Mon, 18 Mar 2013 13:19:06 +0100
8008555: Debugging code in compiled method sometimes leaks memory
Summary: support for strings that have same life-time as code that uses them.
Reviewed-by: kvn, twisti
duke@435 | 1 | /* |
never@3494 | 2 | * Copyright (c) 1997, 2012, 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" |
coleenp@3865 | 26 | #include "classfile/symbolTable.hpp" |
stefank@2314 | 27 | #include "classfile/systemDictionary.hpp" |
stefank@2314 | 28 | #include "code/codeCache.hpp" |
stefank@2314 | 29 | #include "code/icBuffer.hpp" |
stefank@2314 | 30 | #include "code/nmethod.hpp" |
stefank@2314 | 31 | #include "code/pcDesc.hpp" |
stefank@2314 | 32 | #include "code/scopeDesc.hpp" |
stefank@2314 | 33 | #include "gc_interface/collectedHeap.hpp" |
stefank@2314 | 34 | #include "interpreter/interpreter.hpp" |
stefank@2314 | 35 | #include "memory/resourceArea.hpp" |
stefank@2314 | 36 | #include "memory/universe.inline.hpp" |
stefank@2314 | 37 | #include "oops/oop.inline.hpp" |
coleenp@2497 | 38 | #include "oops/symbol.hpp" |
stefank@2314 | 39 | #include "runtime/compilationPolicy.hpp" |
stefank@2314 | 40 | #include "runtime/deoptimization.hpp" |
stefank@2314 | 41 | #include "runtime/frame.inline.hpp" |
stefank@2314 | 42 | #include "runtime/interfaceSupport.hpp" |
stefank@2314 | 43 | #include "runtime/mutexLocker.hpp" |
stefank@2314 | 44 | #include "runtime/osThread.hpp" |
stefank@2314 | 45 | #include "runtime/safepoint.hpp" |
stefank@2314 | 46 | #include "runtime/signature.hpp" |
stefank@2314 | 47 | #include "runtime/stubCodeGenerator.hpp" |
stefank@2314 | 48 | #include "runtime/stubRoutines.hpp" |
stefank@2314 | 49 | #include "runtime/sweeper.hpp" |
stefank@2314 | 50 | #include "runtime/synchronizer.hpp" |
stefank@4299 | 51 | #include "runtime/thread.inline.hpp" |
zgu@3900 | 52 | #include "services/memTracker.hpp" |
stefank@2314 | 53 | #include "services/runtimeService.hpp" |
stefank@2314 | 54 | #include "utilities/events.hpp" |
jprovino@4542 | 55 | #include "utilities/macros.hpp" |
stefank@2314 | 56 | #ifdef TARGET_ARCH_x86 |
stefank@2314 | 57 | # include "nativeInst_x86.hpp" |
stefank@2314 | 58 | # include "vmreg_x86.inline.hpp" |
stefank@2314 | 59 | #endif |
stefank@2314 | 60 | #ifdef TARGET_ARCH_sparc |
stefank@2314 | 61 | # include "nativeInst_sparc.hpp" |
stefank@2314 | 62 | # include "vmreg_sparc.inline.hpp" |
stefank@2314 | 63 | #endif |
stefank@2314 | 64 | #ifdef TARGET_ARCH_zero |
stefank@2314 | 65 | # include "nativeInst_zero.hpp" |
stefank@2314 | 66 | # include "vmreg_zero.inline.hpp" |
stefank@2314 | 67 | #endif |
bobv@2508 | 68 | #ifdef TARGET_ARCH_arm |
bobv@2508 | 69 | # include "nativeInst_arm.hpp" |
bobv@2508 | 70 | # include "vmreg_arm.inline.hpp" |
bobv@2508 | 71 | #endif |
bobv@2508 | 72 | #ifdef TARGET_ARCH_ppc |
bobv@2508 | 73 | # include "nativeInst_ppc.hpp" |
bobv@2508 | 74 | # include "vmreg_ppc.inline.hpp" |
bobv@2508 | 75 | #endif |
jprovino@4542 | 76 | #if INCLUDE_ALL_GCS |
stefank@2314 | 77 | #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" |
stefank@2314 | 78 | #include "gc_implementation/shared/concurrentGCThread.hpp" |
jprovino@4542 | 79 | #endif // INCLUDE_ALL_GCS |
stefank@2314 | 80 | #ifdef COMPILER1 |
stefank@2314 | 81 | #include "c1/c1_globals.hpp" |
stefank@2314 | 82 | #endif |
duke@435 | 83 | |
duke@435 | 84 | // -------------------------------------------------------------------------------------------------- |
duke@435 | 85 | // Implementation of Safepoint begin/end |
duke@435 | 86 | |
duke@435 | 87 | SafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized; |
duke@435 | 88 | volatile int SafepointSynchronize::_waiting_to_block = 0; |
duke@435 | 89 | volatile int SafepointSynchronize::_safepoint_counter = 0; |
never@3494 | 90 | int SafepointSynchronize::_current_jni_active_count = 0; |
xlu@1726 | 91 | long SafepointSynchronize::_end_of_last_safepoint = 0; |
duke@435 | 92 | static volatile int PageArmed = 0 ; // safepoint polling page is RO|RW vs PROT_NONE |
duke@435 | 93 | static volatile int TryingToBlock = 0 ; // proximate value -- for advisory use only |
duke@435 | 94 | static bool timeout_error_printed = false; |
duke@435 | 95 | |
duke@435 | 96 | // Roll all threads forward to a safepoint and suspend them all |
duke@435 | 97 | void SafepointSynchronize::begin() { |
duke@435 | 98 | |
duke@435 | 99 | Thread* myThread = Thread::current(); |
duke@435 | 100 | assert(myThread->is_VM_thread(), "Only VM thread may execute a safepoint"); |
duke@435 | 101 | |
xlu@1726 | 102 | if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) { |
xlu@1726 | 103 | _safepoint_begin_time = os::javaTimeNanos(); |
xlu@1726 | 104 | _ts_of_current_safepoint = tty->time_stamp().seconds(); |
xlu@1726 | 105 | } |
duke@435 | 106 | |
jprovino@4542 | 107 | #if INCLUDE_ALL_GCS |
duke@435 | 108 | if (UseConcMarkSweepGC) { |
duke@435 | 109 | // In the future we should investigate whether CMS can use the |
duke@435 | 110 | // more-general mechanism below. DLD (01/05). |
duke@435 | 111 | ConcurrentMarkSweepThread::synchronize(false); |
ysr@1280 | 112 | } else if (UseG1GC) { |
duke@435 | 113 | ConcurrentGCThread::safepoint_synchronize(); |
duke@435 | 114 | } |
jprovino@4542 | 115 | #endif // INCLUDE_ALL_GCS |
duke@435 | 116 | |
duke@435 | 117 | // By getting the Threads_lock, we assure that no threads are about to start or |
duke@435 | 118 | // exit. It is released again in SafepointSynchronize::end(). |
duke@435 | 119 | Threads_lock->lock(); |
duke@435 | 120 | |
duke@435 | 121 | assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state"); |
duke@435 | 122 | |
duke@435 | 123 | int nof_threads = Threads::number_of_threads(); |
duke@435 | 124 | |
duke@435 | 125 | if (TraceSafepoint) { |
duke@435 | 126 | tty->print_cr("Safepoint synchronization initiated. (%d)", nof_threads); |
duke@435 | 127 | } |
duke@435 | 128 | |
duke@435 | 129 | RuntimeService::record_safepoint_begin(); |
duke@435 | 130 | |
duke@435 | 131 | MutexLocker mu(Safepoint_lock); |
duke@435 | 132 | |
never@3494 | 133 | // Reset the count of active JNI critical threads |
never@3494 | 134 | _current_jni_active_count = 0; |
never@3494 | 135 | |
duke@435 | 136 | // Set number of threads to wait for, before we initiate the callbacks |
duke@435 | 137 | _waiting_to_block = nof_threads; |
duke@435 | 138 | TryingToBlock = 0 ; |
duke@435 | 139 | int still_running = nof_threads; |
duke@435 | 140 | |
duke@435 | 141 | // Save the starting time, so that it can be compared to see if this has taken |
duke@435 | 142 | // too long to complete. |
duke@435 | 143 | jlong safepoint_limit_time; |
duke@435 | 144 | timeout_error_printed = false; |
duke@435 | 145 | |
xlu@1438 | 146 | // PrintSafepointStatisticsTimeout can be specified separately. When |
xlu@1438 | 147 | // specified, PrintSafepointStatistics will be set to true in |
xlu@1438 | 148 | // deferred_initialize_stat method. The initialization has to be done |
xlu@1438 | 149 | // early enough to avoid any races. See bug 6880029 for details. |
xlu@1438 | 150 | if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) { |
xlu@1438 | 151 | deferred_initialize_stat(); |
xlu@1438 | 152 | } |
xlu@1438 | 153 | |
duke@435 | 154 | // Begin the process of bringing the system to a safepoint. |
duke@435 | 155 | // Java threads can be in several different states and are |
duke@435 | 156 | // stopped by different mechanisms: |
duke@435 | 157 | // |
duke@435 | 158 | // 1. Running interpreted |
duke@435 | 159 | // The interpeter dispatch table is changed to force it to |
duke@435 | 160 | // check for a safepoint condition between bytecodes. |
duke@435 | 161 | // 2. Running in native code |
duke@435 | 162 | // When returning from the native code, a Java thread must check |
duke@435 | 163 | // the safepoint _state to see if we must block. If the |
duke@435 | 164 | // VM thread sees a Java thread in native, it does |
duke@435 | 165 | // not wait for this thread to block. The order of the memory |
duke@435 | 166 | // writes and reads of both the safepoint state and the Java |
duke@435 | 167 | // threads state is critical. In order to guarantee that the |
duke@435 | 168 | // memory writes are serialized with respect to each other, |
duke@435 | 169 | // the VM thread issues a memory barrier instruction |
duke@435 | 170 | // (on MP systems). In order to avoid the overhead of issuing |
duke@435 | 171 | // a memory barrier for each Java thread making native calls, each Java |
duke@435 | 172 | // thread performs a write to a single memory page after changing |
duke@435 | 173 | // the thread state. The VM thread performs a sequence of |
duke@435 | 174 | // mprotect OS calls which forces all previous writes from all |
duke@435 | 175 | // Java threads to be serialized. This is done in the |
duke@435 | 176 | // os::serialize_thread_states() call. This has proven to be |
duke@435 | 177 | // much more efficient than executing a membar instruction |
duke@435 | 178 | // on every call to native code. |
duke@435 | 179 | // 3. Running compiled Code |
duke@435 | 180 | // Compiled code reads a global (Safepoint Polling) page that |
duke@435 | 181 | // is set to fault if we are trying to get to a safepoint. |
