Mercurial > hg > graal-compiler
annotate src/share/vm/runtime/objectMonitor.hpp @ 1878:fa83ab460c54
6988353: refactor contended sync subsystem
Summary: reduce complexity by factoring synchronizer.cpp
Reviewed-by: dholmes, never, coleenp
author | acorn |
---|---|
date | Fri, 22 Oct 2010 15:59:34 -0400 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1878 | 25 |
26 // ObjectWaiter serves as a "proxy" or surrogate thread. | |
27 // TODO-FIXME: Eliminate ObjectWaiter and use the thread-specific | |
28 // ParkEvent instead. Beware, however, that the JVMTI code | |
29 // knows about ObjectWaiters, so we'll have to reconcile that code. | |
30 // See next_waiter(), first_waiter(), etc. | |
31 | |
32 class ObjectWaiter : public StackObj { | |
33 public: | |
34 enum TStates { TS_UNDEF, TS_READY, TS_RUN, TS_WAIT, TS_ENTER, TS_CXQ } ; | |
35 enum Sorted { PREPEND, APPEND, SORTED } ; | |
36 ObjectWaiter * volatile _next; | |
37 ObjectWaiter * volatile _prev; | |
38 Thread* _thread; | |
39 ParkEvent * _event; | |
40 volatile int _notified ; | |
41 volatile TStates TState ; | |
42 Sorted _Sorted ; // List placement disposition | |
43 bool _active ; // Contention monitoring is enabled | |
44 public: | |
45 ObjectWaiter(Thread* thread); | |
46 | |
47 void wait_reenter_begin(ObjectMonitor *mon); | |
48 void wait_reenter_end(ObjectMonitor *mon); | |
49 }; | |
50 | |
0 | 51 // WARNING: |
52 // This is a very sensitive and fragile class. DO NOT make any | |
53 // change unless you are fully aware of the underlying semantics. | |
54 | |
55 // This class can not inherit from any other class, because I have | |
56 // to let the displaced header be the very first word. Otherwise I | |
57 // have to let markOop include this file, which would export the | |
58 // monitor data structure to everywhere. | |
59 // | |
60 // The ObjectMonitor class is used to implement JavaMonitors which have | |
61 // transformed from the lightweight structure of the thread stack to a | |
62 // heavy weight lock due to contention | |
63 | |
64 // It is also used as RawMonitor by the JVMTI | |
65 | |
66 | |
67 class ObjectMonitor { | |
68 public: | |
69 enum { | |
70 OM_OK, // no error | |
71 OM_SYSTEM_ERROR, // operating system error | |
72 OM_ILLEGAL_MONITOR_STATE, // IllegalMonitorStateException | |
73 OM_INTERRUPTED, // Thread.interrupt() | |
74 OM_TIMED_OUT // Object.wait() timed out | |
75 }; | |
76 | |
77 public: | |
78 // TODO-FIXME: the "offset" routines should return a type of off_t instead of int ... | |
79 // ByteSize would also be an appropriate type. | |
80 static int header_offset_in_bytes() { return offset_of(ObjectMonitor, _header); } | |
81 static int object_offset_in_bytes() { return offset_of(ObjectMonitor, _object); } | |
82 static int owner_offset_in_bytes() { return offset_of(ObjectMonitor, _owner); } | |
83 static int count_offset_in_bytes() { return offset_of(ObjectMonitor, _count); } | |
84 static int recursions_offset_in_bytes() { return offset_of(ObjectMonitor, _recursions); } | |
85 static int cxq_offset_in_bytes() { return offset_of(ObjectMonitor, _cxq) ; } | |
86 static int succ_offset_in_bytes() { return offset_of(ObjectMonitor, _succ) ; } | |
87 static int EntryList_offset_in_bytes() { return offset_of(ObjectMonitor, _EntryList); } | |
88 static int FreeNext_offset_in_bytes() { return offset_of(ObjectMonitor, FreeNext); } | |
89 static int WaitSet_offset_in_bytes() { return offset_of(ObjectMonitor, _WaitSet) ; } | |
90 static int Responsible_offset_in_bytes() { return offset_of(ObjectMonitor, _Responsible);} | |
91 static int Spinner_offset_in_bytes() { return offset_of(ObjectMonitor, _Spinner); } | |
92 | |
93 public: | |
94 // Eventaully we'll make provisions for multiple callbacks, but | |
95 // now one will suffice. | |
96 static int (*SpinCallbackFunction)(intptr_t, int) ; | |
97 static intptr_t SpinCallbackArgument ; | |
98 | |
99 | |
100 public: | |
101 markOop header() const; | |
102 void set_header(markOop hdr); | |
