Thu, 07 Sep 2017 09:17:43 -0400
8072428: Enable UseLoopCounter ergonomically if on-stack-replacement is enabled
Summary: Set UseLoopCounter ergonomically if on-stack-replacement is enabled. Print warning.
Reviewed-by: kvn
duke@435 | 1 | /* |
drchase@6680 | 2 | * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
stefank@2314 | 26 | #include "compiler/compileBroker.hpp" |
stefank@2314 | 27 | #include "gc_interface/collectedHeap.hpp" |
stefank@2314 | 28 | #include "memory/resourceArea.hpp" |
coleenp@4037 | 29 | #include "oops/method.hpp" |
stefank@2314 | 30 | #include "oops/oop.inline.hpp" |
stefank@2314 | 31 | #include "runtime/interfaceSupport.hpp" |
stefank@2314 | 32 | #include "runtime/mutexLocker.hpp" |
stefank@2314 | 33 | #include "runtime/os.hpp" |
stefank@4299 | 34 | #include "runtime/thread.inline.hpp" |
stefank@2314 | 35 | #include "runtime/vmThread.hpp" |
stefank@2314 | 36 | #include "runtime/vm_operations.hpp" |
stefank@2314 | 37 | #include "services/runtimeService.hpp" |
sla@5237 | 38 | #include "trace/tracing.hpp" |
stefank@2314 | 39 | #include "utilities/dtrace.hpp" |
stefank@2314 | 40 | #include "utilities/events.hpp" |
stefank@2314 | 41 | #include "utilities/xmlstream.hpp" |
duke@435 | 42 | |
dcubed@3202 | 43 | #ifndef USDT2 |
fparain@1759 | 44 | HS_DTRACE_PROBE_DECL3(hotspot, vmops__request, char *, uintptr_t, int); |
fparain@1759 | 45 | HS_DTRACE_PROBE_DECL3(hotspot, vmops__begin, char *, uintptr_t, int); |
fparain@1759 | 46 | HS_DTRACE_PROBE_DECL3(hotspot, vmops__end, char *, uintptr_t, int); |
dcubed@3202 | 47 | #endif /* !USDT2 */ |
fparain@1759 | 48 | |
drchase@6680 | 49 | PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
drchase@6680 | 50 | |
duke@435 | 51 | // Dummy VM operation to act as first element in our circular double-linked list |
duke@435 | 52 | class VM_Dummy: public VM_Operation { |
duke@435 | 53 | VMOp_Type type() const { return VMOp_Dummy; } |
duke@435 | 54 | void doit() {}; |
duke@435 | 55 | }; |
duke@435 | 56 | |
duke@435 | 57 | VMOperationQueue::VMOperationQueue() { |
duke@435 | 58 | // The queue is a circular doubled-linked list, which always contains |
duke@435 | 59 | // one element (i.e., one element means empty). |
duke@435 | 60 | for(int i = 0; i < nof_priorities; i++) { |
duke@435 | 61 | _queue_length[i] = 0; |
duke@435 | 62 | _queue_counter = 0; |
duke@435 | 63 | _queue[i] = new VM_Dummy(); |
duke@435 | 64 | _queue[i]->set_next(_queue[i]); |
duke@435 | 65 | _queue[i]->set_prev(_queue[i]); |
duke@435 | 66 | } |
duke@435 | 67 | _drain_list = NULL; |
duke@435 | 68 | } |
duke@435 | 69 | |
duke@435 | 70 | |
duke@435 | 71 | bool VMOperationQueue::queue_empty(int prio) { |
duke@435 | 72 | // It is empty if there is exactly one element |
duke@435 | 73 | bool empty = (_queue[prio] == _queue[prio]->next()); |
duke@435 | 74 | assert( (_queue_length[prio] == 0 && empty) || |
duke@435 | 75 | (_queue_length[prio] > 0 && !empty), "sanity check"); |
duke@435 | 76 | return _queue_length[prio] == 0; |
duke@435 | 77 | } |
duke@435 | 78 | |
duke@435 | 79 | // Inserts an element to the right of the q element |
duke@435 | 80 | void VMOperationQueue::insert(VM_Operation* q, VM_Operation* n) { |
duke@435 | 81 | assert(q->next()->prev() == q && q->prev()->next() == q, "sanity check"); |
duke@435 | 82 | n->set_prev(q); |
duke@435 | 83 | n->set_next(q->next()); |
duke@435 | 84 | q->next()->set_prev(n); |
duke@435 | 85 | q->set_next(n); |
duke@435 | 86 | } |
duke@435 | 87 | |
duke@435 | 88 | void VMOperationQueue::queue_add_front(int prio, VM_Operation *op) { |
duke@435 | 89 | _queue_length[prio]++; |
duke@435 | 90 | insert(_queue[prio]->next(), op); |
duke@435 | 91 | } |
duke@435 | 92 | |
duke@435 | 93 | void VMOperationQueue::queue_add_back(int prio, VM_Operation *op) { |
duke@435 | 94 | _queue_length[prio]++; |
duke@435 | 95 | insert(_queue[prio]->prev(), op); |
duke@435 | 96 | } |
duke@435 | 97 | |
duke@435 | 98 | |
duke@435 | 99 | void VMOperationQueue::unlink(VM_Operation* q) { |
duke@435 | 100 | assert(q->next()->prev() == q && q->prev()->next() == q, "sanity check"); |
duke@435 | 101 | q->prev()->set_next(q->next()); |
duke@435 | 102 | q->next()->set_prev(q->prev()); |
duke@435 | 103 | } |
duke@435 | 104 | |
duke@435 | 105 | VM_Operation* VMOperationQueue::queue_remove_front(int prio) { |
duke@435 | 106 | if (queue_empty(prio)) return NULL; |
