Fri, 08 Oct 2010 09:29:09 -0700
Merge
1 /*
2 * Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 class BasicLock VALUE_OBJ_CLASS_SPEC {
26 friend class VMStructs;
27 private:
28 volatile markOop _displaced_header;
29 public:
30 markOop displaced_header() const { return _displaced_header; }
31 void set_displaced_header(markOop header) { _displaced_header = header; }
33 void print_on(outputStream* st) const;
35 // move a basic lock (used during deoptimization
36 void move_to(oop obj, BasicLock* dest);
38 static int displaced_header_offset_in_bytes() { return offset_of(BasicLock, _displaced_header); }
39 };
41 // A BasicObjectLock associates a specific Java object with a BasicLock.
42 // It is currently embedded in an interpreter frame.
44 // Because some machines have alignment restrictions on the control stack,
45 // the actual space allocated by the interpreter may include padding words
46 // after the end of the BasicObjectLock. Also, in order to guarantee
47 // alignment of the embedded BasicLock objects on such machines, we
48 // put the embedded BasicLock at the beginning of the struct.
50 class BasicObjectLock VALUE_OBJ_CLASS_SPEC {
51 friend class VMStructs;
52 private:
53 BasicLock _lock; // the lock, must be double word aligned
54 oop _obj; // object holds the lock;
56 public:
57 // Manipulation
58 oop obj() const { return _obj; }
59 void set_obj(oop obj) { _obj = obj; }
60 BasicLock* lock() { return &_lock; }
62 // Note: Use frame::interpreter_frame_monitor_size() for the size of BasicObjectLocks
63 // in interpreter activation frames since it includes machine-specific padding.
64 static int size() { return sizeof(BasicObjectLock)/wordSize; }
66 // GC support
67 void oops_do(OopClosure* f) { f->do_oop(&_obj); }
69 static int obj_offset_in_bytes() { return offset_of(BasicObjectLock, _obj); }
70 static int lock_offset_in_bytes() { return offset_of(BasicObjectLock, _lock); }
71 };
73 class ObjectMonitor;
75 class ObjectSynchronizer : AllStatic {
76 friend class VMStructs;
77 public:
78 typedef enum {
79 owner_self,
80 owner_none,
81 owner_other
82 } LockOwnership;
83 // exit must be implemented non-blocking, since the compiler cannot easily handle
84 // deoptimization at monitor exit. Hence, it does not take a Handle argument.
86 // This is full version of monitor enter and exit. I choose not
87 // to use enter() and exit() in order to make sure user be ware
88 // of the performance and semantics difference. They are normally
89 // used by ObjectLocker etc. The interpreter and compiler use
90 // assembly copies of these routines. Please keep them synchornized.
91 //
92 // attempt_rebias flag is used by UseBiasedLocking implementation
93 static void fast_enter (Handle obj, BasicLock* lock, bool attempt_rebias, TRAPS);
94 static void fast_exit (oop obj, BasicLock* lock, Thread* THREAD);
96 // WARNING: They are ONLY used to handle the slow cases. They should
97 // only be used when the fast cases failed. Use of these functions
98 // without previous fast case check may cause fatal error.
99 static void slow_enter (Handle obj, BasicLock* lock, TRAPS);
100 static void slow_exit (oop obj, BasicLock* lock, Thread* THREAD);
102 // Used only to handle jni locks or other unmatched monitor enter/exit
103 // Internally they will use heavy weight monitor.
104 static void jni_enter (Handle obj, TRAPS);
105 static bool jni_try_enter(Handle obj, Thread* THREAD); // Implements Unsafe.tryMonitorEnter
106 static void jni_exit (oop obj, Thread* THREAD);
108 // Handle all interpreter, compiler and jni cases
109 static void wait (Handle obj, jlong millis, TRAPS);
110 static void notify (Handle obj, TRAPS);
111 static void notifyall (Handle obj, TRAPS);
113 // Special internal-use-only method for use by JVM infrastructure
114 // that needs to wait() on a java-level object but that can't risk
115 // throwing unexpected InterruptedExecutionExceptions.