duke@435 | 182 | // 4. Blocked |
duke@435 | 183 | // A thread which is blocked will not be allowed to return from the |
duke@435 | 184 | // block condition until the safepoint operation is complete. |
duke@435 | 185 | // 5. In VM or Transitioning between states |
duke@435 | 186 | // If a Java thread is currently running in the VM or transitioning |
duke@435 | 187 | // between states, the safepointing code will wait for the thread to |
duke@435 | 188 | // block itself when it attempts transitions to a new state. |
duke@435 | 189 | // |
duke@435 | 190 | _state = _synchronizing; |
duke@435 | 191 | OrderAccess::fence(); |
duke@435 | 192 | |
duke@435 | 193 | // Flush all thread states to memory |
duke@435 | 194 | if (!UseMembar) { |
duke@435 | 195 | os::serialize_thread_states(); |
duke@435 | 196 | } |
duke@435 | 197 | |
duke@435 | 198 | // Make interpreter safepoint aware |
duke@435 | 199 | Interpreter::notice_safepoints(); |
duke@435 | 200 | |
duke@435 | 201 | if (UseCompilerSafepoints && DeferPollingPageLoopCount < 0) { |
duke@435 | 202 | // Make polling safepoint aware |
duke@435 | 203 | guarantee (PageArmed == 0, "invariant") ; |
duke@435 | 204 | PageArmed = 1 ; |
duke@435 | 205 | os::make_polling_page_unreadable(); |
duke@435 | 206 | } |
duke@435 | 207 | |
duke@435 | 208 | // Consider using active_processor_count() ... but that call is expensive. |
duke@435 | 209 | int ncpus = os::processor_count() ; |
duke@435 | 210 | |
duke@435 | 211 | #ifdef ASSERT |
duke@435 | 212 | for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { |
duke@435 | 213 | assert(cur->safepoint_state()->is_running(), "Illegal initial state"); |
never@3632 | 214 | // Clear the visited flag to ensure that the critical counts are collected properly. |
never@3632 | 215 | cur->set_visited_for_critical_count(false); |
duke@435 | 216 | } |
duke@435 | 217 | #endif // ASSERT |
duke@435 | 218 | |
duke@435 | 219 | if (SafepointTimeout) |
duke@435 | 220 | safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS; |
duke@435 | 221 | |
duke@435 | 222 | // Iterate through all threads until it have been determined how to stop them all at a safepoint |
duke@435 | 223 | unsigned int iterations = 0; |
duke@435 | 224 | int steps = 0 ; |
duke@435 | 225 | while(still_running > 0) { |
duke@435 | 226 | for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { |
duke@435 | 227 | assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended"); |
duke@435 | 228 | ThreadSafepointState *cur_state = cur->safepoint_state(); |
duke@435 | 229 | if (cur_state->is_running()) { |
duke@435 | 230 | cur_state->examine_state_of_thread(); |
duke@435 | 231 | if (!cur_state->is_running()) { |
duke@435 | 232 | still_running--; |
duke@435 | 233 | // consider adjusting steps downward: |
duke@435 | 234 | // steps = 0 |
duke@435 | 235 | // steps -= NNN |
duke@435 | 236 | // steps >>= 1 |
duke@435 | 237 | // steps = MIN(steps, 2000-100) |
duke@435 | 238 | // if (iterations != 0) steps -= NNN |
duke@435 | 239 | } |
duke@435 | 240 | if (TraceSafepoint && Verbose) cur_state->print(); |
duke@435 | 241 | } |
duke@435 | 242 | } |
duke@435 | 243 | |
xlu@1438 | 244 | if (PrintSafepointStatistics && iterations == 0) { |
duke@435 | 245 | begin_statistics(nof_threads, still_running); |
duke@435 | 246 | } |
duke@435 | 247 | |
duke@435 | 248 | if (still_running > 0) { |
duke@435 | 249 | // Check for if it takes to long |
duke@435 | 250 | if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) { |
duke@435 | 251 | print_safepoint_timeout(_spinning_timeout); |
duke@435 | 252 | } |
duke@435 | 253 | |
duke@435 | 254 | // Spin to avoid context switching. |
duke@435 | 255 | // There's a tension between allowing the mutators to run (and rendezvous) |
duke@435 | 256 | // vs spinning. As the VM thread spins, wasting cycles, it consumes CPU that |
duke@435 | 257 | // a mutator might otherwise use profitably to reach a safepoint. Excessive |
duke@435 | 258 | // spinning by the VM thread on a saturated system can increase rendezvous latency. |
duke@435 | 259 | // Blocking or yielding incur their own penalties in the form of context switching |
duke@435 | 260 | // and the resultant loss of $ residency. |
duke@435 | 261 | // |
duke@435 | 262 | // Further complicating matters is that yield() does not work as naively expected |
duke@435 | 263 | // on many platforms -- yield() does not guarantee that any other ready threads |
duke@435 | 264 | // will run. As such we revert yield_all() after some number of iterations. |
duke@435 | 265 | // Yield_all() is implemented as a short unconditional sleep on some platforms. |
duke@435 | 266 | // Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping |
duke@435 | 267 | // can actually increase the time it takes the VM thread to detect that a system-wide |
duke@435 | 268 | // stop-the-world safepoint has been reached. In a pathological scenario such as that |
duke@435 | 269 | // described in CR6415670 the VMthread may sleep just before the mutator(s) become safe. |
duke@435 | 270 | // In that case the mutators will be stalled waiting for the safepoint to complete and the |
duke@435 | 271 | // the VMthread will be sleeping, waiting for the mutators to rendezvous. The VMthread |
duke@435 | 272 | // will eventually wake up and detect that all mutators are safe, at which point |
duke@435 | 273 | // we'll again make progress. |
duke@435 | 274 | // |
duke@435 | 275 | // Beware too that that the VMThread typically runs at elevated priority. |
duke@435 | 276 | // Its default priority is higher than the default mutator priority. |
duke@435 | 277 | // Obviously, this complicates spinning. |
duke@435 | 278 | // |
duke@435 | 279 | // Note too that on Windows XP SwitchThreadTo() has quite different behavior than Sleep(0). |
duke@435 | 280 | // Sleep(0) will _not yield to lower priority threads, while SwitchThreadTo() will. |
duke@435 | 281 | // |
duke@435 | 282 | // See the comments in synchronizer.cpp for additional remarks on spinning. |
duke@435 | 283 | // |
duke@435 | 284 | // In the future we might: |
duke@435 | 285 | // 1. Modify the safepoint scheme to avoid potentally unbounded spinning. |
duke@435 | 286 | // This is tricky as the path used by a thread exiting the JVM (say on |
duke@435 | 287 | // on JNI call-out) simply stores into its state field. The burden |
duke@435 | 288 | // is placed on the VM thread, which must poll (spin). |
duke@435 | 289 | // 2. Find something useful to do while spinning. If the safepoint is GC-related |
duke@435 | 290 | // we might aggressively scan the stacks of threads that are already safe. |
duke@435 | 291 | // 3. Use Solaris schedctl to examine the state of the still-running mutators. |
duke@435 | 292 | // If all the mutators are ONPROC there's no reason to sleep or yield. |
duke@435 | 293 | // 4. YieldTo() any still-running mutators that are ready but OFFPROC. |
duke@435 | 294 | // 5. Check system saturation. If the system is not fully saturated then |
duke@435 | 295 | // simply spin and avoid sleep/yield. |
duke@435 | 296 | // 6. As still-running mutators rendezvous they could unpark the sleeping |
duke@435 | 297 | // VMthread. This works well for still-running mutators that become |
duke@435 | 298 | // safe. The VMthread must still poll for mutators that call-out. |
duke@435 | 299 | // 7. Drive the policy on time-since-begin instead of iterations. |
duke@435 | 300 | // 8. Consider making the spin duration a function of the # of CPUs: |
duke@435 | 301 | // Spin = (((ncpus-1) * M) + K) + F(still_running) |
duke@435 | 302 | // Alternately, instead of counting iterations of the outer loop |
duke@435 | 303 | // we could count the # of threads visited in the inner loop, above. |
duke@435 | 304 | // 9. On windows consider using the return value from SwitchThreadTo() |
duke@435 | 305 | // to drive subsequent spin/SwitchThreadTo()/Sleep(N) decisions. |
duke@435 | 306 | |
duke@435 | 307 | if (UseCompilerSafepoints && int(iterations) == DeferPollingPageLoopCount) { |
duke@435 | 308 | guarantee (PageArmed == 0, "invariant") ; |
duke@435 | 309 | PageArmed = 1 ; |
duke@435 | 310 | os::make_polling_page_unreadable(); |
duke@435 | 311 | } |
duke@435 | 312 | |
duke@435 | 313 | // Instead of (ncpus > 1) consider either (still_running < (ncpus + EPSILON)) or |
duke@435 | 314 | // ((still_running + _waiting_to_block - TryingToBlock)) < ncpus) |
duke@435 | 315 | ++steps ; |
duke@435 | 316 | if (ncpus > 1 && steps < SafepointSpinBeforeYield) { |
duke@435 | 317 | SpinPause() ; // MP-Polite spin |
duke@435 | 318 | } else |
duke@435 | 319 | if (steps < DeferThrSuspendLoopCount) { |
duke@435 | 320 | os::NakedYield() ; |
duke@435 | 321 | } else { |
duke@435 | 322 | os::yield_all(steps) ; |
duke@435 | 323 | // Alternately, the VM thread could transiently depress its scheduling priority or |
duke@435 | 324 | // transiently increase the priority of the tardy mutator(s). |
duke@435 | 325 | } |
duke@435 | 326 | |
duke@435 | 327 | iterations ++ ; |
duke@435 | 328 | } |
duke@435 | 329 | assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long"); |
duke@435 | 330 | } |
