src/share/vm/runtime/thread.cpp

Thu, 10 Apr 2008 15:49:16 -0400

author
sbohne
date
Thu, 10 Apr 2008 15:49:16 -0400
changeset 528
c6ff24ceec1c
parent 497
cd0742ba123c
child 627
6d13fcb3663f
child 777
37f87013dfd8
permissions
-rw-r--r--

6686407: Fix for 6666698 broke -XX:BiasedLockingStartupDelay=0
Summary: Stack allocated VM_EnableBiasedLocking op must be marked as such
Reviewed-by: xlu, acorn, never, dholmes

     1 /*
     2  * Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
    20  * CA 95054 USA or visit www.sun.com if you need additional information or
    21  * have any questions.
    22  *
    23  */
    25 # include "incls/_precompiled.incl"
    26 # include "incls/_thread.cpp.incl"
    28 #ifdef DTRACE_ENABLED
    30 // Only bother with this argument setup if dtrace is available
    32 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
    33 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
    34 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
    35   intptr_t, intptr_t, bool);
    36 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
    37   intptr_t, intptr_t, bool);
    39 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
    40   {                                                                        \
    41     ResourceMark rm(this);                                                 \
    42     int len = 0;                                                           \
    43     const char* name = (javathread)->get_thread_name();                    \
    44     len = strlen(name);                                                    \
    45     HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
    46       name, len,                                                           \
    47       java_lang_Thread::thread_id((javathread)->threadObj()),              \
    48       (javathread)->osthread()->thread_id(),                               \
    49       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
    50   }
    52 #else //  ndef DTRACE_ENABLED
    54 #define DTRACE_THREAD_PROBE(probe, javathread)
    56 #endif // ndef DTRACE_ENABLED
    58 // Class hierarchy
    59 // - Thread
    60 //   - VMThread
    61 //   - WatcherThread
    62 //   - ConcurrentMarkSweepThread
    63 //   - JavaThread
    64 //     - CompilerThread
    66 // ======= Thread ========
    68 // Support for forcing alignment of thread objects for biased locking
    69 void* Thread::operator new(size_t size) {
    70   if (UseBiasedLocking) {
    71     const int alignment = markOopDesc::biased_lock_alignment;
    72     size_t aligned_size = size + (alignment - sizeof(intptr_t));
    73     void* real_malloc_addr = CHeapObj::operator new(aligned_size);
    74     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
    75     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
    76            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
    77            "JavaThread alignment code overflowed allocated storage");
    78     if (TraceBiasedLocking) {
    79       if (aligned_addr != real_malloc_addr)
    80         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
    81                       real_malloc_addr, aligned_addr);
    82     }
    83     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
    84     return aligned_addr;
    85   } else {
    86     return CHeapObj::operator new(size);
    87   }
    88 }
    90 void Thread::operator delete(void* p) {
    91   if (UseBiasedLocking) {
    92     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
    93     CHeapObj::operator delete(real_malloc_addr);
    94   } else {
    95     CHeapObj::operator delete(p);
    96   }
    97 }
   100 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
   101 // JavaThread
   104 Thread::Thread() {
   105   // stack
   106   _stack_base   = NULL;
   107   _stack_size   = 0;
   108   _self_raw_id  = 0;
   109   _lgrp_id      = -1;
   110   _osthread     = NULL;
   112   // allocated data structures
   113   set_resource_area(new ResourceArea());
   114   set_handle_area(new HandleArea(NULL));
   115   set_active_handles(NULL);
   116   set_free_handle_block(NULL);
   117   set_last_handle_mark(NULL);
   118   set_osthread(NULL);
   120   // This initial value ==> never claimed.
   121   _oops_do_parity = 0;
   123   // the handle mark links itself to last_handle_mark
   124   new HandleMark(this);
   126   // plain initialization
   127   debug_only(_owned_locks = NULL;)
   128   debug_only(_allow_allocation_count = 0;)
   129   NOT_PRODUCT(_allow_safepoint_count = 0;)
   130   CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
   131   _highest_lock = NULL;
   132   _jvmti_env_iteration_count = 0;
   133   _vm_operation_started_count = 0;
   134   _vm_operation_completed_count = 0;
   135   _current_pending_monitor = NULL;
   136   _current_pending_monitor_is_from_java = true;
   137   _current_waiting_monitor = NULL;
   138   _num_nested_signal = 0;
   139   omFreeList = NULL ;
   140   omFreeCount = 0 ;
   141   omFreeProvision = 32 ;
   143   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
   144   _suspend_flags = 0;
   146   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
   147   _hashStateX = os::random() ;
   148   _hashStateY = 842502087 ;
   149   _hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
   150   _hashStateW = 273326509 ;
   152   _OnTrap   = 0 ;
   153   _schedctl = NULL ;
   154   _Stalled  = 0 ;
   155   _TypeTag  = 0x2BAD ;
   157   // Many of the following fields are effectively final - immutable
   158   // Note that nascent threads can't use the Native Monitor-Mutex
   159   // construct until the _MutexEvent is initialized ...
   160   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
   161   // we might instead use a stack of ParkEvents that we could provision on-demand.
   162   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
   163   // and ::Release()
   164   _ParkEvent   = ParkEvent::Allocate (this) ;
   165   _SleepEvent  = ParkEvent::Allocate (this) ;
   166   _MutexEvent  = ParkEvent::Allocate (this) ;
   167   _MuxEvent    = ParkEvent::Allocate (this) ;
   169 #ifdef CHECK_UNHANDLED_OOPS
   170   if (CheckUnhandledOops) {
   171     _unhandled_oops = new UnhandledOops(this);
   172   }
   173 #endif // CHECK_UNHANDLED_OOPS
   174 #ifdef ASSERT
   175   if (UseBiasedLocking) {
   176     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
   177     assert(this == _real_malloc_address ||
   178            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
   179            "bug in forced alignment of thread objects");
   180   }
   181 #endif /* ASSERT */
   182 }
   184 void Thread::initialize_thread_local_storage() {
   185   // Note: Make sure this method only calls
   186   // non-blocking operations. Otherwise, it might not work
   187   // with the thread-startup/safepoint interaction.
   189   // During Java thread startup, safepoint code should allow this
   190   // method to complete because it may need to allocate memory to
   191   // store information for the new thread.
   193   // initialize structure dependent on thread local storage
   194   ThreadLocalStorage::set_thread(this);
   196   // set up any platform-specific state.
