author | never |
Tue, 19 Oct 2010 16:14:34 -0700 | |
changeset 7106 | 867c9d296c6b |
parent 5547 | f4b087cbb361 |
child 6975 | dc9b63952682 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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* |
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*/ |
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// WARNING: |
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// This is a very sensitive and fragile class. DO NOT make any |
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// change unless you are fully aware of the underlying semantics. |
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// This class can not inherit from any other class, because I have |
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// to let the displaced header be the very first word. Otherwise I |
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// have to let markOop include this file, which would export the |
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// monitor data structure to everywhere. |
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// |
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// The ObjectMonitor class is used to implement JavaMonitors which have |
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// transformed from the lightweight structure of the thread stack to a |
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// heavy weight lock due to contention |
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// It is also used as RawMonitor by the JVMTI |
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class ObjectWaiter; |
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class ObjectMonitor { |
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public: |
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enum { |
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OM_OK, // no error |
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OM_SYSTEM_ERROR, // operating system error |
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OM_ILLEGAL_MONITOR_STATE, // IllegalMonitorStateException |
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OM_INTERRUPTED, // Thread.interrupt() |
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OM_TIMED_OUT // Object.wait() timed out |
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}; |
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public: |
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// TODO-FIXME: the "offset" routines should return a type of off_t instead of int ... |
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// ByteSize would also be an appropriate type. |
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static int header_offset_in_bytes() { return offset_of(ObjectMonitor, _header); } |
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static int object_offset_in_bytes() { return offset_of(ObjectMonitor, _object); } |
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static int owner_offset_in_bytes() { return offset_of(ObjectMonitor, _owner); } |
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static int count_offset_in_bytes() { return offset_of(ObjectMonitor, _count); } |
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static int recursions_offset_in_bytes() { return offset_of(ObjectMonitor, _recursions); } |
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static int cxq_offset_in_bytes() { return offset_of(ObjectMonitor, _cxq) ; } |
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static int succ_offset_in_bytes() { return offset_of(ObjectMonitor, _succ) ; } |
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static int EntryList_offset_in_bytes() { return offset_of(ObjectMonitor, _EntryList); } |
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static int FreeNext_offset_in_bytes() { return offset_of(ObjectMonitor, FreeNext); } |
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static int WaitSet_offset_in_bytes() { return offset_of(ObjectMonitor, _WaitSet) ; } |
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static int Responsible_offset_in_bytes() { return offset_of(ObjectMonitor, _Responsible);} |
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static int Spinner_offset_in_bytes() { return offset_of(ObjectMonitor, _Spinner); } |
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public: |
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// Eventaully we'll make provisions for multiple callbacks, but |
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// now one will suffice. |
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static int (*SpinCallbackFunction)(intptr_t, int) ; |
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static intptr_t SpinCallbackArgument ; |
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public: |
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ObjectMonitor(); |
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~ObjectMonitor(); |
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markOop header() const; |
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void set_header(markOop hdr); |
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intptr_t is_busy() const; |
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intptr_t is_entered(Thread* current) const; |
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void* owner() const; |
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void set_owner(void* owner); |
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intptr_t waiters() const; |
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intptr_t count() const; |
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void set_count(intptr_t count); |
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intptr_t contentions() const ; |
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// JVM/DI GetMonitorInfo() needs this |
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Thread * thread_of_waiter (ObjectWaiter *) ; |
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ObjectWaiter * first_waiter () ; |
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ObjectWaiter * next_waiter(ObjectWaiter* o); |
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intptr_t recursions() const { return _recursions; } |
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void* object() const; |
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void* object_addr(); |
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void set_object(void* obj); |
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bool check(TRAPS); // true if the thread owns the monitor. |
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void check_slow(TRAPS); |
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void clear(); |
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#ifndef PRODUCT |
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void verify(); |
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void print(); |
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#endif |
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bool try_enter (TRAPS) ; |
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void enter(TRAPS); |
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void exit(TRAPS); |
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void wait(jlong millis, bool interruptable, TRAPS); |