duke@435 | 107 | assert(_queue_length[prio] >= 0, "sanity check"); |
duke@435 | 108 | _queue_length[prio]--; |
duke@435 | 109 | VM_Operation* r = _queue[prio]->next(); |
duke@435 | 110 | assert(r != _queue[prio], "cannot remove base element"); |
duke@435 | 111 | unlink(r); |
duke@435 | 112 | return r; |
duke@435 | 113 | } |
duke@435 | 114 | |
duke@435 | 115 | VM_Operation* VMOperationQueue::queue_drain(int prio) { |
duke@435 | 116 | if (queue_empty(prio)) return NULL; |
duke@435 | 117 | DEBUG_ONLY(int length = _queue_length[prio];); |
duke@435 | 118 | assert(length >= 0, "sanity check"); |
duke@435 | 119 | _queue_length[prio] = 0; |
duke@435 | 120 | VM_Operation* r = _queue[prio]->next(); |
duke@435 | 121 | assert(r != _queue[prio], "cannot remove base element"); |
duke@435 | 122 | // remove links to base element from head and tail |
duke@435 | 123 | r->set_prev(NULL); |
duke@435 | 124 | _queue[prio]->prev()->set_next(NULL); |
duke@435 | 125 | // restore queue to empty state |
duke@435 | 126 | _queue[prio]->set_next(_queue[prio]); |
duke@435 | 127 | _queue[prio]->set_prev(_queue[prio]); |
jcoomes@1844 | 128 | assert(queue_empty(prio), "drain corrupted queue"); |
drchase@4942 | 129 | #ifdef ASSERT |
duke@435 | 130 | int len = 0; |
duke@435 | 131 | VM_Operation* cur; |
duke@435 | 132 | for(cur = r; cur != NULL; cur=cur->next()) len++; |
duke@435 | 133 | assert(len == length, "drain lost some ops"); |
duke@435 | 134 | #endif |
duke@435 | 135 | return r; |
duke@435 | 136 | } |
duke@435 | 137 | |
duke@435 | 138 | void VMOperationQueue::queue_oops_do(int queue, OopClosure* f) { |
duke@435 | 139 | VM_Operation* cur = _queue[queue]; |
duke@435 | 140 | cur = cur->next(); |
duke@435 | 141 | while (cur != _queue[queue]) { |
duke@435 | 142 | cur->oops_do(f); |
duke@435 | 143 | cur = cur->next(); |
duke@435 | 144 | } |
duke@435 | 145 | } |
duke@435 | 146 | |
duke@435 | 147 | void VMOperationQueue::drain_list_oops_do(OopClosure* f) { |
duke@435 | 148 | VM_Operation* cur = _drain_list; |
duke@435 | 149 | while (cur != NULL) { |
duke@435 | 150 | cur->oops_do(f); |
duke@435 | 151 | cur = cur->next(); |
duke@435 | 152 | } |
duke@435 | 153 | } |
duke@435 | 154 | |
duke@435 | 155 | //----------------------------------------------------------------- |
duke@435 | 156 | // High-level interface |
duke@435 | 157 | bool VMOperationQueue::add(VM_Operation *op) { |
fparain@1759 | 158 | |
dcubed@3202 | 159 | #ifndef USDT2 |
fparain@1759 | 160 | HS_DTRACE_PROBE3(hotspot, vmops__request, op->name(), strlen(op->name()), |
fparain@1759 | 161 | op->evaluation_mode()); |
dcubed@3202 | 162 | #else /* USDT2 */ |
dcubed@3202 | 163 | HOTSPOT_VMOPS_REQUEST( |
dcubed@3202 | 164 | (char *) op->name(), strlen(op->name()), |
dcubed@3202 | 165 | op->evaluation_mode()); |
dcubed@3202 | 166 | #endif /* USDT2 */ |
fparain@1759 | 167 | |
duke@435 | 168 | // Encapsulates VM queue policy. Currently, that |
duke@435 | 169 | // only involves putting them on the right list |
duke@435 | 170 | if (op->evaluate_at_safepoint()) { |
duke@435 | 171 | queue_add_back(SafepointPriority, op); |
duke@435 | 172 | return true; |
duke@435 | 173 | } |
duke@435 | 174 | |
duke@435 | 175 | queue_add_back(MediumPriority, op); |
duke@435 | 176 | return true; |
duke@435 | 177 | } |
duke@435 | 178 | |
duke@435 | 179 | VM_Operation* VMOperationQueue::remove_next() { |
duke@435 | 180 | // Assuming VMOperation queue is two-level priority queue. If there are |
duke@435 | 181 | // more than two priorities, we need a different scheduling algorithm. |
duke@435 | 182 | assert(SafepointPriority == 0 && MediumPriority == 1 && nof_priorities == 2, |
duke@435 | 183 | "current algorithm does not work"); |
duke@435 | 184 | |
duke@435 | 185 | // simple counter based scheduling to prevent starvation of lower priority |
duke@435 | 186 | // queue. -- see 4390175 |
duke@435 | 187 | int high_prio, low_prio; |
duke@435 | 188 | if (_queue_counter++ < 10) { |
duke@435 | 189 | high_prio = SafepointPriority; |
duke@435 | 190 | low_prio = MediumPriority; |
duke@435 | 191 | } else { |
duke@435 | 192 | _queue_counter = 0; |
duke@435 | 193 | high_prio = MediumPriority; |
duke@435 | 194 | low_prio = SafepointPriority; |
duke@435 | 195 | } |
duke@435 | 196 | |
duke@435 | 197 | return queue_remove_front(queue_empty(high_prio) ? low_prio : high_prio); |