   197   os::initialize_thread();
   199 }
   201 void Thread::record_stack_base_and_size() {
   202   set_stack_base(os::current_stack_base());
   203   set_stack_size(os::current_stack_size());
   204 }
   207 Thread::~Thread() {
   208   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
   209   ObjectSynchronizer::omFlush (this) ;
   211   // deallocate data structures
   212   delete resource_area();
   213   // since the handle marks are using the handle area, we have to deallocated the root
   214   // handle mark before deallocating the thread's handle area,
   215   assert(last_handle_mark() != NULL, "check we have an element");
   216   delete last_handle_mark();
   217   assert(last_handle_mark() == NULL, "check we have reached the end");
   219   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
   220   // We NULL out the fields for good hygiene.
   221   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
   222   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
   223   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
   224   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
   226   delete handle_area();
   228   // osthread() can be NULL, if creation of thread failed.
   229   if (osthread() != NULL) os::free_thread(osthread());
   231   delete _SR_lock;
   233   // clear thread local storage if the Thread is deleting itself
   234   if (this == Thread::current()) {
   235     ThreadLocalStorage::set_thread(NULL);
   236   } else {
   237     // In the case where we're not the current thread, invalidate all the
   238     // caches in case some code tries to get the current thread or the
   239     // thread that was destroyed, and gets stale information.
   240     ThreadLocalStorage::invalidate_all();
   241   }
   242   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
   243 }
   245 // NOTE: dummy function for assertion purpose.
   246 void Thread::run() {
   247   ShouldNotReachHere();
   248 }
   250 #ifdef ASSERT
   251 // Private method to check for dangling thread pointer
   252 void check_for_dangling_thread_pointer(Thread *thread) {
   253  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
   254          "possibility of dangling Thread pointer");
   255 }
   256 #endif
   259 #ifndef PRODUCT
   260 // Tracing method for basic thread operations
   261 void Thread::trace(const char* msg, const Thread* const thread) {
   262   if (!TraceThreadEvents) return;
   263   ResourceMark rm;
   264   ThreadCritical tc;
   265   const char *name = "non-Java thread";
   266   int prio = -1;
   267   if (thread->is_Java_thread()
   268       && !thread->is_Compiler_thread()) {
   269     // The Threads_lock must be held to get information about
   270     // this thread but may not be in some situations when
   271     // tracing  thread events.
   272     bool release_Threads_lock = false;
   273     if (!Threads_lock->owned_by_self()) {
   274       Threads_lock->lock();
   275       release_Threads_lock = true;
   276     }
   277     JavaThread* jt = (JavaThread *)thread;
   278     name = (char *)jt->get_thread_name();
   279     oop thread_oop = jt->threadObj();
   280     if (thread_oop != NULL) {
   281       prio = java_lang_Thread::priority(thread_oop);
   282     }
   283     if (release_Threads_lock) {
   284       Threads_lock->unlock();
   285     }
   286   }
   287   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
   288 }
   289 #endif
   292 ThreadPriority Thread::get_priority(const Thread* const thread) {
   293   trace("get priority", thread);
   294   ThreadPriority priority;
   295   // Can return an error!
   296   (void)os::get_priority(thread, priority);
   297   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
   298   return priority;
   299 }
   301 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
   302   trace("set priority", thread);
   303   debug_only(check_for_dangling_thread_pointer(thread);)
   304   // Can return an error!
   305   (void)os::set_priority(thread, priority);
   306 }
   309 void Thread::start(Thread* thread) {
   310   trace("start", thread);
   311   // Start is different from resume in that its safety is guaranteed by context or
   312   // being called from a Java method synchronized on the Thread object.
   313   if (!DisableStartThread) {
   314     if (thread->is_Java_thread()) {
   315       // Initialize the thread state to RUNNABLE before starting this thread.
   316       // Can not set it after the thread started because we do not know the
   317       // exact thread state at that time. It could be in MONITOR_WAIT or
   318       // in SLEEPING or some other state.
   319       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
   320                                           java_lang_Thread::RUNNABLE);
   321     }
   322     os::start_thread(thread);
   323   }
   324 }
   326 // Enqueue a VM_Operation to do the job for us - sometime later
   327 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
   328   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
   329   VMThread::execute(vm_stop);
   330 }
   333 //
   334 // Check if an external suspend request has completed (or has been
   335 // cancelled). Returns true if the thread is externally suspended and
   336 // false otherwise.
   337 //
   338 // The bits parameter returns information about the code path through
   339 // the routine. Useful for debugging:
   340 //
   341 // set in is_ext_suspend_completed():
   342 // 0x00000001 - routine was entered
   343 // 0x00000010 - routine return false at end
   344 // 0x00000100 - thread exited (return false)
   345 // 0x00000200 - suspend request cancelled (return false)
   346 // 0x00000400 - thread suspended (return true)
   347 // 0x00001000 - thread is in a suspend equivalent state (return true)
   348 // 0x00002000 - thread is native and walkable (return true)
   349 // 0x00004000 - thread is native_trans and walkable (needed retry)
   350 //
   351 // set in wait_for_ext_suspend_completion():
   352 // 0x00010000 - routine was entered
   353 // 0x00020000 - suspend request cancelled before loop (return false)
   354 // 0x00040000 - thread suspended before loop (return true)
   355 // 0x00080000 - suspend request cancelled in loop (return false)
   356 // 0x00100000 - thread suspended in loop (return true)
   357 // 0x00200000 - suspend not completed during retry loop (return false)
   358 //
   360 // Helper class for tracing suspend wait debug bits.
   361 //
   362 // 0x00000100 indicates that the target thread exited before it could
   363 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
   364 // 0x00080000 each indicate a cancelled suspend request so they don't
   365 // count as wait failures either.
   366 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
   368 class TraceSuspendDebugBits : public StackObj {
   369  private:
   370   JavaThread * jt;
   371   bool         is_wait;
   372   bool         called_by_wait;  // meaningful when !is_wait
   373   uint32_t *   bits;
   375  public:
   376   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
   377                         uint32_t *_bits) {
   378     jt             = _jt;
   379     is_wait        = _is_wait;
   380     called_by_wait = _called_by_wait;
   381     bits           = _bits;
   382   }
   384   ~TraceSuspendDebugBits() {
   385     if (!is_wait) {
   386 #if 1
   387       // By default, don't trace bits for is_ext_suspend_completed() calls.
   388       // That trace is very chatty.
   389       return;
   390 #else
   391       if (!called_by_wait) {
   392         // If tracing for is_ext_suspend_completed() is enabled, then only
   393         // trace calls to it from wait_for_ext_suspend_completion()
   394         return;
   395       }
   396 #endif
   397     }
   399     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
   400       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
   401         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
   402         ResourceMark rm;
   404         tty->print_cr(
   405             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
   406             jt->get_thread_name(), *bits);
   408         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
   409       }
   410     }
   411   }
   412 };
   413 #undef DEBUG_FALSE_BITS
   416 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
   417   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
   419   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
   420   bool do_trans_retry;           // flag to force the retry
   422   *bits |= 0x00000001;
   424   do {
   425     do_trans_retry = false;
   427     if (is_exiting()) {
   428       // Thread is in the process of exiting. This is always checked
   429       // first to reduce the risk of dereferencing a freed JavaThread.
