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rev 6902 : 8062036: ConcurrentMarkThread::slt may be invoked before ConcurrentMarkThread::makeSurrogateLockerThread causing intermittent crashes
Summary: Suppress gc_alot during VM init, improve error for SLT uninitialized.
Reviewed-by: jmasa, brutisso, tschatzl
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--- old/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp
+++ new/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp
1 1 /*
2 2 * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 #include "precompiled.hpp"
26 26 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.inline.hpp"
27 27 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
28 28 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp"
29 29 #include "gc_implementation/shared/gcTimer.hpp"
30 30 #include "gc_implementation/shared/gcTraceTime.hpp"
31 31 #include "gc_implementation/shared/isGCActiveMark.hpp"
32 32 #include "memory/gcLocker.inline.hpp"
33 33 #include "runtime/interfaceSupport.hpp"
34 34 #include "runtime/os.hpp"
35 35 #include "utilities/dtrace.hpp"
36 36
37 37 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
38 38
39 39 #ifndef USDT2
40 40 HS_DTRACE_PROBE_DECL(hs_private, cms__initmark__begin);
41 41 HS_DTRACE_PROBE_DECL(hs_private, cms__initmark__end);
42 42
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43 43 HS_DTRACE_PROBE_DECL(hs_private, cms__remark__begin);
44 44 HS_DTRACE_PROBE_DECL(hs_private, cms__remark__end);
45 45 #endif /* !USDT2 */
46 46
47 47 //////////////////////////////////////////////////////////
48 48 // Methods in abstract class VM_CMS_Operation
49 49 //////////////////////////////////////////////////////////
50 50 void VM_CMS_Operation::acquire_pending_list_lock() {
51 51 // The caller may block while communicating
52 52 // with the SLT thread in order to acquire/release the PLL.
53 - ConcurrentMarkSweepThread::slt()->
54 - manipulatePLL(SurrogateLockerThread::acquirePLL);
53 + SurrogateLockerThread* slt = ConcurrentMarkSweepThread::slt();
54 + if (slt != NULL) {
55 + slt->manipulatePLL(SurrogateLockerThread::acquirePLL);
56 + } else {
57 + SurrogateLockerThread::report_missing_slt();
58 + }
55 59 }
56 60
57 61 void VM_CMS_Operation::release_and_notify_pending_list_lock() {
58 62 // The caller may block while communicating
59 63 // with the SLT thread in order to acquire/release the PLL.
60 64 ConcurrentMarkSweepThread::slt()->
61 65 manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
62 66 }
63 67
64 68 void VM_CMS_Operation::verify_before_gc() {
65 69 if (VerifyBeforeGC &&
66 70 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
67 71 GCTraceTime tm("Verify Before", false, false, _collector->_gc_timer_cm, _collector->_gc_tracer_cm->gc_id());
68 72 HandleMark hm;
69 73 FreelistLocker x(_collector);
70 74 MutexLockerEx y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
71 75 Universe::heap()->prepare_for_verify();
72 76 Universe::verify();
73 77 }
74 78 }
75 79
76 80 void VM_CMS_Operation::verify_after_gc() {
77 81 if (VerifyAfterGC &&
78 82 GenCollectedHeap::heap()->total_collections() >= VerifyGCStartAt) {
79 83 GCTraceTime tm("Verify After", false, false, _collector->_gc_timer_cm, _collector->_gc_tracer_cm->gc_id());
80 84 HandleMark hm;
81 85 FreelistLocker x(_collector);
82 86 MutexLockerEx y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
83 87 Universe::verify();
84 88 }
85 89 }
86 90
87 91 bool VM_CMS_Operation::lost_race() const {
88 92 if (CMSCollector::abstract_state() == CMSCollector::Idling) {
89 93 // We lost a race to a foreground collection
90 94 // -- there's nothing to do
91 95 return true;
92 96 }
93 97 assert(CMSCollector::abstract_state() == legal_state(),
94 98 "Inconsistent collector state?");
95 99 return false;
96 100 }
97 101
98 102 bool VM_CMS_Operation::doit_prologue() {
99 103 assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
100 104 assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
101 105 assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
102 106 "Possible deadlock");
103 107
104 108 if (needs_pll()) {
105 109 acquire_pending_list_lock();
106 110 }
107 111 // Get the Heap_lock after the pending_list_lock.
