src/share/vm/gc_implementation/g1/g1RemSet.hpp - platform/external/jetbrains/jdk8u_hotspot - Git at Google

 /*
  * Copyright (c) 2001, 2014, 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.
  *
  */

 #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;
 class G1ParPushHeapRSClosure;

 // 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;
   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.
   G1ParPushHeapRSClosure** _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(G1ParPushHeapRSClosure* 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(G1ParPushHeapRSClosure* 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
	/*
	* Copyright (c) 2001, 2014, 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.
	*
	*/

	#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;
	class G1ParPushHeapRSClosure;

	// 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;
	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.
	G1ParPushHeapRSClosure** _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(G1ParPushHeapRSClosure* 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(G1ParPushHeapRSClosure* 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