duke@435 | 198 | } |
duke@435 | 199 | |
duke@435 | 200 | void VMOperationQueue::oops_do(OopClosure* f) { |
duke@435 | 201 | for(int i = 0; i < nof_priorities; i++) { |
duke@435 | 202 | queue_oops_do(i, f); |
duke@435 | 203 | } |
duke@435 | 204 | drain_list_oops_do(f); |
duke@435 | 205 | } |
duke@435 | 206 | |
duke@435 | 207 | |
duke@435 | 208 | //------------------------------------------------------------------------------------------------------------------ |
duke@435 | 209 | // Implementation of VMThread stuff |
duke@435 | 210 | |
duke@435 | 211 | bool VMThread::_should_terminate = false; |
duke@435 | 212 | bool VMThread::_terminated = false; |
duke@435 | 213 | Monitor* VMThread::_terminate_lock = NULL; |
duke@435 | 214 | VMThread* VMThread::_vm_thread = NULL; |
duke@435 | 215 | VM_Operation* VMThread::_cur_vm_operation = NULL; |
duke@435 | 216 | VMOperationQueue* VMThread::_vm_queue = NULL; |
duke@435 | 217 | PerfCounter* VMThread::_perf_accumulated_vm_operation_time = NULL; |
duke@435 | 218 | |
duke@435 | 219 | |
duke@435 | 220 | void VMThread::create() { |
duke@435 | 221 | assert(vm_thread() == NULL, "we can only allocate one VMThread"); |
duke@435 | 222 | _vm_thread = new VMThread(); |
duke@435 | 223 | |
duke@435 | 224 | // Create VM operation queue |
duke@435 | 225 | _vm_queue = new VMOperationQueue(); |
duke@435 | 226 | guarantee(_vm_queue != NULL, "just checking"); |
duke@435 | 227 | |
duke@435 | 228 | _terminate_lock = new Monitor(Mutex::safepoint, "VMThread::_terminate_lock", true); |
duke@435 | 229 | |
duke@435 | 230 | if (UsePerfData) { |
duke@435 | 231 | // jvmstat performance counters |
duke@435 | 232 | Thread* THREAD = Thread::current(); |
duke@435 | 233 | _perf_accumulated_vm_operation_time = |
duke@435 | 234 | PerfDataManager::create_counter(SUN_THREADS, "vmOperationTime", |
duke@435 | 235 | PerfData::U_Ticks, CHECK); |
duke@435 | 236 | } |
duke@435 | 237 | } |
duke@435 | 238 | |
duke@435 | 239 | |
minqi@1554 | 240 | VMThread::VMThread() : NamedThread() { |
minqi@1554 | 241 | set_name("VM Thread"); |
duke@435 | 242 | } |
duke@435 | 243 | |
duke@435 | 244 | void VMThread::destroy() { |
duke@435 | 245 | if (_vm_thread != NULL) { |
duke@435 | 246 | delete _vm_thread; |
duke@435 | 247 | _vm_thread = NULL; // VM thread is gone |
duke@435 | 248 | } |
duke@435 | 249 | } |
duke@435 | 250 | |
duke@435 | 251 | void VMThread::run() { |
duke@435 | 252 | assert(this == vm_thread(), "check"); |
duke@435 | 253 | |
duke@435 | 254 | this->initialize_thread_local_storage(); |
duke@435 | 255 | this->record_stack_base_and_size(); |
duke@435 | 256 | // Notify_lock wait checks on active_handles() to rewait in |
duke@435 | 257 | // case of spurious wakeup, it should wait on the last |
duke@435 | 258 | // value set prior to the notify |
duke@435 | 259 | this->set_active_handles(JNIHandleBlock::allocate_block()); |
duke@435 | 260 | |
duke@435 | 261 | { |
duke@435 | 262 | MutexLocker ml(Notify_lock); |
duke@435 | 263 | Notify_lock->notify(); |
duke@435 | 264 | } |
duke@435 | 265 | // Notify_lock is destroyed by Threads::create_vm() |
duke@435 | 266 | |
duke@435 | 267 | int prio = (VMThreadPriority == -1) |
duke@435 | 268 | ? os::java_to_os_priority[NearMaxPriority] |
duke@435 | 269 | : VMThreadPriority; |
duke@435 | 270 | // Note that I cannot call os::set_priority because it expects Java |
duke@435 | 271 | // priorities and I am *explicitly* using OS priorities so that it's |
duke@435 | 272 | // possible to set the VM thread priority higher than any Java thread. |
duke@435 | 273 | os::set_native_priority( this, prio ); |
duke@435 | 274 | |
duke@435 | 275 | // Wait for VM_Operations until termination |
duke@435 | 276 | this->loop(); |
duke@435 | 277 | |
duke@435 | 278 | // Note the intention to exit before safepointing. |
duke@435 | 279 | // 6295565 This has the effect of waiting for any large tty |
duke@435 | 280 | // outputs to finish. |
duke@435 | 281 | if (xtty != NULL) { |
duke@435 | 282 | ttyLocker ttyl; |
duke@435 | 283 | xtty->begin_elem("destroy_vm"); |
duke@435 | 284 | xtty->stamp(); |
duke@435 | 285 | xtty->end_elem(); |
duke@435 | 286 | assert(should_terminate(), "termination flag must be set"); |
duke@435 | 287 | } |
duke@435 | 288 | |
duke@435 | 289 | // 4526887 let VM thread exit at Safepoint |
duke@435 | 290 | SafepointSynchronize::begin(); |
duke@435 | 291 | |