103 | |
1878 | 104 intptr_t is_busy() const { |
105 // TODO-FIXME: merge _count and _waiters. | |
106 // TODO-FIXME: assert _owner == null implies _recursions = 0 | |
107 // TODO-FIXME: assert _WaitSet != null implies _count > 0 | |
108 return _count|_waiters|intptr_t(_owner)|intptr_t(_cxq)|intptr_t(_EntryList ) ; | |
109 } | |
110 | |
0 | 111 intptr_t is_entered(Thread* current) const; |
112 | |
113 void* owner() const; | |
114 void set_owner(void* owner); | |
115 | |
116 intptr_t waiters() const; | |
117 | |
118 intptr_t count() const; | |
119 void set_count(intptr_t count); | |
120 intptr_t contentions() const ; | |
1878 | 121 intptr_t recursions() const { return _recursions; } |
0 | 122 |
123 // JVM/DI GetMonitorInfo() needs this | |
1878 | 124 ObjectWaiter* first_waiter() { return _WaitSet; } |
125 ObjectWaiter* next_waiter(ObjectWaiter* o) { return o->_next; } | |
126 Thread* thread_of_waiter(ObjectWaiter* o) { return o->_thread; } | |
127 | |
128 // initialize the monitor, exception the semaphore, all other fields | |
129 // are simple integers or pointers | |
130 ObjectMonitor() { | |
131 _header = NULL; | |
132 _count = 0; | |
133 _waiters = 0, | |
134 _recursions = 0; | |
135 _object = NULL; | |
136 _owner = NULL; | |
137 _WaitSet = NULL; | |
138 _WaitSetLock = 0 ; | |
139 _Responsible = NULL ; | |
140 _succ = NULL ; | |
141 _cxq = NULL ; | |
142 FreeNext = NULL ; | |
143 _EntryList = NULL ; | |
144 _SpinFreq = 0 ; | |
145 _SpinClock = 0 ; | |
146 OwnerIsThread = 0 ; | |
147 } | |
0 | 148 |
1878 | 149 ~ObjectMonitor() { |
150 // TODO: Add asserts ... | |
151 // _cxq == 0 _succ == NULL _owner == NULL _waiters == 0 | |
152 // _count == 0 _EntryList == NULL etc | |
153 } | |
154 | |
155 private: | |
156 void Recycle () { | |
157 // TODO: add stronger asserts ... | |
158 // _cxq == 0 _succ == NULL _owner == NULL _waiters == 0 | |
159 // _count == 0 EntryList == NULL | |
160 // _recursions == 0 _WaitSet == NULL | |
161 // TODO: assert (is_busy()|_recursions) == 0 | |
162 _succ = NULL ; | |
163 _EntryList = NULL ; | |
164 _cxq = NULL ; | |
165 _WaitSet = NULL ; | |
166 _recursions = 0 ; | |
167 _SpinFreq = 0 ; | |
168 _SpinClock = 0 ; | |
169 OwnerIsThread = 0 ; | |
170 } | |
171 | |
172 public: | |
0 | 173 |
174 void* object() const; | |
175 void* object_addr(); | |
176 void set_object(void* obj); | |
177 | |
178 bool check(TRAPS); // true if the thread owns the monitor. | |
179 void check_slow(TRAPS); | |
180 void clear(); | |
181 #ifndef PRODUCT | |
182 void verify(); | |
183 void print(); | |
184 #endif | |
185 | |
186 bool try_enter (TRAPS) ; | |
187 void enter(TRAPS); | |
188 void exit(TRAPS); | |
189 void wait(jlong millis, bool interruptable, TRAPS); | |
190 void notify(TRAPS); | |
191 void notifyAll(TRAPS); | |
192 | |
193 // Use the following at your own risk | |
194 intptr_t complete_exit(TRAPS); | |
195 void reenter(intptr_t recursions, TRAPS); | |
196 | |
197 private: | |
198 void AddWaiter (ObjectWaiter * waiter) ; | |
1878 | 199 static void DeferredInitialize(); |
0 | 200 |
201 ObjectWaiter * DequeueWaiter () ; | |
202 void DequeueSpecificWaiter (ObjectWaiter * waiter) ; | |
203 void EnterI (TRAPS) ; | |
204 void ReenterI (Thread * Self, ObjectWaiter * SelfNode) ; | |
205 void UnlinkAfterAcquire (Thread * Self, ObjectWaiter * SelfNode) ; | |
206 int TryLock (Thread * Self) ; | |
207 int NotRunnable (Thread * Self, Thread * Owner) ; | |
208 int TrySpin_Fixed (Thread * Self) ; | |
209 int TrySpin_VaryFrequency (Thread * Self) ; | |
210 int TrySpin_VaryDuration (Thread * Self) ; | |
211 void ctAsserts () ; | |
212 void ExitEpilog (Thread * Self, ObjectWaiter * Wakee) ; | |
213 bool ExitSuspendEquivalent (JavaThread * Self) ; | |
214 | |
215 private: | |
216 friend class ObjectSynchronizer; | |
217 friend class ObjectWaiter; | |
218 friend class VMStructs; | |
219 | |
220 // WARNING: this must be the very first word of ObjectMonitor | |
221 // This means this class can't use any virtual member functions. | |
