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comparison src/share/vm/gc_implementation/shared/concurrentGCThread.cpp @ 342:37f87013dfd8

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6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author ysr
date Thu, 05 Jun 2008 15:57:56 -0700
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children 315a5d70b295
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189:0b27f3512f9e 342:37f87013dfd8
1 /*
2 * Copyright 2001-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // CopyrightVersion 1.2
26
27 # include "incls/_precompiled.incl"
28 # include "incls/_concurrentGCThread.cpp.incl"
29
30 bool ConcurrentGCThread::_should_terminate = false;
31 bool ConcurrentGCThread::_has_terminated = false;
32 int ConcurrentGCThread::_CGC_flag = CGC_nil;
33
34 SuspendibleThreadSet ConcurrentGCThread::_sts;
35
36 ConcurrentGCThread::ConcurrentGCThread() {
37 _sts.initialize();
38 };
39
40 void ConcurrentGCThread::stopWorldAndDo(VoidClosure* op) {
41 MutexLockerEx x(Heap_lock,
42 Mutex::_no_safepoint_check_flag);
43 // warning("CGC: about to try stopping world");
44 SafepointSynchronize::begin();
45 // warning("CGC: successfully stopped world");
46 op->do_void();
47 SafepointSynchronize::end();
48 // warning("CGC: successfully restarted world");
49 }
50
51 void ConcurrentGCThread::safepoint_synchronize() {
52 _sts.suspend_all();
53 }
54
55 void ConcurrentGCThread::safepoint_desynchronize() {
56 _sts.resume_all();
57 }
58
59 void ConcurrentGCThread::create_and_start() {
60 if (os::create_thread(this, os::cgc_thread)) {
61 // XXX: need to set this to low priority
62 // unless "agressive mode" set; priority
63 // should be just less than that of VMThread.
64 os::set_priority(this, NearMaxPriority);
65 if (!_should_terminate && !DisableStartThread) {
66 os::start_thread(this);
67 }
68 }
69 }
70
71 void ConcurrentGCThread::initialize_in_thread() {
72 this->record_stack_base_and_size();
73 this->initialize_thread_local_storage();
74 this->set_active_handles(JNIHandleBlock::allocate_block());
75 // From this time Thread::current() should be working.
76 assert(this == Thread::current(), "just checking");
77 }
78
79 void ConcurrentGCThread::wait_for_universe_init() {
80 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
81 while (!is_init_completed() && !_should_terminate) {
82 CGC_lock->wait(Mutex::_no_safepoint_check_flag, 200);
83 }
84 }
85
86 void ConcurrentGCThread::terminate() {
87 // Signal that it is terminated
88 {
89 MutexLockerEx mu(Terminator_lock,
90 Mutex::_no_safepoint_check_flag);
91 _has_terminated = true;
92 Terminator_lock->notify();
93 }
94
95 // Thread destructor usually does this..
96 ThreadLocalStorage::set_thread(NULL);
97 }
98
99
100 void SuspendibleThreadSet::initialize_work() {
101 MutexLocker x(STS_init_lock);
102 if (!_initialized) {
103 _m = new Monitor(Mutex::leaf,
104 "SuspendibleThreadSetLock", true);
105 _async = 0;
106 _async_stop = false;
107 _async_stopped = 0;
108 _initialized = true;
109 }
110 }
111
112 void SuspendibleThreadSet::join() {
113 initialize();
114 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
115 while (_async_stop) _m->wait(Mutex::_no_safepoint_check_flag);
116 _async++;
117 assert(_async > 0, "Huh.");
118 }
119
120 void SuspendibleThreadSet::leave() {
121 assert(_initialized, "Must be initialized.");
122 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
123 _async--;
124 assert(_async >= 0, "Huh.");
125 if (_async_stop) _m->notify_all();
126 }
127
128 void SuspendibleThreadSet::yield(const char* id) {
129 assert(_initialized, "Must be initialized.");
130 if (_async_stop) {
131 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
132 if (_async_stop) {
133 _async_stopped++;
134 assert(_async_stopped > 0, "Huh.");
135 if (_async_stopped == _async) {
136 if (ConcGCYieldTimeout > 0) {
137 double now = os::elapsedTime();
138 guarantee((now - _suspend_all_start) * 1000.0 <
139 (double)ConcGCYieldTimeout,
140 "Long delay; whodunit?");
141 }
142 }
143 _m->notify_all();
144 while (_async_stop) _m->wait(Mutex::_no_safepoint_check_flag);
145 _async_stopped--;
146 assert(_async >= 0, "Huh");
147 _m->notify_all();
148 }
149 }
150 }
151
152 void SuspendibleThreadSet::suspend_all() {
153 initialize(); // If necessary.