   430       *bits |= 0x00000100;
   431       return false;
   432     }
   434     if (!is_external_suspend()) {
   435       // Suspend request is cancelled. This is always checked before
   436       // is_ext_suspended() to reduce the risk of a rogue resume
   437       // confusing the thread that made the suspend request.
   438       *bits |= 0x00000200;
   439       return false;
   440     }
   442     if (is_ext_suspended()) {
   443       // thread is suspended
   444       *bits |= 0x00000400;
   445       return true;
   446     }
   448     // Now that we no longer do hard suspends of threads running
   449     // native code, the target thread can be changing thread state
   450     // while we are in this routine:
   451     //
   452     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
   453     //
   454     // We save a copy of the thread state as observed at this moment
   455     // and make our decision about suspend completeness based on the
   456     // copy. This closes the race where the thread state is seen as
   457     // _thread_in_native_trans in the if-thread_blocked check, but is
   458     // seen as _thread_blocked in if-thread_in_native_trans check.
   459     JavaThreadState save_state = thread_state();
   461     if (save_state == _thread_blocked && is_suspend_equivalent()) {
   462       // If the thread's state is _thread_blocked and this blocking
   463       // condition is known to be equivalent to a suspend, then we can
   464       // consider the thread to be externally suspended. This means that
   465       // the code that sets _thread_blocked has been modified to do
   466       // self-suspension if the blocking condition releases. We also
   467       // used to check for CONDVAR_WAIT here, but that is now covered by
   468       // the _thread_blocked with self-suspension check.
   469       //
   470       // Return true since we wouldn't be here unless there was still an
   471       // external suspend request.
   472       *bits |= 0x00001000;
   473       return true;
   474     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
   475       // Threads running native code will self-suspend on native==>VM/Java
   476       // transitions. If its stack is walkable (should always be the case
   477       // unless this function is called before the actual java_suspend()
   478       // call), then the wait is done.
   479       *bits |= 0x00002000;
   480       return true;
   481     } else if (!called_by_wait && !did_trans_retry &&
   482                save_state == _thread_in_native_trans &&
   483                frame_anchor()->walkable()) {
   484       // The thread is transitioning from thread_in_native to another
   485       // thread state. check_safepoint_and_suspend_for_native_trans()
   486       // will force the thread to self-suspend. If it hasn't gotten
   487       // there yet we may have caught the thread in-between the native
   488       // code check above and the self-suspend. Lucky us. If we were
   489       // called by wait_for_ext_suspend_completion(), then it
   490       // will be doing the retries so we don't have to.
   491       //
   492       // Since we use the saved thread state in the if-statement above,
   493       // there is a chance that the thread has already transitioned to
   494       // _thread_blocked by the time we get here. In that case, we will
   495       // make a single unnecessary pass through the logic below. This
   496       // doesn't hurt anything since we still do the trans retry.
   498       *bits |= 0x00004000;
   500       // Once the thread leaves thread_in_native_trans for another
   501       // thread state, we break out of this retry loop. We shouldn't
   502       // need this flag to prevent us from getting back here, but
   503       // sometimes paranoia is good.
   504       did_trans_retry = true;
   506       // We wait for the thread to transition to a more usable state.
   507       for (int i = 1; i <= SuspendRetryCount; i++) {
   508         // We used to do an "os::yield_all(i)" call here with the intention
   509         // that yielding would increase on each retry. However, the parameter
   510         // is ignored on Linux which means the yield didn't scale up. Waiting
   511         // on the SR_lock below provides a much more predictable scale up for
   512         // the delay. It also provides a simple/direct point to check for any
   513         // safepoint requests from the VMThread
   515         // temporarily drops SR_lock while doing wait with safepoint check
   516         // (if we're a JavaThread - the WatcherThread can also call this)
   517         // and increase delay with each retry
   518         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
   520         // check the actual thread state instead of what we saved above
   521         if (thread_state() != _thread_in_native_trans) {
   522           // the thread has transitioned to another thread state so
   523           // try all the checks (except this one) one more time.
   524           do_trans_retry = true;
   525           break;
   526         }
   527       } // end retry loop
   530     }
   531   } while (do_trans_retry);
   533   *bits |= 0x00000010;
   534   return false;
   535 }
   537 //
   538 // Wait for an external suspend request to complete (or be cancelled).
   539 // Returns true if the thread is externally suspended and false otherwise.
   540 //
   541 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
   542        uint32_t *bits) {
   543   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
   544                              false /* !called_by_wait */, bits);
   546   // local flag copies to minimize SR_lock hold time
   547   bool is_suspended;
   548   bool pending;
   549   uint32_t reset_bits;
   551   // set a marker so is_ext_suspend_completed() knows we are the caller
   552   *bits |= 0x00010000;
   554   // We use reset_bits to reinitialize the bits value at the top of
   555   // each retry loop. This allows the caller to make use of any
   556   // unused bits for their own marking purposes.
   557   reset_bits = *bits;
   559   {
   560     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
   561     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
   562                                             delay, bits);
   563     pending = is_external_suspend();
   564   }
   565   // must release SR_lock to allow suspension to complete
   567   if (!pending) {
   568     // A cancelled suspend request is the only false return from
   569     // is_ext_suspend_completed() that keeps us from entering the
   570     // retry loop.
   571     *bits |= 0x00020000;
   572     return false;
   573   }
   575   if (is_suspended) {
   576     *bits |= 0x00040000;
   577     return true;
   578   }
   580   for (int i = 1; i <= retries; i++) {
   581     *bits = reset_bits;  // reinit to only track last retry
   583     // We used to do an "os::yield_all(i)" call here with the intention
   584     // that yielding would increase on each retry. However, the parameter
   585     // is ignored on Linux which means the yield didn't scale up. Waiting
   586     // on the SR_lock below provides a much more predictable scale up for
   587     // the delay. It also provides a simple/direct point to check for any
   588     // safepoint requests from the VMThread
   590     {
   591       MutexLocker ml(SR_lock());
   592       // wait with safepoint check (if we're a JavaThread - the WatcherThread
   593       // can also call this)  and increase delay with each retry
   594       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
   596       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
   597                                               delay, bits);
   599       // It is possible for the external suspend request to be cancelled
   600       // (by a resume) before the actual suspend operation is completed.
   601       // Refresh our local copy to see if we still need to wait.
   602       pending = is_external_suspend();
   603     }
   605     if (!pending) {
   606       // A cancelled suspend request is the only false return from
   607       // is_ext_suspend_completed() that keeps us from staying in the
   608       // retry loop.
