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src/share/vm/gc_implementation/shared/markSweep.hpp@54b3b351d6f9 (annotated)

src/share/vm/gc_implementation/shared/markSweep.hpp

Wed, 23 Sep 2009 23:56:15 -0700

author

jrose

date

Wed, 23 Sep 2009 23:56:15 -0700

changeset 1428

54b3b351d6f9

parent 1424

148e5441d916

parent 1376

8b46c4d82093

child 1429

753cf9794df9

permissions

-rw-r--r--

Merge

duke@435	1	/*
xdono@631	2	* Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	class ReferenceProcessor;
ysr@1376	26	class DataLayout;
duke@435	27
duke@435	28	// MarkSweep takes care of global mark-compact garbage collection for a
duke@435	29	// GenCollectedHeap using a four-phase pointer forwarding algorithm. All
duke@435	30	// generations are assumed to support marking; those that can also support
duke@435	31	// compaction.
duke@435	32	//
duke@435	33	// Class unloading will only occur when a full gc is invoked.
duke@435	34
duke@435	35	// If VALIDATE_MARK_SWEEP is defined, the -XX:+ValidateMarkSweep flag will
duke@435	36	// be operational, and will provide slow but comprehensive self-checks within
duke@435	37	// the GC. This is not enabled by default in product or release builds,
duke@435	38	// since the extra call to track_adjusted_pointer() in _adjust_pointer()
duke@435	39	// would be too much overhead, and would disturb performance measurement.
duke@435	40	// However, debug builds are sometimes way too slow to run GC tests!
duke@435	41	#ifdef ASSERT
duke@435	42	#define VALIDATE_MARK_SWEEP 1
duke@435	43	#endif
duke@435	44	#ifdef VALIDATE_MARK_SWEEP
duke@435	45	#define VALIDATE_MARK_SWEEP_ONLY(code) code
duke@435	46	#else
duke@435	47	#define VALIDATE_MARK_SWEEP_ONLY(code)
duke@435	48	#endif
duke@435	49
duke@435	50	// declared at end
duke@435	51	class PreservedMark;
duke@435	52
duke@435	53	class MarkSweep : AllStatic {
duke@435	54	//
coleenp@548	55	// Inline closure decls
duke@435	56	//
coleenp@548	57	class FollowRootClosure: public OopsInGenClosure {
duke@435	58	public:
coleenp@548	59	virtual void do_oop(oop* p);
coleenp@548	60	virtual void do_oop(narrowOop* p);
duke@435	61	};
duke@435	62
duke@435	63	class MarkAndPushClosure: public OopClosure {
duke@435	64	public:
coleenp@548	65	virtual void do_oop(oop* p);
coleenp@548	66	virtual void do_oop(narrowOop* p);
duke@435	67	virtual const bool do_nmethods() const { return true; }
ysr@1376	68	virtual const bool should_remember_mdo() const { return true; }
ysr@1376	69	virtual void remember_mdo(DataLayout* p) { MarkSweep::revisit_mdo(p); }
duke@435	70	};
duke@435	71
duke@435	72	class FollowStackClosure: public VoidClosure {
duke@435	73	public:
coleenp@548	74	virtual void do_void();
duke@435	75	};
duke@435	76
duke@435	77	class AdjustPointerClosure: public OopsInGenClosure {
coleenp@548	78	private:
duke@435	79	bool _is_root;
duke@435	80	public:
duke@435	81	AdjustPointerClosure(bool is_root) : _is_root(is_root) {}
coleenp@548	82	virtual void do_oop(oop* p);
coleenp@548	83	virtual void do_oop(narrowOop* p);
duke@435	84	};
duke@435	85
duke@435	86	// Used for java/lang/ref handling
duke@435	87	class IsAliveClosure: public BoolObjectClosure {
duke@435	88	public:
coleenp@548	89	virtual void do_object(oop p);
coleenp@548	90	virtual bool do_object_b(oop p);
duke@435	91	};
duke@435	92
duke@435	93	class KeepAliveClosure: public OopClosure {
coleenp@548	94	protected:
coleenp@548	95	template <class T> void do_oop_work(T* p);
duke@435	96	public:
coleenp@548	97	virtual void do_oop(oop* p);
coleenp@548	98	virtual void do_oop(narrowOop* p);
duke@435	99	};
duke@435	100
duke@435	101	//
duke@435	102	// Friend decls