duke@435 | 331 | assert(still_running == 0, "sanity check"); |
duke@435 | 332 | |
duke@435 | 333 | if (PrintSafepointStatistics) { |
duke@435 | 334 | update_statistics_on_spin_end(); |
duke@435 | 335 | } |
duke@435 | 336 | |
duke@435 | 337 | // wait until all threads are stopped |
duke@435 | 338 | while (_waiting_to_block > 0) { |
duke@435 | 339 | if (TraceSafepoint) tty->print_cr("Waiting for %d thread(s) to block", _waiting_to_block); |
duke@435 | 340 | if (!SafepointTimeout || timeout_error_printed) { |
duke@435 | 341 | Safepoint_lock->wait(true); // true, means with no safepoint checks |
duke@435 | 342 | } else { |
duke@435 | 343 | // Compute remaining time |
duke@435 | 344 | jlong remaining_time = safepoint_limit_time - os::javaTimeNanos(); |
duke@435 | 345 | |
duke@435 | 346 | // If there is no remaining time, then there is an error |
duke@435 | 347 | if (remaining_time < 0 || Safepoint_lock->wait(true, remaining_time / MICROUNITS)) { |
duke@435 | 348 | print_safepoint_timeout(_blocking_timeout); |
duke@435 | 349 | } |
duke@435 | 350 | } |
duke@435 | 351 | } |
duke@435 | 352 | assert(_waiting_to_block == 0, "sanity check"); |
duke@435 | 353 | |
duke@435 | 354 | #ifndef PRODUCT |
duke@435 | 355 | if (SafepointTimeout) { |
duke@435 | 356 | jlong current_time = os::javaTimeNanos(); |
duke@435 | 357 | if (safepoint_limit_time < current_time) { |
duke@435 | 358 | tty->print_cr("# SafepointSynchronize: Finished after " |
duke@435 | 359 | INT64_FORMAT_W(6) " ms", |
duke@435 | 360 | ((current_time - safepoint_limit_time) / MICROUNITS + |
duke@435 | 361 | SafepointTimeoutDelay)); |
duke@435 | 362 | } |
duke@435 | 363 | } |
duke@435 | 364 | #endif |
duke@435 | 365 | |
duke@435 | 366 | assert((_safepoint_counter & 0x1) == 0, "must be even"); |
duke@435 | 367 | assert(Threads_lock->owned_by_self(), "must hold Threads_lock"); |
duke@435 | 368 | _safepoint_counter ++; |
duke@435 | 369 | |
duke@435 | 370 | // Record state |
duke@435 | 371 | _state = _synchronized; |
duke@435 | 372 | |
duke@435 | 373 | OrderAccess::fence(); |
duke@435 | 374 | |
never@3632 | 375 | #ifdef ASSERT |
never@3632 | 376 | for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { |
never@3632 | 377 | // make sure all the threads were visited |
never@3632 | 378 | assert(cur->was_visited_for_critical_count(), "missed a thread"); |
never@3632 | 379 | } |
never@3632 | 380 | #endif // ASSERT |
never@3632 | 381 | |
never@3494 | 382 | // Update the count of active JNI critical regions |
never@3494 | 383 | GC_locker::set_jni_lock_count(_current_jni_active_count); |
never@3494 | 384 | |
duke@435 | 385 | if (TraceSafepoint) { |
duke@435 | 386 | VM_Operation *op = VMThread::vm_operation(); |
duke@435 | 387 | tty->print_cr("Entering safepoint region: %s", (op != NULL) ? op->name() : "no vm operation"); |
duke@435 | 388 | } |
duke@435 | 389 | |
duke@435 | 390 | RuntimeService::record_safepoint_synchronized(); |
duke@435 | 391 | if (PrintSafepointStatistics) { |
duke@435 | 392 | update_statistics_on_sync_end(os::javaTimeNanos()); |
duke@435 | 393 | } |
duke@435 | 394 | |
duke@435 | 395 | // Call stuff that needs to be run when a safepoint is just about to be completed |
duke@435 | 396 | do_cleanup_tasks(); |
xlu@1726 | 397 | |
xlu@1726 | 398 | if (PrintSafepointStatistics) { |
xlu@1726 | 399 | // Record how much time spend on the above cleanup tasks |
xlu@1726 | 400 | update_statistics_on_cleanup_end(os::javaTimeNanos()); |
xlu@1726 | 401 | } |
duke@435 | 402 | } |
duke@435 | 403 | |
duke@435 | 404 | // Wake up all threads, so they are ready to resume execution after the safepoint |
duke@435 | 405 | // operation has been carried out |
duke@435 | 406 | void SafepointSynchronize::end() { |
duke@435 | 407 | |
duke@435 | 408 | assert(Threads_lock->owned_by_self(), "must hold Threads_lock"); |
duke@435 | 409 | assert((_safepoint_counter & 0x1) == 1, "must be odd"); |
duke@435 | 410 | _safepoint_counter ++; |
duke@435 | 411 | // memory fence isn't required here since an odd _safepoint_counter |
duke@435 | 412 | // value can do no harm and a fence is issued below anyway. |
duke@435 | 413 | |
duke@435 | 414 | DEBUG_ONLY(Thread* myThread = Thread::current();) |
duke@435 | 415 | assert(myThread->is_VM_thread(), "Only VM thread can execute a safepoint"); |
duke@435 | 416 | |
duke@435 | 417 | if (PrintSafepointStatistics) { |
duke@435 | 418 | end_statistics(os::javaTimeNanos()); |
duke@435 | 419 | } |
duke@435 | 420 | |
duke@435 | 421 | #ifdef ASSERT |
duke@435 | 422 | // A pending_exception cannot be installed during a safepoint. The threads |
duke@435 | 423 | // may install an async exception after they come back from a safepoint into |
duke@435 | 424 | // pending_exception after they unblock. But that should happen later. |
duke@435 | 425 | for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) { |
duke@435 | 426 | assert (!(cur->has_pending_exception() && |
duke@435 | 427 | cur->safepoint_state()->is_at_poll_safepoint()), |
duke@435 | 428 | "safepoint installed a pending exception"); |
duke@435 | 429 | } |
duke@435 | 430 | #endif // ASSERT |
duke@435 | 431 | |
duke@435 | 432 | if (PageArmed) { |
duke@435 | 433 | // Make polling safepoint aware |
duke@435 | 434 | os::make_polling_page_readable(); |
duke@435 | 435 | PageArmed = 0 ; |
duke@435 | 436 | } |
duke@435 | 437 | |
duke@435 | 438 | // Remove safepoint check from interpreter |
duke@435 | 439 | Interpreter::ignore_safepoints(); |
duke@435 | 440 | |
duke@435 | 441 | { |
duke@435 | 442 | MutexLocker mu(Safepoint_lock); |
duke@435 | 443 | |
duke@435 | 444 | assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization"); |
duke@435 | 445 | |
duke@435 | 446 | // Set to not synchronized, so the threads will not go into the signal_thread_blocked method |
duke@435 | 447 | // when they get restarted. |
duke@435 | 448 | _state = _not_synchronized; |
duke@435 | 449 | OrderAccess::fence(); |
duke@435 | 450 | |
duke@435 | 451 | if (TraceSafepoint) { |
duke@435 | 452 | tty->print_cr("Leaving safepoint region"); |
duke@435 | 453 | } |
duke@435 | 454 | |
duke@435 | 455 | // Start suspended threads |
duke@435 | 456 | for(JavaThread *current = Threads::first(); current; current = current->next()) { |
twisti@1040 | 457 | // A problem occurring on Solaris is when attempting to restart threads |
duke@435 | 458 | // the first #cpus - 1 go well, but then the VMThread is preempted when we get |
duke@435 | 459 | // to the next one (since it has been running the longest). We then have |
duke@435 | 460 | // to wait for a cpu to become available before we can continue restarting |
duke@435 | 461 | // threads. |
duke@435 | 462 | // FIXME: This causes the performance of the VM to degrade when active and with |
duke@435 | 463 | // large numbers of threads. Apparently this is due to the synchronous nature |
duke@435 | 464 | // of suspending threads. |
duke@435 | 465 | // |
duke@435 | 466 | // TODO-FIXME: the comments above are vestigial and no longer apply. |
duke@435 | 467 | // Furthermore, using solaris' schedctl in this particular context confers no benefit |
duke@435 | 468 | if (VMThreadHintNoPreempt) { |
duke@435 | 469 | os::hint_no_preempt(); |
duke@435 | 470 | } |
duke@435 | 471 | ThreadSafepointState* cur_state = current->safepoint_state(); |
duke@435 | 472 | assert(cur_state->type() != ThreadSafepointState::_running, "Thread not suspended at safepoint"); |
duke@435 | 473 | cur_state->restart(); |
duke@435 | 474 | assert(cur_state->is_running(), "safepoint state has not been reset"); |
duke@435 | 475 | } |
duke@435 | 476 | |
duke@435 | 477 | RuntimeService::record_safepoint_end(); |
duke@435 | 478 | |
duke@435 | 479 | // Release threads lock, so threads can be created/destroyed again. It will also starts all threads |
duke@435 | 480 | // blocked in signal_thread_blocked |
duke@435 | 481 | Threads_lock->unlock(); |
duke@435 | 482 | |
duke@435 | 483 | } |
jprovino@4542 | 484 | #if INCLUDE_ALL_GCS |
duke@435 | 485 | // If there are any concurrent GC threads resume them. |
duke@435 | 486 | if (UseConcMarkSweepGC) { |
duke@435 | 487 | ConcurrentMarkSweepThread::desynchronize(false); |
ysr@1280 | 488 | } else if (UseG1GC) { |
duke@435 | 489 | ConcurrentGCThread::safepoint_desynchronize(); |
duke@435 | 490 | } |
jprovino@4542 | 491 | #endif // INCLUDE_ALL_GCS |
xlu@1726 | 492 | // record this time so VMThread can keep track how much time has elasped |
xlu@1726 | 493 | // since last safepoint. |
xlu@1726 | 494 | _end_of_last_safepoint = os::javaTimeMillis(); |
duke@435 | 495 | } |
duke@435 | 496 | |
duke@435 | 497 | bool SafepointSynchronize::is_cleanup_needed() { |
duke@435 | 498 | // Need a safepoint if some inline cache buffers is non-empty |
duke@435 | 499 | if (!InlineCacheBuffer::is_empty()) return true; |
duke@435 | 500 | return false; |
duke@435 | 501 | } |
duke@435 | 502 | |
duke@435 | 503 | |
duke@435 | 504 | |
duke@435 | 505 | // Various cleaning tasks that should be done periodically at safepoints |
duke@435 | 506 | void SafepointSynchronize::do_cleanup_tasks() { |
xlu@1726 | 507 | { |
xlu@1756 | 508 | TraceTime t1("deflating idle monitors", TraceSafepointCleanupTime); |
