Summary: Repaired or selectively disabled offending formats; future-proofed with additional checking
Reviewed-by: kvn, jrose, stefank

Reviewed-by: jmasa, tschatzl, ehelin
Contributed-by: tony.printezis@oracle.com, bengt.rutisson@oracle.com

Reviewed-by: tschatzl, jmasa

Reviewed-by: brutisso, tschatzl, mgerdin

Reviewed-by: jmasa, sjohanss
Contributed-by: stefan.karlsson@oracle.com, mikael.vidstedt@oracle.com

Reviewed-by: brutisso, tschatzl

Summary: Replaced the verification call to a conditional one that only runs verification in debug builds.
Reviewed-by: brutisso, tschatzl

Reviewed-by: tschatzl, jwilhelm

Summary: Allocate temporary BitMaps in the VMThread's resource area
Reviewed-by: stefank, sjohanss

Summary: The free list is being maintained in a sorted fashion and old and humongous regions are allocated from the bottom of the heap while young regions are allocated at the top.
Reviewed-by: tschatzl, mgerdin
Contributed-by: jesper.wilhelmsson@oracle.com, staffan.friberg@oracle.com

Reviewed-by: brutisso, tschatzl

Reviewed-by: tschatzl, pliden

Summary: Fix about 440 typos in comments in the VM code
Reviewed-by: mgerdin, tschatzl, coleenp, kmo, jcoomes

8027454: Do not traverse string table during G1 remark when treating them as strong roots during initial mark
Summary: Do not try to unlink string table entries unconditionally during remark. This is without side effects as the preceding initial mark always uses the string table as strong roots. Needs to be fixed with class unloading during concurrent mark.
Reviewed-by: brutisso, mgerdin

8027455: Improve symbol table scan times during gc pauses
Summary: Parallelize string table and symbol table scan during remark and full GC. Some additional statistics output if the experimental flag G1TraceStringSymbolTableScrubbing is set.
Reviewed-by: mgerdin, coleenp, brutisso

Reviewed-by: brutisso, jmasa, jwilhelm

Summary: Enable CHECK_UNHANDLED_OOPS in fastdebug builds across all supported platforms.
Reviewed-by: coleenp, hseigel, dholmes, stefank, twisti, ihse, rdurbin
Contributed-by: lois.foltan@oracle.com

Summary: Correctly calculate the initialization value for the shift between object start and bitmap bit in the G1 mark bitmaps.
Reviewed-by: tonyp

Summary: Add a list of nmethods to the RSet for a region that contain references into the region. Skip scanning the code cache during root scanning and scan the nmethod lists during RSet scanning instead.
Reviewed-by: tschatzl, brutisso, mgerdin, twisti, kvn

Reviewed-by: acorn, coleenp, sla
Contributed-by: NKaren Kinnear &lt;karen.kinnear@oracle.com&gt;, Bengt Rutisson &lt;bengt.rutisson@oracle.com&gt;, Calvin Cheung &lt;calvin.cheung@oracle.com&gt;, Erik Gahlin &lt;erik.gahlin@oracle.com&gt;, Erik Helin &lt;erik.helin@oracle.com&gt;, Jesper Wilhelmsson &lt;jesper.wilhelmsson@oracle.com&gt;, Keith McGuigan &lt;keith.mcguigan@oracle.com&gt;, Mattias Tobiasson &lt;mattias.tobiasson@oracle.com&gt;, Markus Gronlund &lt;markus.gronlund@oracle.com&gt;, Mikael Auno &lt;mikael.auno@oracle.com&gt;, Nils Eliasson &lt;nils.eliasson@oracle.com&gt;, Nils Loodin &lt;nils.loodin@oracle.com&gt;, Rickard Backman &lt;rickard.backman@oracle.com&gt;, Staffan Larsen &lt;staffan.larsen@oracle.com&gt;, Stefan Karlsson &lt;stefan.karlsson@oracle.com&gt;, Yekaterina Kantserova <yekaterina.kantserova@oracle.com>

Summary: Improve the output of G1PrintRegionLivenessInfo by adding a per-region remembered set size information column
Reviewed-by: jwilhelm, johnc

Reviewed-by: johnc, brutisso

Reviewed-by: brutisso, jmasa

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

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

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: 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: brutisso, johnc, ysr
Contributed-by: NHal Mo <kungu.mjh@taobao.com>

Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Contributed-by: Njmasa &lt;jon.masamitsu@oracle.com&gt;, stefank &lt;stefan.karlsson@oracle.com&gt;, mgerdin &lt;mikael.gerdin@oracle.com&gt;, never <tom.rodriguez@oracle.com>