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src/share/vm/gc_implementation/shared/vmGCOperations.hpp@0bfd3fb24150 (annotated)

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

Tue, 13 Apr 2010 13:52:10 -0700

author

jmasa

date

Tue, 13 Apr 2010 13:52:10 -0700

changeset 1822

0bfd3fb24150

parent 1050

c6c601a0f2d6

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
Summary: Ensure a full GC that clears SoftReferences before throwing an out-of-memory
Reviewed-by: ysr, jcoomes

duke@435	1	/*
jmasa@1822	2	* Copyright 2005-2010 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	// The following class hierarchy represents
duke@435	26	// a set of operations (VM_Operation) related to GC.
duke@435	27	//
duke@435	28	// VM_Operation
duke@435	29	// VM_GC_Operation
duke@435	30	// VM_GC_HeapInspection
duke@435	31	// VM_GenCollectForAllocation
duke@435	32	// VM_GenCollectFull
duke@435	33	// VM_GenCollectFullConcurrent
duke@435	34	// VM_ParallelGCFailedAllocation
duke@435	35	// VM_ParallelGCFailedPermanentAllocation
duke@435	36	// VM_ParallelGCSystemGC
duke@435	37	// VM_GC_Operation
duke@435	38	// - implements methods common to all classes in the hierarchy:
duke@435	39	// prevents multiple gc requests and manages lock on heap;
duke@435	40	//
duke@435	41	// VM_GC_HeapInspection
duke@435	42	// - prints class histogram on SIGBREAK if PrintClassHistogram
duke@435	43	// is specified; and also the attach "inspectheap" operation
duke@435	44	//
duke@435	45	// VM_GenCollectForAllocation
apetrusenko@574	46	// VM_GenCollectForPermanentAllocation
duke@435	47	// VM_ParallelGCFailedAllocation
duke@435	48	// VM_ParallelGCFailedPermanentAllocation
duke@435	49	// - this operation is invoked when allocation is failed;
duke@435	50	// operation performs garbage collection and tries to
duke@435	51	// allocate afterwards;
duke@435	52	//
duke@435	53	// VM_GenCollectFull
duke@435	54	// VM_GenCollectFullConcurrent
duke@435	55	// VM_ParallelGCSystemGC
duke@435	56	// - these operations preform full collection of heaps of
duke@435	57	// different kind
duke@435	58	//
duke@435	59
duke@435	60	class VM_GC_Operation: public VM_Operation {
duke@435	61	protected:
duke@435	62	BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL)
duke@435	63	unsigned int _gc_count_before; // gc count before acquiring PLL
duke@435	64	unsigned int _full_gc_count_before; // full gc count before acquiring PLL
duke@435	65	bool _full; // whether a "full" collection
duke@435	66	bool _prologue_succeeded; // whether doit_prologue succeeded
duke@435	67	GCCause::Cause _gc_cause; // the putative cause for this gc op
duke@435	68	bool _gc_locked; // will be set if gc was locked
duke@435	69
duke@435	70	virtual bool skip_operation() const;
duke@435	71
duke@435	72	// java.lang.ref.Reference support
duke@435	73	void acquire_pending_list_lock();
duke@435	74	void release_and_notify_pending_list_lock();
duke@435	75
duke@435	76	public:
duke@435	77	VM_GC_Operation(unsigned int gc_count_before,
duke@435	78	unsigned int full_gc_count_before = 0,
duke@435	79	bool full = false) {
duke@435	80	_full = full;
duke@435	81	_prologue_succeeded = false;
duke@435	82	_gc_count_before = gc_count_before;
duke@435	83
duke@435	84	// A subclass constructor will likely overwrite the following
duke@435	85	_gc_cause = GCCause::_no_cause_specified;
duke@435	86
duke@435	87	_gc_locked = false;
duke@435	88
duke@435	89	if (full) {
duke@435	90	_full_gc_count_before = full_gc_count_before;
duke@435	91	}
jmasa@1822	92	// In ParallelScavengeHeap::mem_allocate() collections can be
jmasa@1822	93	// executed within a loop and _all_soft_refs_clear can be set
jmasa@1822	94	// true after they have been cleared by a collection and another
jmasa@1822	95	// collection started so that _all_soft_refs_clear can be true
jmasa@1822	96	// when this collection is started. Don't assert that
jmasa@1822	97	// _all_soft_refs_clear have to be false here even though
jmasa@1822	98	// mutators have run. Soft refs will be cleared again in this
jmasa@1822	99	// collection.
duke@435	100	}
jmasa@1822	101	~VM_GC_Operation() {
jmasa@1822	102	CollectedHeap* ch = Universe::heap();