   609       *bits |= 0x00080000;
   610       return false;
   611     }
   613     if (is_suspended) {
   614       *bits |= 0x00100000;
   615       return true;
   616     }
   617   } // end retry loop
   619   // thread did not suspend after all our retries
   620   *bits |= 0x00200000;
   621   return false;
   622 }
   624 #ifndef PRODUCT
   625 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
   627   // This should not need to be atomic as the only way for simultaneous
   628   // updates is via interrupts. Even then this should be rare or non-existant
   629   // and we don't care that much anyway.
   631   int index = _jmp_ring_index;
   632   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
   633   _jmp_ring[index]._target = (intptr_t) target;
   634   _jmp_ring[index]._instruction = (intptr_t) instr;
   635   _jmp_ring[index]._file = file;
   636   _jmp_ring[index]._line = line;
   637 }
   638 #endif /* PRODUCT */
   640 // Called by flat profiler
   641 // Callers have already called wait_for_ext_suspend_completion
   642 // The assertion for that is currently too complex to put here:
   643 bool JavaThread::profile_last_Java_frame(frame* _fr) {
   644   bool gotframe = false;
   645   // self suspension saves needed state.
   646   if (has_last_Java_frame() && _anchor.walkable()) {
   647      *_fr = pd_last_frame();
   648      gotframe = true;
   649   }
   650   return gotframe;
   651 }
   653 void Thread::interrupt(Thread* thread) {
   654   trace("interrupt", thread);
   655   debug_only(check_for_dangling_thread_pointer(thread);)
   656   os::interrupt(thread);
   657 }
   659 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
   660   trace("is_interrupted", thread);
   661   debug_only(check_for_dangling_thread_pointer(thread);)
   662   // Note:  If clear_interrupted==false, this simply fetches and
   663   // returns the value of the field osthread()->interrupted().
   664   return os::is_interrupted(thread, clear_interrupted);
   665 }
   668 // GC Support
   669 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
   670   jint thread_parity = _oops_do_parity;
   671   if (thread_parity != strong_roots_parity) {
   672     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
   673     if (res == thread_parity) return true;
   674     else {
   675       guarantee(res == strong_roots_parity, "Or else what?");
   676       assert(SharedHeap::heap()->n_par_threads() > 0,
   677              "Should only fail when parallel.");
   678       return false;
   679     }
   680   }
   681   assert(SharedHeap::heap()->n_par_threads() > 0,
   682          "Should only fail when parallel.");
   683   return false;
   684 }
   686 void Thread::oops_do(OopClosure* f) {
   687   active_handles()->oops_do(f);
   688   // Do oop for ThreadShadow
   689   f->do_oop((oop*)&_pending_exception);
   690   handle_area()->oops_do(f);
   691 }
   693 void Thread::nmethods_do() {
   694 }
   696 void Thread::print_on(outputStream* st) const {
   697   // get_priority assumes osthread initialized
   698   if (osthread() != NULL) {
   699     st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
   700     osthread()->print_on(st);
   701   }
   702   debug_only(if (WizardMode) print_owned_locks_on(st);)
   703 }
   705 // Thread::print_on_error() is called by fatal error handler. Don't use
   706 // any lock or allocate memory.
   707 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
   708   if      (is_VM_thread())                  st->print("VMThread");
   709   else if (is_Compiler_thread())            st->print("CompilerThread");
   710   else if (is_Java_thread())                st->print("JavaThread");
   711   else if (is_GC_task_thread())             st->print("GCTaskThread");
   712   else if (is_Watcher_thread())             st->print("WatcherThread");
   713   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
   714   else st->print("Thread");
   716   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
   717             _stack_base - _stack_size, _stack_base);
   719   if (osthread()) {
   720     st->print(" [id=%d]", osthread()->thread_id());
   721   }
   722 }
   724 #ifdef ASSERT
   725 void Thread::print_owned_locks_on(outputStream* st) const {
   726   Monitor *cur = _owned_locks;
   727   if (cur == NULL) {
   728     st->print(" (no locks) ");
   729   } else {
   730     st->print_cr(" Locks owned:");
   731     while(cur) {
   732       cur->print_on(st);
   733       cur = cur->next();
   734     }
   735   }
   736 }
   738 static int ref_use_count  = 0;
   740 bool Thread::owns_locks_but_compiled_lock() const {
   741   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
   742     if (cur != Compile_lock) return true;
   743   }
   744   return false;
   745 }
   748 #endif
   750 #ifndef PRODUCT
   752 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
   753 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
   754 // no threads which allow_vm_block's are held
   755 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
   756     // Check if current thread is allowed to block at a safepoint
   757     if (!(_allow_safepoint_count == 0))
   758       fatal("Possible safepoint reached by thread that does not allow it");
   759     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
   760       fatal("LEAF method calling lock?");
   761     }
   763 #ifdef ASSERT
   764     if (potential_vm_operation && is_Java_thread()
   765         && !Universe::is_bootstrapping()) {
   766       // Make sure we do not hold any locks that the VM thread also uses.
   767       // This could potentially lead to deadlocks
   768       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
   769         // Threads_lock is special, since the safepoint synchronization will not start before this is
   770         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
   771         // since it is used to transfer control between JavaThreads and the VMThread
   772         // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
   773         if ( (cur->allow_vm_block() &&
   774               cur != Threads_lock &&
   775               cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
   776               cur != VMOperationRequest_lock &&
   777               cur != VMOperationQueue_lock) ||
   778               cur->rank() == Mutex::special) {
   779           warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
   780         }
   781       }
   782     }
   784     if (GCALotAtAllSafepoints) {
   785       // We could enter a safepoint here and thus have a gc
   786       InterfaceSupport::check_gc_alot();
   787     }
   789 #endif
   790 }
   791 #endif
   793 bool Thread::lock_is_in_stack(address adr) const {
   794   assert(Thread::current() == this, "lock_is_in_stack can only be called from current thread");
   795   // High limit: highest_lock is set during thread execution
   796   // Low  limit: address of the local variable dummy, rounded to 4K boundary.
   797   // (The rounding helps finding threads in unsafe mode, even if the particular stack
   798   // frame has been popped already.  Correct as long as stacks are at least 4K long and aligned.)
   799   address end = os::current_stack_pointer();
   800   if (_highest_lock >= adr && adr >= end) return true;
   802   return false;
   803 }
   806 bool Thread::is_in_stack(address adr) const {
   807   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
   808   address end = os::current_stack_pointer();
   809   if (stack_base() >= adr && adr >= end) return true;
   811   return false;
   812 }
   815 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
   816 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
   817 // used for compilation in the future. If that change is made, the need for these methods
   818 // should be revisited, and they should be removed if possible.
