1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/runtime/objectMonitor.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,208 @@
1.4 +/*
1.5 + * Copyright 1998-2007 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +// WARNING:
1.29 +// This is a very sensitive and fragile class. DO NOT make any
1.30 +// change unless you are fully aware of the underlying semantics.
1.31 +
1.32 +// This class can not inherit from any other class, because I have
1.33 +// to let the displaced header be the very first word. Otherwise I
1.34 +// have to let markOop include this file, which would export the
1.35 +// monitor data structure to everywhere.
1.36 +//
1.37 +// The ObjectMonitor class is used to implement JavaMonitors which have
1.38 +// transformed from the lightweight structure of the thread stack to a
1.39 +// heavy weight lock due to contention
1.40 +
1.41 +// It is also used as RawMonitor by the JVMTI
1.42 +
1.43 +
1.44 +class ObjectWaiter;
1.45 +
1.46 +class ObjectMonitor {
1.47 + public:
1.48 + enum {
1.49 + OM_OK, // no error
1.50 + OM_SYSTEM_ERROR, // operating system error
1.51 + OM_ILLEGAL_MONITOR_STATE, // IllegalMonitorStateException
1.52 + OM_INTERRUPTED, // Thread.interrupt()
1.53 + OM_TIMED_OUT // Object.wait() timed out
1.54 + };
1.55 +
1.56 + public:
1.57 + // TODO-FIXME: the "offset" routines should return a type of off_t instead of int ...
1.58 + // ByteSize would also be an appropriate type.
1.59 + static int header_offset_in_bytes() { return offset_of(ObjectMonitor, _header); }
1.60 + static int object_offset_in_bytes() { return offset_of(ObjectMonitor, _object); }
1.61 + static int owner_offset_in_bytes() { return offset_of(ObjectMonitor, _owner); }
1.62 + static int count_offset_in_bytes() { return offset_of(ObjectMonitor, _count); }
1.63 + static int recursions_offset_in_bytes() { return offset_of(ObjectMonitor, _recursions); }
1.64 + static int cxq_offset_in_bytes() { return offset_of(ObjectMonitor, _cxq) ; }
1.65 + static int succ_offset_in_bytes() { return offset_of(ObjectMonitor, _succ) ; }
1.66 + static int EntryList_offset_in_bytes() { return offset_of(ObjectMonitor, _EntryList); }
1.67 + static int FreeNext_offset_in_bytes() { return offset_of(ObjectMonitor, FreeNext); }
1.68 + static int WaitSet_offset_in_bytes() { return offset_of(ObjectMonitor, _WaitSet) ; }
1.69 + static int Responsible_offset_in_bytes() { return offset_of(ObjectMonitor, _Responsible);}
1.70 + static int Spinner_offset_in_bytes() { return offset_of(ObjectMonitor, _Spinner); }
1.71 +
1.72 + public:
1.73 + // Eventaully we'll make provisions for multiple callbacks, but
1.74 + // now one will suffice.
1.75 + static int (*SpinCallbackFunction)(intptr_t, int) ;
1.76 + static intptr_t SpinCallbackArgument ;
1.77 +
1.78 +
1.79 + public:
1.80 + ObjectMonitor();
1.81 + ~ObjectMonitor();
1.82 +
1.83 + markOop header() const;
1.84 + void set_header(markOop hdr);
1.85 +
1.86 + intptr_t is_busy() const;
1.87 + intptr_t is_entered(Thread* current) const;
1.88 +
1.89 + void* owner() const;
1.90 + void set_owner(void* owner);
1.91 +
1.92 + intptr_t waiters() const;
1.93 +
1.94 + intptr_t count() const;
1.95 + void set_count(intptr_t count);
1.96 + intptr_t contentions() const ;
1.97 +
1.98 + // JVM/DI GetMonitorInfo() needs this
1.99 + Thread * thread_of_waiter (ObjectWaiter *) ;
1.100 + ObjectWaiter * first_waiter () ;
1.101 + ObjectWaiter * next_waiter(ObjectWaiter* o);
1.102 +
1.103 + intptr_t recursions() const { return _recursions; }
1.104 +
1.105 + void* object() const;
1.106 + void* object_addr();
1.107 + void set_object(void* obj);
1.108 +
1.109 + bool check(TRAPS); // true if the thread owns the monitor.
