/*

 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

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

// collection set.

class G1CollectedHeap;

class CardTableModRefBarrierSet;

class ConcurrentG1Refine;

class G1RemSet: public CHeapObj {

protected:

  G1CollectedHeap* _g1;

  unsigned _conc_refine_cards;

  size_t 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;

  // _traversal_in_progress is "true" iff a traversal is in progress.

  bool _traversal_in_progress;

  void set_traversal(bool b) { _traversal_in_progress = b; }

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

  // references into the collection set.

  OopsInHeapRegionClosure** _cset_rs_update_cl;

  // The routine that performs the actual work of refining a dirty

  // card.

  // If check_for_refs_into_refs is true then a true result is returned

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

  // collection set.

  bool concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i,

                                    bool check_for_refs_into_cset);

protected:

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

  template <class T> void par_write_ref_nv(HeapRegion* from, T* p, int tid);

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();

  void oops_into_collection_set_do(OopsInHeapRegionClosure* blk,

                                   int worker_i);

  void prepare_for_oops_into_collection_set_do();

  void cleanup_after_oops_into_collection_set_do();

  void scanRS(OopsInHeapRegionClosure* oc, int worker_i);

  void updateRS(DirtyCardQueue* into_cset_dcq, int worker_i);

  HeapRegion* calculateStartRegion(int 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.

  // [Below the virtual version calls a non-virtual protected

  // workhorse that is templatified for narrow vs wide oop.]

  inline void write_ref(HeapRegion* from, oop* p) {

    write_ref_nv(from, p);

  }

  inline void write_ref(HeapRegion* from, narrowOop* p) {

    write_ref_nv(from, p);

  }

  inline void par_write_ref(HeapRegion* from, oop* p, int tid) {

    par_write_ref_nv(from, p, tid);

  }

  inline void par_write_ref(HeapRegion* from, narrowOop* p, int tid) {

    par_write_ref_nv(from, p, tid);

  }

  bool self_forwarded(oop obj);

  void scrub(BitMap* region_bm, BitMap* card_bm);

  void scrub_par(BitMap* region_bm, BitMap* card_bm,

                 int worker_num, int claim_val);

  virtual bool concurrentRefineOneCard(jbyte* card_ptr, int worker_i,

                                       bool check_for_refs_into_cset);

  virtual void print_summary_info();

  virtual void prepare_for_verify();

};

#define G1_REM_SET_LOGGING 0

class CountNonCleanMemRegionClosure: public MemRegionClosure {

  G1CollectedHeap* _g1;

  int _n;

  HeapWord* _start_first;

public:

  CountNonCleanMemRegionClosure(G1CollectedHeap* g1) :

    _g1(g1), _n(0), _start_first(NULL)

  {}

  void do_MemRegion(MemRegion mr);

  int n() { return _n; };

  HeapWord* start_first() { return _start_first; }

};

class UpdateRSOopClosure: public OopClosure {

  HeapRegion* _from;

  int _worker_i;

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

public:

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

    guarantee(_rs != NULL, "Requires an HRIntoG1RemSet");

  }

  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; }

};

class UpdateRSetImmediate: public OopsInHeapRegionClosure {

private:

  G1RemSet* _g1_rem_set;

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

public:

  UpdateRSetImmediate(G1RemSet* rs) :

    _g1_rem_set(rs) {}

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

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

};