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

src/share/vm/runtime/objectMonitor.hpp@9f4457a14b58 (annotated)

src/share/vm/runtime/objectMonitor.hpp

Wed, 09 Apr 2008 15:10:22 -0700

author

rasbold

date

Wed, 09 Apr 2008 15:10:22 -0700

changeset 544

9f4457a14b58

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

permissions

-rw-r--r--

Merge

duke@435	1	/*
duke@435	2	* Copyright 1998-2007 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	// WARNING:
duke@435	26	// This is a very sensitive and fragile class. DO NOT make any
duke@435	27	// change unless you are fully aware of the underlying semantics.
duke@435	28
duke@435	29	// This class can not inherit from any other class, because I have
duke@435	30	// to let the displaced header be the very first word. Otherwise I
duke@435	31	// have to let markOop include this file, which would export the
duke@435	32	// monitor data structure to everywhere.
duke@435	33	//
duke@435	34	// The ObjectMonitor class is used to implement JavaMonitors which have
duke@435	35	// transformed from the lightweight structure of the thread stack to a
duke@435	36	// heavy weight lock due to contention
duke@435	37
duke@435	38	// It is also used as RawMonitor by the JVMTI
duke@435	39
duke@435	40
duke@435	41	class ObjectWaiter;
duke@435	42
duke@435	43	class ObjectMonitor {
duke@435	44	public:
duke@435	45	enum {
duke@435	46	OM_OK, // no error
duke@435	47	OM_SYSTEM_ERROR, // operating system error
duke@435	48	OM_ILLEGAL_MONITOR_STATE, // IllegalMonitorStateException
duke@435	49	OM_INTERRUPTED, // Thread.interrupt()
duke@435	50	OM_TIMED_OUT // Object.wait() timed out
duke@435	51	};
duke@435	52
duke@435	53	public:
duke@435	54	// TODO-FIXME: the "offset" routines should return a type of off_t instead of int ...
duke@435	55	// ByteSize would also be an appropriate type.
duke@435	56	static int header_offset_in_bytes() { return offset_of(ObjectMonitor, _header); }
duke@435	57	static int object_offset_in_bytes() { return offset_of(ObjectMonitor, _object); }
duke@435	58	static int owner_offset_in_bytes() { return offset_of(ObjectMonitor, _owner); }
duke@435	59	static int count_offset_in_bytes() { return offset_of(ObjectMonitor, _count); }
duke@435	60	static int recursions_offset_in_bytes() { return offset_of(ObjectMonitor, _recursions); }
duke@435	61	static int cxq_offset_in_bytes() { return offset_of(ObjectMonitor, _cxq) ; }
duke@435	62	static int succ_offset_in_bytes() { return offset_of(ObjectMonitor, _succ) ; }
duke@435	63	static int EntryList_offset_in_bytes() { return offset_of(ObjectMonitor, _EntryList); }
duke@435	64	static int FreeNext_offset_in_bytes() { return offset_of(ObjectMonitor, FreeNext); }
duke@435	65	static int WaitSet_offset_in_bytes() { return offset_of(ObjectMonitor, _WaitSet) ; }
duke@435	66	static int Responsible_offset_in_bytes() { return offset_of(ObjectMonitor, _Responsible);}
duke@435	67	static int Spinner_offset_in_bytes() { return offset_of(ObjectMonitor, _Spinner); }
duke@435	68
duke@435	69	public:
duke@435	70	// Eventaully we'll make provisions for multiple callbacks, but
duke@435	71	// now one will suffice.
duke@435	72	static int (*SpinCallbackFunction)(intptr_t, int) ;
duke@435	73	static intptr_t SpinCallbackArgument ;
duke@435	74
duke@435	75
duke@435	76	public:
duke@435	77	ObjectMonitor();
duke@435	78	~ObjectMonitor();
duke@435	79
duke@435	80	markOop header() const;
duke@435	81	void set_header(markOop hdr);
duke@435	82
duke@435	83	intptr_t is_busy() const;
duke@435	84	intptr_t is_entered(Thread* current) const;
duke@435	85
duke@435	86	void* owner() const;
duke@435	87	void set_owner(void* owner);
duke@435	88
duke@435	89	intptr_t waiters() const;
duke@435	90
duke@435	91	intptr_t count() const;
duke@435	92	void set_count(intptr_t count);
duke@435	93	intptr_t contentions() const ;
duke@435	94
duke@435	95	// JVM/DI GetMonitorInfo() needs this
duke@435	96	Thread * thread_of_waiter (ObjectWaiter *) ;
duke@435	97	ObjectWaiter * first_waiter () ;
duke@435	98	ObjectWaiter * next_waiter(ObjectWaiter* o);
duke@435	99
duke@435	100	intptr_t recursions() const { return _recursions; }
duke@435	101
duke@435	102	void* object() const;
duke@435	103	void* object_addr();
duke@435	104	void set_object(void* obj);
duke@435	105
duke@435	106	bool check(TRAPS); // true if the thread owns the monitor.
duke@435	107	void check_slow(TRAPS);
duke@435	108	void clear();
duke@435	109	#ifndef PRODUCT
duke@435	110	void verify();
duke@435	111	void print();
duke@435	112	#endif
duke@435	113
duke@435	114	bool try_enter (TRAPS) ;
duke@435	115	void enter(TRAPS);
duke@435	116	void exit(TRAPS);