xlu@1726 | 509 | ObjectSynchronizer::deflate_idle_monitors(); |
duke@435 | 510 | } |
duke@435 | 511 | |
xlu@1726 | 512 | { |
xlu@1756 | 513 | TraceTime t2("updating inline caches", TraceSafepointCleanupTime); |
xlu@1726 | 514 | InlineCacheBuffer::update_inline_caches(); |
xlu@1726 | 515 | } |
iveresov@2138 | 516 | { |
iveresov@2138 | 517 | TraceTime t3("compilation policy safepoint handler", TraceSafepointCleanupTime); |
iveresov@2138 | 518 | CompilationPolicy::policy()->do_safepoint_work(); |
duke@435 | 519 | } |
xlu@1726 | 520 | |
coleenp@3865 | 521 | { |
coleenp@3865 | 522 | TraceTime t4("sweeping nmethods", TraceSafepointCleanupTime); |
coleenp@3865 | 523 | NMethodSweeper::scan_stacks(); |
coleenp@3865 | 524 | } |
coleenp@3865 | 525 | |
coleenp@3865 | 526 | if (SymbolTable::needs_rehashing()) { |
coleenp@3865 | 527 | TraceTime t5("rehashing symbol table", TraceSafepointCleanupTime); |
coleenp@3865 | 528 | SymbolTable::rehash_table(); |
coleenp@3865 | 529 | } |
coleenp@3865 | 530 | |
coleenp@3865 | 531 | if (StringTable::needs_rehashing()) { |
coleenp@3865 | 532 | TraceTime t6("rehashing string table", TraceSafepointCleanupTime); |
coleenp@3865 | 533 | StringTable::rehash_table(); |
coleenp@3865 | 534 | } |
minqi@2964 | 535 | |
minqi@2964 | 536 | // rotate log files? |
minqi@2964 | 537 | if (UseGCLogFileRotation) { |
minqi@2964 | 538 | gclog_or_tty->rotate_log(); |
minqi@2964 | 539 | } |
zgu@3900 | 540 | |
zgu@3900 | 541 | if (MemTracker::is_on()) { |
zgu@3900 | 542 | MemTracker::sync(); |
zgu@3900 | 543 | } |
duke@435 | 544 | } |
duke@435 | 545 | |
duke@435 | 546 | |
duke@435 | 547 | bool SafepointSynchronize::safepoint_safe(JavaThread *thread, JavaThreadState state) { |
duke@435 | 548 | switch(state) { |
duke@435 | 549 | case _thread_in_native: |
duke@435 | 550 | // native threads are safe if they have no java stack or have walkable stack |
duke@435 | 551 | return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable(); |
duke@435 | 552 | |
duke@435 | 553 | // blocked threads should have already have walkable stack |
duke@435 | 554 | case _thread_blocked: |
duke@435 | 555 | assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable"); |
duke@435 | 556 | return true; |
duke@435 | 557 | |
duke@435 | 558 | default: |
duke@435 | 559 | return false; |
duke@435 | 560 | } |
duke@435 | 561 | } |
duke@435 | 562 | |
duke@435 | 563 | |
never@3500 | 564 | // See if the thread is running inside a lazy critical native and |
never@3500 | 565 | // update the thread critical count if so. Also set a suspend flag to |
never@3500 | 566 | // cause the native wrapper to return into the JVM to do the unlock |
never@3500 | 567 | // once the native finishes. |
never@3500 | 568 | void SafepointSynchronize::check_for_lazy_critical_native(JavaThread *thread, JavaThreadState state) { |
never@3500 | 569 | if (state == _thread_in_native && |
never@3500 | 570 | thread->has_last_Java_frame() && |
never@3500 | 571 | thread->frame_anchor()->walkable()) { |
never@3500 | 572 | // This thread might be in a critical native nmethod so look at |
never@3500 | 573 | // the top of the stack and increment the critical count if it |
never@3500 | 574 | // is. |
never@3500 | 575 | frame wrapper_frame = thread->last_frame(); |
never@3500 | 576 | CodeBlob* stub_cb = wrapper_frame.cb(); |
never@3500 | 577 | if (stub_cb != NULL && |
never@3500 | 578 | stub_cb->is_nmethod() && |
never@3500 | 579 | stub_cb->as_nmethod_or_null()->is_lazy_critical_native()) { |
never@3500 | 580 | // A thread could potentially be in a critical native across |
never@3500 | 581 | // more than one safepoint, so only update the critical state on |
never@3500 | 582 | // the first one. When it returns it will perform the unlock. |
never@3500 | 583 | if (!thread->do_critical_native_unlock()) { |
never@3500 | 584 | #ifdef ASSERT |
never@3500 | 585 | if (!thread->in_critical()) { |
never@3500 | 586 | GC_locker::increment_debug_jni_lock_count(); |
never@3500 | 587 | } |
never@3500 | 588 | #endif |
never@3500 | 589 | thread->enter_critical(); |
never@3500 | 590 | // Make sure the native wrapper calls back on return to |
never@3500 | 591 | // perform the needed critical unlock. |
never@3500 | 592 | thread->set_critical_native_unlock(); |
never@3500 | 593 | } |
never@3500 | 594 | } |
never@3500 | 595 | } |
never@3500 | 596 | } |
never@3500 | 597 | |
never@3500 | 598 | |
never@3500 | 599 | |
duke@435 | 600 | // ------------------------------------------------------------------------------------------------------- |
duke@435 | 601 | // Implementation of Safepoint callback point |
duke@435 | 602 | |
duke@435 | 603 | void SafepointSynchronize::block(JavaThread *thread) { |
duke@435 | 604 | assert(thread != NULL, "thread must be set"); |
duke@435 | 605 | assert(thread->is_Java_thread(), "not a Java thread"); |
duke@435 | 606 | |
duke@435 | 607 | // Threads shouldn't block if they are in the middle of printing, but... |
duke@435 | 608 | ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id()); |
duke@435 | 609 | |
duke@435 | 610 | // Only bail from the block() call if the thread is gone from the |
duke@435 | 611 | // thread list; starting to exit should still block. |
duke@435 | 612 | if (thread->is_terminated()) { |
duke@435 | 613 | // block current thread if we come here from native code when VM is gone |
duke@435 | 614 | thread->block_if_vm_exited(); |
duke@435 | 615 | |
duke@435 | 616 | // otherwise do nothing |
duke@435 | 617 | return; |
duke@435 | 618 | } |
duke@435 | 619 | |
duke@435 | 620 | JavaThreadState state = thread->thread_state(); |
duke@435 | 621 | thread->frame_anchor()->make_walkable(thread); |
duke@435 | 622 | |
duke@435 | 623 | // Check that we have a valid thread_state at this point |
duke@435 | 624 | switch(state) { |
duke@435 | 625 | case _thread_in_vm_trans: |
duke@435 | 626 | case _thread_in_Java: // From compiled code |
duke@435 | 627 | |
duke@435 | 628 | // We are highly likely to block on the Safepoint_lock. In order to avoid blocking in this case, |
duke@435 | 629 | // we pretend we are still in the VM. |
duke@435 | 630 | thread->set_thread_state(_thread_in_vm); |
duke@435 | 631 | |
duke@435 | 632 | if (is_synchronizing()) { |
duke@435 | 633 | Atomic::inc (&TryingToBlock) ; |
duke@435 | 634 | } |
duke@435 | 635 | |
duke@435 | 636 | // We will always be holding the Safepoint_lock when we are examine the state |
duke@435 | 637 | // of a thread. Hence, the instructions between the Safepoint_lock->lock() and |
duke@435 | 638 | // Safepoint_lock->unlock() are happening atomic with regards to the safepoint code |
duke@435 | 639 | Safepoint_lock->lock_without_safepoint_check(); |
duke@435 | 640 | if (is_synchronizing()) { |
duke@435 | 641 | // Decrement the number of threads to wait for and signal vm thread |
duke@435 | 642 | assert(_waiting_to_block > 0, "sanity check"); |
duke@435 | 643 | _waiting_to_block--; |
duke@435 | 644 | thread->safepoint_state()->set_has_called_back(true); |
duke@435 | 645 | |
never@3632 | 646 | DEBUG_ONLY(thread->set_visited_for_critical_count(true)); |
never@3494 | 647 | if (thread->in_critical()) { |
never@3494 | 648 | // Notice that this thread is in a critical section |
never@3494 | 649 | increment_jni_active_count(); |
never@3494 | 650 | } |
never@3494 | 651 | |
duke@435 | 652 | // Consider (_waiting_to_block < 2) to pipeline the wakeup of the VM thread |
duke@435 | 653 | if (_waiting_to_block == 0) { |
duke@435 | 654 | Safepoint_lock->notify_all(); |
duke@435 | 655 | } |
duke@435 | 656 | } |
duke@435 | 657 | |
duke@435 | 658 | // We transition the thread to state _thread_blocked here, but |
duke@435 | 659 | // we can't do our usual check for external suspension and then |
duke@435 | 660 | // self-suspend after the lock_without_safepoint_check() call |
duke@435 | 661 | // below because we are often called during transitions while |
duke@435 | 662 | // we hold different locks. That would leave us suspended while |
duke@435 | 663 | // holding a resource which results in deadlocks. |
duke@435 | 664 | thread->set_thread_state(_thread_blocked); |
duke@435 | 665 | Safepoint_lock->unlock(); |
duke@435 | 666 | |
duke@435 | 667 | // We now try to acquire the threads lock. Since this lock is hold by the VM thread during |
duke@435 | 668 | // the entire safepoint, the threads will all line up here during the safepoint. |
duke@435 | 669 | Threads_lock->lock_without_safepoint_check(); |
duke@435 | 670 | // restore original state. This is important if the thread comes from compiled code, so it |
duke@435 | 671 | // will continue to execute with the _thread_in_Java state. |
duke@435 | 672 | thread->set_thread_state(state); |
duke@435 | 673 | Threads_lock->unlock(); |
duke@435 | 674 | break; |
duke@435 | 675 | |
duke@435 | 676 | case _thread_in_native_trans: |
duke@435 | 677 | case _thread_blocked_trans: |
duke@435 | 678 | case _thread_new_trans: |
duke@435 | 679 | if (thread->safepoint_state()->type() == ThreadSafepointState::_call_back) { |
duke@435 | 680 | thread->print_thread_state(); |
duke@435 | 681 | fatal("Deadlock in safepoint code. " |
duke@435 | 682 | "Should have called back to the VM before blocking."); |