duke@435 | 292 | if (VerifyBeforeExit) { |
duke@435 | 293 | HandleMark hm(VMThread::vm_thread()); |
duke@435 | 294 | // Among other things, this ensures that Eden top is correct. |
duke@435 | 295 | Universe::heap()->prepare_for_verify(); |
duke@435 | 296 | os::check_heap(); |
ysr@2825 | 297 | // Silent verification so as not to pollute normal output, |
ysr@2825 | 298 | // unless we really asked for it. |
stefank@5018 | 299 | Universe::verify(!(PrintGCDetails || Verbose) || VerifySilently); |
duke@435 | 300 | } |
duke@435 | 301 | |
duke@435 | 302 | CompileBroker::set_should_block(); |
duke@435 | 303 | |
duke@435 | 304 | // wait for threads (compiler threads or daemon threads) in the |
duke@435 | 305 | // _thread_in_native state to block. |
duke@435 | 306 | VM_Exit::wait_for_threads_in_native_to_block(); |
duke@435 | 307 | |
duke@435 | 308 | // signal other threads that VM process is gone |
duke@435 | 309 | { |
duke@435 | 310 | // Note: we must have the _no_safepoint_check_flag. Mutex::lock() allows |
duke@435 | 311 | // VM thread to enter any lock at Safepoint as long as its _owner is NULL. |
duke@435 | 312 | // If that happens after _terminate_lock->wait() has unset _owner |
duke@435 | 313 | // but before it actually drops the lock and waits, the notification below |
duke@435 | 314 | // may get lost and we will have a hang. To avoid this, we need to use |
duke@435 | 315 | // Mutex::lock_without_safepoint_check(). |
duke@435 | 316 | MutexLockerEx ml(_terminate_lock, Mutex::_no_safepoint_check_flag); |
duke@435 | 317 | _terminated = true; |
duke@435 | 318 | _terminate_lock->notify(); |
duke@435 | 319 | } |
duke@435 | 320 | |
kevinw@6553 | 321 | // Thread destructor usually does this. |
kevinw@6553 | 322 | ThreadLocalStorage::set_thread(NULL); |
kevinw@6553 | 323 | |
duke@435 | 324 | // Deletion must be done synchronously by the JNI DestroyJavaVM thread |
duke@435 | 325 | // so that the VMThread deletion completes before the main thread frees |
duke@435 | 326 | // up the CodeHeap. |
duke@435 | 327 | |
duke@435 | 328 | } |
duke@435 | 329 | |
duke@435 | 330 | |
duke@435 | 331 | // Notify the VMThread that the last non-daemon JavaThread has terminated, |
duke@435 | 332 | // and wait until operation is performed. |
duke@435 | 333 | void VMThread::wait_for_vm_thread_exit() { |
duke@435 | 334 | { MutexLocker mu(VMOperationQueue_lock); |
duke@435 | 335 | _should_terminate = true; |
duke@435 | 336 | VMOperationQueue_lock->notify(); |
duke@435 | 337 | } |
duke@435 | 338 | |
duke@435 | 339 | // Note: VM thread leaves at Safepoint. We are not stopped by Safepoint |
duke@435 | 340 | // because this thread has been removed from the threads list. But anything |
duke@435 | 341 | // that could get blocked by Safepoint should not be used after this point, |
duke@435 | 342 | // otherwise we will hang, since there is no one can end the safepoint. |
duke@435 | 343 | |
duke@435 | 344 | // Wait until VM thread is terminated |
duke@435 | 345 | // Note: it should be OK to use Terminator_lock here. But this is called |
duke@435 | 346 | // at a very delicate time (VM shutdown) and we are operating in non- VM |
duke@435 | 347 | // thread at Safepoint. It's safer to not share lock with other threads. |
duke@435 | 348 | { MutexLockerEx ml(_terminate_lock, Mutex::_no_safepoint_check_flag); |
duke@435 | 349 | while(!VMThread::is_terminated()) { |
duke@435 | 350 | _terminate_lock->wait(Mutex::_no_safepoint_check_flag); |
duke@435 | 351 | } |
duke@435 | 352 | } |
duke@435 | 353 | } |
duke@435 | 354 | |
duke@435 | 355 | void VMThread::print_on(outputStream* st) const { |
duke@435 | 356 | st->print("\"%s\" ", name()); |
duke@435 | 357 | Thread::print_on(st); |
duke@435 | 358 | st->cr(); |
duke@435 | 359 | } |
duke@435 | 360 | |
duke@435 | 361 | void VMThread::evaluate_operation(VM_Operation* op) { |
duke@435 | 362 | ResourceMark rm; |
duke@435 | 363 | |
duke@435 | 364 | { |
duke@435 | 365 | PerfTraceTime vm_op_timer(perf_accumulated_vm_operation_time()); |
dcubed@3202 | 366 | #ifndef USDT2 |
fparain@1759 | 367 | HS_DTRACE_PROBE3(hotspot, vmops__begin, op->name(), strlen(op->name()), |
fparain@1759 | 368 | op->evaluation_mode()); |
dcubed@3202 | 369 | #else /* USDT2 */ |
dcubed@3202 | 370 | HOTSPOT_VMOPS_BEGIN( |
dcubed@3202 | 371 | (char *) op->name(), strlen(op->name()), |
dcubed@3202 | 372 | op->evaluation_mode()); |
