the underlying space for the marking stack from virtual memory.
Reviewed-by: jmasa, brutisso

Summary: The clipping code in the routine that sets the bits for a range of cards, in the liveness accounting verification code was incorrect. It set all the bits in the card bitmap from the given starting index which would lead to spurious marking verification failures.
Reviewed-by: brutisso, jwilhelm, jmasa

Reviewed-by: kvn

Summary: Removed the unused keep_alive parameter
Reviewed-by: stefank, dholmes, kamg, coleenp

Summary: Reset the fields in ParGCAllocBuffer, that are used for accumulating values for the ResizePLAB sensors in PLABStats, to zero after flushing the values to the PLABStats fields. Flush PLABStats values only when retiring the final allocation buffers prior to disposing of a G1ParScanThreadState object, rather than when retiring every allocation buffer.
Reviewed-by: jwilhelm, jmasa, ysr

Summary: The warnings associated with the UseMemSetInBOT flag are duplicated in CMS and G1. The separate warnings have been removed and single instance of the warning has been placed in a common location.
Reviewed-by: brutisso, ysr

Summary: The is_zeroed parameter is no longer used and so can be removed.
Reviewed-by: johnc, jmasa, brutisso
Contributed-by: NBrandon Mitchell <brandon@twitter.com>