duke@435 | 683 | } |
duke@435 | 684 | |
duke@435 | 685 | // We transition the thread to state _thread_blocked here, but |
duke@435 | 686 | // we can't do our usual check for external suspension and then |
duke@435 | 687 | // self-suspend after the lock_without_safepoint_check() call |
duke@435 | 688 | // below because we are often called during transitions while |
duke@435 | 689 | // we hold different locks. That would leave us suspended while |
duke@435 | 690 | // holding a resource which results in deadlocks. |
duke@435 | 691 | thread->set_thread_state(_thread_blocked); |
duke@435 | 692 | |
duke@435 | 693 | // It is not safe to suspend a thread if we discover it is in _thread_in_native_trans. Hence, |
duke@435 | 694 | // the safepoint code might still be waiting for it to block. We need to change the state here, |
duke@435 | 695 | // so it can see that it is at a safepoint. |
duke@435 | 696 | |
duke@435 | 697 | // Block until the safepoint operation is completed. |
duke@435 | 698 | Threads_lock->lock_without_safepoint_check(); |
duke@435 | 699 | |
duke@435 | 700 | // Restore state |
duke@435 | 701 | thread->set_thread_state(state); |
duke@435 | 702 | |
duke@435 | 703 | Threads_lock->unlock(); |
duke@435 | 704 | break; |
duke@435 | 705 | |
duke@435 | 706 | default: |
jcoomes@1845 | 707 | fatal(err_msg("Illegal threadstate encountered: %d", state)); |
duke@435 | 708 | } |
duke@435 | 709 | |
duke@435 | 710 | // Check for pending. async. exceptions or suspends - except if the |
duke@435 | 711 | // thread was blocked inside the VM. has_special_runtime_exit_condition() |
duke@435 | 712 | // is called last since it grabs a lock and we only want to do that when |
duke@435 | 713 | // we must. |
duke@435 | 714 | // |
duke@435 | 715 | // Note: we never deliver an async exception at a polling point as the |
duke@435 | 716 | // compiler may not have an exception handler for it. The polling |
duke@435 | 717 | // code will notice the async and deoptimize and the exception will |
duke@435 | 718 | // be delivered. (Polling at a return point is ok though). Sure is |
duke@435 | 719 | // a lot of bother for a deprecated feature... |
duke@435 | 720 | // |
duke@435 | 721 | // We don't deliver an async exception if the thread state is |
duke@435 | 722 | // _thread_in_native_trans so JNI functions won't be called with |
duke@435 | 723 | // a surprising pending exception. If the thread state is going back to java, |
duke@435 | 724 | // async exception is checked in check_special_condition_for_native_trans(). |
duke@435 | 725 | |
duke@435 | 726 | if (state != _thread_blocked_trans && |
duke@435 | 727 | state != _thread_in_vm_trans && |
duke@435 | 728 | thread->has_special_runtime_exit_condition()) { |
duke@435 | 729 | thread->handle_special_runtime_exit_condition( |
duke@435 | 730 | !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans)); |
duke@435 | 731 | } |
duke@435 | 732 | } |
duke@435 | 733 | |
duke@435 | 734 | // ------------------------------------------------------------------------------------------------------ |
duke@435 | 735 | // Exception handlers |
duke@435 | 736 | |
duke@435 | 737 | #ifndef PRODUCT |
duke@435 | 738 | #ifdef _LP64 |
duke@435 | 739 | #define PTR_PAD "" |
duke@435 | 740 | #else |
duke@435 | 741 | #define PTR_PAD " " |
duke@435 | 742 | #endif |
duke@435 | 743 | |
duke@435 | 744 | static void print_ptrs(intptr_t oldptr, intptr_t newptr, bool wasoop) { |
duke@435 | 745 | bool is_oop = newptr ? ((oop)newptr)->is_oop() : false; |
duke@435 | 746 | tty->print_cr(PTR_FORMAT PTR_PAD " %s %c " PTR_FORMAT PTR_PAD " %s %s", |
duke@435 | 747 | oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!', |
duke@435 | 748 | newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" ")); |
duke@435 | 749 | } |
duke@435 | 750 | |
duke@435 | 751 | static void print_longs(jlong oldptr, jlong newptr, bool wasoop) { |
duke@435 | 752 | bool is_oop = newptr ? ((oop)(intptr_t)newptr)->is_oop() : false; |
duke@435 | 753 | tty->print_cr(PTR64_FORMAT " %s %c " PTR64_FORMAT " %s %s", |
duke@435 | 754 | oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!', |
duke@435 | 755 | newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" ")); |
duke@435 | 756 | } |
duke@435 | 757 | |
duke@435 | 758 | #ifdef SPARC |
duke@435 | 759 | static void print_me(intptr_t *new_sp, intptr_t *old_sp, bool *was_oops) { |
duke@435 | 760 | #ifdef _LP64 |
duke@435 | 761 | tty->print_cr("--------+------address-----+------before-----------+-------after----------+"); |
duke@435 | 762 | const int incr = 1; // Increment to skip a long, in units of intptr_t |
duke@435 | 763 | #else |
duke@435 | 764 | tty->print_cr("--------+--address-+------before-----------+-------after----------+"); |
duke@435 | 765 | const int incr = 2; // Increment to skip a long, in units of intptr_t |
duke@435 | 766 | #endif |
duke@435 | 767 | tty->print_cr("---SP---|"); |
duke@435 | 768 | for( int i=0; i<16; i++ ) { |
duke@435 | 769 | tty->print("blob %c%d |"PTR_FORMAT" ","LO"[i>>3],i&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } |
duke@435 | 770 | tty->print_cr("--------|"); |
duke@435 | 771 | for( int i1=0; i1<frame::memory_parameter_word_sp_offset-16; i1++ ) { |
duke@435 | 772 | tty->print("argv pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } |
duke@435 | 773 | tty->print(" pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); |
duke@435 | 774 | tty->print_cr("--------|"); |
duke@435 | 775 | tty->print(" G1 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; |
duke@435 | 776 | tty->print(" G3 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; |
duke@435 | 777 | tty->print(" G4 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; |
duke@435 | 778 | tty->print(" G5 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; |
duke@435 | 779 | tty->print_cr(" FSR |"PTR_FORMAT" "PTR64_FORMAT" "PTR64_FORMAT,new_sp,*(jlong*)old_sp,*(jlong*)new_sp); |
duke@435 | 780 | old_sp += incr; new_sp += incr; was_oops += incr; |
duke@435 | 781 | // Skip the floats |
duke@435 | 782 | tty->print_cr("--Float-|"PTR_FORMAT,new_sp); |
duke@435 | 783 | tty->print_cr("---FP---|"); |
duke@435 | 784 | old_sp += incr*32; new_sp += incr*32; was_oops += incr*32; |
duke@435 | 785 | for( int i2=0; i2<16; i2++ ) { |
duke@435 | 786 | tty->print("call %c%d |"PTR_FORMAT" ","LI"[i2>>3],i2&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } |
duke@435 | 787 | tty->print_cr(""); |
duke@435 | 788 | } |
duke@435 | 789 | #endif // SPARC |
duke@435 | 790 | #endif // PRODUCT |
duke@435 | 791 | |
duke@435 | 792 | |
duke@435 | 793 | void SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) { |
duke@435 | 794 | assert(thread->is_Java_thread(), "polling reference encountered by VM thread"); |
duke@435 | 795 | assert(thread->thread_state() == _thread_in_Java, "should come from Java code"); |
duke@435 | 796 | assert(SafepointSynchronize::is_synchronizing(), "polling encountered outside safepoint synchronization"); |
duke@435 | 797 | |
duke@435 | 798 | // Uncomment this to get some serious before/after printing of the |
duke@435 | 799 | // Sparc safepoint-blob frame structure. |
duke@435 | 800 | /* |
duke@435 | 801 | intptr_t* sp = thread->last_Java_sp(); |
duke@435 | 802 | intptr_t stack_copy[150]; |
duke@435 | 803 | for( int i=0; i<150; i++ ) stack_copy[i] = sp[i]; |
duke@435 | 804 | bool was_oops[150]; |
duke@435 | 805 | for( int i=0; i<150; i++ ) |
duke@435 | 806 | was_oops[i] = stack_copy[i] ? ((oop)stack_copy[i])->is_oop() : false; |
duke@435 | 807 | */ |
duke@435 | 808 | |
duke@435 | 809 | if (ShowSafepointMsgs) { |
duke@435 | 810 | tty->print("handle_polling_page_exception: "); |
duke@435 | 811 | } |
duke@435 | 812 | |
duke@435 | 813 | if (PrintSafepointStatistics) { |
duke@435 | 814 | inc_page_trap_count(); |
duke@435 | 815 | } |
duke@435 | 816 | |
duke@435 | 817 | ThreadSafepointState* state = thread->safepoint_state(); |
duke@435 | 818 | |
duke@435 | 819 | state->handle_polling_page_exception(); |
duke@435 | 820 | // print_me(sp,stack_copy,was_oops); |
duke@435 | 821 | } |
duke@435 | 822 | |
duke@435 | 823 | |
duke@435 | 824 | void SafepointSynchronize::print_safepoint_timeout(SafepointTimeoutReason reason) { |
duke@435 | 825 | if (!timeout_error_printed) { |
duke@435 | 826 | timeout_error_printed = true; |
duke@435 | 827 | // Print out the thread infor which didn't reach the safepoint for debugging |
duke@435 | 828 | // purposes (useful when there are lots of threads in the debugger). |
duke@435 | 829 | tty->print_cr(""); |
duke@435 | 830 | tty->print_cr("# SafepointSynchronize::begin: Timeout detected:"); |
duke@435 | 831 | if (reason == _spinning_timeout) { |
duke@435 | 832 | tty->print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint."); |
duke@435 | 833 | } else if (reason == _blocking_timeout) { |
duke@435 | 834 | tty->print_cr("# SafepointSynchronize::begin: Timed out while waiting for threads to stop."); |
duke@435 | 835 | } |
duke@435 | 836 | |
duke@435 | 837 | tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:"); |
duke@435 | 838 | ThreadSafepointState *cur_state; |
duke@435 | 839 | ResourceMark rm; |
