--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/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 ;
+
+};