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 /*

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

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  * 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

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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, int 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.

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

   // Like the above, but assumes is called in parallel: "worker_num" is the

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

   // value that should be used to claim heap regions.

   void scrub_par(BitMap* region_bm, BitMap* card_bm,

                  uint worker_num, int claim_val);

   // 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 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 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