dcubed@3202 | 373 | #endif /* USDT2 */ |
sla@5237 | 374 | |
sla@5237 | 375 | EventExecuteVMOperation event; |
sla@5237 | 376 | |
duke@435 | 377 | op->evaluate(); |
sla@5237 | 378 | |
sla@5237 | 379 | if (event.should_commit()) { |
sla@5237 | 380 | bool is_concurrent = op->evaluate_concurrently(); |
sla@5237 | 381 | event.set_operation(op->type()); |
sla@5237 | 382 | event.set_safepoint(op->evaluate_at_safepoint()); |
sla@5237 | 383 | event.set_blocking(!is_concurrent); |
sla@5237 | 384 | // Only write caller thread information for non-concurrent vm operations. |
sla@5237 | 385 | // For concurrent vm operations, the thread id is set to 0 indicating thread is unknown. |
sla@5237 | 386 | // This is because the caller thread could have exited already. |
sla@5237 | 387 | event.set_caller(is_concurrent ? 0 : op->calling_thread()->osthread()->thread_id()); |
sla@5237 | 388 | event.commit(); |
sla@5237 | 389 | } |
sla@5237 | 390 | |
dcubed@3202 | 391 | #ifndef USDT2 |
fparain@1759 | 392 | HS_DTRACE_PROBE3(hotspot, vmops__end, op->name(), strlen(op->name()), |
fparain@1759 | 393 | op->evaluation_mode()); |
dcubed@3202 | 394 | #else /* USDT2 */ |
dcubed@3202 | 395 | HOTSPOT_VMOPS_END( |
dcubed@3202 | 396 | (char *) op->name(), strlen(op->name()), |
dcubed@3202 | 397 | op->evaluation_mode()); |
dcubed@3202 | 398 | #endif /* USDT2 */ |
duke@435 | 399 | } |
duke@435 | 400 | |
duke@435 | 401 | // Last access of info in _cur_vm_operation! |
duke@435 | 402 | bool c_heap_allocated = op->is_cheap_allocated(); |
duke@435 | 403 | |
duke@435 | 404 | // Mark as completed |
duke@435 | 405 | if (!op->evaluate_concurrently()) { |
duke@435 | 406 | op->calling_thread()->increment_vm_operation_completed_count(); |
duke@435 | 407 | } |
duke@435 | 408 | // It is unsafe to access the _cur_vm_operation after the 'increment_vm_operation_completed_count' call, |
duke@435 | 409 | // since if it is stack allocated the calling thread might have deallocated |
duke@435 | 410 | if (c_heap_allocated) { |
duke@435 | 411 | delete _cur_vm_operation; |
duke@435 | 412 | } |
duke@435 | 413 | } |
duke@435 | 414 | |
duke@435 | 415 | |
duke@435 | 416 | void VMThread::loop() { |
duke@435 | 417 | assert(_cur_vm_operation == NULL, "no current one should be executing"); |
duke@435 | 418 | |
duke@435 | 419 | while(true) { |
duke@435 | 420 | VM_Operation* safepoint_ops = NULL; |
duke@435 | 421 | // |
duke@435 | 422 | // Wait for VM operation |
duke@435 | 423 | // |
duke@435 | 424 | // use no_safepoint_check to get lock without attempting to "sneak" |
duke@435 | 425 | { MutexLockerEx mu_queue(VMOperationQueue_lock, |
duke@435 | 426 | Mutex::_no_safepoint_check_flag); |
duke@435 | 427 | |
duke@435 | 428 | // Look for new operation |
duke@435 | 429 | assert(_cur_vm_operation == NULL, "no current one should be executing"); |
duke@435 | 430 | _cur_vm_operation = _vm_queue->remove_next(); |
duke@435 | 431 | |
duke@435 | 432 | // Stall time tracking code |
duke@435 | 433 | if (PrintVMQWaitTime && _cur_vm_operation != NULL && |
duke@435 | 434 | !_cur_vm_operation->evaluate_concurrently()) { |
duke@435 | 435 | long stall = os::javaTimeMillis() - _cur_vm_operation->timestamp(); |
duke@435 | 436 | if (stall > 0) |
duke@435 | 437 | tty->print_cr("%s stall: %Ld", _cur_vm_operation->name(), stall); |
duke@435 | 438 | } |
duke@435 | 439 | |
duke@435 | 440 | while (!should_terminate() && _cur_vm_operation == NULL) { |
duke@435 | 441 | // wait with a timeout to guarantee safepoints at regular intervals |
duke@435 | 442 | bool timedout = |
duke@435 | 443 | VMOperationQueue_lock->wait(Mutex::_no_safepoint_check_flag, |
duke@435 | 444 | GuaranteedSafepointInterval); |
duke@435 | 445 | |
duke@435 | 446 | // Support for self destruction |
duke@435 | 447 | if ((SelfDestructTimer != 0) && !is_error_reported() && |
duke@435 | 448 | (os::elapsedTime() > SelfDestructTimer * 60)) { |
duke@435 | 449 | tty->print_cr("VM self-destructed"); |
duke@435 | 450 | exit(-1); |
duke@435 | 451 | } |
duke@435 | 452 | |
duke@435 | 453 | if (timedout && (SafepointALot || |
duke@435 | 454 | SafepointSynchronize::is_cleanup_needed())) { |
duke@435 | 455 | MutexUnlockerEx mul(VMOperationQueue_lock, |
duke@435 | 456 | Mutex::_no_safepoint_check_flag); |
duke@435 | 457 | // Force a safepoint since we have not had one for at least |
