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

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 * 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).

 *

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 * 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_G1_G1REMSET_HPP

#define SHARE_VM_GC_G1_G1REMSET_HPP

#include "gc/g1/dirtyCardQueue.hpp"

#include "gc/g1/g1CardLiveData.hpp"

#include "gc/g1/g1RemSetSummary.hpp"

#include "gc/g1/heapRegion.hpp"

#include "memory/allocation.hpp"

#include "memory/iterator.hpp"

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

// collection set.

class BitMap;

class CardTableModRefBS;

class G1BlockOffsetTable;

class CodeBlobClosure;

class G1CollectedHeap;

class G1HotCardCache;

class G1ParPushHeapRSClosure;

class G1RemSetScanState;

class G1Policy;

class G1SATBCardTableModRefBS;

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;

  G1CardLiveData _card_live_data;

  G1RemSetSummary _prev_period_summary;

  // A DirtyCardQueueSet that is used to hold cards that contain

  // references into the current collection set. This is used to

  // update the remembered sets of the regions in the collection

  // set in the event of an evacuation failure.

  DirtyCardQueueSet _into_cset_dirty_card_queue_set;

protected:

  G1CollectedHeap* _g1;

  size_t _conc_refine_cards;

  uint n_workers();

protected:

  CardTableModRefBS*     _ct_bs;

  G1Policy*              _g1p;

  G1HotCardCache*        _hot_card_cache;

public:

  // 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);

  // 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,

           G1HotCardCache* hot_card_cache);

  ~G1RemSet();

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

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

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

  // beforehand.)

  //

  // Apply non_heap_roots on the oops of 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.

  //

  // Returns the number of cards scanned while looking for pointers

  // into the collection set.

  size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* cl,

                                     CodeBlobClosure* heap_region_codeblobs,

                                     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();

  size_t scan_rem_set(G1ParPushHeapRSClosure* oops_in_heap_closure,

                      CodeBlobClosure* heap_region_codeblobs,

                      uint worker_i);

  G1RemSetScanState* scan_state() const { return _scan_state; }

  // Flush remaining refinement buffers into the remembered set,

  // applying oops_in_heap_closure on the references found.

  void update_rem_set(DirtyCardQueue* into_cset_dcq, G1ParPushHeapRSClosure* oops_in_heap_closure, uint worker_i);

  // 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 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(uint worker_num, HeapRegionClaimer* hrclaimer);

  // Refine the card corresponding to "card_ptr".

  // If oops_in_heap_closure is not NULL, 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,

                           G1ParPushHeapRSClosure* oops_in_heap_closure);

  // 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, uint period_count);

  // Prepare remembered set for verification.

  virtual void prepare_for_verify();

  size_t conc_refine_cards() const {

    return _conc_refine_cards;

  }

  void create_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);

  void finalize_card_live_data(WorkGang* workers, G1CMBitMap* mark_bitmap);

  // Verify that the liveness count data created concurrently matches one created

  // during this safepoint.

  void verify_card_live_data(WorkGang* workers, G1CMBitMap* actual_bitmap);

  void clear_card_live_data(WorkGang* workers);

#ifdef ASSERT

  void verify_card_live_data_is_clear();

#endif

};

class G1ScanRSClosure : public HeapRegionClosure {

  G1RemSetScanState* _scan_state;

  size_t _cards_done;

  size_t _cards;

  G1CollectedHeap* _g1h;

  G1ParPushHeapRSClosure* _push_heap_cl;

  CodeBlobClosure* _code_root_cl;

  G1BlockOffsetTable* _bot;

  G1SATBCardTableModRefBS *_ct_bs;

  double _strong_code_root_scan_time_sec;

  uint   _worker_i;

  size_t _block_size;

  void scan_card(size_t index, HeapRegion *r);

  void scan_strong_code_roots(HeapRegion* r);

public:

  G1ScanRSClosure(G1RemSetScanState* scan_state,

                  G1ParPushHeapRSClosure* push_heap_cl,

                  CodeBlobClosure* code_root_cl,

                  uint worker_i);

  bool doHeapRegion(HeapRegion* r);

  double strong_code_root_scan_time_sec() {

    return _strong_code_root_scan_time_sec;

  }

  size_t cards_done() { return _cards_done;}

  size_t cards_looked_up() { return _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); }

};

#endif // SHARE_VM_GC_G1_G1REMSET_HPP