duke@435	103	//
duke@435	104	friend class AdjustPointerClosure;
duke@435	105	friend class KeepAliveClosure;
duke@435	106	friend class VM_MarkSweep;
duke@435	107	friend void marksweep_init();
ysr@1376	108	friend class DataLayout;
duke@435	109
duke@435	110	//
duke@435	111	// Vars
duke@435	112	//
duke@435	113	protected:
duke@435	114	// Traversal stack used during phase1
duke@435	115	static GrowableArray<oop>* _marking_stack;
duke@435	116	// Stack for live klasses to revisit at end of marking phase
duke@435	117	static GrowableArray<Klass*>* _revisit_klass_stack;
ysr@1376	118	// Set (stack) of MDO's to revisit at end of marking phase
ysr@1376	119	static GrowableArray<DataLayout*>* _revisit_mdo_stack;
duke@435	120
duke@435	121	// Space for storing/restoring mark word
duke@435	122	static GrowableArray<markOop>* _preserved_mark_stack;
duke@435	123	static GrowableArray<oop>* _preserved_oop_stack;
duke@435	124	static size_t _preserved_count;
duke@435	125	static size_t _preserved_count_max;
duke@435	126	static PreservedMark* _preserved_marks;
duke@435	127
duke@435	128	// Reference processing (used in ...follow_contents)
duke@435	129	static ReferenceProcessor* _ref_processor;
duke@435	130
duke@435	131	#ifdef VALIDATE_MARK_SWEEP
coleenp@548	132	static GrowableArray<void*>* _root_refs_stack;
duke@435	133	static GrowableArray<oop> * _live_oops;
duke@435	134	static GrowableArray<oop> * _live_oops_moved_to;
duke@435	135	static GrowableArray<size_t>* _live_oops_size;
duke@435	136	static size_t _live_oops_index;
duke@435	137	static size_t _live_oops_index_at_perm;
coleenp@548	138	static GrowableArray<void*>* _other_refs_stack;
coleenp@548	139	static GrowableArray<void*>* _adjusted_pointers;
duke@435	140	static bool _pointer_tracking;
duke@435	141	static bool _root_tracking;
duke@435	142
duke@435	143	// The following arrays are saved since the time of the last GC and
duke@435	144	// assist in tracking down problems where someone has done an errant
duke@435	145	// store into the heap, usually to an oop that wasn't properly
duke@435	146	// handleized across a GC. If we crash or otherwise fail before the
duke@435	147	// next GC, we can query these arrays to find out the object we had
duke@435	148	// intended to do the store to (assuming it is still alive) and the
duke@435	149	// offset within that object. Covered under RecordMarkSweepCompaction.
duke@435	150	static GrowableArray<HeapWord*> * _cur_gc_live_oops;
duke@435	151	static GrowableArray<HeapWord*> * _cur_gc_live_oops_moved_to;
duke@435	152	static GrowableArray<size_t>* _cur_gc_live_oops_size;
duke@435	153	static GrowableArray<HeapWord*> * _last_gc_live_oops;
duke@435	154	static GrowableArray<HeapWord*> * _last_gc_live_oops_moved_to;
duke@435	155	static GrowableArray<size_t>* _last_gc_live_oops_size;
duke@435	156	#endif
duke@435	157
duke@435	158	// Non public closures
coleenp@548	159	static IsAliveClosure is_alive;
duke@435	160	static KeepAliveClosure keep_alive;
duke@435	161
duke@435	162	// Class unloading. Update subklass/sibling/implementor links at end of marking phase.
duke@435	163	static void follow_weak_klass_links();
duke@435	164
ysr@1376	165	// Class unloading. Clear weak refs in MDO's (ProfileData)
ysr@1376	166	// at the end of the marking phase.
ysr@1376	167	static void follow_mdo_weak_refs();
ysr@1376	168
duke@435	169	// Debugging
duke@435	170	static void trace(const char* msg) PRODUCT_RETURN;
duke@435	171
duke@435	172	public:
duke@435	173	// Public closures
coleenp@548	174	static FollowRootClosure follow_root_closure;
jrose@1424	175	static CodeBlobToOopClosure follow_code_root_closure; // => follow_root_closure