   820 bool Thread::is_lock_owned(address adr) const {
   821   if (lock_is_in_stack(adr) ) return true;
   822   return false;
   823 }
   825 bool Thread::set_as_starting_thread() {
   826  // NOTE: this must be called inside the main thread.
   827   return os::create_main_thread((JavaThread*)this);
   828 }
   830 static void initialize_class(symbolHandle class_name, TRAPS) {
   831   klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
   832   instanceKlass::cast(klass)->initialize(CHECK);
   833 }
   836 // Creates the initial ThreadGroup
   837 static Handle create_initial_thread_group(TRAPS) {
   838   klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
   839   instanceKlassHandle klass (THREAD, k);
   841   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
   842   {
   843     JavaValue result(T_VOID);
   844     JavaCalls::call_special(&result,
   845                             system_instance,
   846                             klass,
   847                             vmSymbolHandles::object_initializer_name(),
   848                             vmSymbolHandles::void_method_signature(),
   849                             CHECK_NH);
   850   }
   851   Universe::set_system_thread_group(system_instance());
   853   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
   854   {
   855     JavaValue result(T_VOID);
   856     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
   857     JavaCalls::call_special(&result,
   858                             main_instance,
   859                             klass,
   860                             vmSymbolHandles::object_initializer_name(),
   861                             vmSymbolHandles::threadgroup_string_void_signature(),
   862                             system_instance,
   863                             string,
   864                             CHECK_NH);
   865   }
   866   return main_instance;
   867 }
   869 // Creates the initial Thread
   870 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
   871   klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
   872   instanceKlassHandle klass (THREAD, k);
   873   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
   875   java_lang_Thread::set_thread(thread_oop(), thread);
   876   java_lang_Thread::set_priority(thread_oop(), NormPriority);
   877   thread->set_threadObj(thread_oop());
   879   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
   881   JavaValue result(T_VOID);
   882   JavaCalls::call_special(&result, thread_oop,
   883                                    klass,
   884                                    vmSymbolHandles::object_initializer_name(),
   885                                    vmSymbolHandles::threadgroup_string_void_signature(),
   886                                    thread_group,
   887                                    string,
   888                                    CHECK_NULL);
   889   return thread_oop();
   890 }
   892 static void call_initializeSystemClass(TRAPS) {
   893   klassOop k =  SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
   894   instanceKlassHandle klass (THREAD, k);
   896   JavaValue result(T_VOID);
   897   JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
   898                                          vmSymbolHandles::void_method_signature(), CHECK);
   899 }
   901 static void reset_vm_info_property(TRAPS) {
   902   // the vm info string
   903   ResourceMark rm(THREAD);
   904   const char *vm_info = VM_Version::vm_info_string();
   906   // java.lang.System class
   907   klassOop k =  SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
   908   instanceKlassHandle klass (THREAD, k);
   910   // setProperty arguments
   911   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
   912   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
   914   // return value
   915   JavaValue r(T_OBJECT);
   917   // public static String setProperty(String key, String value);
   918   JavaCalls::call_static(&r,
   919                          klass,
   920                          vmSymbolHandles::setProperty_name(),
   921                          vmSymbolHandles::string_string_string_signature(),
   922                          key_str,
   923                          value_str,
   924                          CHECK);
   925 }
   928 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
   929   assert(thread_group.not_null(), "thread group should be specified");
   930   assert(threadObj() == NULL, "should only create Java thread object once");
   932   klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
   933   instanceKlassHandle klass (THREAD, k);
   934   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
   936   java_lang_Thread::set_thread(thread_oop(), this);
   937   java_lang_Thread::set_priority(thread_oop(), NormPriority);
   938   set_threadObj(thread_oop());
   940   JavaValue result(T_VOID);
   941   if (thread_name != NULL) {
   942     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
   943     // Thread gets assigned specified name and null target
   944     JavaCalls::call_special(&result,
   945                             thread_oop,
   946                             klass,
   947                             vmSymbolHandles::object_initializer_name(),
   948                             vmSymbolHandles::threadgroup_string_void_signature(),
   949                             thread_group, // Argument 1
   950                             name,         // Argument 2
   951                             THREAD);
   952   } else {
   953     // Thread gets assigned name "Thread-nnn" and null target
   954     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
   955     JavaCalls::call_special(&result,
   956                             thread_oop,
   957                             klass,
   958                             vmSymbolHandles::object_initializer_name(),
   959                             vmSymbolHandles::threadgroup_runnable_void_signature(),
   960                             thread_group, // Argument 1
   961                             Handle(),     // Argument 2
   962                             THREAD);
   963   }
   966   if (daemon) {
   967       java_lang_Thread::set_daemon(thread_oop());
   968   }
   970   if (HAS_PENDING_EXCEPTION) {
   971     return;
   972   }
   974   KlassHandle group(this, SystemDictionary::threadGroup_klass());
   975   Handle threadObj(this, this->threadObj());
   977   JavaCalls::call_special(&result,
   978                          thread_group,
   979                          group,
   980                          vmSymbolHandles::add_method_name(),
   981                          vmSymbolHandles::thread_void_signature(),
   982                          threadObj,          // Arg 1
   983                          THREAD);
   986 }
   988 // NamedThread --  non-JavaThread subclasses with multiple
   989 // uniquely named instances should derive from this.
   990 NamedThread::NamedThread() : Thread() {
   991   _name = NULL;
   992 }
   994 NamedThread::~NamedThread() {
   995   if (_name != NULL) {
   996     FREE_C_HEAP_ARRAY(char, _name);
   997     _name = NULL;
   998   }
   999 }
  1001 void NamedThread::set_name(const char* format, ...) {
  1002   guarantee(_name == NULL, "Only get to set name once.");
  1003   _name = NEW_C_HEAP_ARRAY(char, max_name_len);
  1004   guarantee(_name != NULL, "alloc failure");
  1005   va_list ap;
  1006   va_start(ap, format);
  1007   jio_vsnprintf(_name, max_name_len, format, ap);
  1008   va_end(ap);
  1011 // ======= WatcherThread ========
  1013 // The watcher thread exists to simulate timer interrupts.  It should
  1014 // be replaced by an abstraction over whatever native support for
  1015 // timer interrupts exists on the platform.
  1017 WatcherThread* WatcherThread::_watcher_thread   = NULL;
  1018 bool           WatcherThread::_should_terminate = false;
  1020 WatcherThread::WatcherThread() : Thread() {
  1021   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
  1022   if (os::create_thread(this, os::watcher_thread)) {
  1023     _watcher_thread = this;
  1025     // Set the watcher thread to the highest OS priority which should not be
  1026     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
  1027     // is created. The only normal thread using this priority is the reference
  1028     // handler thread, which runs for very short intervals only.
