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 * version 2 for more details (a copy is included in the LICENSE file that

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#ifndef SHARE_GC_G1_G1REMSET_HPP

#define SHARE_GC_G1_G1REMSET_HPP

#include "gc/g1/g1CardTable.hpp"

#include "gc/g1/g1OopClosures.hpp"

#include "gc/g1/g1GCPhaseTimes.hpp"

#include "gc/g1/g1RemSetSummary.hpp"

#include "gc/g1/heapRegion.hpp"

#include "memory/allocation.hpp"

#include "memory/iterator.hpp"

#include "utilities/ticks.hpp"

// A G1RemSet provides ways of iterating over pointers into a selected

// collection set.

class BitMap;

class CardTableBarrierSet;

class G1BlockOffsetTable;

class CodeBlobClosure;

class G1CollectedHeap;

class G1CMBitMap;

class G1HotCardCache;

class G1RemSetScanState;

class G1ParScanThreadState;

class G1Policy;

class G1ScanCardClosure;

class HeapRegionClaimer;

// A G1RemSet in which each heap region has a rem set that records the

// external heap references into it.  Uses a mod ref bs to track updates,

// so that they can be used to update the individual region remsets.

class G1RemSet: public CHeapObj<mtGC> {

private:

  G1RemSetScanState* _scan_state;

  G1RemSetSummary _prev_period_summary;

  G1CollectedHeap* _g1h;

  size_t _num_conc_refined_cards; // Number of cards refined concurrently to the mutator.

  G1CardTable*           _ct;

  G1Policy*              _g1p;

  G1HotCardCache*        _hot_card_cache;

public:

  typedef CardTable::CardValue CardValue;

  // Gives an approximation on how many threads can be expected to add records to

  // a remembered set in parallel. This can be used for sizing data structures to

  // decrease performance losses due to data structure sharing.

  // Examples for quantities that influence this value are the maximum number of

  // mutator threads, maximum number of concurrent refinement or GC threads.

  static uint num_par_rem_sets();

  // Initialize data that depends on the heap size being known.

  void initialize(size_t capacity, uint max_regions);

  G1RemSet(G1CollectedHeap* g1h,

           G1CardTable* ct,

           G1HotCardCache* hot_card_cache);

  ~G1RemSet();

  // Scan all remembered sets of the collection set for references into the collection

  // set.

  // Further applies heap_region_codeblobs on the oops of the unmarked nmethods on the strong code

  // roots list for each region in the collection set.

  void scan_rem_set(G1ParScanThreadState* pss,

                    uint worker_i,

                    G1GCPhaseTimes::GCParPhases scan_phase,

                    G1GCPhaseTimes::GCParPhases objcopy_phase,

                    G1GCPhaseTimes::GCParPhases coderoots_phase);

  // Flush remaining refinement buffers for cross-region references to either evacuate references

  // into the collection set or update the remembered set.

  void update_rem_set(G1ParScanThreadState* pss, uint worker_i);

  // Prepare for and cleanup after scanning the remembered sets. Must be called

  // once before and after in sequential code.

  void prepare_for_scan_rem_set();

  void cleanup_after_scan_rem_set();

  // Prepares the given region for remembered set scanning.

  void prepare_for_scan_rem_set(uint region_idx);

  G1RemSetScanState* scan_state() const { return _scan_state; }

  // Refine the card corresponding to "card_ptr". Safe to be called concurrently

  // to the mutator.

  void refine_card_concurrently(CardValue* card_ptr,

                                uint worker_i);

  // Refine the card corresponding to "card_ptr", applying the given closure to

  // all references found. Must only be called during gc.

  // Returns whether the card has been scanned.

  bool refine_card_during_gc(CardValue* card_ptr, G1ScanCardClosure* update_rs_cl);

  // Print accumulated summary info from the start of the VM.

  void print_summary_info();

  // Print accumulated summary info from the last time called.

  void print_periodic_summary_info(const char* header, uint period_count);

  size_t num_conc_refined_cards() const { return _num_conc_refined_cards; }

  // Rebuilds the remembered set by scanning from bottom to TARS for all regions

  // using the given work gang.

  void rebuild_rem_set(G1ConcurrentMark* cm, WorkGang* workers, uint worker_id_offset);

};

#endif // SHARE_GC_G1_G1REMSET_HPP