duke@435	117	void wait(jlong millis, bool interruptable, TRAPS);
duke@435	118	void notify(TRAPS);
duke@435	119	void notifyAll(TRAPS);
duke@435	120
duke@435	121	// Use the following at your own risk
duke@435	122	intptr_t complete_exit(TRAPS);
duke@435	123	void reenter(intptr_t recursions, TRAPS);
duke@435	124
duke@435	125	int raw_enter(TRAPS);
duke@435	126	int raw_exit(TRAPS);
duke@435	127	int raw_wait(jlong millis, bool interruptable, TRAPS);
duke@435	128	int raw_notify(TRAPS);
duke@435	129	int raw_notifyAll(TRAPS);
duke@435	130
duke@435	131	private:
duke@435	132	// JVMTI support -- remove ASAP
duke@435	133	int SimpleEnter (Thread * Self) ;
duke@435	134	int SimpleExit (Thread * Self) ;
duke@435	135	int SimpleWait (Thread * Self, jlong millis) ;
duke@435	136	int SimpleNotify (Thread * Self, bool All) ;
duke@435	137
duke@435	138	private:
duke@435	139	void Recycle () ;
duke@435	140	void AddWaiter (ObjectWaiter * waiter) ;
duke@435	141
duke@435	142	ObjectWaiter * DequeueWaiter () ;
duke@435	143	void DequeueSpecificWaiter (ObjectWaiter * waiter) ;
duke@435	144	void EnterI (TRAPS) ;
duke@435	145	void ReenterI (Thread * Self, ObjectWaiter * SelfNode) ;
duke@435	146	void UnlinkAfterAcquire (Thread * Self, ObjectWaiter * SelfNode) ;
duke@435	147	int TryLock (Thread * Self) ;
duke@435	148	int NotRunnable (Thread * Self, Thread * Owner) ;
duke@435	149	int TrySpin_Fixed (Thread * Self) ;
duke@435	150	int TrySpin_VaryFrequency (Thread * Self) ;
duke@435	151	int TrySpin_VaryDuration (Thread * Self) ;
duke@435	152	void ctAsserts () ;
duke@435	153	void ExitEpilog (Thread * Self, ObjectWaiter * Wakee) ;
duke@435	154	bool ExitSuspendEquivalent (JavaThread * Self) ;
duke@435	155
duke@435	156	private:
duke@435	157	friend class ObjectSynchronizer;
duke@435	158	friend class ObjectWaiter;
duke@435	159	friend class VMStructs;
duke@435	160
duke@435	161	// WARNING: this must be the very first word of ObjectMonitor
duke@435	162	// This means this class can't use any virtual member functions.
duke@435	163	// TODO-FIXME: assert that offsetof(_header) is 0 or get rid of the
duke@435	164	// implicit 0 offset in emitted code.
duke@435	165
duke@435	166	volatile markOop _header; // displaced object header word - mark
duke@435	167	void* volatile _object; // backward object pointer - strong root
duke@435	168
duke@435	169	double SharingPad [1] ; // temp to reduce false sharing
duke@435	170
duke@435	171	// All the following fields must be machine word aligned
duke@435	172	// The VM assumes write ordering wrt these fields, which can be
duke@435	173	// read from other threads.
duke@435	174
duke@435	175	void * volatile _owner; // pointer to owning thread OR BasicLock
duke@435	176	volatile intptr_t _recursions; // recursion count, 0 for first entry
duke@435	177	int OwnerIsThread ; // _owner is (Thread *) vs SP/BasicLock
duke@435	178	ObjectWaiter * volatile _cxq ; // LL of recently-arrived threads blocked on entry.
duke@435	179	// The list is actually composed of WaitNodes, acting
duke@435	180	// as proxies for Threads.
duke@435	181	ObjectWaiter * volatile _EntryList ; // Threads blocked on entry or reentry.
duke@435	182	Thread * volatile _succ ; // Heir presumptive thread - used for futile wakeup throttling
duke@435	183	Thread * volatile _Responsible ;
duke@435	184	int _PromptDrain ; // rqst to drain cxq into EntryList ASAP
duke@435	185
duke@435	186	volatile int _Spinner ; // for exit->spinner handoff optimization
duke@435	187	volatile int _SpinFreq ; // Spin 1-out-of-N attempts: success rate
duke@435	188	volatile int _SpinClock ;
duke@435	189	volatile int _SpinDuration ;
duke@435	190	volatile intptr_t _SpinState ; // MCS/CLH list of spinners
duke@435	191
duke@435	192	// TODO-FIXME: _count, _waiters and _recursions should be of
duke@435	193	// type int, or int32_t but not intptr_t. There's no reason
duke@435	194	// to use 64-bit fields for these variables on a 64-bit JVM.
duke@435	195
duke@435	196	volatile intptr_t _count; // reference count to prevent reclaimation/deflation
duke@435	197	// at stop-the-world time. See deflate_idle_monitors().
duke@435	198	// _count is approximately |_WaitSet| + |_EntryList|
duke@435	199	volatile intptr_t _waiters; // number of waiting threads
duke@435	200	ObjectWaiter * volatile _WaitSet; // LL of threads wait()ing on the monitor
duke@435	201	volatile int _WaitSetLock; // protects Wait Queue - simple spinlock
duke@435	202
duke@435	203	public:
duke@435	204	int _QMix ; // Mixed prepend queue discipline
duke@435	205	ObjectMonitor * FreeNext ; // Free list linkage
duke@435	206	intptr_t StatA, StatsB ;
duke@435	207
duke@435	208	};