154 if (ConcGCYieldTimeout > 0) {
155 _suspend_all_start = os::elapsedTime();
156 }
157 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
158 assert(!_async_stop, "Only one at a time.");
159 _async_stop = true;
160 while (_async_stopped < _async) _m->wait(Mutex::_no_safepoint_check_flag);
161 }
162
163 void SuspendibleThreadSet::resume_all() {
164 assert(_initialized, "Must be initialized.");
165 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
166 assert(_async_stopped == _async, "Huh.");
167 _async_stop = false;
168 _m->notify_all();
169 }
170
171 static void _sltLoop(JavaThread* thread, TRAPS) {
172 SurrogateLockerThread* slt = (SurrogateLockerThread*)thread;
173 slt->loop();
174 }
175
176 SurrogateLockerThread::SurrogateLockerThread() :
177 JavaThread(&_sltLoop),
178 _monitor(Mutex::nonleaf, "SLTMonitor"),
179 _buffer(empty)
180 {}
181
182 SurrogateLockerThread* SurrogateLockerThread::make(TRAPS) {
183 klassOop k =
184 SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(),
185 true, CHECK_NULL);
186 instanceKlassHandle klass (THREAD, k);
187 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
188
189 const char thread_name[] = "Surrogate Locker Thread (CMS)";
190 Handle string = java_lang_String::create_from_str(thread_name, CHECK_NULL);
191
192 // Initialize thread_oop to put it into the system threadGroup
193 Handle thread_group (THREAD, Universe::system_thread_group());
194 JavaValue result(T_VOID);
195 JavaCalls::call_special(&result, thread_oop,
196 klass,
197 vmSymbolHandles::object_initializer_name(),
198 vmSymbolHandles::threadgroup_string_void_signature(),
199 thread_group,
200 string,
201 CHECK_NULL);
202
203 SurrogateLockerThread* res;
204 {
205 MutexLocker mu(Threads_lock);
206 res = new SurrogateLockerThread();
207
208 // At this point it may be possible that no osthread was created for the
209 // JavaThread due to lack of memory. We would have to throw an exception
210 // in that case. However, since this must work and we do not allow
211 // exceptions anyway, check and abort if this fails.
212 if (res == NULL || res->osthread() == NULL) {
213 vm_exit_during_initialization("java.lang.OutOfMemoryError",
214 "unable to create new native thread");
215 }
216 java_lang_Thread::set_thread(thread_oop(), res);
217 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
218 java_lang_Thread::set_daemon(thread_oop());
219
220 res->set_threadObj(thread_oop());
221 Threads::add(res);
222 Thread::start(res);
223 }
224 os::yield(); // This seems to help with initial start-up of SLT
225 return res;
226 }
227
228 void SurrogateLockerThread::manipulatePLL(SLT_msg_type msg) {
229 MutexLockerEx x(&_monitor, Mutex::_no_safepoint_check_flag);
230 assert(_buffer == empty, "Should be empty");
231 assert(msg != empty, "empty message");
232 _buffer = msg;
233 while (_buffer != empty) {
234 _monitor.notify();
235 _monitor.wait(Mutex::_no_safepoint_check_flag);
236 }
237 }
238
239 // ======= Surrogate Locker Thread =============
240
241 void SurrogateLockerThread::loop() {
242 BasicLock pll_basic_lock;
243 SLT_msg_type msg;
244 debug_only(unsigned int owned = 0;)
245
246 while (/* !isTerminated() */ 1) {
247 {
248 MutexLocker x(&_monitor);
249 // Since we are a JavaThread, we can't be here at a safepoint.
250 assert(!SafepointSynchronize::is_at_safepoint(),
251 "SLT is a JavaThread");
252 // wait for msg buffer to become non-empty
253 while (_buffer == empty) {
254 _monitor.notify();
255 _monitor.wait();
256 }
257 msg = _buffer;
258 }
259 switch(msg) {
260 case acquirePLL: {
261 instanceRefKlass::acquire_pending_list_lock(&pll_basic_lock);
262 debug_only(owned++;)
263 break;
264 }
265 case releaseAndNotifyPLL: {
266 assert(owned > 0, "Don't have PLL");
267 instanceRefKlass::release_and_notify_pending_list_lock(&pll_basic_lock);
268 debug_only(owned--;)
269 break;
270 }
271 case empty:
272 default: {
273 guarantee(false,"Unexpected message in _buffer");
274 break;
275 }
276 }
277 {
278 MutexLocker x(&_monitor);
279 // Since we are a JavaThread, we can't be here at a safepoint.
280 assert(!SafepointSynchronize::is_at_safepoint(),
281 "SLT is a JavaThread");
282 _buffer = empty;
283 _monitor.notify();
284 }
285 }
286 assert(!_monitor.owned_by_self(), "Should unlock before exit.");
287 }
288
289
290 // ===== STS Access From Outside CGCT =====
291
292 void ConcurrentGCThread::stsYield(const char* id) {
293 assert( Thread::current()->is_ConcurrentGC_thread(),
294 "only a conc GC thread can call this" );
295 _sts.yield(id);
296 }
297
298 bool ConcurrentGCThread::stsShouldYield() {
299 assert( Thread::current()->is_ConcurrentGC_thread(),
300 "only a conc GC thread can call this" );
301 return _sts.should_yield();
302 }
303
304 void ConcurrentGCThread::stsJoin() {
305 assert( Thread::current()->is_ConcurrentGC_thread(),
306 "only a conc GC thread can call this" );
307 _sts.join();
308 }
309
310 void ConcurrentGCThread::stsLeave() {
311 assert( Thread::current()->is_ConcurrentGC_thread(),
312 "only a conc GC thread can call this" );
313 _sts.leave();
314 }