duke@435 | 458 | // 'GuaranteedSafepointInterval' milliseconds. This will run all |
duke@435 | 459 | // the clean-up processing that needs to be done regularly at a |
duke@435 | 460 | // safepoint |
duke@435 | 461 | SafepointSynchronize::begin(); |
duke@435 | 462 | #ifdef ASSERT |
duke@435 | 463 | if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot(); |
duke@435 | 464 | #endif |
duke@435 | 465 | SafepointSynchronize::end(); |
duke@435 | 466 | } |
duke@435 | 467 | _cur_vm_operation = _vm_queue->remove_next(); |
duke@435 | 468 | |
duke@435 | 469 | // If we are at a safepoint we will evaluate all the operations that |
duke@435 | 470 | // follow that also require a safepoint |
duke@435 | 471 | if (_cur_vm_operation != NULL && |
duke@435 | 472 | _cur_vm_operation->evaluate_at_safepoint()) { |
duke@435 | 473 | safepoint_ops = _vm_queue->drain_at_safepoint_priority(); |
duke@435 | 474 | } |
duke@435 | 475 | } |
duke@435 | 476 | |
duke@435 | 477 | if (should_terminate()) break; |
duke@435 | 478 | } // Release mu_queue_lock |
duke@435 | 479 | |
duke@435 | 480 | // |
duke@435 | 481 | // Execute VM operation |
duke@435 | 482 | // |
duke@435 | 483 | { HandleMark hm(VMThread::vm_thread()); |
duke@435 | 484 | |
duke@435 | 485 | EventMark em("Executing VM operation: %s", vm_operation()->name()); |
duke@435 | 486 | assert(_cur_vm_operation != NULL, "we should have found an operation to execute"); |
duke@435 | 487 | |
duke@435 | 488 | // Give the VM thread an extra quantum. Jobs tend to be bursty and this |
duke@435 | 489 | // helps the VM thread to finish up the job. |
duke@435 | 490 | // FIXME: When this is enabled and there are many threads, this can degrade |
duke@435 | 491 | // performance significantly. |
duke@435 | 492 | if( VMThreadHintNoPreempt ) |
duke@435 | 493 | os::hint_no_preempt(); |
duke@435 | 494 | |
duke@435 | 495 | // If we are at a safepoint we will evaluate all the operations that |
duke@435 | 496 | // follow that also require a safepoint |
duke@435 | 497 | if (_cur_vm_operation->evaluate_at_safepoint()) { |
duke@435 | 498 | |
duke@435 | 499 | _vm_queue->set_drain_list(safepoint_ops); // ensure ops can be scanned |
duke@435 | 500 | |
duke@435 | 501 | SafepointSynchronize::begin(); |
duke@435 | 502 | evaluate_operation(_cur_vm_operation); |
duke@435 | 503 | // now process all queued safepoint ops, iteratively draining |
duke@435 | 504 | // the queue until there are none left |
duke@435 | 505 | do { |
duke@435 | 506 | _cur_vm_operation = safepoint_ops; |
duke@435 | 507 | if (_cur_vm_operation != NULL) { |
duke@435 | 508 | do { |
duke@435 | 509 | // evaluate_operation deletes the op object so we have |
duke@435 | 510 | // to grab the next op now |
duke@435 | 511 | VM_Operation* next = _cur_vm_operation->next(); |
duke@435 | 512 | _vm_queue->set_drain_list(next); |
duke@435 | 513 | evaluate_operation(_cur_vm_operation); |
duke@435 | 514 | _cur_vm_operation = next; |
duke@435 | 515 | if (PrintSafepointStatistics) { |
duke@435 | 516 | SafepointSynchronize::inc_vmop_coalesced_count(); |
duke@435 | 517 | } |
duke@435 | 518 | } while (_cur_vm_operation != NULL); |
duke@435 | 519 | } |
duke@435 | 520 | // There is a chance that a thread enqueued a safepoint op |
duke@435 | 521 | // since we released the op-queue lock and initiated the safepoint. |
duke@435 | 522 | // So we drain the queue again if there is anything there, as an |
duke@435 | 523 | // optimization to try and reduce the number of safepoints. |
duke@435 | 524 | // As the safepoint synchronizes us with JavaThreads we will see |
duke@435 | 525 | // any enqueue made by a JavaThread, but the peek will not |
duke@435 | 526 | // necessarily detect a concurrent enqueue by a GC thread, but |
duke@435 | 527 | // that simply means the op will wait for the next major cycle of the |
duke@435 | 528 | // VMThread - just as it would if the GC thread lost the race for |
duke@435 | 529 | // the lock. |
duke@435 | 530 | if (_vm_queue->peek_at_safepoint_priority()) { |
duke@435 | 531 | // must hold lock while draining queue |
duke@435 | 532 | MutexLockerEx mu_queue(VMOperationQueue_lock, |
duke@435 | 533 | Mutex::_no_safepoint_check_flag); |
duke@435 | 534 | safepoint_ops = _vm_queue->drain_at_safepoint_priority(); |
duke@435 | 535 | } else { |
duke@435 | 536 | safepoint_ops = NULL; |
duke@435 | 537 | } |
duke@435 | 538 | } while(safepoint_ops != NULL); |