duke@435 | 840 | for(JavaThread *cur_thread = Threads::first(); cur_thread; |
duke@435 | 841 | cur_thread = cur_thread->next()) { |
duke@435 | 842 | cur_state = cur_thread->safepoint_state(); |
duke@435 | 843 | |
duke@435 | 844 | if (cur_thread->thread_state() != _thread_blocked && |
duke@435 | 845 | ((reason == _spinning_timeout && cur_state->is_running()) || |
duke@435 | 846 | (reason == _blocking_timeout && !cur_state->has_called_back()))) { |
duke@435 | 847 | tty->print("# "); |
duke@435 | 848 | cur_thread->print(); |
duke@435 | 849 | tty->print_cr(""); |
duke@435 | 850 | } |
duke@435 | 851 | } |
duke@435 | 852 | tty->print_cr("# SafepointSynchronize::begin: (End of list)"); |
duke@435 | 853 | } |
duke@435 | 854 | |
duke@435 | 855 | // To debug the long safepoint, specify both DieOnSafepointTimeout & |
duke@435 | 856 | // ShowMessageBoxOnError. |
duke@435 | 857 | if (DieOnSafepointTimeout) { |
duke@435 | 858 | char msg[1024]; |
duke@435 | 859 | VM_Operation *op = VMThread::vm_operation(); |
xlu@948 | 860 | sprintf(msg, "Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.", |
duke@435 | 861 | SafepointTimeoutDelay, |
duke@435 | 862 | op != NULL ? op->name() : "no vm operation"); |
duke@435 | 863 | fatal(msg); |
duke@435 | 864 | } |
duke@435 | 865 | } |
duke@435 | 866 | |
duke@435 | 867 | |
duke@435 | 868 | // ------------------------------------------------------------------------------------------------------- |
duke@435 | 869 | // Implementation of ThreadSafepointState |
duke@435 | 870 | |
duke@435 | 871 | ThreadSafepointState::ThreadSafepointState(JavaThread *thread) { |
duke@435 | 872 | _thread = thread; |
duke@435 | 873 | _type = _running; |
duke@435 | 874 | _has_called_back = false; |
duke@435 | 875 | _at_poll_safepoint = false; |
duke@435 | 876 | } |
duke@435 | 877 | |
duke@435 | 878 | void ThreadSafepointState::create(JavaThread *thread) { |
duke@435 | 879 | ThreadSafepointState *state = new ThreadSafepointState(thread); |
duke@435 | 880 | thread->set_safepoint_state(state); |
duke@435 | 881 | } |
duke@435 | 882 | |
duke@435 | 883 | void ThreadSafepointState::destroy(JavaThread *thread) { |
duke@435 | 884 | if (thread->safepoint_state()) { |
duke@435 | 885 | delete(thread->safepoint_state()); |
duke@435 | 886 | thread->set_safepoint_state(NULL); |
duke@435 | 887 | } |
duke@435 | 888 | } |
duke@435 | 889 | |
duke@435 | 890 | void ThreadSafepointState::examine_state_of_thread() { |
duke@435 | 891 | assert(is_running(), "better be running or just have hit safepoint poll"); |
duke@435 | 892 | |
duke@435 | 893 | JavaThreadState state = _thread->thread_state(); |
duke@435 | 894 | |
never@2082 | 895 | // Save the state at the start of safepoint processing. |
never@2082 | 896 | _orig_thread_state = state; |
never@2082 | 897 | |
duke@435 | 898 | // Check for a thread that is suspended. Note that thread resume tries |
duke@435 | 899 | // to grab the Threads_lock which we own here, so a thread cannot be |
duke@435 | 900 | // resumed during safepoint synchronization. |
duke@435 | 901 | |
dcubed@1414 | 902 | // We check to see if this thread is suspended without locking to |
dcubed@1414 | 903 | // avoid deadlocking with a third thread that is waiting for this |
dcubed@1414 | 904 | // thread to be suspended. The third thread can notice the safepoint |
dcubed@1414 | 905 | // that we're trying to start at the beginning of its SR_lock->wait() |
dcubed@1414 | 906 | // call. If that happens, then the third thread will block on the |
dcubed@1414 | 907 | // safepoint while still holding the underlying SR_lock. We won't be |
dcubed@1414 | 908 | // able to get the SR_lock and we'll deadlock. |
dcubed@1414 | 909 | // |
dcubed@1414 | 910 | // We don't need to grab the SR_lock here for two reasons: |
dcubed@1414 | 911 | // 1) The suspend flags are both volatile and are set with an |
dcubed@1414 | 912 | // Atomic::cmpxchg() call so we should see the suspended |
dcubed@1414 | 913 | // state right away. |
dcubed@1414 | 914 | // 2) We're being called from the safepoint polling loop; if |
dcubed@1414 | 915 | // we don't see the suspended state on this iteration, then |
dcubed@1414 | 916 | // we'll come around again. |
dcubed@1414 | 917 | // |
dcubed@1414 | 918 | bool is_suspended = _thread->is_ext_suspended(); |
duke@435 | 919 | if (is_suspended) { |
duke@435 | 920 | roll_forward(_at_safepoint); |
duke@435 | 921 | return; |
duke@435 | 922 | } |
duke@435 | 923 | |
duke@435 | 924 | // Some JavaThread states have an initial safepoint state of |
duke@435 | 925 | // running, but are actually at a safepoint. We will happily |
duke@435 | 926 | // agree and update the safepoint state here. |
duke@435 | 927 | if (SafepointSynchronize::safepoint_safe(_thread, state)) { |
never@3632 | 928 | SafepointSynchronize::check_for_lazy_critical_native(_thread, state); |
never@3494 | 929 | roll_forward(_at_safepoint); |
never@3494 | 930 | return; |
duke@435 | 931 | } |
duke@435 | 932 | |
duke@435 | 933 | if (state == _thread_in_vm) { |
duke@435 | 934 | roll_forward(_call_back); |
duke@435 | 935 | return; |
duke@435 | 936 | } |
duke@435 | 937 | |
duke@435 | 938 | // All other thread states will continue to run until they |
duke@435 | 939 | // transition and self-block in state _blocked |
duke@435 | 940 | // Safepoint polling in compiled code causes the Java threads to do the same. |
duke@435 | 941 | // Note: new threads may require a malloc so they must be allowed to finish |
duke@435 | 942 | |
duke@435 | 943 | assert(is_running(), "examine_state_of_thread on non-running thread"); |
duke@435 | 944 | return; |
duke@435 | 945 | } |
duke@435 | 946 | |
duke@435 | 947 | // Returns true is thread could not be rolled forward at present position. |
duke@435 | 948 | void ThreadSafepointState::roll_forward(suspend_type type) { |
duke@435 | 949 | _type = type; |
duke@435 | 950 | |
duke@435 | 951 | switch(_type) { |
duke@435 | 952 | case _at_safepoint: |
duke@435 | 953 | SafepointSynchronize::signal_thread_at_safepoint(); |
never@3632 | 954 | DEBUG_ONLY(_thread->set_visited_for_critical_count(true)); |
never@3632 | 955 | if (_thread->in_critical()) { |
never@3632 | 956 | // Notice that this thread is in a critical section |
never@3632 | 957 | SafepointSynchronize::increment_jni_active_count(); |
never@3632 | 958 | } |
duke@435 | 959 | break; |
duke@435 | 960 | |
duke@435 | 961 | case _call_back: |
duke@435 | 962 | set_has_called_back(false); |
duke@435 | 963 | break; |
duke@435 | 964 | |
duke@435 | 965 | case _running: |
duke@435 | 966 | default: |
duke@435 | 967 | ShouldNotReachHere(); |
duke@435 | 968 | } |
duke@435 | 969 | } |
duke@435 | 970 | |
duke@435 | 971 | void ThreadSafepointState::restart() { |
duke@435 | 972 | switch(type()) { |
duke@435 | 973 | case _at_safepoint: |
duke@435 | 974 | case _call_back: |
duke@435 | 975 | break; |
duke@435 | 976 | |
duke@435 | 977 | case _running: |
duke@435 | 978 | default: |
duke@435 | 979 | tty->print_cr("restart thread "INTPTR_FORMAT" with state %d", |
duke@435 | 980 | _thread, _type); |
duke@435 | 981 | _thread->print(); |
duke@435 | 982 | ShouldNotReachHere(); |
duke@435 | 983 | } |
duke@435 | 984 | _type = _running; |
duke@435 | 985 | set_has_called_back(false); |
duke@435 | 986 | } |
duke@435 | 987 | |
duke@435 | 988 | |
duke@435 | 989 | void ThreadSafepointState::print_on(outputStream *st) const { |
duke@435 | 990 | const char *s; |
duke@435 | 991 | |
duke@435 | 992 | switch(_type) { |
duke@435 | 993 | case _running : s = "_running"; break; |
duke@435 | 994 | case _at_safepoint : s = "_at_safepoint"; break; |
duke@435 | 995 | case _call_back : s = "_call_back"; break; |
duke@435 | 996 | default: |
duke@435 | 997 | ShouldNotReachHere(); |
duke@435 | 998 | } |
duke@435 | 999 | |
duke@435 | 1000 | st->print_cr("Thread: " INTPTR_FORMAT |
duke@435 | 1001 | " [0x%2x] State: %s _has_called_back %d _at_poll_safepoint %d", |
duke@435 | 1002 | _thread, _thread->osthread()->thread_id(), s, _has_called_back, |
duke@435 | 1003 | _at_poll_safepoint); |
duke@435 | 1004 | |
duke@435 | 1005 | _thread->print_thread_state_on(st); |
duke@435 | 1006 | } |
duke@435 | 1007 | |
duke@435 | 1008 | |
duke@435 | 1009 | // --------------------------------------------------------------------------------------------------------------------- |
duke@435 | 1010 | |
duke@435 | 1011 | // Block the thread at the safepoint poll or poll return. |
duke@435 | 1012 | void ThreadSafepointState::handle_polling_page_exception() { |
duke@435 | 1013 | |
duke@435 | 1014 | // Check state. block() will set thread state to thread_in_vm which will |
duke@435 | 1015 | // cause the safepoint state _type to become _call_back. |
duke@435 | 1016 | assert(type() == ThreadSafepointState::_running, |
duke@435 | 1017 | "polling page exception on thread not running state"); |
duke@435 | 1018 | |
duke@435 | 1019 | // Step 1: Find the nmethod from the return address |
duke@435 | 1020 | if (ShowSafepointMsgs && Verbose) { |
duke@435 | 1021 | tty->print_cr("Polling page exception at " INTPTR_FORMAT, thread()->saved_exception_pc()); |
duke@435 | 1022 | } |
duke@435 | 1023 | address real_return_addr = thread()->saved_exception_pc(); |
