Mercurial > hg > truffle
annotate src/share/vm/prims/jvmtiRawMonitor.cpp @ 20197:ce8f6bb717c9
8042195: Introduce umbrella header orderAccess.inline.hpp.
Reviewed-by: dholmes, kvn, stefank, twisti
| author | goetz |
|---|---|
| date | Tue, 29 Apr 2014 15:17:27 +0200 |
| parents | b9a9ed0f8eeb |
| children |
| rev | line source |
|---|---|
| 1878 | 1 /* |
|
6842
b9a9ed0f8eeb
7197424: update copyright year to match last edit in jdk8 hotspot repository
mikael
parents:
6197
diff
changeset
|
2 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved. |
| 1878 | 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 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "prims/jvmtiRawMonitor.hpp" | |
| 27 #include "runtime/interfaceSupport.hpp" | |
|
20197
ce8f6bb717c9
8042195: Introduce umbrella header orderAccess.inline.hpp.
goetz
parents:
6842
diff
changeset
|
28 #include "runtime/orderAccess.inline.hpp" |
|
ce8f6bb717c9
8042195: Introduce umbrella header orderAccess.inline.hpp.
goetz
parents:
6842
diff
changeset
|
29 #include "runtime/thread.inline.hpp" |
| 1878 | 30 |
| 6197 | 31 GrowableArray<JvmtiRawMonitor*> *JvmtiPendingMonitors::_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JvmtiRawMonitor*>(1,true); |
| 1878 | 32 |
| 33 void JvmtiPendingMonitors::transition_raw_monitors() { | |
| 34 assert((Threads::number_of_threads()==1), | |
| 35 "Java thread has not created yet or more than one java thread \ | |
| 36 is running. Raw monitor transition will not work"); | |
| 37 JavaThread *current_java_thread = JavaThread::current(); | |
| 38 assert(current_java_thread->thread_state() == _thread_in_vm, "Must be in vm"); | |
| 39 { | |
| 40 ThreadBlockInVM __tbivm(current_java_thread); | |
| 41 for(int i=0; i< count(); i++) { | |
| 42 JvmtiRawMonitor *rmonitor = monitors()->at(i); | |
| 43 int r = rmonitor->raw_enter(current_java_thread); | |
| 44 assert(r == ObjectMonitor::OM_OK, "raw_enter should have worked"); | |
| 45 } | |
| 46 } | |
| 47 // pending monitors are converted to real monitor so delete them all. | |
| 48 dispose(); | |
| 49 } | |
| 50 | |
| 51 // | |
| 52 // class JvmtiRawMonitor | |
| 53 // | |
| 54 | |
| 55 JvmtiRawMonitor::JvmtiRawMonitor(const char *name) { | |
| 56 #ifdef ASSERT | |
| 6197 | 57 _name = strcpy(NEW_C_HEAP_ARRAY(char, strlen(name) + 1, mtInternal), name); |
| 1878 | 58 #else |
| 59 _name = NULL; | |
| 60 #endif | |
| 61 _magic = JVMTI_RM_MAGIC; | |
| 62 } | |
| 63 | |
| 64 JvmtiRawMonitor::~JvmtiRawMonitor() { | |
| 65 #ifdef ASSERT | |
| 66 FreeHeap(_name); | |
| 67 #endif | |
| 68 _magic = 0; | |
| 69 } | |
| 70 | |
| 71 | |
| 72 bool | |
| 73 JvmtiRawMonitor::is_valid() { | |
| 74 int value = 0; | |
| 75 | |
| 76 // This object might not be a JvmtiRawMonitor so we can't assume | |
| 77 // the _magic field is properly aligned. Get the value in a safe | |
| 78 // way and then check against JVMTI_RM_MAGIC. | |
| 79 | |
| 80 switch (sizeof(_magic)) { | |
| 81 case 2: | |
| 82 value = Bytes::get_native_u2((address)&_magic); | |
| 83 break; | |
| 84 | |
| 85 case 4: | |
| 86 value = Bytes::get_native_u4((address)&_magic); | |
| 87 break; | |
| 88 | |
| 89 case 8: | |
| 90 value = Bytes::get_native_u8((address)&_magic); | |