jmasa@1822	103	ch->collector_policy()->set_all_soft_refs_clear(false);
jmasa@1822	104	}
duke@435	105
duke@435	106	// Acquire the reference synchronization lock
duke@435	107	virtual bool doit_prologue();
duke@435	108	// Do notifyAll (if needed) and release held lock
duke@435	109	virtual void doit_epilogue();
duke@435	110
duke@435	111	virtual bool allow_nested_vm_operations() const { return true; }
duke@435	112	bool prologue_succeeded() const { return _prologue_succeeded; }
duke@435	113
duke@435	114	void set_gc_locked() { _gc_locked = true; }
duke@435	115	bool gc_locked() const { return _gc_locked; }
duke@435	116
duke@435	117	static void notify_gc_begin(bool full = false);
duke@435	118	static void notify_gc_end();
duke@435	119	};
duke@435	120
duke@435	121
duke@435	122	class VM_GC_HeapInspection: public VM_GC_Operation {
duke@435	123	private:
duke@435	124	outputStream* _out;
duke@435	125	bool _full_gc;
ysr@1050	126	bool _need_prologue;
duke@435	127	public:
ysr@1050	128	VM_GC_HeapInspection(outputStream* out, bool request_full_gc,
ysr@1050	129	bool need_prologue) :
duke@435	130	VM_GC_Operation(0 /* total collections, dummy, ignored */,
duke@435	131	0 /* total full collections, dummy, ignored */,
duke@435	132	request_full_gc) {
duke@435	133	_out = out;
duke@435	134	_full_gc = request_full_gc;
ysr@1050	135	_need_prologue = need_prologue;
duke@435	136	}
duke@435	137
duke@435	138	~VM_GC_HeapInspection() {}
duke@435	139	virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
duke@435	140	virtual bool skip_operation() const;
duke@435	141	virtual bool doit_prologue();
duke@435	142	virtual void doit();
duke@435	143	};
duke@435	144
duke@435	145
duke@435	146	class VM_GenCollectForAllocation: public VM_GC_Operation {
duke@435	147	private:
duke@435	148	HeapWord* _res;
duke@435	149	size_t _size; // size of object to be allocated.
duke@435	150	bool _tlab; // alloc is of a tlab.
duke@435	151	public:
duke@435	152	VM_GenCollectForAllocation(size_t size,
duke@435	153	bool tlab,
duke@435	154	unsigned int gc_count_before)
duke@435	155	: VM_GC_Operation(gc_count_before),
duke@435	156	_size(size),
duke@435	157	_tlab(tlab) {
duke@435	158	_res = NULL;
duke@435	159	}
duke@435	160	~VM_GenCollectForAllocation() {}
duke@435	161	virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
duke@435	162	virtual void doit();
duke@435	163	HeapWord* result() const { return _res; }
duke@435	164	};
duke@435	165
duke@435	166
duke@435	167	// VM operation to invoke a collection of the heap as a
duke@435	168	// GenCollectedHeap heap.
duke@435	169	class VM_GenCollectFull: public VM_GC_Operation {
duke@435	170	private:
duke@435	171	int _max_level;
duke@435	172	public:
duke@435	173	VM_GenCollectFull(unsigned int gc_count_before,
duke@435	174	unsigned int full_gc_count_before,
duke@435	175	GCCause::Cause gc_cause,
duke@435	176	int max_level)
duke@435	177	: VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */),
duke@435	178	_max_level(max_level)
duke@435	179	{ _gc_cause = gc_cause; }
duke@435	180	~VM_GenCollectFull() {}
duke@435	181	virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
duke@435	182	virtual void doit();
duke@435	183	};
apetrusenko@574	184
apetrusenko@574	185	class VM_GenCollectForPermanentAllocation: public VM_GC_Operation {
apetrusenko@574	186	private:
apetrusenko@574	187	HeapWord* _res;
apetrusenko@574	188	size_t _size; // size of object to be allocated
apetrusenko@574	189	public:
apetrusenko@574	190	VM_GenCollectForPermanentAllocation(size_t size,
apetrusenko@574	191	unsigned int gc_count_before,
apetrusenko@574	192	unsigned int full_gc_count_before,
apetrusenko@574	193	GCCause::Cause gc_cause)
apetrusenko@574	194	: VM_GC_Operation(gc_count_before, full_gc_count_before, true),
apetrusenko@574	195	_size(size) {
apetrusenko@574	196	_res = NULL;
apetrusenko@574	197	_gc_cause = gc_cause;
apetrusenko@574	198	}
apetrusenko@574	199	~VM_GenCollectForPermanentAllocation() {}
apetrusenko@574	200	virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; }
apetrusenko@574	201	virtual void doit();
apetrusenko@574	202	HeapWord* result() const { return _res; }
apetrusenko@574	203	};