diff -r 000000000000 -r a61af66fc99e src/share/vm/runtime/objectMonitor.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/runtime/objectMonitor.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,208 @@ +/* + * Copyright 1998-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// WARNING: +// This is a very sensitive and fragile class. DO NOT make any +// change unless you are fully aware of the underlying semantics. + +// This class can not inherit from any other class, because I have +// to let the displaced header be the very first word. Otherwise I +// have to let markOop include this file, which would export the +// monitor data structure to everywhere. +// +// The ObjectMonitor class is used to implement JavaMonitors which have +// transformed from the lightweight structure of the thread stack to a +// heavy weight lock due to contention + +// It is also used as RawMonitor by the JVMTI + + +class ObjectWaiter; + +class ObjectMonitor { + public: + enum { + OM_OK, // no error + OM_SYSTEM_ERROR, // operating system error + OM_ILLEGAL_MONITOR_STATE, // IllegalMonitorStateException + OM_INTERRUPTED, // Thread.interrupt() + OM_TIMED_OUT // Object.wait() timed out + }; + + public: + // TODO-FIXME: the "offset" routines should return a type of off_t instead of int ... + // ByteSize would also be an appropriate type. + static int header_offset_in_bytes() { return offset_of(ObjectMonitor, _header); } + static int object_offset_in_bytes() { return offset_of(ObjectMonitor, _object); } + static int owner_offset_in_bytes() { return offset_of(ObjectMonitor, _owner); } + static int count_offset_in_bytes() { return offset_of(ObjectMonitor, _count); } + static int recursions_offset_in_bytes() { return offset_of(ObjectMonitor, _recursions); } + static int cxq_offset_in_bytes() { return offset_of(ObjectMonitor, _cxq) ; } + static int succ_offset_in_bytes() { return offset_of(ObjectMonitor, _succ) ; } + static int EntryList_offset_in_bytes() { return offset_of(ObjectMonitor, _EntryList); } + static int FreeNext_offset_in_bytes() { return offset_of(ObjectMonitor, FreeNext); } + static int WaitSet_offset_in_bytes() { return offset_of(ObjectMonitor, _WaitSet) ; } + static int Responsible_offset_in_bytes() { return offset_of(ObjectMonitor, _Responsible);} + static int Spinner_offset_in_bytes() { return offset_of(ObjectMonitor, _Spinner); } + + public: + // Eventaully we'll make provisions for multiple callbacks, but + // now one will suffice. + static int (*SpinCallbackFunction)(intptr_t, int) ; + static intptr_t SpinCallbackArgument ; + + + public: + ObjectMonitor(); + ~ObjectMonitor(); + + markOop header() const; + void set_header(markOop hdr); + + intptr_t is_busy() const; + intptr_t is_entered(Thread* current) const; + + void* owner() const; + void set_owner(void* owner); + + intptr_t waiters() const; + + intptr_t count() const; + void set_count(intptr_t count); + intptr_t contentions() const ; + + // JVM/DI GetMonitorInfo() needs this + Thread * thread_of_waiter (ObjectWaiter *) ; + ObjectWaiter * first_waiter () ; + ObjectWaiter * next_waiter(ObjectWaiter* o); + + intptr_t recursions() const { return _recursions; } + + void* object() const; + void* object_addr(); + void set_object(void* obj); + + bool check(TRAPS); // true if the thread owns the monitor. + void check_slow(TRAPS); + void clear(); +#ifndef PRODUCT + void verify(); + void print(); +#endif + + bool try_enter (TRAPS) ; + void enter(TRAPS); + void exit(TRAPS); + void wait(jlong millis, bool interruptable, TRAPS); + void notify(TRAPS); + void notifyAll(TRAPS); + +// Use the following at your own risk + intptr_t complete_exit(TRAPS); + void reenter(intptr_t recursions, TRAPS); + + int raw_enter(TRAPS); + int raw_exit(TRAPS); + int raw_wait(jlong millis, bool interruptable, TRAPS); + int raw_notify(TRAPS); + int raw_notifyAll(TRAPS); + + private: + // JVMTI support -- remove ASAP + int SimpleEnter (Thread * Self) ; + int SimpleExit (Thread * Self) ; + int SimpleWait (Thread * Self, jlong millis) ; + int SimpleNotify (Thread * Self, bool All) ; + + private: + void Recycle () ; + void AddWaiter (ObjectWaiter * waiter) ; + + ObjectWaiter * DequeueWaiter () ; + void DequeueSpecificWaiter (ObjectWaiter * waiter) ; + void EnterI (TRAPS) ; + void ReenterI (Thread * Self, ObjectWaiter * SelfNode) ; + void UnlinkAfterAcquire (Thread * Self, ObjectWaiter * SelfNode) ; + int TryLock (Thread * Self) ; + int NotRunnable (Thread * Self, Thread * Owner) ; + int TrySpin_Fixed (Thread * Self) ; + int TrySpin_VaryFrequency (Thread * Self) ; + int TrySpin_VaryDuration (Thread * Self) ; + void ctAsserts () ; + void ExitEpilog (Thread * Self, ObjectWaiter * Wakee) ; + bool ExitSuspendEquivalent (JavaThread * Self) ; + + private: + friend class ObjectSynchronizer; + friend class ObjectWaiter; + friend class VMStructs; + + // WARNING: this must be the very first word of ObjectMonitor + // This means this class can't use any virtual member functions. + // TODO-FIXME: assert that offsetof(_header) is 0 or get rid of the + // implicit 0 offset in emitted code. + + volatile markOop _header; // displaced object header word - mark + void* volatile _object; // backward object pointer - strong root + + double SharingPad [1] ; // temp to reduce false sharing + + // All the following fields must be machine word aligned + // The VM assumes write ordering wrt these fields, which can be + // read from other threads. + + void * volatile _owner; // pointer to owning thread OR BasicLock + volatile intptr_t _recursions; // recursion count, 0 for first entry + int OwnerIsThread ; // _owner is (Thread *) vs SP/BasicLock + ObjectWaiter * volatile _cxq ; // LL of recently-arrived threads blocked on entry. + // The list is actually composed of WaitNodes, acting + // as proxies for Threads. + ObjectWaiter * volatile _EntryList ; // Threads blocked on entry or reentry. + Thread * volatile _succ ; // Heir presumptive thread - used for futile wakeup throttling + Thread * volatile _Responsible ; + int _PromptDrain ; // rqst to drain cxq into EntryList ASAP + + volatile int _Spinner ; // for exit->spinner handoff optimization + volatile int _SpinFreq ; // Spin 1-out-of-N attempts: success rate + volatile int _SpinClock ; + volatile int _SpinDuration ; + volatile intptr_t _SpinState ; // MCS/CLH list of spinners + + // TODO-FIXME: _count, _waiters and _recursions should be of + // type int, or int32_t but not intptr_t. There's no reason + // to use 64-bit fields for these variables on a 64-bit JVM. + + volatile intptr_t _count; // reference count to prevent reclaimation/deflation + // at stop-the-world time. See deflate_idle_monitors(). + // _count is approximately |_WaitSet| + |_EntryList| + volatile intptr_t _waiters; // number of waiting threads + ObjectWaiter * volatile _WaitSet; // LL of threads wait()ing on the monitor + volatile int _WaitSetLock; // protects Wait Queue - simple spinlock + + public: + int _QMix ; // Mixed prepend queue discipline + ObjectMonitor * FreeNext ; // Free list linkage + intptr_t StatA, StatsB ; + +};