8223689: Add JFR Thread Sampling Support
8223690: Add JFR BiasedLock Event Support
8223691: Add JFR G1 Region Type Change Event Support
8223692: Add JFR G1 Heap Summary Event Support
Summary: Backport JFR from JDK11, additional fixes
Reviewed-by: neugens, apetushkov
Contributed-by: denghui.ddh@alibaba-inc.com

Summary: Adding missing check for valid oop.
Reviewed-by: dcubed
Contributed-by: NShafi Ahmad <shafi.s.ahmad@oracle.com>

Summary: Implement remembered sets verification for G1 with option VerifyRememberedSets
Reviewed-by: jmasa, mgerdin

Summary: Read _top before _gc_time_stamp in saved_mark_word() with LoadLoad order to ensure we get a consistent view
Reviewed-by: brutisso, dcubed, dholmes, stefank

Reviewed-by: brutisso, tschatzl

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: Implement remembered sets verification for G1 with option VerifyRememberedSets
Reviewed-by: jmasa, mgerdin

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: jwilhelm, jmasa

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

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

8069760: When iterating over a card, G1 often iterates over much more references than are contained in the card
Summary: Properly bound the iteration work for objArray-oops.
Reviewed-by: mgerdin, kbarrett

Summary: Stop using save_marks in G1 related code and make setting the replacement field less racy.
Reviewed-by: brutisso, tschatzl

8081202: Hotspot compile warning: "Invalid suffix on literal; C++11 requires a space between literal and identifier"
Summary: Need to add a space between macro identifier and string literal
Reviewed-by: bpittore, stefank, dholmes, kbarrett

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

Summary: Change parent of G1OffsetTableContigSpace to CompactibleSpace, reimplement missing functionality
Reviewed-by: stefank, jmasa, tschatzl

Summary: Rename save_marks to record_top_and_timestamp and remove som unused but related methods
Reviewed-by: stefank, ehelin

Reviewed-by: stefank, 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

Summary: Refactored the defines to instead be static const in a HeapRegionBounds class.
Reviewed-by: mgerdin, tschatzl

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

Reviewed-by: tschatzl, mgerdin

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: twisti, stefank

Reviewed-by: dholmes, kvn, stefank, twisti

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: 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: 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

8019902: G1: Use the average heap size rather than the minimum heap size to calculate the region size
Reviewed-by: tonyp, tschatzl, sjohanss

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: tschatzl, jmasa

Summary: Minimize redundant verifications of Klasses.
Reviewed-by: hseigel, jmasa

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: The is_zeroed parameter is no longer used and so can be removed.
Reviewed-by: johnc, jmasa, brutisso
Contributed-by: NBrandon Mitchell <brandon@twitter.com>