116 static void waitUninterruptibly (Handle obj, jlong Millis, Thread * THREAD) ;
118 // used by classloading to free classloader object lock,
119 // wait on an internal lock, and reclaim original lock
120 // with original recursion count
121 static intptr_t complete_exit (Handle obj, TRAPS);
122 static void reenter (Handle obj, intptr_t recursion, TRAPS);
124 // thread-specific and global objectMonitor free list accessors
125 // static void verifyInUse (Thread * Self) ; too slow for general assert/debug
126 static ObjectMonitor * omAlloc (Thread * Self) ;
127 static void omRelease (Thread * Self, ObjectMonitor * m, bool FromPerThreadAlloc) ;
128 static void omFlush (Thread * Self) ;
130 // Inflate light weight monitor to heavy weight monitor
131 static ObjectMonitor* inflate(Thread * Self, oop obj);
132 // This version is only for internal use
133 static ObjectMonitor* inflate_helper(oop obj);
135 // Returns the identity hash value for an oop
136 // NOTE: It may cause monitor inflation
137 static intptr_t identity_hash_value_for(Handle obj);
138 static intptr_t FastHashCode (Thread * Self, oop obj) ;
140 // java.lang.Thread support
141 static bool current_thread_holds_lock(JavaThread* thread, Handle h_obj);
142 static LockOwnership query_lock_ownership(JavaThread * self, Handle h_obj);
144 static JavaThread* get_lock_owner(Handle h_obj, bool doLock);
146 // JNI detach support
147 static void release_monitors_owned_by_thread(TRAPS);
148 static void monitors_iterate(MonitorClosure* m);
150 // GC: we current use aggressive monitor deflation policy
151 // Basically we deflate all monitors that are not busy.
152 // An adaptive profile-based deflation policy could be used if needed
153 static void deflate_idle_monitors();
154 static int walk_monitor_list(ObjectMonitor** listheadp,
155 ObjectMonitor** FreeHeadp,
156 ObjectMonitor** FreeTailp);
157 static bool deflate_monitor(ObjectMonitor* mid, oop obj, ObjectMonitor** FreeHeadp,
158 ObjectMonitor** FreeTailp);
159 static void oops_do(OopClosure* f);
161 // debugging
162 static void trace_locking(Handle obj, bool is_compiled, bool is_method, bool is_locking) PRODUCT_RETURN;
163 static void verify() PRODUCT_RETURN;
164 static int verify_objmon_isinpool(ObjectMonitor *addr) PRODUCT_RETURN0;
166 private:
167 enum { _BLOCKSIZE = 128 };
168 static ObjectMonitor* gBlockList;
169 static ObjectMonitor * volatile gFreeList;
170 static ObjectMonitor * volatile gOmInUseList; // for moribund thread, so monitors they inflated still get scanned
171 static int gOmInUseCount;
173 public:
174 static void Initialize () ;
175 static PerfCounter * _sync_ContendedLockAttempts ;
176 static PerfCounter * _sync_FutileWakeups ;
177 static PerfCounter * _sync_Parks ;
178 static PerfCounter * _sync_EmptyNotifications ;
179 static PerfCounter * _sync_Notifications ;
180 static PerfCounter * _sync_SlowEnter ;
181 static PerfCounter * _sync_SlowExit ;
182 static PerfCounter * _sync_SlowNotify ;
183 static PerfCounter * _sync_SlowNotifyAll ;
184 static PerfCounter * _sync_FailedSpins ;
185 static PerfCounter * _sync_SuccessfulSpins ;
186 static PerfCounter * _sync_PrivateA ;
187 static PerfCounter * _sync_PrivateB ;
188 static PerfCounter * _sync_MonInCirculation ;
189 static PerfCounter * _sync_MonScavenged ;
190 static PerfCounter * _sync_Inflations ;
191 static PerfCounter * _sync_Deflations ;
192 static PerfLongVariable * _sync_MonExtant ;
194 public:
195 static void RegisterSpinCallback (int (*)(intptr_t, int), intptr_t) ;
197 };
199 // ObjectLocker enforced balanced locking and can never thrown an
200 // IllegalMonitorStateException. However, a pending exception may
201 // have to pass through, and we must also be able to deal with
202 // asynchronous exceptions. The caller is responsible for checking
203 // the threads pending exception if needed.
204 // doLock was added to support classloading with UnsyncloadClass which
205 // requires flag based choice of locking the classloader lock.
206 class ObjectLocker : public StackObj {
207 private:
208 Thread* _thread;
209 Handle _obj;
210 BasicLock _lock;
211 bool _dolock; // default true
212 public:
213 ObjectLocker(Handle obj, Thread* thread, bool doLock = true);
214 ~ObjectLocker();
216 // Monitor behavior
217 void wait (TRAPS) { ObjectSynchronizer::wait (_obj, 0, CHECK); } // wait forever
218 void notify_all(TRAPS) { ObjectSynchronizer::notifyall(_obj, CHECK); }
219 void waitUninterruptibly (TRAPS) { ObjectSynchronizer::waitUninterruptibly (_obj, 0, CHECK);}
220 // complete_exit gives up lock completely, returning recursion count
221 // reenter reclaims lock with original recursion count
222 intptr_t complete_exit(TRAPS) { return ObjectSynchronizer::complete_exit(_obj, CHECK_0); }
223 void reenter(intptr_t recursion, TRAPS) { ObjectSynchronizer::reenter(_obj, recursion, CHECK); }
224 };