1.110 + void check_slow(TRAPS);
1.111 + void clear();
1.112 +#ifndef PRODUCT
1.113 + void verify();
1.114 + void print();
1.115 +#endif
1.116 +
1.117 + bool try_enter (TRAPS) ;
1.118 + void enter(TRAPS);
1.119 + void exit(TRAPS);
1.120 + void wait(jlong millis, bool interruptable, TRAPS);
1.121 + void notify(TRAPS);
1.122 + void notifyAll(TRAPS);
1.123 +
1.124 +// Use the following at your own risk
1.125 + intptr_t complete_exit(TRAPS);
1.126 + void reenter(intptr_t recursions, TRAPS);
1.127 +
1.128 + int raw_enter(TRAPS);
1.129 + int raw_exit(TRAPS);
1.130 + int raw_wait(jlong millis, bool interruptable, TRAPS);
1.131 + int raw_notify(TRAPS);
1.132 + int raw_notifyAll(TRAPS);
1.133 +
1.134 + private:
1.135 + // JVMTI support -- remove ASAP
1.136 + int SimpleEnter (Thread * Self) ;
1.137 + int SimpleExit (Thread * Self) ;
1.138 + int SimpleWait (Thread * Self, jlong millis) ;
1.139 + int SimpleNotify (Thread * Self, bool All) ;
1.140 +
1.141 + private:
1.142 + void Recycle () ;
1.143 + void AddWaiter (ObjectWaiter * waiter) ;
1.144 +
1.145 + ObjectWaiter * DequeueWaiter () ;
1.146 + void DequeueSpecificWaiter (ObjectWaiter * waiter) ;
1.147 + void EnterI (TRAPS) ;
1.148 + void ReenterI (Thread * Self, ObjectWaiter * SelfNode) ;
1.149 + void UnlinkAfterAcquire (Thread * Self, ObjectWaiter * SelfNode) ;
1.150 + int TryLock (Thread * Self) ;
1.151 + int NotRunnable (Thread * Self, Thread * Owner) ;
1.152 + int TrySpin_Fixed (Thread * Self) ;
1.153 + int TrySpin_VaryFrequency (Thread * Self) ;
1.154 + int TrySpin_VaryDuration (Thread * Self) ;
1.155 + void ctAsserts () ;
1.156 + void ExitEpilog (Thread * Self, ObjectWaiter * Wakee) ;
1.157 + bool ExitSuspendEquivalent (JavaThread * Self) ;
1.158 +
1.159 + private:
1.160 + friend class ObjectSynchronizer;
1.161 + friend class ObjectWaiter;
1.162 + friend class VMStructs;
1.163 +
1.164 + // WARNING: this must be the very first word of ObjectMonitor
1.165 + // This means this class can't use any virtual member functions.
1.166 + // TODO-FIXME: assert that offsetof(_header) is 0 or get rid of the
1.167 + // implicit 0 offset in emitted code.
1.168 +
1.169 + volatile markOop _header; // displaced object header word - mark
1.170 + void* volatile _object; // backward object pointer - strong root
1.171 +
1.172 + double SharingPad [1] ; // temp to reduce false sharing
1.173 +
1.174 + // All the following fields must be machine word aligned
1.175 + // The VM assumes write ordering wrt these fields, which can be
1.176 + // read from other threads.
1.177 +
1.178 + void * volatile _owner; // pointer to owning thread OR BasicLock
1.179 + volatile intptr_t _recursions; // recursion count, 0 for first entry
1.180 + int OwnerIsThread ; // _owner is (Thread *) vs SP/BasicLock
1.181 + ObjectWaiter * volatile _cxq ; // LL of recently-arrived threads blocked on entry.
1.182 + // The list is actually composed of WaitNodes, acting
1.183 + // as proxies for Threads.
1.184 + ObjectWaiter * volatile _EntryList ; // Threads blocked on entry or reentry.
1.185 + Thread * volatile _succ ; // Heir presumptive thread - used for futile wakeup throttling
1.186 + Thread * volatile _Responsible ;
1.187 + int _PromptDrain ; // rqst to drain cxq into EntryList ASAP
1.188 +
1.189 + volatile int _Spinner ; // for exit->spinner handoff optimization
1.190 + volatile int _SpinFreq ; // Spin 1-out-of-N attempts: success rate
1.191 + volatile int _SpinClock ;
1.192 + volatile int _SpinDuration ;
1.193 + volatile intptr_t _SpinState ; // MCS/CLH list of spinners
1.194 +
1.195 + // TODO-FIXME: _count, _waiters and _recursions should be of
1.196 + // type int, or int32_t but not intptr_t. There's no reason
1.197 + // to use 64-bit fields for these variables on a 64-bit JVM.
1.198 +
1.199 + volatile intptr_t _count; // reference count to prevent reclaimation/deflation
1.200 + // at stop-the-world time. See deflate_idle_monitors().
1.201 + // _count is approximately |_WaitSet| + |_EntryList|
1.202 + volatile intptr_t _waiters; // number of waiting threads
1.203 + ObjectWaiter * volatile _WaitSet; // LL of threads wait()ing on the monitor
1.204 + volatile int _WaitSetLock; // protects Wait Queue - simple spinlock
1.205 +
1.206 + public:
1.207 + int _QMix ; // Mixed prepend queue discipline
1.208 + ObjectMonitor * FreeNext ; // Free list linkage
1.209 + intptr_t StatA, StatsB ;
1.210 +
1.211 +};