222 // TODO-FIXME: assert that offsetof(_header) is 0 or get rid of the | |
223 // implicit 0 offset in emitted code. | |
224 | |
225 volatile markOop _header; // displaced object header word - mark | |
226 void* volatile _object; // backward object pointer - strong root | |
227 | |
228 double SharingPad [1] ; // temp to reduce false sharing | |
229 | |
230 // All the following fields must be machine word aligned | |
231 // The VM assumes write ordering wrt these fields, which can be | |
232 // read from other threads. | |
233 | |
1878 | 234 protected: // protected for jvmtiRawMonitor |
0 | 235 void * volatile _owner; // pointer to owning thread OR BasicLock |
236 volatile intptr_t _recursions; // recursion count, 0 for first entry | |
1878 | 237 private: |
0 | 238 int OwnerIsThread ; // _owner is (Thread *) vs SP/BasicLock |
239 ObjectWaiter * volatile _cxq ; // LL of recently-arrived threads blocked on entry. | |
240 // The list is actually composed of WaitNodes, acting | |
241 // as proxies for Threads. | |
1878 | 242 protected: |
0 | 243 ObjectWaiter * volatile _EntryList ; // Threads blocked on entry or reentry. |
1878 | 244 private: |
0 | 245 Thread * volatile _succ ; // Heir presumptive thread - used for futile wakeup throttling |
246 Thread * volatile _Responsible ; | |
247 int _PromptDrain ; // rqst to drain cxq into EntryList ASAP | |
248 | |
249 volatile int _Spinner ; // for exit->spinner handoff optimization | |
250 volatile int _SpinFreq ; // Spin 1-out-of-N attempts: success rate | |
251 volatile int _SpinClock ; | |
252 volatile int _SpinDuration ; | |
253 volatile intptr_t _SpinState ; // MCS/CLH list of spinners | |
254 | |
255 // TODO-FIXME: _count, _waiters and _recursions should be of | |
256 // type int, or int32_t but not intptr_t. There's no reason | |
257 // to use 64-bit fields for these variables on a 64-bit JVM. | |
258 | |
259 volatile intptr_t _count; // reference count to prevent reclaimation/deflation | |
260 // at stop-the-world time. See deflate_idle_monitors(). | |
261 // _count is approximately |_WaitSet| + |_EntryList| | |
1878 | 262 protected: |
0 | 263 volatile intptr_t _waiters; // number of waiting threads |
1878 | 264 private: |
265 protected: | |
0 | 266 ObjectWaiter * volatile _WaitSet; // LL of threads wait()ing on the monitor |
1878 | 267 private: |
0 | 268 volatile int _WaitSetLock; // protects Wait Queue - simple spinlock |
269 | |
270 public: | |
271 int _QMix ; // Mixed prepend queue discipline | |
272 ObjectMonitor * FreeNext ; // Free list linkage | |
273 intptr_t StatA, StatsB ; | |
274 | |
1878 | 275 public: |
276 static void Initialize () ; | |
277 static PerfCounter * _sync_ContendedLockAttempts ; | |
278 static PerfCounter * _sync_FutileWakeups ; | |
279 static PerfCounter * _sync_Parks ; | |
280 static PerfCounter * _sync_EmptyNotifications ; | |
281 static PerfCounter * _sync_Notifications ; | |
282 static PerfCounter * _sync_SlowEnter ; | |
283 static PerfCounter * _sync_SlowExit ; | |
284 static PerfCounter * _sync_SlowNotify ; | |
285 static PerfCounter * _sync_SlowNotifyAll ; | |
286 static PerfCounter * _sync_FailedSpins ; | |
287 static PerfCounter * _sync_SuccessfulSpins ; | |
288 static PerfCounter * _sync_PrivateA ; | |
289 static PerfCounter * _sync_PrivateB ; | |
290 static PerfCounter * _sync_MonInCirculation ; | |
291 static PerfCounter * _sync_MonScavenged ; | |
292 static PerfCounter * _sync_Inflations ; | |
293 static PerfCounter * _sync_Deflations ; | |
294 static PerfLongVariable * _sync_MonExtant ; | |
295 | |
296 public: | |
297 static int Knob_Verbose; | |
298 static int Knob_SpinLimit; | |
0 | 299 }; |
1878 | 300 |
301 #undef TEVENT | |
302 #define TEVENT(nom) {if (SyncVerbose) FEVENT(nom); } | |
303 | |
304 #define FEVENT(nom) { static volatile int ctr = 0 ; int v = ++ctr ; if ((v & (v-1)) == 0) { ::printf (#nom " : %d \n", v); ::fflush(stdout); }} | |
305 | |
306 #undef TEVENT | |
307 #define TEVENT(nom) {;} | |
308 |