duke@435 | 1024 | |
duke@435 | 1025 | CodeBlob *cb = CodeCache::find_blob(real_return_addr); |
duke@435 | 1026 | assert(cb != NULL && cb->is_nmethod(), "return address should be in nmethod"); |
duke@435 | 1027 | nmethod* nm = (nmethod*)cb; |
duke@435 | 1028 | |
duke@435 | 1029 | // Find frame of caller |
duke@435 | 1030 | frame stub_fr = thread()->last_frame(); |
duke@435 | 1031 | CodeBlob* stub_cb = stub_fr.cb(); |
duke@435 | 1032 | assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub"); |
duke@435 | 1033 | RegisterMap map(thread(), true); |
duke@435 | 1034 | frame caller_fr = stub_fr.sender(&map); |
duke@435 | 1035 | |
duke@435 | 1036 | // Should only be poll_return or poll |
duke@435 | 1037 | assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" ); |
duke@435 | 1038 | |
duke@435 | 1039 | // This is a poll immediately before a return. The exception handling code |
duke@435 | 1040 | // has already had the effect of causing the return to occur, so the execution |
duke@435 | 1041 | // will continue immediately after the call. In addition, the oopmap at the |
duke@435 | 1042 | // return point does not mark the return value as an oop (if it is), so |
duke@435 | 1043 | // it needs a handle here to be updated. |
duke@435 | 1044 | if( nm->is_at_poll_return(real_return_addr) ) { |
duke@435 | 1045 | // See if return type is an oop. |
duke@435 | 1046 | bool return_oop = nm->method()->is_returning_oop(); |
duke@435 | 1047 | Handle return_value; |
duke@435 | 1048 | if (return_oop) { |
duke@435 | 1049 | // The oop result has been saved on the stack together with all |
duke@435 | 1050 | // the other registers. In order to preserve it over GCs we need |
duke@435 | 1051 | // to keep it in a handle. |
duke@435 | 1052 | oop result = caller_fr.saved_oop_result(&map); |
duke@435 | 1053 | assert(result == NULL || result->is_oop(), "must be oop"); |
duke@435 | 1054 | return_value = Handle(thread(), result); |
duke@435 | 1055 | assert(Universe::heap()->is_in_or_null(result), "must be heap pointer"); |
duke@435 | 1056 | } |
duke@435 | 1057 | |
duke@435 | 1058 | // Block the thread |
duke@435 | 1059 | SafepointSynchronize::block(thread()); |
duke@435 | 1060 | |
duke@435 | 1061 | // restore oop result, if any |
duke@435 | 1062 | if (return_oop) { |
duke@435 | 1063 | caller_fr.set_saved_oop_result(&map, return_value()); |
duke@435 | 1064 | } |
duke@435 | 1065 | } |
duke@435 | 1066 | |
duke@435 | 1067 | // This is a safepoint poll. Verify the return address and block. |
duke@435 | 1068 | else { |
duke@435 | 1069 | set_at_poll_safepoint(true); |
duke@435 | 1070 | |
duke@435 | 1071 | // verify the blob built the "return address" correctly |
duke@435 | 1072 | assert(real_return_addr == caller_fr.pc(), "must match"); |
duke@435 | 1073 | |
duke@435 | 1074 | // Block the thread |
duke@435 | 1075 | SafepointSynchronize::block(thread()); |
duke@435 | 1076 | set_at_poll_safepoint(false); |
duke@435 | 1077 | |
duke@435 | 1078 | // If we have a pending async exception deoptimize the frame |
duke@435 | 1079 | // as otherwise we may never deliver it. |
duke@435 | 1080 | if (thread()->has_async_condition()) { |
duke@435 | 1081 | ThreadInVMfromJavaNoAsyncException __tiv(thread()); |
never@2260 | 1082 | Deoptimization::deoptimize_frame(thread(), caller_fr.id()); |
duke@435 | 1083 | } |
duke@435 | 1084 | |
duke@435 | 1085 | // If an exception has been installed we must check for a pending deoptimization |
duke@435 | 1086 | // Deoptimize frame if exception has been thrown. |
duke@435 | 1087 | |
duke@435 | 1088 | if (thread()->has_pending_exception() ) { |
duke@435 | 1089 | RegisterMap map(thread(), true); |
duke@435 | 1090 | frame caller_fr = stub_fr.sender(&map); |
duke@435 | 1091 | if (caller_fr.is_deoptimized_frame()) { |
duke@435 | 1092 | // The exception patch will destroy registers that are still |
duke@435 | 1093 | // live and will be needed during deoptimization. Defer the |
duke@435 | 1094 | // Async exception should have defered the exception until the |
duke@435 | 1095 | // next safepoint which will be detected when we get into |
duke@435 | 1096 | // the interpreter so if we have an exception now things |
duke@435 | 1097 | // are messed up. |
duke@435 | 1098 | |
duke@435 | 1099 | fatal("Exception installed and deoptimization is pending"); |
duke@435 | 1100 | } |
duke@435 | 1101 | } |
duke@435 | 1102 | } |
duke@435 | 1103 | } |
duke@435 | 1104 | |
duke@435 | 1105 | |
duke@435 | 1106 | // |
duke@435 | 1107 | // Statistics & Instrumentations |
duke@435 | 1108 | // |
duke@435 | 1109 | SafepointSynchronize::SafepointStats* SafepointSynchronize::_safepoint_stats = NULL; |
xlu@1726 | 1110 | jlong SafepointSynchronize::_safepoint_begin_time = 0; |
duke@435 | 1111 | int SafepointSynchronize::_cur_stat_index = 0; |
duke@435 | 1112 | julong SafepointSynchronize::_safepoint_reasons[VM_Operation::VMOp_Terminating]; |
duke@435 | 1113 | julong SafepointSynchronize::_coalesced_vmop_count = 0; |
duke@435 | 1114 | jlong SafepointSynchronize::_max_sync_time = 0; |
xlu@1726 | 1115 | jlong SafepointSynchronize::_max_vmop_time = 0; |
xlu@1726 | 1116 | float SafepointSynchronize::_ts_of_current_safepoint = 0.0f; |
duke@435 | 1117 | |
xlu@1726 | 1118 | static jlong cleanup_end_time = 0; |
duke@435 | 1119 | static bool need_to_track_page_armed_status = false; |
duke@435 | 1120 | static bool init_done = false; |
duke@435 | 1121 | |
xlu@1726 | 1122 | // Helper method to print the header. |
xlu@1726 | 1123 | static void print_header() { |
xlu@1726 | 1124 | tty->print(" vmop " |
xlu@1726 | 1125 | "[threads: total initially_running wait_to_block] "); |
xlu@1726 | 1126 | tty->print("[time: spin block sync cleanup vmop] "); |
xlu@1726 | 1127 | |
xlu@1726 | 1128 | // no page armed status printed out if it is always armed. |
xlu@1726 | 1129 | if (need_to_track_page_armed_status) { |
xlu@1726 | 1130 | tty->print("page_armed "); |
xlu@1726 | 1131 | } |
xlu@1726 | 1132 | |
xlu@1726 | 1133 | tty->print_cr("page_trap_count"); |
xlu@1726 | 1134 | } |
xlu@1726 | 1135 | |
duke@435 | 1136 | void SafepointSynchronize::deferred_initialize_stat() { |
duke@435 | 1137 | if (init_done) return; |
duke@435 | 1138 | |
duke@435 | 1139 | if (PrintSafepointStatisticsCount <= 0) { |
duke@435 | 1140 | fatal("Wrong PrintSafepointStatisticsCount"); |
duke@435 | 1141 | } |
duke@435 | 1142 | |
duke@435 | 1143 | // If PrintSafepointStatisticsTimeout is specified, the statistics data will |
duke@435 | 1144 | // be printed right away, in which case, _safepoint_stats will regress to |
duke@435 | 1145 | // a single element array. Otherwise, it is a circular ring buffer with default |
duke@435 | 1146 | // size of PrintSafepointStatisticsCount. |
duke@435 | 1147 | int stats_array_size; |
duke@435 | 1148 | if (PrintSafepointStatisticsTimeout > 0) { |
duke@435 | 1149 | stats_array_size = 1; |
duke@435 | 1150 | PrintSafepointStatistics = true; |
duke@435 | 1151 | } else { |
duke@435 | 1152 | stats_array_size = PrintSafepointStatisticsCount; |
duke@435 | 1153 | } |
duke@435 | 1154 | _safepoint_stats = (SafepointStats*)os::malloc(stats_array_size |
zgu@3900 | 1155 | * sizeof(SafepointStats), mtInternal); |
duke@435 | 1156 | guarantee(_safepoint_stats != NULL, |
duke@435 | 1157 | "not enough memory for safepoint instrumentation data"); |
duke@435 | 1158 | |
duke@435 | 1159 | if (UseCompilerSafepoints && DeferPollingPageLoopCount >= 0) { |
duke@435 | 1160 | need_to_track_page_armed_status = true; |
duke@435 | 1161 | } |
duke@435 | 1162 | init_done = true; |
duke@435 | 1163 | } |
duke@435 | 1164 | |
duke@435 | 1165 | void SafepointSynchronize::begin_statistics(int nof_threads, int nof_running) { |
xlu@1438 | 1166 | assert(init_done, "safepoint statistics array hasn't been initialized"); |
duke@435 | 1167 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1168 | |
xlu@1726 | 1169 | spstat->_time_stamp = _ts_of_current_safepoint; |
xlu@1726 | 1170 | |
duke@435 | 1171 | VM_Operation *op = VMThread::vm_operation(); |
duke@435 | 1172 | spstat->_vmop_type = (op != NULL ? op->type() : -1); |
duke@435 | 1173 | if (op != NULL) { |
duke@435 | 1174 | _safepoint_reasons[spstat->_vmop_type]++; |
duke@435 | 1175 | } |
duke@435 | 1176 | |
duke@435 | 1177 | spstat->_nof_total_threads = nof_threads; |
duke@435 | 1178 | spstat->_nof_initial_running_threads = nof_running; |
duke@435 | 1179 | spstat->_nof_threads_hit_page_trap = 0; |
duke@435 | 1180 | |
duke@435 | 1181 | // Records the start time of spinning. The real time spent on spinning |
duke@435 | 1182 | // will be adjusted when spin is done. Same trick is applied for time |
duke@435 | 1183 | // spent on waiting for threads to block. |
duke@435 | 1184 | if (nof_running != 0) { |
duke@435 | 1185 | spstat->_time_to_spin = os::javaTimeNanos(); |
duke@435 | 1186 | } else { |
duke@435 | 1187 | spstat->_time_to_spin = 0; |
duke@435 | 1188 | } |
duke@435 | 1189 | } |
duke@435 | 1190 | |
duke@435 | 1191 | void SafepointSynchronize::update_statistics_on_spin_end() { |
duke@435 | 1192 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1193 | |
duke@435 | 1194 | jlong cur_time = os::javaTimeNanos(); |