108 112 Heap_lock->lock();
109 113 if (lost_race()) {
110 114 assert(_prologue_succeeded == false, "Initialized in c'tor");
111 115 Heap_lock->unlock();
112 116 if (needs_pll()) {
113 117 release_and_notify_pending_list_lock();
114 118 }
115 119 } else {
116 120 _prologue_succeeded = true;
117 121 }
118 122 return _prologue_succeeded;
119 123 }
120 124
121 125 void VM_CMS_Operation::doit_epilogue() {
122 126 assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
123 127 assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
124 128 assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
125 129 "Possible deadlock");
126 130
127 131 // Release the Heap_lock first.
128 132 Heap_lock->unlock();
129 133 if (needs_pll()) {
130 134 release_and_notify_pending_list_lock();
131 135 }
132 136 }
133 137
134 138 //////////////////////////////////////////////////////////
135 139 // Methods in class VM_CMS_Initial_Mark
136 140 //////////////////////////////////////////////////////////
137 141 void VM_CMS_Initial_Mark::doit() {
138 142 if (lost_race()) {
139 143 // Nothing to do.
140 144 return;
141 145 }
142 146 #ifndef USDT2
143 147 HS_DTRACE_PROBE(hs_private, cms__initmark__begin);
144 148 #else /* USDT2 */
145 149 HS_PRIVATE_CMS_INITMARK_BEGIN(
146 150 );
147 151 #endif /* USDT2 */
148 152
149 153 _collector->_gc_timer_cm->register_gc_pause_start("Initial Mark");
150 154
151 155 GenCollectedHeap* gch = GenCollectedHeap::heap();
152 156 GCCauseSetter gccs(gch, GCCause::_cms_initial_mark);
153 157
154 158 VM_CMS_Operation::verify_before_gc();
155 159
156 160 IsGCActiveMark x; // stop-world GC active
157 161 _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsInitial, gch->gc_cause());
158 162
159 163 VM_CMS_Operation::verify_after_gc();
160 164
161 165 _collector->_gc_timer_cm->register_gc_pause_end();
162 166
163 167 #ifndef USDT2
164 168 HS_DTRACE_PROBE(hs_private, cms__initmark__end);
165 169 #else /* USDT2 */
166 170 HS_PRIVATE_CMS_INITMARK_END(
167 171 );
168 172 #endif /* USDT2 */
169 173 }
170 174
171 175 //////////////////////////////////////////////////////////
172 176 // Methods in class VM_CMS_Final_Remark_Operation
173 177 //////////////////////////////////////////////////////////
174 178 void VM_CMS_Final_Remark::doit() {
175 179 if (lost_race()) {
176 180 // Nothing to do.
177 181 return;
178 182 }
179 183 #ifndef USDT2
180 184 HS_DTRACE_PROBE(hs_private, cms__remark__begin);
181 185 #else /* USDT2 */
182 186 HS_PRIVATE_CMS_REMARK_BEGIN(
183 187 );
184 188 #endif /* USDT2 */
185 189
186 190 _collector->_gc_timer_cm->register_gc_pause_start("Final Mark");
187 191
188 192 GenCollectedHeap* gch = GenCollectedHeap::heap();
189 193 GCCauseSetter gccs(gch, GCCause::_cms_final_remark);
190 194
191 195 VM_CMS_Operation::verify_before_gc();
192 196
193 197 IsGCActiveMark x; // stop-world GC active
194 198 _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsFinal, gch->gc_cause());
195 199
196 200 VM_CMS_Operation::verify_after_gc();
197 201
198 202 _collector->save_heap_summary();
199 203 _collector->_gc_timer_cm->register_gc_pause_end();
200 204
201 205 #ifndef USDT2
202 206 HS_DTRACE_PROBE(hs_private, cms__remark__end);
203 207 #else /* USDT2 */
204 208 HS_PRIVATE_CMS_REMARK_END(
205 209 );
206 210 #endif /* USDT2 */
207 211 }
208 212
209 213 // VM operation to invoke a concurrent collection of a
210 214 // GenCollectedHeap heap.
211 215 void VM_GenCollectFullConcurrent::doit() {
212 216 assert(Thread::current()->is_VM_thread(), "Should be VM thread");
213 217 assert(GCLockerInvokesConcurrent || ExplicitGCInvokesConcurrent, "Unexpected");
214 218
215 219 GenCollectedHeap* gch = GenCollectedHeap::heap();
216 220 if (_gc_count_before == gch->total_collections()) {
217 221 // The "full" of do_full_collection call below "forces"
218 222 // a collection; the second arg, 0, below ensures that
219 223 // only the young gen is collected. XXX In the future,
220 224 // we'll probably need to have something in this interface
221 225 // to say do this only if we are sure we will not bail
222 226 // out to a full collection in this attempt, but that's
223 227 // for the future.