  1029     // If the VMThread's priority is not lower than the WatcherThread profiling
  1030     // will be inaccurate.
  1031     os::set_priority(this, MaxPriority);
  1032     if (!DisableStartThread) {
  1033       os::start_thread(this);
  1038 void WatcherThread::run() {
  1039   assert(this == watcher_thread(), "just checking");
  1041   this->record_stack_base_and_size();
  1042   this->initialize_thread_local_storage();
  1043   this->set_active_handles(JNIHandleBlock::allocate_block());
  1044   while(!_should_terminate) {
  1045     assert(watcher_thread() == Thread::current(),  "thread consistency check");
  1046     assert(watcher_thread() == this,  "thread consistency check");
  1048     // Calculate how long it'll be until the next PeriodicTask work
  1049     // should be done, and sleep that amount of time.
  1050     const size_t time_to_wait = PeriodicTask::time_to_wait();
  1051     os::sleep(this, time_to_wait, false);
  1053     if (is_error_reported()) {
  1054       // A fatal error has happened, the error handler(VMError::report_and_die)
  1055       // should abort JVM after creating an error log file. However in some
  1056       // rare cases, the error handler itself might deadlock. Here we try to
  1057       // kill JVM if the fatal error handler fails to abort in 2 minutes.
  1058       //
  1059       // This code is in WatcherThread because WatcherThread wakes up
  1060       // periodically so the fatal error handler doesn't need to do anything;
  1061       // also because the WatcherThread is less likely to crash than other
  1062       // threads.
  1064       for (;;) {
  1065         if (!ShowMessageBoxOnError
  1066          && (OnError == NULL || OnError[0] == '\0')
  1067          && Arguments::abort_hook() == NULL) {
  1068              os::sleep(this, 2 * 60 * 1000, false);
  1069              fdStream err(defaultStream::output_fd());
  1070              err.print_raw_cr("# [ timer expired, abort... ]");
  1071              // skip atexit/vm_exit/vm_abort hooks
  1072              os::die();
  1075         // Wake up 5 seconds later, the fatal handler may reset OnError or
  1076         // ShowMessageBoxOnError when it is ready to abort.
  1077         os::sleep(this, 5 * 1000, false);
  1081     PeriodicTask::real_time_tick(time_to_wait);
  1083     // If we have no more tasks left due to dynamic disenrollment,
  1084     // shut down the thread since we don't currently support dynamic enrollment
  1085     if (PeriodicTask::num_tasks() == 0) {
  1086       _should_terminate = true;
  1090   // Signal that it is terminated
  1092     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
  1093     _watcher_thread = NULL;
  1094     Terminator_lock->notify();
  1097   // Thread destructor usually does this..
  1098   ThreadLocalStorage::set_thread(NULL);
  1101 void WatcherThread::start() {
  1102   if (watcher_thread() == NULL) {
  1103     _should_terminate = false;
  1104     // Create the single instance of WatcherThread
  1105     new WatcherThread();
  1109 void WatcherThread::stop() {
  1110   // it is ok to take late safepoints here, if needed
  1111   MutexLocker mu(Terminator_lock);
  1112   _should_terminate = true;
  1113   while(watcher_thread() != NULL) {
  1114     // This wait should make safepoint checks, wait without a timeout,
  1115     // and wait as a suspend-equivalent condition.
  1116     //
  1117     // Note: If the FlatProfiler is running, then this thread is waiting
  1118     // for the WatcherThread to terminate and the WatcherThread, via the
  1119     // FlatProfiler task, is waiting for the external suspend request on
  1120     // this thread to complete. wait_for_ext_suspend_completion() will
  1121     // eventually timeout, but that takes time. Making this wait a
  1122     // suspend-equivalent condition solves that timeout problem.
  1123     //
  1124     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
  1125                           Mutex::_as_suspend_equivalent_flag);
  1129 void WatcherThread::print_on(outputStream* st) const {
  1130   st->print("\"%s\" ", name());
  1131   Thread::print_on(st);
  1132   st->cr();
  1135 // ======= JavaThread ========
  1137 // A JavaThread is a normal Java thread
  1139 void JavaThread::initialize() {
  1140   // Initialize fields
  1141   set_saved_exception_pc(NULL);
  1142   set_threadObj(NULL);
  1143   _anchor.clear();
  1144   set_entry_point(NULL);
  1145   set_jni_functions(jni_functions());
  1146   set_callee_target(NULL);
  1147   set_vm_result(NULL);
  1148   set_vm_result_2(NULL);
  1149   set_vframe_array_head(NULL);
  1150   set_vframe_array_last(NULL);
  1151   set_deferred_locals(NULL);
  1152   set_deopt_mark(NULL);
  1153   clear_must_deopt_id();
  1154   set_monitor_chunks(NULL);
  1155   set_next(NULL);
  1156   set_thread_state(_thread_new);
  1157   _terminated = _not_terminated;
  1158   _privileged_stack_top = NULL;
  1159   _array_for_gc = NULL;
  1160   _suspend_equivalent = false;
  1161   _in_deopt_handler = 0;
  1162   _doing_unsafe_access = false;
  1163   _stack_guard_state = stack_guard_unused;
  1164   _exception_oop = NULL;
  1165   _exception_pc  = 0;
  1166   _exception_handler_pc = 0;
  1167   _exception_stack_size = 0;
  1168   _jvmti_thread_state= NULL;
  1169   _jvmti_get_loaded_classes_closure = NULL;
  1170   _interp_only_mode    = 0;
  1171   _special_runtime_exit_condition = _no_async_condition;
  1172   _pending_async_exception = NULL;
  1173   _is_compiling = false;
  1174   _thread_stat = NULL;
  1175   _thread_stat = new ThreadStatistics();
  1176   _blocked_on_compilation = false;
  1177   _jni_active_critical = 0;
  1178   _do_not_unlock_if_synchronized = false;
  1179   _cached_monitor_info = NULL;
  1180   _parker = Parker::Allocate(this) ;
  1182 #ifndef PRODUCT
  1183   _jmp_ring_index = 0;
  1184   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
  1185     record_jump(NULL, NULL, NULL, 0);
  1187 #endif /* PRODUCT */
  1189   set_thread_profiler(NULL);
  1190   if (FlatProfiler::is_active()) {
  1191     // This is where we would decide to either give each thread it's own profiler
  1192     // or use one global one from FlatProfiler,
  1193     // or up to some count of the number of profiled threads, etc.
