8075210: Refactor strong root processing in order to allow G1 to evolve separately from GenCollectedHeap
Summary: Create a G1RootProcessor and move SharedHeap root processing to GenCollectedHeap
Reviewed-by: brutisso, tschatzl, ehelin

Summary: Pass on the static type G1ParPushHeapRSClosure to allow oop_iterate devirtualization
Reviewed-by: jmasa, kbarrett

Summary: Evaluate and improve object copy time by micro-optimizations and splitting out slow and fast paths aggressively.
Reviewed-by: kbarrett, mgerdin, jmasa
Contributed-by: NTony Printezis &lt;tprintezis@twitter.com&gt;, Thomas Schatzl <thomas.schatzl@oracle.com>

Reviewed-by: brutisso, ehelin

Summary: Replace G1CodeRootSet with a Hashtable based implementation, merge Code Root Migration phase into Code Root Scanning
Reviewed-by: jmasa, brutisso, tschatzl

Summary: Splitting out a g1 allocator class to simply specialized allocators which can associate each allocation with a given context.
Reviewed-by: mgerdin, brutisso

Summary: Allow G1 to decommit memory of arbitrary regions within the heap and their associated auxiliary data structures card table, BOT, hot card cache, and mark bitmaps.
Reviewed-by: mgerdin, brutisso, jwilhelm

Summary: Let HeapRegionSeq manage the heap region and auxiliary data to decrease the amount of responsibilities of G1CollectedHeap, and encapsulate this work from other code.
Reviewed-by: jwilhelm, jmasa, mgerdin, brutisso

Reviewed-by: tschatzl, jmasa

Reviewed-by: jwilhelm, jmasa

Reviewed-by: pliden, jmasa

Summary: Changing copy_allocation_context_stats to return if there are more stats available after the copy.
Reviewed-by: rriggs, jcoomes

Reviewed-by: brutisso, sjohanss

Summary: Remove dead code.
Reviewed-by: stefank, brutisso

Summary: Remove dead code.
Reviewed-by: stefank, brutisso

Summary: Try to reclaim humongous objects at every young collection after doing a conservative estimate of its liveness.
Reviewed-by: brutisso, mgerdin

Summary: Try to reclaim humongous objects at every young collection after doing a conservative estimate of its liveness.
Reviewed-by: brutisso, mgerdin

Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso

Summary: Refactor preparation for compaction during Full GC so that it lazily initializes the first compaction point. This also avoids problems later when the first region may not be committed. Also reviewed by K. Barrett.
Reviewed-by: brutisso

Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

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

Reviewed-by: brutisso, mgerdin

Summary: Fill the last card that has been allocated into with a dummy object
Reviewed-by: tschatzl, mgerdin

Reviewed-by: tschatzl, pliden

Reviewed-by: mikael, jmasa, tschatzl

Reviewed-by: mikael, jmasa

Summary: Refactored the G1 FullGC code to enable it to be extended.
Reviewed-by: mgerdin, brutisso

Reviewed-by: tschatzl, jwilhelm

Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

Reviewed-by: tschatzl, mgerdin, jmasa

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: 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: 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: 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

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: tschatzl, stefank, jmasa

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