Summary: Removed all write barriers during reference processing and added explicit write barriers when iterating through the discovered list.
Reviewed-by: pliden, jmasa, tschatzl

8043029: Change 8037816 breaks HS build with older GCC versions which don't support diagnostic pragmas
8043164: Format warning in traceStream.hpp
Summary: Backport of main fix + two corrections, enables clang compilation, turns on format attributes, corrects/mutes warnings
Reviewed-by: kvn, coleenp, iveresov, twisti

Reviewed-by: jwilhelm, ehelin, tschatzl

Reviewed-by: jmasa, coleenp

Summary: Reducing the number of calls to follow_class_loader to speed up the marking phase. Also removed some unnecessary calls to adjust_klass.
Reviewed-by: stefank, jmasa, mgerdin

Reviewed-by: dholmes, egahlin

Summary: Removed stray includes and some minor cleanup of GenerationSizer
Reviewed-by: tschatzl, jcoomes

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>

Reviewed-by: jmasa, tschatzl

Summary: Split SystemDictionary and ClassLoaderDataGraph root processing to help load balancing.
Reviewed-by: tschatzl, johnc

Summary: Rename: compute_generations_free_space() = compute_eden_space_size() + compute_old_gen_free_space(); update related logging messages
Reviewed-by: jmasa, johnc, tschatzl, brutisso
Contributed-by: Ntamao <tao.mao@oracle.com>

Summary: Print helpful error message when VM aborts due to inability of allocating bit maps or card tables
Reviewed-by: jmasa, stefank
Contributed-by: Ntamao <tao.mao@oracle.com>

Reviewed-by: brutisso, tschatzl

8007763: Refactoring: split up compute_generation_free_space() into two functions for class PSAdaptiveSizePolicy
Summary: split up compute_generation_free_space() into two functions: compute_eden_space_size() + compute_old_gen_free_space(), each of which (if needed) can be reused without executing an overhead of the other.
Reviewed-by: jmasa, tschatzl
Contributed-by: Ntamao <tao.mao@oracle.com>

Reviewed-by: stefank, tschatzl

Reviewed-by: coleenp, mgerdin

Reviewed-by: johnc, brutisso

Reviewed-by: brutisso, jmasa

Reviewed-by: mgerdin, coleenp

Reviewed-by: tschatzl, jmasa

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

Summary: Pass down a closure during root scanning to keep the class of the method alive.
Reviewed-by: coleenp, jcoomes

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

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

Reviewed-by: stefank, coleenp, kvn

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>

7151532: DCmd for hotspot native memory tracking
Summary: Implementation of native memory tracking phase 1, which tracks VM native memory usage, and related DCmd
Reviewed-by: acorn, coleenp, fparain

Reviewed-by: mgerdin, johnc

Reviewed-by: stefank, jmasa

Reviewed-by: kvn, jrose, kevinw, brutisso, twisti, jmasa

Summary: Replaces calls to os::javaTimeMillis(), which does not (and cannot) guarantee monotonicity, in GC code to an equivalent expression that uses os::javaTimeNanos(). os::javaTimeNanos is guaranteed monotonically non-decreasing if the underlying platform provides a monotonic time source. Changes in OS files are to make use of the newly defined constants in globalDefinitions.hpp.
Reviewed-by: dholmes, ysr

Summary: Remove obsolete code.
Reviewed-by: brutisso, ysr, jcoomes

Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp

Summary: Remove the sentinelRef and let the last Reference in a discovered chain point back to itself.
Reviewed-by: ysr, jmasa

Summary: Select number of GC threads dynamically based on heap usage and number of Java threads
Reviewed-by: johnc, ysr, jcoomes

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

Summary: ignore UseParallel{OldGCDensePrefix,OldGCCompacting,DensePrefixUpdate}
Reviewed-by: jwilhelm, brutisso

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

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

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