duke@435 | 539 | |
duke@435 | 540 | _vm_queue->set_drain_list(NULL); |
duke@435 | 541 | |
duke@435 | 542 | // Complete safepoint synchronization |
duke@435 | 543 | SafepointSynchronize::end(); |
duke@435 | 544 | |
duke@435 | 545 | } else { // not a safepoint operation |
duke@435 | 546 | if (TraceLongCompiles) { |
duke@435 | 547 | elapsedTimer t; |
duke@435 | 548 | t.start(); |
duke@435 | 549 | evaluate_operation(_cur_vm_operation); |
duke@435 | 550 | t.stop(); |
duke@435 | 551 | double secs = t.seconds(); |
duke@435 | 552 | if (secs * 1e3 > LongCompileThreshold) { |
duke@435 | 553 | // XXX - _cur_vm_operation should not be accessed after |
duke@435 | 554 | // the completed count has been incremented; the waiting |
duke@435 | 555 | // thread may have already freed this memory. |
duke@435 | 556 | tty->print_cr("vm %s: %3.7f secs]", _cur_vm_operation->name(), secs); |
duke@435 | 557 | } |
duke@435 | 558 | } else { |
duke@435 | 559 | evaluate_operation(_cur_vm_operation); |
duke@435 | 560 | } |
duke@435 | 561 | |
duke@435 | 562 | _cur_vm_operation = NULL; |
duke@435 | 563 | } |
duke@435 | 564 | } |
duke@435 | 565 | |
duke@435 | 566 | // |
duke@435 | 567 | // Notify (potential) waiting Java thread(s) - lock without safepoint |
duke@435 | 568 | // check so that sneaking is not possible |
duke@435 | 569 | { MutexLockerEx mu(VMOperationRequest_lock, |
duke@435 | 570 | Mutex::_no_safepoint_check_flag); |
duke@435 | 571 | VMOperationRequest_lock->notify_all(); |
duke@435 | 572 | } |
duke@435 | 573 | |
duke@435 | 574 | // |
duke@435 | 575 | // We want to make sure that we get to a safepoint regularly. |
duke@435 | 576 | // |
duke@435 | 577 | if (SafepointALot || SafepointSynchronize::is_cleanup_needed()) { |
duke@435 | 578 | long interval = SafepointSynchronize::last_non_safepoint_interval(); |
duke@435 | 579 | bool max_time_exceeded = GuaranteedSafepointInterval != 0 && (interval > GuaranteedSafepointInterval); |
duke@435 | 580 | if (SafepointALot || max_time_exceeded) { |
duke@435 | 581 | HandleMark hm(VMThread::vm_thread()); |
duke@435 | 582 | SafepointSynchronize::begin(); |
duke@435 | 583 | SafepointSynchronize::end(); |
duke@435 | 584 | } |
duke@435 | 585 | } |
duke@435 | 586 | } |
duke@435 | 587 | } |
duke@435 | 588 | |
duke@435 | 589 | void VMThread::execute(VM_Operation* op) { |
duke@435 | 590 | Thread* t = Thread::current(); |
duke@435 | 591 | |
duke@435 | 592 | if (!t->is_VM_thread()) { |
ysr@1241 | 593 | SkipGCALot sgcalot(t); // avoid re-entrant attempts to gc-a-lot |
duke@435 | 594 | // JavaThread or WatcherThread |
dcubed@4472 | 595 | bool concurrent = op->evaluate_concurrently(); |
dcubed@4472 | 596 | // only blocking VM operations need to verify the caller's safepoint state: |
dcubed@4472 | 597 | if (!concurrent) { |
dcubed@4472 | 598 | t->check_for_valid_safepoint_state(true); |
dcubed@4472 | 599 | } |
duke@435 | 600 | |
duke@435 | 601 | // New request from Java thread, evaluate prologue |
duke@435 | 602 | if (!op->doit_prologue()) { |
duke@435 | 603 | return; // op was cancelled |
duke@435 | 604 | } |
duke@435 | 605 | |
duke@435 | 606 | // Setup VM_operations for execution |
duke@435 | 607 | op->set_calling_thread(t, Thread::get_priority(t)); |
duke@435 | 608 | |
duke@435 | 609 | // It does not make sense to execute the epilogue, if the VM operation object is getting |
duke@435 | 610 | // deallocated by the VM thread. |
duke@435 | 611 | bool execute_epilog = !op->is_cheap_allocated(); |
duke@435 | 612 | assert(!concurrent || op->is_cheap_allocated(), "concurrent => cheap_allocated"); |
duke@435 | 613 | |
duke@435 | 614 | // Get ticket number for non-concurrent VM operations |
duke@435 | 615 | int ticket = 0; |
duke@435 | 616 | if (!concurrent) { |
duke@435 | 617 | ticket = t->vm_operation_ticket(); |
duke@435 | 618 | } |
duke@435 | 619 | |
duke@435 | 620 | // Add VM operation to list of waiting threads. We are guaranteed not to block while holding the |
duke@435 | 621 | // VMOperationQueue_lock, so we can block without a safepoint check. This allows vm operation requests |
duke@435 | 622 | // to be queued up during a safepoint synchronization. |
duke@435 | 623 | { |
duke@435 | 624 | VMOperationQueue_lock->lock_without_safepoint_check(); |
duke@435 | 625 | bool ok = _vm_queue->add(op); |
sla@5237 | 626 | op->set_timestamp(os::javaTimeMillis()); |