  1194     ThreadProfiler* pp = new ThreadProfiler();
  1195     pp->engage();
  1196     set_thread_profiler(pp);
  1199   // Setup safepoint state info for this thread
  1200   ThreadSafepointState::create(this);
  1202   debug_only(_java_call_counter = 0);
  1204   // JVMTI PopFrame support
  1205   _popframe_condition = popframe_inactive;
  1206   _popframe_preserved_args = NULL;
  1207   _popframe_preserved_args_size = 0;
  1209   pd_initialize();
  1212 JavaThread::JavaThread(bool is_attaching) : Thread() {
  1213   initialize();
  1214   _is_attaching = is_attaching;
  1217 bool JavaThread::reguard_stack(address cur_sp) {
  1218   if (_stack_guard_state != stack_guard_yellow_disabled) {
  1219     return true; // Stack already guarded or guard pages not needed.
  1222   if (register_stack_overflow()) {
  1223     // For those architectures which have separate register and
  1224     // memory stacks, we must check the register stack to see if
  1225     // it has overflowed.
  1226     return false;
  1229   // Java code never executes within the yellow zone: the latter is only
  1230   // there to provoke an exception during stack banging.  If java code
  1231   // is executing there, either StackShadowPages should be larger, or
  1232   // some exception code in c1, c2 or the interpreter isn't unwinding
  1233   // when it should.
  1234   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
  1236   enable_stack_yellow_zone();
  1237   return true;
  1240 bool JavaThread::reguard_stack(void) {
  1241   return reguard_stack(os::current_stack_pointer());
  1245 void JavaThread::block_if_vm_exited() {
  1246   if (_terminated == _vm_exited) {
  1247     // _vm_exited is set at safepoint, and Threads_lock is never released
  1248     // we will block here forever
  1249     Threads_lock->lock_without_safepoint_check();
  1250     ShouldNotReachHere();
  1255 // Remove this ifdef when C1 is ported to the compiler interface.
  1256 static void compiler_thread_entry(JavaThread* thread, TRAPS);
  1258 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : Thread() {
  1259   if (TraceThreadEvents) {
  1260     tty->print_cr("creating thread %p", this);
  1262   initialize();
  1263   _is_attaching = false;
  1264   set_entry_point(entry_point);
  1265   // Create the native thread itself.
  1266   // %note runtime_23
  1267   os::ThreadType thr_type = os::java_thread;
  1268   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
  1269                                                      os::java_thread;
  1270   os::create_thread(this, thr_type, stack_sz);
  1272   // The _osthread may be NULL here because we ran out of memory (too many threads active).
  1273   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
  1274   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
  1275   // the exception consists of creating the exception object & initializing it, initialization
  1276   // will leave the VM via a JavaCall and then all locks must be unlocked).
  1277   //
  1278   // The thread is still suspended when we reach here. Thread must be explicit started
  1279   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
  1280   // by calling Threads:add. The reason why this is not done here, is because the thread
  1281   // object must be fully initialized (take a look at JVM_Start)
  1284 JavaThread::~JavaThread() {
  1285   if (TraceThreadEvents) {
  1286       tty->print_cr("terminate thread %p", this);
  1289   // JSR166 -- return the parker to the free list
  1290   Parker::Release(_parker);
  1291   _parker = NULL ;
  1293   // Free any remaining  previous UnrollBlock
  1294   vframeArray* old_array = vframe_array_last();
  1296   if (old_array != NULL) {
  1297     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
  1298     old_array->set_unroll_block(NULL);
  1299     delete old_info;
  1300     delete old_array;
  1303   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
  1304   if (deferred != NULL) {
  1305     // This can only happen if thread is destroyed before deoptimization occurs.
  1306     assert(deferred->length() != 0, "empty array!");
  1307     do {
  1308       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
  1309       deferred->remove_at(0);
  1310       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
  1311       delete dlv;
  1312     } while (deferred->length() != 0);
  1313     delete deferred;
  1316   // All Java related clean up happens in exit
  1317   ThreadSafepointState::destroy(this);
  1318   if (_thread_profiler != NULL) delete _thread_profiler;
  1319   if (_thread_stat != NULL) delete _thread_stat;
  1323 // The first routine called by a new Java thread
  1324 void JavaThread::run() {
  1325   // initialize thread-local alloc buffer related fields
  1326   this->initialize_tlab();
  1328   // used to test validitity of stack trace backs
  1329   this->record_base_of_stack_pointer();
  1331   // Record real stack base and size.
  1332   this->record_stack_base_and_size();
  1334   // Initialize thread local storage; set before calling MutexLocker
  1335   this->initialize_thread_local_storage();
  1337   this->create_stack_guard_pages();
  1339   // Thread is now sufficient initialized to be handled by the safepoint code as being
  1340   // in the VM. Change thread state from _thread_new to _thread_in_vm
  1341   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
  1343   assert(JavaThread::current() == this, "sanity check");
  1344   assert(!Thread::current()->owns_locks(), "sanity check");
  1346   DTRACE_THREAD_PROBE(start, this);
  1348   // This operation might block. We call that after all safepoint checks for a new thread has
  1349   // been completed.
  1350   this->set_active_handles(JNIHandleBlock::allocate_block());
  1352   if (JvmtiExport::should_post_thread_life()) {
  1353     JvmtiExport::post_thread_start(this);
  1356   // We call another function to do the rest so we are sure that the stack addresses used
  1357   // from there will be lower than the stack base just computed
  1358   thread_main_inner();
  1360   // Note, thread is no longer valid at this point!
  1364 void JavaThread::thread_main_inner() {
  1365   assert(JavaThread::current() == this, "sanity check");
  1366   assert(this->threadObj() != NULL, "just checking");
  1368   // Execute thread entry point. If this thread is being asked to restart,
  1369   // or has been stopped before starting, do not reexecute entry point.
  1370   // Note: Due to JVM_StopThread we can have pending exceptions already!
  1371   if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
  1372     // enter the thread's entry point only if we have no pending exceptions
  1373     HandleMark hm(this);
  1374     this->entry_point()(this, this);
  1377   DTRACE_THREAD_PROBE(stop, this);
  1379   this->exit(false);
  1380   delete this;
  1384 static void ensure_join(JavaThread* thread) {
  1385   // We do not need to grap the Threads_lock, since we are operating on ourself.
  1386   Handle threadObj(thread, thread->threadObj());
  1387   assert(threadObj.not_null(), "java thread object must exist");
  1388   ObjectLocker lock(threadObj, thread);
  1389   // Ignore pending exception (ThreadDeath), since we are exiting anyway
  1390   thread->clear_pending_exception();
  1391   // It is of profound importance that we set the stillborn bit and reset the thread object,
  1392   // before we do the notify. Since, changing these two variable will make JVM_IsAlive return
  1393   // false. So in case another thread is doing a join on this thread , it will detect that the thread
  1394   // is dead when it gets notified.