| 91 break; | |
| 92 | |
| 93 default: | |
| 94 guarantee(false, "_magic field is an unexpected size"); | |
| 95 } | |
| 96 | |
| 97 return value == JVMTI_RM_MAGIC; | |
| 98 } | |
| 99 | |
| 100 // ------------------------------------------------------------------------- | |
| 101 // The raw monitor subsystem is entirely distinct from normal | |
| 102 // java-synchronization or jni-synchronization. raw monitors are not | |
| 103 // associated with objects. They can be implemented in any manner | |
| 104 // that makes sense. The original implementors decided to piggy-back | |
| 105 // the raw-monitor implementation on the existing Java objectMonitor mechanism. | |
| 106 // This flaw needs to fixed. We should reimplement raw monitors as sui-generis. | |
| 107 // Specifically, we should not implement raw monitors via java monitors. | |
| 108 // Time permitting, we should disentangle and deconvolve the two implementations | |
| 109 // and move the resulting raw monitor implementation over to the JVMTI directories. | |
| 110 // Ideally, the raw monitor implementation would be built on top of | |
| 111 // park-unpark and nothing else. | |
| 112 // | |
| 113 // raw monitors are used mainly by JVMTI | |
| 114 // The raw monitor implementation borrows the ObjectMonitor structure, | |
| 115 // but the operators are degenerate and extremely simple. | |
| 116 // | |
| 117 // Mixed use of a single objectMonitor instance -- as both a raw monitor | |
| 118 // and a normal java monitor -- is not permissible. | |
| 119 // | |
| 120 // Note that we use the single RawMonitor_lock to protect queue operations for | |
| 121 // _all_ raw monitors. This is a scalability impediment, but since raw monitor usage | |
| 122 // is deprecated and rare, this is not of concern. The RawMonitor_lock can not | |
| 123 // be held indefinitely. The critical sections must be short and bounded. | |
| 124 // | |
| 125 // ------------------------------------------------------------------------- | |
| 126 | |
| 127 int JvmtiRawMonitor::SimpleEnter (Thread * Self) { | |
| 128 for (;;) { | |
| 129 if (Atomic::cmpxchg_ptr (Self, &_owner, NULL) == NULL) { | |
| 130 return OS_OK ; | |
| 131 } | |
| 132 | |
| 133 ObjectWaiter Node (Self) ; | |
| 134 Self->_ParkEvent->reset() ; // strictly optional | |
| 135 Node.TState = ObjectWaiter::TS_ENTER ; | |
| 136 | |
| 137 RawMonitor_lock->lock_without_safepoint_check() ; | |
| 138 Node._next = _EntryList ; | |
| 139 _EntryList = &Node ; | |
| 140 OrderAccess::fence() ; | |
| 141 if (_owner == NULL && Atomic::cmpxchg_ptr (Self, &_owner, NULL) == NULL) { | |
| 142 _EntryList = Node._next ; | |
| 143 RawMonitor_lock->unlock() ; | |
| 144 return OS_OK ; | |
| 145 } | |
| 146 RawMonitor_lock->unlock() ; | |
| 147 while (Node.TState == ObjectWaiter::TS_ENTER) { | |
| 148 Self->_ParkEvent->park() ; | |
| 149 } | |
| 150 } | |
| 151 } | |
| 152 | |
| 153 int JvmtiRawMonitor::SimpleExit (Thread * Self) { | |
| 154 guarantee (_owner == Self, "invariant") ; | |
| 155 OrderAccess::release_store_ptr (&_owner, NULL) ; | |
| 156 OrderAccess::fence() ; | |
| 157 if (_EntryList == NULL) return OS_OK ; | |
| 158 ObjectWaiter * w ; | |
| 159 | |
