Reviewed-by: brutisso, sjohanss

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

Reviewed-by: tschatzl, mgerdin

Reviewed-by: brutisso, tschatzl

Reviewed-by: brutisso, ehelin

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

Summary: Only prune metaspace virtual spaces at safepoint so walking them is safe outside a safepoint.
Reviewed-by: mgerdin, mgronlun, hseigel, stefank

Summary: temporarily disable the shutdown of the concurrent GC threads introduced in JDK-8037112
Reviewed-by: brutisso, tschatzl, jmasa

Reviewed-by: brutisso, mgerdin

Reviewed-by: tschatzl, pliden

Reviewed-by: tschatzl, pliden

Reviewed-by: tschatzl, jwilhelm

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

Summary: Preventing GCs to occur before VM is completely initialized. This was previously partly done by one part of the GC locker which not was removed.
Reviewed-by: coleenp, pliden

Reviewed-by: jmasa, coleenp

Reviewed-by: jmasa, stefank

Reviewed-by: mgerdin, jmasa
Contributed-by: matthias.baesken@sap.com

Summary: Revert JDK-6976350 because it does not improve PLAB fragmentation. To the contrary, it tends to increase the amount of wasted space with many threads.
Reviewed-by: brutisso

Summary: Move G1ParCopyClosure::copy_to_survivor_space to decrease code size.
Reviewed-by: stefank, jmasa

Summary: Remove the assumption that G1CollectedHeap::in_cset_fast_test needs to check for NULL references. Most of the time this is not required, making the code doing this check multiple times.
Reviewed-by: stefank, mgerdin, jmasa

Summary: Move methods that are not dependent on any of G1ParCopyClosure's template parameters into G1ParCopyHelper. Further remove unused methods and members of the class hierarchy.
Reviewed-by: mgerdin, stefank

Summary: When string and symbol table unlink are not performed in parallel, the claim index we check is not updated, and so a guarantee fails. Take this into account when checking the guarantee.
Reviewed-by: brutisso, jwilhelm

8033106: Wrong predicate for checking whether the correct amount of symbol table entries have been processed in G1
Summary: The change fixes the predicate check.
Reviewed-by: jmasa, tonyp, stefank

Summary: Clean up and slightly optimize reference handling from the GC reference task queue. Since we never push partial array chunks as narrowOop* we can manually specialize the code so that some code can be optimized away.
Reviewed-by: tonyp, brutisso, stefank

Summary: Made the flags Min- and MaxHeapFreeRatio manageable, and implemented support for these flags in ParallelGC.
Reviewed-by: sla, mgerdin, brutisso

Summary: Pad and cache-align BiasedMappedArray instances by default to avoid performance variability problems due to false sharing, as instances of this data structures are typically used for performance sensitive code.
Reviewed-by: brutisso, stefank

Summary: Mentioned closures are actually wrapped methods. This adds confusion to readers, and in this case also increases code size as G1ParScanHeapEvacClosure is part of the oop_oop_iterate() methods. Move them into G1ParScanThreadState as methods.
Reviewed-by: stefank

Summary: Refactor the From Card Cache into a separate class.
Reviewed-by: jmasa

Summary: Detailed breakdown of time spent in the evacuation failure handling phases to make the "Other" time roughly correspond to the sum of its parts.
Reviewed-by: jwilhelm, jmasa

Summary: Show the time taken by card redirtying during GC in a new "Redirty Cards" line.
Reviewed-by: jwilhelm, brutisso

Summary: Improve fast card cache iteration and avoid taking locks when freeing the collection set.
Reviewed-by: brutisso

Summary: The from card cache is a very frequently accessed data structure. It is essentially a 2d array of per-region values, one row of values for every GC thread. Pad and align the data structure to avoid false sharing.
Reviewed-by: stefank

Summary: Change the code cache remembered sets data structure from a GrowableArray to a chunked list of nmethods. This makes the data structure more amenable to parallelization, and decreases freeing time.
Reviewed-by: mgerdin, brutisso

Reviewed-by: stefank, mgerdin, coleenp, egahlin

Reviewed-by: jmasa, stefank, mgerdin

Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp

Reviewed-by: brutisso, tschatzl

Reviewed-by: brutisso, tschatzl

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: tonyp, tschatzl