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void notify(TRAPS); |
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void notifyAll(TRAPS); |
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// Use the following at your own risk |
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intptr_t complete_exit(TRAPS); |
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void reenter(intptr_t recursions, TRAPS); |
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int raw_enter(TRAPS); |
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int raw_exit(TRAPS); |
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int raw_wait(jlong millis, bool interruptable, TRAPS); |
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int raw_notify(TRAPS); |
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int raw_notifyAll(TRAPS); |
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private: |
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// JVMTI support -- remove ASAP |
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int SimpleEnter (Thread * Self) ; |
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int SimpleExit (Thread * Self) ; |
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int SimpleWait (Thread * Self, jlong millis) ; |
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int SimpleNotify (Thread * Self, bool All) ; |
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private: |
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void Recycle () ; |
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void AddWaiter (ObjectWaiter * waiter) ; |
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ObjectWaiter * DequeueWaiter () ; |
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void DequeueSpecificWaiter (ObjectWaiter * waiter) ; |
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void EnterI (TRAPS) ; |
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void ReenterI (Thread * Self, ObjectWaiter * SelfNode) ; |
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void UnlinkAfterAcquire (Thread * Self, ObjectWaiter * SelfNode) ; |
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int TryLock (Thread * Self) ; |
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int NotRunnable (Thread * Self, Thread * Owner) ; |
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int TrySpin_Fixed (Thread * Self) ; |
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int TrySpin_VaryFrequency (Thread * Self) ; |
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int TrySpin_VaryDuration (Thread * Self) ; |
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void ctAsserts () ; |
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void ExitEpilog (Thread * Self, ObjectWaiter * Wakee) ; |
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bool ExitSuspendEquivalent (JavaThread * Self) ; |
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private: |
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friend class ObjectSynchronizer; |
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friend class ObjectWaiter; |
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friend class VMStructs; |
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// WARNING: this must be the very first word of ObjectMonitor |
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// This means this class can't use any virtual member functions. |
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// TODO-FIXME: assert that offsetof(_header) is 0 or get rid of the |
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// implicit 0 offset in emitted code. |
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volatile markOop _header; // displaced object header word - mark |
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void* volatile _object; // backward object pointer - strong root |
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double SharingPad [1] ; // temp to reduce false sharing |
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// All the following fields must be machine word aligned |
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// The VM assumes write ordering wrt these fields, which can be |
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// read from other threads. |
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void * volatile _owner; // pointer to owning thread OR BasicLock |
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volatile intptr_t _recursions; // recursion count, 0 for first entry |
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int OwnerIsThread ; // _owner is (Thread *) vs SP/BasicLock |
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ObjectWaiter * volatile _cxq ; // LL of recently-arrived threads blocked on entry. |
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// The list is actually composed of WaitNodes, acting |
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// as proxies for Threads. |
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ObjectWaiter * volatile _EntryList ; // Threads blocked on entry or reentry. |
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Thread * volatile _succ ; // Heir presumptive thread - used for futile wakeup throttling |
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Thread * volatile _Responsible ; |
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int _PromptDrain ; // rqst to drain cxq into EntryList ASAP |
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volatile int _Spinner ; // for exit->spinner handoff optimization |
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volatile int _SpinFreq ; // Spin 1-out-of-N attempts: success rate |
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volatile int _SpinClock ; |
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volatile int _SpinDuration ; |
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volatile intptr_t _SpinState ; // MCS/CLH list of spinners |
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// TODO-FIXME: _count, _waiters and _recursions should be of |
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// type int, or int32_t but not intptr_t. There's no reason |
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// to use 64-bit fields for these variables on a 64-bit JVM. |
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volatile intptr_t _count; // reference count to prevent reclaimation/deflation |
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// at stop-the-world time. See deflate_idle_monitors(). |
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// _count is approximately |_WaitSet| + |_EntryList| |
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volatile intptr_t _waiters; // number of waiting threads |
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ObjectWaiter * volatile _WaitSet; // LL of threads wait()ing on the monitor |
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volatile int _WaitSetLock; // protects Wait Queue - simple spinlock |
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public: |
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int _QMix ; // Mixed prepend queue discipline |
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ObjectMonitor * FreeNext ; // Free list linkage |
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intptr_t StatA, StatsB ; |
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}; |