| 160 RawMonitor_lock->lock_without_safepoint_check() ; | |
| 161 w = _EntryList ; | |
| 162 if (w != NULL) { | |
| 163 _EntryList = w->_next ; | |
| 164 } | |
| 165 RawMonitor_lock->unlock() ; | |
| 166 if (w != NULL) { | |
| 167 guarantee (w ->TState == ObjectWaiter::TS_ENTER, "invariant") ; | |
| 168 ParkEvent * ev = w->_event ; | |
| 169 w->TState = ObjectWaiter::TS_RUN ; | |
| 170 OrderAccess::fence() ; | |
| 171 ev->unpark() ; | |
| 172 } | |
| 173 return OS_OK ; | |
| 174 } | |
| 175 | |
| 176 int JvmtiRawMonitor::SimpleWait (Thread * Self, jlong millis) { | |
| 177 guarantee (_owner == Self , "invariant") ; | |
| 178 guarantee (_recursions == 0, "invariant") ; | |
| 179 | |
| 180 ObjectWaiter Node (Self) ; | |
| 181 Node._notified = 0 ; | |
| 182 Node.TState = ObjectWaiter::TS_WAIT ; | |
| 183 | |
| 184 RawMonitor_lock->lock_without_safepoint_check() ; | |
| 185 Node._next = _WaitSet ; | |
| 186 _WaitSet = &Node ; | |
| 187 RawMonitor_lock->unlock() ; | |
| 188 | |
| 189 SimpleExit (Self) ; | |
| 190 guarantee (_owner != Self, "invariant") ; | |
| 191 | |
| 192 int ret = OS_OK ; | |
| 193 if (millis <= 0) { | |
| 194 Self->_ParkEvent->park(); | |
| 195 } else { | |
| 196 ret = Self->_ParkEvent->park(millis); | |
| 197 } | |
| 198 | |
| 199 // If thread still resides on the waitset then unlink it. | |
| 200 // Double-checked locking -- the usage is safe in this context | |
| 201 // as we TState is volatile and the lock-unlock operators are | |
| 202 // serializing (barrier-equivalent). | |
| 203 | |
| 204 if (Node.TState == ObjectWaiter::TS_WAIT) { | |
| 205 RawMonitor_lock->lock_without_safepoint_check() ; | |
| 206 if (Node.TState == ObjectWaiter::TS_WAIT) { | |
| 207 // Simple O(n) unlink, but performance isn't critical here. | |
| 208 ObjectWaiter * p ; | |
| 209 ObjectWaiter * q = NULL ; | |
| 210 for (p = _WaitSet ; p != &Node; p = p->_next) { | |
| 211 q = p ; | |
| 212 } | |
| 213 guarantee (p == &Node, "invariant") ; | |
| 214 if (q == NULL) { | |
| 215 guarantee (p == _WaitSet, "invariant") ; | |
| 216 _WaitSet = p->_next ; | |
| 217 } else { | |
| 218 guarantee (p == q->_next, "invariant") ; | |
| 219 q->_next = p->_next ; | |
| 220 } | |
| 221 Node.TState = ObjectWaiter::TS_RUN ; | |
| 222 } | |
| 223 RawMonitor_lock->unlock() ; | |
| 224 } | |
| 225 | |
| 226 guarantee (Node.TState == ObjectWaiter::TS_RUN, "invariant") ; | |
| 227 SimpleEnter (Self) ; | |
| 228 | |
| 229 guarantee (_owner == Self, "invariant") ; | |
| 230 guarantee (_recursions == 0, "invariant") ; | |
| 231 return ret ; | |
| 232 } | |
| 233 | |
| 234 int JvmtiRawMonitor::SimpleNotify (Thread * Self, bool All) { | |
| 235 guarantee (_owner == Self, "invariant") ; | |
| 236 if (_WaitSet == NULL) return OS_OK ; | |
| 237 | |
| 238 // We have two options: | |
| 239 // A. Transfer the threads from the WaitSet to the EntryList | |
| 240 // B. Remove the thread from the WaitSet and unpark() it. | |
| 241 // | |
| 242 // We use (B), which is crude and results in lots of futile | |
| 243 // context switching. In particular (B) induces lots of contention. | |
| 244 | |
| 245 ParkEvent * ev = NULL ; // consider using a small auto array ... | |
| 246 RawMonitor_lock->lock_without_safepoint_check() ; | |