duke@435 | 627 | VMOperationQueue_lock->notify(); |
duke@435 | 628 | VMOperationQueue_lock->unlock(); |
duke@435 | 629 | // VM_Operation got skipped |
duke@435 | 630 | if (!ok) { |
duke@435 | 631 | assert(concurrent, "can only skip concurrent tasks"); |
duke@435 | 632 | if (op->is_cheap_allocated()) delete op; |
duke@435 | 633 | return; |
duke@435 | 634 | } |
duke@435 | 635 | } |
duke@435 | 636 | |
duke@435 | 637 | if (!concurrent) { |
duke@435 | 638 | // Wait for completion of request (non-concurrent) |
duke@435 | 639 | // Note: only a JavaThread triggers the safepoint check when locking |
duke@435 | 640 | MutexLocker mu(VMOperationRequest_lock); |
duke@435 | 641 | while(t->vm_operation_completed_count() < ticket) { |
duke@435 | 642 | VMOperationRequest_lock->wait(!t->is_Java_thread()); |
duke@435 | 643 | } |
duke@435 | 644 | } |
duke@435 | 645 | |
duke@435 | 646 | if (execute_epilog) { |
duke@435 | 647 | op->doit_epilogue(); |
duke@435 | 648 | } |
duke@435 | 649 | } else { |
duke@435 | 650 | // invoked by VM thread; usually nested VM operation |
duke@435 | 651 | assert(t->is_VM_thread(), "must be a VM thread"); |
duke@435 | 652 | VM_Operation* prev_vm_operation = vm_operation(); |
duke@435 | 653 | if (prev_vm_operation != NULL) { |
duke@435 | 654 | // Check the VM operation allows nested VM operation. This normally not the case, e.g., the compiler |
duke@435 | 655 | // does not allow nested scavenges or compiles. |
duke@435 | 656 | if (!prev_vm_operation->allow_nested_vm_operations()) { |
jcoomes@1845 | 657 | fatal(err_msg("Nested VM operation %s requested by operation %s", |
jcoomes@1845 | 658 | op->name(), vm_operation()->name())); |
duke@435 | 659 | } |
duke@435 | 660 | op->set_calling_thread(prev_vm_operation->calling_thread(), prev_vm_operation->priority()); |
duke@435 | 661 | } |
duke@435 | 662 | |
duke@435 | 663 | EventMark em("Executing %s VM operation: %s", prev_vm_operation ? "nested" : "", op->name()); |
duke@435 | 664 | |
duke@435 | 665 | // Release all internal handles after operation is evaluated |
duke@435 | 666 | HandleMark hm(t); |
duke@435 | 667 | _cur_vm_operation = op; |
duke@435 | 668 | |
duke@435 | 669 | if (op->evaluate_at_safepoint() && !SafepointSynchronize::is_at_safepoint()) { |
duke@435 | 670 | SafepointSynchronize::begin(); |
duke@435 | 671 | op->evaluate(); |
duke@435 | 672 | SafepointSynchronize::end(); |
duke@435 | 673 | } else { |
duke@435 | 674 | op->evaluate(); |
duke@435 | 675 | } |
duke@435 | 676 | |
duke@435 | 677 | // Free memory if needed |
duke@435 | 678 | if (op->is_cheap_allocated()) delete op; |
duke@435 | 679 | |
duke@435 | 680 | _cur_vm_operation = prev_vm_operation; |
duke@435 | 681 | } |
duke@435 | 682 | } |
duke@435 | 683 | |
duke@435 | 684 | |
stefank@6973 | 685 | void VMThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { |
stefank@4298 | 686 | Thread::oops_do(f, cld_f, cf); |
duke@435 | 687 | _vm_queue->oops_do(f); |
duke@435 | 688 | } |
duke@435 | 689 | |
duke@435 | 690 | //------------------------------------------------------------------------------------------------------------------ |
duke@435 | 691 | #ifndef PRODUCT |
duke@435 | 692 | |
duke@435 | 693 | void VMOperationQueue::verify_queue(int prio) { |
duke@435 | 694 | // Check that list is correctly linked |
duke@435 | 695 | int length = _queue_length[prio]; |
duke@435 | 696 | VM_Operation *cur = _queue[prio]; |
duke@435 | 697 | int i; |
duke@435 | 698 | |
duke@435 | 699 | // Check forward links |
duke@435 | 700 | for(i = 0; i < length; i++) { |
duke@435 | 701 | cur = cur->next(); |
duke@435 | 702 | assert(cur != _queue[prio], "list to short (forward)"); |
duke@435 | 703 | } |
duke@435 | 704 | assert(cur->next() == _queue[prio], "list to long (forward)"); |
duke@435 | 705 | |
duke@435 | 706 | // Check backwards links |
duke@435 | 707 | cur = _queue[prio]; |
duke@435 | 708 | for(i = 0; i < length; i++) { |
duke@435 | 709 | cur = cur->prev(); |
duke@435 | 710 | assert(cur != _queue[prio], "list to short (backwards)"); |
duke@435 | 711 | } |
duke@435 | 712 | assert(cur->prev() == _queue[prio], "list to long (backwards)"); |
duke@435 | 713 | } |
duke@435 | 714 | |
duke@435 | 715 | #endif |
duke@435 | 716 | |
duke@435 | 717 | void VMThread::verify() { |
stefank@4298 | 718 | oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); |
duke@435 | 719 | } |