duke@435 | 1195 | |
duke@435 | 1196 | spstat->_nof_threads_wait_to_block = _waiting_to_block; |
duke@435 | 1197 | if (spstat->_nof_initial_running_threads != 0) { |
duke@435 | 1198 | spstat->_time_to_spin = cur_time - spstat->_time_to_spin; |
duke@435 | 1199 | } |
duke@435 | 1200 | |
duke@435 | 1201 | if (need_to_track_page_armed_status) { |
duke@435 | 1202 | spstat->_page_armed = (PageArmed == 1); |
duke@435 | 1203 | } |
duke@435 | 1204 | |
duke@435 | 1205 | // Records the start time of waiting for to block. Updated when block is done. |
duke@435 | 1206 | if (_waiting_to_block != 0) { |
duke@435 | 1207 | spstat->_time_to_wait_to_block = cur_time; |
duke@435 | 1208 | } else { |
duke@435 | 1209 | spstat->_time_to_wait_to_block = 0; |
duke@435 | 1210 | } |
duke@435 | 1211 | } |
duke@435 | 1212 | |
duke@435 | 1213 | void SafepointSynchronize::update_statistics_on_sync_end(jlong end_time) { |
duke@435 | 1214 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1215 | |
duke@435 | 1216 | if (spstat->_nof_threads_wait_to_block != 0) { |
duke@435 | 1217 | spstat->_time_to_wait_to_block = end_time - |
duke@435 | 1218 | spstat->_time_to_wait_to_block; |
duke@435 | 1219 | } |
duke@435 | 1220 | |
duke@435 | 1221 | // Records the end time of sync which will be used to calculate the total |
duke@435 | 1222 | // vm operation time. Again, the real time spending in syncing will be deducted |
duke@435 | 1223 | // from the start of the sync time later when end_statistics is called. |
xlu@1726 | 1224 | spstat->_time_to_sync = end_time - _safepoint_begin_time; |
duke@435 | 1225 | if (spstat->_time_to_sync > _max_sync_time) { |
duke@435 | 1226 | _max_sync_time = spstat->_time_to_sync; |
duke@435 | 1227 | } |
xlu@1726 | 1228 | |
xlu@1726 | 1229 | spstat->_time_to_do_cleanups = end_time; |
xlu@1726 | 1230 | } |
xlu@1726 | 1231 | |
xlu@1726 | 1232 | void SafepointSynchronize::update_statistics_on_cleanup_end(jlong end_time) { |
xlu@1726 | 1233 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
xlu@1726 | 1234 | |
xlu@1726 | 1235 | // Record how long spent in cleanup tasks. |
xlu@1726 | 1236 | spstat->_time_to_do_cleanups = end_time - spstat->_time_to_do_cleanups; |
xlu@1726 | 1237 | |
xlu@1726 | 1238 | cleanup_end_time = end_time; |
duke@435 | 1239 | } |
duke@435 | 1240 | |
duke@435 | 1241 | void SafepointSynchronize::end_statistics(jlong vmop_end_time) { |
duke@435 | 1242 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1243 | |
duke@435 | 1244 | // Update the vm operation time. |
xlu@1726 | 1245 | spstat->_time_to_exec_vmop = vmop_end_time - cleanup_end_time; |
xlu@1726 | 1246 | if (spstat->_time_to_exec_vmop > _max_vmop_time) { |
xlu@1726 | 1247 | _max_vmop_time = spstat->_time_to_exec_vmop; |
xlu@1726 | 1248 | } |
duke@435 | 1249 | // Only the sync time longer than the specified |
duke@435 | 1250 | // PrintSafepointStatisticsTimeout will be printed out right away. |
duke@435 | 1251 | // By default, it is -1 meaning all samples will be put into the list. |
duke@435 | 1252 | if ( PrintSafepointStatisticsTimeout > 0) { |
duke@435 | 1253 | if (spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) { |
duke@435 | 1254 | print_statistics(); |
duke@435 | 1255 | } |
duke@435 | 1256 | } else { |
duke@435 | 1257 | // The safepoint statistics will be printed out when the _safepoin_stats |
duke@435 | 1258 | // array fills up. |
xlu@1726 | 1259 | if (_cur_stat_index == PrintSafepointStatisticsCount - 1) { |
duke@435 | 1260 | print_statistics(); |
duke@435 | 1261 | _cur_stat_index = 0; |
xlu@1726 | 1262 | } else { |
xlu@1726 | 1263 | _cur_stat_index++; |
duke@435 | 1264 | } |
duke@435 | 1265 | } |
duke@435 | 1266 | } |
duke@435 | 1267 | |
duke@435 | 1268 | void SafepointSynchronize::print_statistics() { |
duke@435 | 1269 | SafepointStats* sstats = _safepoint_stats; |
duke@435 | 1270 | |
xlu@1726 | 1271 | for (int index = 0; index <= _cur_stat_index; index++) { |
xlu@1726 | 1272 | if (index % 30 == 0) { |
xlu@1726 | 1273 | print_header(); |
xlu@1726 | 1274 | } |
duke@435 | 1275 | sstats = &_safepoint_stats[index]; |
xlu@1726 | 1276 | tty->print("%.3f: ", sstats->_time_stamp); |
xlu@1726 | 1277 | tty->print("%-26s [" |
duke@435 | 1278 | INT32_FORMAT_W(8)INT32_FORMAT_W(11)INT32_FORMAT_W(15) |
xlu@1726 | 1279 | " ] ", |
duke@435 | 1280 | sstats->_vmop_type == -1 ? "no vm operation" : |
duke@435 | 1281 | VM_Operation::name(sstats->_vmop_type), |
duke@435 | 1282 | sstats->_nof_total_threads, |
duke@435 | 1283 | sstats->_nof_initial_running_threads, |
duke@435 | 1284 | sstats->_nof_threads_wait_to_block); |
duke@435 | 1285 | // "/ MICROUNITS " is to convert the unit from nanos to millis. |
xlu@1726 | 1286 | tty->print(" [" |
xlu@1726 | 1287 | INT64_FORMAT_W(6)INT64_FORMAT_W(6) |
xlu@1726 | 1288 | INT64_FORMAT_W(6)INT64_FORMAT_W(6) |
xlu@1726 | 1289 | INT64_FORMAT_W(6)" ] ", |
duke@435 | 1290 | sstats->_time_to_spin / MICROUNITS, |
duke@435 | 1291 | sstats->_time_to_wait_to_block / MICROUNITS, |
duke@435 | 1292 | sstats->_time_to_sync / MICROUNITS, |
xlu@1726 | 1293 | sstats->_time_to_do_cleanups / MICROUNITS, |
xlu@1726 | 1294 | sstats->_time_to_exec_vmop / MICROUNITS); |
duke@435 | 1295 | |
duke@435 | 1296 | if (need_to_track_page_armed_status) { |
duke@435 | 1297 | tty->print(INT32_FORMAT" ", sstats->_page_armed); |
duke@435 | 1298 | } |
duke@435 | 1299 | tty->print_cr(INT32_FORMAT" ", sstats->_nof_threads_hit_page_trap); |
duke@435 | 1300 | } |
duke@435 | 1301 | } |
duke@435 | 1302 | |
duke@435 | 1303 | // This method will be called when VM exits. It will first call |
duke@435 | 1304 | // print_statistics to print out the rest of the sampling. Then |
duke@435 | 1305 | // it tries to summarize the sampling. |
duke@435 | 1306 | void SafepointSynchronize::print_stat_on_exit() { |
duke@435 | 1307 | if (_safepoint_stats == NULL) return; |
duke@435 | 1308 | |
duke@435 | 1309 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1310 | |
duke@435 | 1311 | // During VM exit, end_statistics may not get called and in that |
duke@435 | 1312 | // case, if the sync time is less than PrintSafepointStatisticsTimeout, |
duke@435 | 1313 | // don't print it out. |
duke@435 | 1314 | // Approximate the vm op time. |
duke@435 | 1315 | _safepoint_stats[_cur_stat_index]._time_to_exec_vmop = |
xlu@1726 | 1316 | os::javaTimeNanos() - cleanup_end_time; |
duke@435 | 1317 | |
duke@435 | 1318 | if ( PrintSafepointStatisticsTimeout < 0 || |
duke@435 | 1319 | spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) { |
duke@435 | 1320 | print_statistics(); |
duke@435 | 1321 | } |
duke@435 | 1322 | tty->print_cr(""); |
duke@435 | 1323 | |
duke@435 | 1324 | // Print out polling page sampling status. |
duke@435 | 1325 | if (!need_to_track_page_armed_status) { |
duke@435 | 1326 | if (UseCompilerSafepoints) { |
duke@435 | 1327 | tty->print_cr("Polling page always armed"); |
duke@435 | 1328 | } |
duke@435 | 1329 | } else { |
duke@435 | 1330 | tty->print_cr("Defer polling page loop count = %d\n", |
duke@435 | 1331 | DeferPollingPageLoopCount); |
duke@435 | 1332 | } |
duke@435 | 1333 | |
duke@435 | 1334 | for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) { |
duke@435 | 1335 | if (_safepoint_reasons[index] != 0) { |
duke@435 | 1336 | tty->print_cr("%-26s"UINT64_FORMAT_W(10), VM_Operation::name(index), |
duke@435 | 1337 | _safepoint_reasons[index]); |
duke@435 | 1338 | } |
duke@435 | 1339 | } |
duke@435 | 1340 | |
duke@435 | 1341 | tty->print_cr(UINT64_FORMAT_W(5)" VM operations coalesced during safepoint", |
duke@435 | 1342 | _coalesced_vmop_count); |
duke@435 | 1343 | tty->print_cr("Maximum sync time "INT64_FORMAT_W(5)" ms", |
duke@435 | 1344 | _max_sync_time / MICROUNITS); |
xlu@1726 | 1345 | tty->print_cr("Maximum vm operation time (except for Exit VM operation) " |
xlu@1726 | 1346 | INT64_FORMAT_W(5)" ms", |
xlu@1726 | 1347 | _max_vmop_time / MICROUNITS); |
duke@435 | 1348 | } |
duke@435 | 1349 | |
duke@435 | 1350 | // ------------------------------------------------------------------------------------------------ |
duke@435 | 1351 | // Non-product code |
duke@435 | 1352 | |
duke@435 | 1353 | #ifndef PRODUCT |
duke@435 | 1354 | |
duke@435 | 1355 | void SafepointSynchronize::print_state() { |
duke@435 | 1356 | if (_state == _not_synchronized) { |
duke@435 | 1357 | tty->print_cr("not synchronized"); |
duke@435 | 1358 | } else if (_state == _synchronizing || _state == _synchronized) { |
duke@435 | 1359 | tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" : |
duke@435 | 1360 | "synchronized"); |
duke@435 | 1361 | |
duke@435 | 1362 | for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) { |
duke@435 | 1363 | cur->safepoint_state()->print(); |
duke@435 | 1364 | } |
duke@435 | 1365 | } |
duke@435 | 1366 | } |
duke@435 | 1367 | |
duke@435 | 1368 | void SafepointSynchronize::safepoint_msg(const char* format, ...) { |
duke@435 | 1369 | if (ShowSafepointMsgs) { |
duke@435 | 1370 | va_list ap; |
duke@435 | 1371 | va_start(ap, format); |
duke@435 | 1372 | tty->vprint_cr(format, ap); |
duke@435 | 1373 | va_end(ap); |
duke@435 | 1374 | } |
duke@435 | 1375 | } |
duke@435 | 1376 | |
duke@435 | 1377 | #endif // !PRODUCT |