| 247 for (;;) { | |
| 248 ObjectWaiter * w = _WaitSet ; | |
| 249 if (w == NULL) break ; | |
| 250 _WaitSet = w->_next ; | |
| 251 if (ev != NULL) { ev->unpark(); ev = NULL; } | |
| 252 ev = w->_event ; | |
| 253 OrderAccess::loadstore() ; | |
| 254 w->TState = ObjectWaiter::TS_RUN ; | |
| 255 OrderAccess::storeload(); | |
| 256 if (!All) break ; | |
| 257 } | |
| 258 RawMonitor_lock->unlock() ; | |
| 259 if (ev != NULL) ev->unpark(); | |
| 260 return OS_OK ; | |
| 261 } | |
| 262 | |
| 263 // Any JavaThread will enter here with state _thread_blocked | |
| 264 int JvmtiRawMonitor::raw_enter(TRAPS) { | |
| 265 TEVENT (raw_enter) ; | |
| 266 void * Contended ; | |
| 267 | |
| 268 // don't enter raw monitor if thread is being externally suspended, it will | |
| 269 // surprise the suspender if a "suspended" thread can still enter monitor | |
| 270 JavaThread * jt = (JavaThread *)THREAD; | |
| 271 if (THREAD->is_Java_thread()) { | |
| 272 jt->SR_lock()->lock_without_safepoint_check(); | |
| 273 while (jt->is_external_suspend()) { | |
| 274 jt->SR_lock()->unlock(); | |
| 275 jt->java_suspend_self(); | |
| 276 jt->SR_lock()->lock_without_safepoint_check(); | |
| 277 } | |
| 278 // guarded by SR_lock to avoid racing with new external suspend requests. | |
| 279 Contended = Atomic::cmpxchg_ptr (THREAD, &_owner, NULL) ; | |
| 280 jt->SR_lock()->unlock(); | |
| 281 } else { | |
| 282 Contended = Atomic::cmpxchg_ptr (THREAD, &_owner, NULL) ; | |
| 283 } | |
| 284 | |
| 285 if (Contended == THREAD) { | |
| 286 _recursions ++ ; | |
| 287 return OM_OK ; | |
| 288 } | |
| 289 | |
| 290 if (Contended == NULL) { | |
| 291 guarantee (_owner == THREAD, "invariant") ; | |
| 292 guarantee (_recursions == 0, "invariant") ; | |
| 293 return OM_OK ; | |
| 294 } | |
| 295 | |
| 296 THREAD->set_current_pending_monitor(this); | |
| 297 | |
| 298 if (!THREAD->is_Java_thread()) { | |
| 299 // No other non-Java threads besides VM thread would acquire | |
| 300 // a raw monitor. | |
| 301 assert(THREAD->is_VM_thread(), "must be VM thread"); | |
| 302 SimpleEnter (THREAD) ; | |
| 303 } else { | |
| 304 guarantee (jt->thread_state() == _thread_blocked, "invariant") ; | |
| 305 for (;;) { | |
| 306 jt->set_suspend_equivalent(); | |
| 307 // cleared by handle_special_suspend_equivalent_condition() or | |
| 308 // java_suspend_self() | |
| 309 SimpleEnter (THREAD) ; | |
| 310 | |
| 311 // were we externally suspended while we were waiting? | |
| 312 if (!jt->handle_special_suspend_equivalent_condition()) break ; | |
| 313 | |
| 314 // This thread was externally suspended | |
| 315 // | |
| 316 // This logic isn't needed for JVMTI raw monitors, | |
| 317 // but doesn't hurt just in case the suspend rules change. This | |
| 318 // logic is needed for the JvmtiRawMonitor.wait() reentry phase. | |
| 319 // We have reentered the contended monitor, but while we were | |
| 320 // waiting another thread suspended us. We don't want to reenter | |
| 321 // the monitor while suspended because that would surprise the | |
| 322 // thread that suspended us. | |
| 323 // | |
| 324 // Drop the lock - | |
| 325 SimpleExit (THREAD) ; | |
| 326 | |
| 327 jt->java_suspend_self(); | |
