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

Summary: Remove the above mentioned template parameter and related unused code. Also remove some classes that are never used.
Reviewed-by: stefank, mgerdin, jwilhelm

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: dholmes, egahlin

Summary: Change checks for isHumongous() to continuesHumongous() as installing a code root for a humongous object is valid, but not for continuations of humongous objects. Cleaned up asserts.
Reviewed-by: jmasa, tamao

7057939: jmap shows MaxNewSize=4GB when Java is using parallel collector
Summary: Major cleanup of the collectorpolicy classes
Reviewed-by: tschatzl, jcoomes

Summary: Add a StoreLoad barrier in the G1 post-barrier to fix a race with concurrent refinement. Also-reviewed-by: martin.doerr@sap.com
Reviewed-by: iveresov, tschatzl, brutisso, roland, kvn

Reviewed-by: tschatzl, jwilhelm, jmasa

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: Add G1BiasedArray<T> that is an array where each element represents a fixed-sized subdivision of the heap. Use this abstraction to refactor the HeapRegionSeq class.
Reviewed-by: brutisso

Summary: Move some G1 specific code from CardTableModRefBS to G1SATBCardTableModRefBS.
Reviewed-by: brutisso, tschatzl, ehelin

Summary: Add memory consumption breakdown on a per region type in the G1 remembered set summary statistics. This simplifies remembered set memory consumption analysis.
Reviewed-by: brutisso

Summary: Use conservative assumptions of required alignment for the various garbage collector components into account when determining the maximum heap size that supports compressed oops. Using this conservative value avoids several circular dependencies in the calculation.
Reviewed-by: stefank, dholmes

Reviewed-by: mgerdin, stefank

Reviewed-by: tonyp, tschatzl

Summary: Replace the broken large pages implementation on Linux. New flag: -XX:+UseTransparentHugePages - Linux specific flag to turn on transparent huge page hinting with madvise(..., MAP_HUGETLB). Changed behavior: -XX:+UseLargePages - tries to use -XX:+UseTransparentHugePages before trying other large pages implementations (on Linux). Changed behavior: -XX:+UseHugeTLBFS - Use upfront allocation of Large Pages instead of using the broken implementation to dynamically committing large pages. Changed behavior: -XX:LargePageSizeInBytes - Turned off the ability to use this flag on Linux and provides warning to user if set to a value different than the OS chosen large page size. Changed behavior: Setting no large page size - Now defaults to use -XX:UseTransparentHugePages if the OS supports it. Previously, -XX:+UseHugeTLBFS was chosen if the OS was configured to use large pages.
Reviewed-by: tschatzl, dcubed, brutisso

Reviewed-by: stefank, mgerdin

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

Summary: Remove -Xaprof and Klass::_alloc_count & ArrayKlass::_alloc_size.
Reviewed-by: stefank, coleenp

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: In a full GC, move the verification after the GC to after RSet rebuilding. Verify RSet entries during a full GC under control of a flag.
Reviewed-by: tschatzl, brutisso

Summary: Fixed the output of G1SummarizeRSetStats: too small datatype for the number of concurrently processed cards, added concurrent remembered set thread time retrieval for Linux and Windows (BSD uses os::elapsedTime() now), and other cleanup. The information presented during VM operation is now relative to the previous output, not always cumulative if G1SummarizeRSetStatsPeriod > 0. At VM exit, the code prints a cumulative summary.
Reviewed-by: johnc, jwilhelm

Reviewed-by: brutisso, tschatzl

8010738: G1: Output for full GCs with +PrintGCDetails should contain perm gen size/meta data change info
Summary: Include metaspace information (used, allocated, reserved) in the PrintGCDetails output for full GCs.
Reviewed-by: poonam, jmasa, brutisso

Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich.
Reviewed-by: tschatzl, jmasa

Summary: Refactored shrink_by() to only use region counts and not byte sizes
Reviewed-by: johnc, tschatzl

Reviewed-by: coleenp, zgu, hseigel

Reviewed-by: johnc, brutisso

Reviewed-by: brutisso, jmasa

Summary: Move the calculation and recording of eden capacity to the start of a GC and print a detailed heap transition for full GCs.
Reviewed-by: tschatzl, jmasa

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

Reviewed-by: mgerdin, coleenp

Summary: Stack allocate instances of HeapRegionRemSetIterator during RSet scanning.
Reviewed-by: brutisso, jwilhelm

Reviewed-by: tschatzl, jmasa

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

Reviewed-by: johnc, ysr

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

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

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