coleenp@548	176	static MarkAndPushClosure mark_and_push_closure;
coleenp@548	177	static FollowStackClosure follow_stack_closure;
duke@435	178	static AdjustPointerClosure adjust_root_pointer_closure;
duke@435	179	static AdjustPointerClosure adjust_pointer_closure;
duke@435	180
duke@435	181	// Reference Processing
duke@435	182	static ReferenceProcessor* const ref_processor() { return _ref_processor; }
duke@435	183
duke@435	184	// Call backs for marking
duke@435	185	static void mark_object(oop obj);
coleenp@548	186	// Mark pointer and follow contents. Empty marking stack afterwards.
coleenp@548	187	template <class T> static inline void follow_root(T* p);
coleenp@548	188	// Mark pointer and follow contents.
coleenp@548	189	template <class T> static inline void mark_and_follow(T* p);
coleenp@548	190	// Check mark and maybe push on marking stack
coleenp@548	191	template <class T> static inline void mark_and_push(T* p);
duke@435	192
coleenp@548	193	static void follow_stack(); // Empty marking stack.
duke@435	194
coleenp@548	195	static void preserve_mark(oop p, markOop mark);
coleenp@548	196	// Save the mark word so it can be restored later
coleenp@548	197	static void adjust_marks(); // Adjust the pointers in the preserved marks table
coleenp@548	198	static void restore_marks(); // Restore the marks that we saved in preserve_mark
duke@435	199
coleenp@548	200	template <class T> static inline void adjust_pointer(T* p, bool isroot);
duke@435	201
coleenp@548	202	static void adjust_root_pointer(oop* p) { adjust_pointer(p, true); }
coleenp@548	203	static void adjust_pointer(oop* p) { adjust_pointer(p, false); }
coleenp@548	204	static void adjust_pointer(narrowOop* p) { adjust_pointer(p, false); }
duke@435	205
duke@435	206	#ifdef VALIDATE_MARK_SWEEP
coleenp@548	207	static void track_adjusted_pointer(void* p, bool isroot);
coleenp@548	208	static void check_adjust_pointer(void* p);
duke@435	209	static void track_interior_pointers(oop obj);
duke@435	210	static void check_interior_pointers();
duke@435	211
duke@435	212	static void reset_live_oop_tracking(bool at_perm);
duke@435	213	static void register_live_oop(oop p, size_t size);
duke@435	214	static void validate_live_oop(oop p, size_t size);
duke@435	215	static void live_oop_moved_to(HeapWord* q, size_t size, HeapWord* compaction_top);
duke@435	216	static void compaction_complete();
duke@435	217
duke@435	218	// Querying operation of RecordMarkSweepCompaction results.
duke@435	219	// Finds and prints the current base oop and offset for a word
duke@435	220	// within an oop that was live during the last GC. Helpful for
duke@435	221	// tracking down heap stomps.
duke@435	222	static void print_new_location_of_heap_address(HeapWord* q);
duke@435	223	#endif
duke@435	224
duke@435	225	// Call backs for class unloading
ysr@1376	226	// Update subklass/sibling/implementor links at end of marking.
ysr@1376	227	static void revisit_weak_klass_link(Klass* k);
ysr@1376	228	// For weak refs clearing in MDO's
ysr@1376	229	static void revisit_mdo(DataLayout* p);
duke@435	230	};
duke@435	231
duke@435	232	class PreservedMark VALUE_OBJ_CLASS_SPEC {
duke@435	233	private:
duke@435	234	oop _obj;
duke@435	235	markOop _mark;
duke@435	236
duke@435	237	public:
duke@435	238	void init(oop obj, markOop mark) {
duke@435	239	_obj = obj;
duke@435	240	_mark = mark;
duke@435	241	}
duke@435	242
duke@435	243	void adjust_pointer() {
duke@435	244	MarkSweep::adjust_pointer(&_obj);
duke@435	245	}
duke@435	246
duke@435	247	void restore() {
duke@435	248	_obj->set_mark(_mark);
duke@435	249	}
duke@435	250	};