| 328 } | |
| 329 | |
| 330 assert(_owner == THREAD, "Fatal error with monitor owner!"); | |
| 331 assert(_recursions == 0, "Fatal error with monitor recursions!"); | |
| 332 } | |
| 333 | |
| 334 THREAD->set_current_pending_monitor(NULL); | |
| 335 guarantee (_recursions == 0, "invariant") ; | |
| 336 return OM_OK; | |
| 337 } | |
| 338 | |
| 339 // Used mainly for JVMTI raw monitor implementation | |
| 340 // Also used for JvmtiRawMonitor::wait(). | |
| 341 int JvmtiRawMonitor::raw_exit(TRAPS) { | |
| 342 TEVENT (raw_exit) ; | |
| 343 if (THREAD != _owner) { | |
| 344 return OM_ILLEGAL_MONITOR_STATE; | |
| 345 } | |
| 346 if (_recursions > 0) { | |
| 347 --_recursions ; | |
| 348 return OM_OK ; | |
| 349 } | |
| 350 | |
| 351 void * List = _EntryList ; | |
| 352 SimpleExit (THREAD) ; | |
| 353 | |
| 354 return OM_OK; | |
| 355 } | |
| 356 | |
| 357 // Used for JVMTI raw monitor implementation. | |
| 358 // All JavaThreads will enter here with state _thread_blocked | |
| 359 | |
| 360 int JvmtiRawMonitor::raw_wait(jlong millis, bool interruptible, TRAPS) { | |
| 361 TEVENT (raw_wait) ; | |
| 362 if (THREAD != _owner) { | |
| 363 return OM_ILLEGAL_MONITOR_STATE; | |
| 364 } | |
| 365 | |
| 366 // To avoid spurious wakeups we reset the parkevent -- This is strictly optional. | |
| 367 // The caller must be able to tolerate spurious returns from raw_wait(). | |
| 368 THREAD->_ParkEvent->reset() ; | |
| 369 OrderAccess::fence() ; | |
| 370 | |
| 371 // check interrupt event | |
| 372 if (interruptible && Thread::is_interrupted(THREAD, true)) { | |
| 373 return OM_INTERRUPTED; | |
| 374 } | |
| 375 | |
| 376 intptr_t save = _recursions ; | |
| 377 _recursions = 0 ; | |
| 378 _waiters ++ ; | |
| 379 if (THREAD->is_Java_thread()) { | |
| 380 guarantee (((JavaThread *) THREAD)->thread_state() == _thread_blocked, "invariant") ; | |
| 381 ((JavaThread *)THREAD)->set_suspend_equivalent(); | |
| 382 } | |
| 383 int rv = SimpleWait (THREAD, millis) ; | |
| 384 _recursions = save ; | |
| 385 _waiters -- ; | |
| 386 | |
| 387 guarantee (THREAD == _owner, "invariant") ; | |
| 388 if (THREAD->is_Java_thread()) { | |
| 389 JavaThread * jSelf = (JavaThread *) THREAD ; | |
| 390 for (;;) { | |
| 391 if (!jSelf->handle_special_suspend_equivalent_condition()) break ; | |
| 392 SimpleExit (THREAD) ; | |
| 393 jSelf->java_suspend_self(); | |
| 394 SimpleEnter (THREAD) ; | |
| 395 jSelf->set_suspend_equivalent() ; | |
| 396 } | |
| 397 } | |
| 398 guarantee (THREAD == _owner, "invariant") ; | |
| 399 | |
| 400 if (interruptible && Thread::is_interrupted(THREAD, true)) { | |
| 401 return OM_INTERRUPTED; | |
| 402 } | |
| 403 return OM_OK ; | |
| 404 } | |
| 405 | |
| 406 int JvmtiRawMonitor::raw_notify(TRAPS) { | |
| 407 TEVENT (raw_notify) ; | |
| 408 if (THREAD != _owner) { | |
| 409 return OM_ILLEGAL_MONITOR_STATE; | |
| 410 } | |
| 411 SimpleNotify (THREAD, false) ; | |
| 412 return OM_OK; | |
| 413 } | |
| 414 | |
| 415 int JvmtiRawMonitor::raw_notifyAll(TRAPS) { | |
| 416 TEVENT (raw_notifyAll) ; | |
| 417 if (THREAD != _owner) { | |
| 418 return OM_ILLEGAL_MONITOR_STATE; | |
| 419 } | |
| 420 SimpleNotify (THREAD, true) ; | |
| 421 return OM_OK; | |
| 422 } | |
| 423 |