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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP

#define SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP

#include "gc_implementation/g1/g1RemSetSummary.hpp"

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

// collection set.

class G1CollectedHeap;

class CardTableModRefBarrierSet;

class ConcurrentG1Refine;

// 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:

  G1RemSetSummary _prev_period_summary;

protected:

  G1CollectedHeap* _g1;

  size_t _conc_refine_cards;

  uint n_workers();

protected:

  enum SomePrivateConstants {

    UpdateRStoMergeSync  = 0,

    MergeRStoDoDirtySync = 1,

    DoDirtySync          = 2,

    LastSync             = 3,

    SeqTask              = 0,

    NumSeqTasks          = 1

  };

  CardTableModRefBS*     _ct_bs;

  SubTasksDone*          _seq_task;

  G1CollectorPolicy*     _g1p;

  ConcurrentG1Refine*    _cg1r;

  size_t*                _cards_scanned;

  size_t                 _total_cards_scanned;

  // Used for caching the closure that is responsible for scanning

  // references into the collection set.

  OopsInHeapRegionClosure** _cset_rs_update_cl;

  // Print the given summary info

  virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);

public:

  // This is called to reset dual hash tables after the gc pause

  // is finished and the initial hash table is no longer being

  // scanned.

  void cleanupHRRS();

  G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);

  ~G1RemSet();

  // Invoke "blk->do_oop" on all pointers into the collection set

  // from objects in regions outside the collection set (having

  // invoked "blk->set_region" to set the "from" region correctly

  // beforehand.)

  //

  // Invoke code_root_cl->do_code_blob on the unmarked nmethods

  // on the strong code roots list for each region in the

  // collection set.

  //

  // The "worker_i" param is for the parallel case where the id

  // of the worker thread calling this function can be helpful in

  // partitioning the work to be done. It should be the same as

  // the "i" passed to the calling thread's work(i) function.

  // In the sequential case this param will be ignored.

  void oops_into_collection_set_do(OopsInHeapRegionClosure* blk,

                                   CodeBlobClosure* code_root_cl,

                                   uint worker_i);

  // Prepare for and cleanup after an oops_into_collection_set_do

  // call.  Must call each of these once before and after (in sequential

  // code) any threads call oops_into_collection_set_do.  (This offers an

  // opportunity to sequential setup and teardown of structures needed by a

  // parallel iteration over the CS's RS.)

  void prepare_for_oops_into_collection_set_do();

  void cleanup_after_oops_into_collection_set_do();

  void scanRS(OopsInHeapRegionClosure* oc,

              CodeBlobClosure* code_root_cl,

              uint worker_i);

  void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);

  CardTableModRefBS* ct_bs() { return _ct_bs; }

  size_t cardsScanned() { return _total_cards_scanned; }

  // Record, if necessary, the fact that *p (where "p" is in region "from",

  // which is required to be non-NULL) has changed to a new non-NULL value.

  template <class T> void write_ref(HeapRegion* from, T* p);

  template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);

  // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region

  // or card, respectively, such that a region or card with a corresponding

  // 0 bit contains no part of any live object.  Eliminates any remembered

  // set entries that correspond to dead heap ranges. "worker_num" is the

  // parallel thread id of the current thread, and "hrclaimer" is the

  // HeapRegionClaimer that should be used.

  void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);

  // Refine the card corresponding to "card_ptr".

  // If check_for_refs_into_cset is true, a true result is returned

  // if the given card contains oops that have references into the

  // current collection set.

  virtual bool refine_card(jbyte* card_ptr,

                           uint worker_i,

                           bool check_for_refs_into_cset);

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

  virtual void print_summary_info();

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

  virtual void print_periodic_summary_info(const char* header);

  // Prepare remembered set for verification.

  virtual void prepare_for_verify();

  size_t conc_refine_cards() const {

    return _conc_refine_cards;

  }

};

class UpdateRSOopClosure: public ExtendedOopClosure {

  HeapRegion* _from;

  G1RemSet* _rs;

  uint _worker_i;

  template <class T> void do_oop_work(T* p);

public:

  UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :

    _from(NULL), _rs(rs), _worker_i(worker_i)

  {}

  void set_from(HeapRegion* from) {

    assert(from != NULL, "from region must be non-NULL");

    _from = from;

  }

  virtual void do_oop(narrowOop* p) { do_oop_work(p); }

  virtual void do_oop(oop* p)       { do_oop_work(p); }

  // Override: this closure is idempotent.

  //  bool idempotent() { return true; }

  bool apply_to_weak_ref_discovered_field() { return true; }

};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1REMSET_HPP