• file
• revisions
• annotate
• diff
• comparison
• raw

src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp@c96030fff130 (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp

Thu, 20 Nov 2008 16:56:09 -0800

author

ysr

date

Thu, 20 Nov 2008 16:56:09 -0800

changeset 888

c96030fff130

parent 435

a61af66fc99e

child 1875

bb843ebc7c55

permissions

-rw-r--r--

6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa

duke@435	1	/*
duke@435	2	* Copyright 2005-2006 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 VM_CMS_Operation is slightly different from
duke@435	26	// a VM_GC_Operation -- and would not have subclassed easily
duke@435	27	// to VM_GC_Operation without several changes to VM_GC_Operation.
duke@435	28	// To minimize the changes, we have replicated some of the VM_GC_Operation
duke@435	29	// functionality here. We will consolidate that back by doing subclassing
duke@435	30	// as appropriate in Dolphin.
duke@435	31	//
duke@435	32	// VM_Operation
duke@435	33	// VM_CMS_Operation
duke@435	34	// - implements the common portion of work done in support
duke@435	35	// of CMS' stop-world phases (initial mark and remark).
duke@435	36	//
duke@435	37	// VM_CMS_Initial_Mark
duke@435	38	// VM_CMS_Final_Mark
duke@435	39	//
duke@435	40
duke@435	41	// Forward decl.
duke@435	42	class CMSCollector;
duke@435	43
duke@435	44	class VM_CMS_Operation: public VM_Operation {
duke@435	45	protected:
duke@435	46	CMSCollector* _collector; // associated collector
duke@435	47	bool _prologue_succeeded; // whether doit_prologue succeeded
duke@435	48
duke@435	49	bool lost_race() const;
duke@435	50
duke@435	51	// java.lang.ref.Reference support
duke@435	52	void acquire_pending_list_lock();
duke@435	53	void release_and_notify_pending_list_lock();
duke@435	54
duke@435	55	public:
duke@435	56	VM_CMS_Operation(CMSCollector* collector):
duke@435	57	_collector(collector),
duke@435	58	_prologue_succeeded(false) {}
duke@435	59	~VM_CMS_Operation() {}
duke@435	60
duke@435	61	// The legal collector state for executing this CMS op.
duke@435	62	virtual const CMSCollector::CollectorState legal_state() const = 0;
duke@435	63
duke@435	64	// Whether the pending list lock needs to be held
duke@435	65	virtual const bool needs_pll() const = 0;
duke@435	66
duke@435	67	// Execute operations in the context of the caller,
duke@435	68	// prior to execution of the vm operation itself.
duke@435	69	virtual bool doit_prologue();
duke@435	70	// Execute operations in the context of the caller,
duke@435	71	// following completion of the vm operation.
duke@435	72	virtual void doit_epilogue();
duke@435	73
duke@435	74	virtual bool evaluate_at_safepoint() const { return true; }
duke@435	75	virtual bool is_cheap_allocated() const { return false; }
duke@435	76	virtual bool allow_nested_vm_operations() const { return false; }
duke@435	77	bool prologue_succeeded() const { return _prologue_succeeded; }
duke@435	78
duke@435	79	void verify_before_gc();
duke@435	80	void verify_after_gc();
duke@435	81	};
duke@435	82
duke@435	83
duke@435	84	// VM_CMS_Operation for the initial marking phase of CMS.
duke@435	85	class VM_CMS_Initial_Mark: public VM_CMS_Operation {
duke@435	86	public:
duke@435	87	VM_CMS_Initial_Mark(CMSCollector* _collector) :
duke@435	88	VM_CMS_Operation(_collector) {}
duke@435	89
duke@435	90	virtual VMOp_Type type() const { return VMOp_CMS_Initial_Mark; }
duke@435	91	virtual void doit();
duke@435	92
duke@435	93	virtual const CMSCollector::CollectorState legal_state() const {
duke@435	94	return CMSCollector::InitialMarking;
duke@435	95	}
duke@435	96
duke@435	97	virtual const bool needs_pll() const {
duke@435	98	return false;
duke@435	99	}
duke@435	100	};
duke@435	101
duke@435	102	// VM_CMS_Operation for the final remark phase of CMS.
duke@435	103	class VM_CMS_Final_Remark: public VM_CMS_Operation {
duke@435	104	public:
duke@435	105	VM_CMS_Final_Remark(CMSCollector* _collector) :
duke@435	106	VM_CMS_Operation(_collector) {}
duke@435	107	virtual VMOp_Type type() const { return VMOp_CMS_Final_Remark; }
duke@435	108	virtual void doit();
duke@435	109
duke@435	110	virtual const CMSCollector::CollectorState legal_state() const {
duke@435	111	return CMSCollector::FinalMarking;
duke@435	112	}
duke@435	113
duke@435	114	virtual const bool needs_pll() const {
duke@435	115	return true;
duke@435	116	}
duke@435	117	};
duke@435	118
duke@435	119
duke@435	120	// VM operation to invoke a concurrent collection of the heap as a
duke@435	121	// GenCollectedHeap heap.
duke@435	122	class VM_GenCollectFullConcurrent: public VM_GC_Operation {
duke@435	123	public:
duke@435	124	VM_GenCollectFullConcurrent(unsigned int gc_count_before,
duke@435	125	unsigned int full_gc_count_before,
duke@435	126	GCCause::Cause gc_cause)
duke@435	127	: VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */) {
duke@435	128	_gc_cause = gc_cause;
duke@435	129	assert(FullGCCount_lock != NULL && UseConcMarkSweepGC &&
duke@435	130	ExplicitGCInvokesConcurrent, "Otherwise shouldn't be here");
duke@435	131	assert(UseAsyncConcMarkSweepGC, "Else will hang caller");
duke@435	132	}
duke@435	133	~VM_GenCollectFullConcurrent() {}
duke@435	134	virtual VMOp_Type type() const { return VMOp_GenCollectFullConcurrent; }
duke@435	135	virtual void doit();
duke@435	136	virtual void doit_epilogue();
duke@435	137	virtual bool is_cheap_allocated() const { return false; }
duke@435	138	virtual bool evaluate_at_safepoint() const;
duke@435	139	};