224 228 assert(SafepointSynchronize::is_at_safepoint(),
225 229 "We can only be executing this arm of if at a safepoint");
226 230 GCCauseSetter gccs(gch, _gc_cause);
227 231 gch->do_full_collection(gch->must_clear_all_soft_refs(),
228 232 0 /* collect only youngest gen */);
229 233 } // Else no need for a foreground young gc
230 234 assert((_gc_count_before < gch->total_collections()) ||
231 235 (GC_locker::is_active() /* gc may have been skipped */
232 236 && (_gc_count_before == gch->total_collections())),
233 237 "total_collections() should be monotonically increasing");
234 238
235 239 MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
236 240 assert(_full_gc_count_before <= gch->total_full_collections(), "Error");
237 241 if (gch->total_full_collections() == _full_gc_count_before) {
238 242 // Disable iCMS until the full collection is done, and
239 243 // remember that we did so.
240 244 CMSCollector::disable_icms();
241 245 _disabled_icms = true;
242 246 // In case CMS thread was in icms_wait(), wake it up.
243 247 CMSCollector::start_icms();
244 248 // Nudge the CMS thread to start a concurrent collection.
245 249 CMSCollector::request_full_gc(_full_gc_count_before, _gc_cause);
246 250 } else {
247 251 assert(_full_gc_count_before < gch->total_full_collections(), "Error");
248 252 FullGCCount_lock->notify_all(); // Inform the Java thread its work is done
249 253 }
250 254 }
251 255
252 256 bool VM_GenCollectFullConcurrent::evaluate_at_safepoint() const {
253 257 Thread* thr = Thread::current();
254 258 assert(thr != NULL, "Unexpected tid");
255 259 if (!thr->is_Java_thread()) {
256 260 assert(thr->is_VM_thread(), "Expected to be evaluated by VM thread");
257 261 GenCollectedHeap* gch = GenCollectedHeap::heap();
258 262 if (_gc_count_before != gch->total_collections()) {
259 263 // No need to do a young gc, we'll just nudge the CMS thread
260 264 // in the doit() method above, to be executed soon.
261 265 assert(_gc_count_before < gch->total_collections(),
262 266 "total_collections() should be monotnically increasing");
263 267 return false; // no need for foreground young gc
264 268 }
265 269 }
266 270 return true; // may still need foreground young gc
267 271 }
268 272
269 273
270 274 void VM_GenCollectFullConcurrent::doit_epilogue() {
271 275 Thread* thr = Thread::current();
272 276 assert(thr->is_Java_thread(), "just checking");
273 277 JavaThread* jt = (JavaThread*)thr;
274 278 // Release the Heap_lock first.
275 279 Heap_lock->unlock();
276 280 release_and_notify_pending_list_lock();
277 281
278 282 // It is fine to test whether completed collections has
279 283 // exceeded our request count without locking because
280 284 // the completion count is monotonically increasing;
281 285 // this will break for very long-running apps when the
282 286 // count overflows and wraps around. XXX fix me !!!
283 287 // e.g. at the rate of 1 full gc per ms, this could
284 288 // overflow in about 1000 years.
285 289 GenCollectedHeap* gch = GenCollectedHeap::heap();
286 290 if (_gc_cause != GCCause::_gc_locker &&
287 291 gch->total_full_collections_completed() <= _full_gc_count_before) {
288 292 // maybe we should change the condition to test _gc_cause ==
289 293 // GCCause::_java_lang_system_gc, instead of
290 294 // _gc_cause != GCCause::_gc_locker
291 295 assert(_gc_cause == GCCause::_java_lang_system_gc,
292 296 "the only way to get here if this was a System.gc()-induced GC");
293 297 assert(ExplicitGCInvokesConcurrent, "Error");
294 298 // Now, wait for witnessing concurrent gc cycle to complete,
295 299 // but do so in native mode, because we want to lock the
296 300 // FullGCEvent_lock, which may be needed by the VM thread
297 301 // or by the CMS thread, so we do not want to be suspended
298 302 // while holding that lock.
299 303 ThreadToNativeFromVM native(jt);
300 304 MutexLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
301 305 // Either a concurrent or a stop-world full gc is sufficient
302 306 // witness to our request.
303 307 while (gch->total_full_collections_completed() <= _full_gc_count_before) {
304 308 FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
305 309 }
306 310 }
307 311 // Enable iCMS back if we disabled it earlier.
308 312 if (_disabled_icms) {
309 313 CMSCollector::enable_icms();
310 314 }
311 315 }
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