  1395   java_lang_Thread::set_stillborn(threadObj());
  1396   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
  1397   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
  1398   java_lang_Thread::set_thread(threadObj(), NULL);
  1399   lock.notify_all(thread);
  1400   // Ignore pending exception (ThreadDeath), since we are exiting anyway
  1401   thread->clear_pending_exception();
  1404 // For any new cleanup additions, please check to see if they need to be applied to
  1405 // cleanup_failed_attach_current_thread as well.
  1406 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
  1407   assert(this == JavaThread::current(),  "thread consistency check");
  1408   if (!InitializeJavaLangSystem) return;
  1410   HandleMark hm(this);
  1411   Handle uncaught_exception(this, this->pending_exception());
  1412   this->clear_pending_exception();
  1413   Handle threadObj(this, this->threadObj());
  1414   assert(threadObj.not_null(), "Java thread object should be created");
  1416   if (get_thread_profiler() != NULL) {
  1417     get_thread_profiler()->disengage();
  1418     ResourceMark rm;
  1419     get_thread_profiler()->print(get_thread_name());
  1423   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
  1425     EXCEPTION_MARK;
  1427     CLEAR_PENDING_EXCEPTION;
  1429   // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
  1430   // has to be fixed by a runtime query method
  1431   if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
  1432     // JSR-166: change call from from ThreadGroup.uncaughtException to
  1433     // java.lang.Thread.dispatchUncaughtException
  1434     if (uncaught_exception.not_null()) {
  1435       Handle group(this, java_lang_Thread::threadGroup(threadObj()));
  1436       Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
  1437         (address)uncaught_exception(), (address)threadObj(), (address)group());
  1439         EXCEPTION_MARK;
  1440         // Check if the method Thread.dispatchUncaughtException() exists. If so
  1441         // call it.  Otherwise we have an older library without the JSR-166 changes,
  1442         // so call ThreadGroup.uncaughtException()
  1443         KlassHandle recvrKlass(THREAD, threadObj->klass());
  1444         CallInfo callinfo;
  1445         KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
  1446         LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
  1447                                            vmSymbolHandles::dispatchUncaughtException_name(),
  1448                                            vmSymbolHandles::throwable_void_signature(),
  1449                                            KlassHandle(), false, false, THREAD);
  1450         CLEAR_PENDING_EXCEPTION;
  1451         methodHandle method = callinfo.selected_method();
  1452         if (method.not_null()) {
  1453           JavaValue result(T_VOID);
  1454           JavaCalls::call_virtual(&result,
  1455                                   threadObj, thread_klass,
  1456                                   vmSymbolHandles::dispatchUncaughtException_name(),
  1457                                   vmSymbolHandles::throwable_void_signature(),
  1458                                   uncaught_exception,
  1459                                   THREAD);
  1460         } else {
  1461           KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass());
  1462           JavaValue result(T_VOID);
  1463           JavaCalls::call_virtual(&result,
  1464                                   group, thread_group,
  1465                                   vmSymbolHandles::uncaughtException_name(),
  1466                                   vmSymbolHandles::thread_throwable_void_signature(),
  1467                                   threadObj,           // Arg 1
  1468                                   uncaught_exception,  // Arg 2
  1469                                   THREAD);
  1471         CLEAR_PENDING_EXCEPTION;
  1475     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
  1476     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
  1477     // is deprecated anyhow.
  1478     { int count = 3;
  1479       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
  1480         EXCEPTION_MARK;
  1481         JavaValue result(T_VOID);
  1482         KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
  1483         JavaCalls::call_virtual(&result,
  1484                               threadObj, thread_klass,
  1485                               vmSymbolHandles::exit_method_name(),
  1486                               vmSymbolHandles::void_method_signature(),
  1487                               THREAD);
  1488         CLEAR_PENDING_EXCEPTION;
  1492     // notify JVMTI
  1493     if (JvmtiExport::should_post_thread_life()) {
  1494       JvmtiExport::post_thread_end(this);
  1497     // We have notified the agents that we are exiting, before we go on,
  1498     // we must check for a pending external suspend request and honor it
  1499     // in order to not surprise the thread that made the suspend request.
  1500     while (true) {
  1502         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
  1503         if (!is_external_suspend()) {
  1504           set_terminated(_thread_exiting);
  1505           ThreadService::current_thread_exiting(this);
  1506           break;
  1508         // Implied else:
  1509         // Things get a little tricky here. We have a pending external
  1510         // suspend request, but we are holding the SR_lock so we
  1511         // can't just self-suspend. So we temporarily drop the lock
  1512         // and then self-suspend.
  1515       ThreadBlockInVM tbivm(this);
  1516       java_suspend_self();
  1518       // We're done with this suspend request, but we have to loop around
  1519       // and check again. Eventually we will get SR_lock without a pending
  1520       // external suspend request and will be able to mark ourselves as
  1521       // exiting.
  1523     // no more external suspends are allowed at this point
  1524   } else {
  1525     // before_exit() has already posted JVMTI THREAD_END events
  1528   // Notify waiters on thread object. This has to be done after exit() is called
  1529   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
  1530   // group should have the destroyed bit set before waiters are notified).
  1531   ensure_join(this);
  1532   assert(!this->has_pending_exception(), "ensure_join should have cleared");
  1534   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
  1535   // held by this thread must be released.  A detach operation must only
  1536   // get here if there are no Java frames on the stack.  Therefore, any
  1537   // owned monitors at this point MUST be JNI-acquired monitors which are
  1538   // pre-inflated and in the monitor cache.
  1539   //
  1540   // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
  1541   if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
  1542     assert(!this->has_last_Java_frame(), "detaching with Java frames?");
  1543     ObjectSynchronizer::release_monitors_owned_by_thread(this);
  1544     assert(!this->has_pending_exception(), "release_monitors should have cleared");
  1547   // These things needs to be done while we are still a Java Thread. Make sure that thread
  1548   // is in a consistent state, in case GC happens
  1549   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
  1551   if (active_handles() != NULL) {
  1552     JNIHandleBlock* block = active_handles();
  1553     set_active_handles(NULL);
  1554     JNIHandleBlock::release_block(block);
  1557   if (free_handle_block() != NULL) {
  1558     JNIHandleBlock* block = free_handle_block();
  1559     set_free_handle_block(NULL);
  1560     JNIHandleBlock::release_block(block);
  1563   // These have to be removed while this is still a valid thread.
  1564   remove_stack_guard_pages();
  1566   if (UseTLAB) {
  1567     tlab().make_parsable(true);  // retire TLAB
  1570   if (jvmti_thread_state() != NULL) {
  1571     JvmtiExport::cleanup_thread(this);
  1574   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
  1575   Threads::remove(this);
  1578 void JavaThread::cleanup_failed_attach_current_thread() {
  1580      if (get_thread_profiler() != NULL) {
  1581        get_thread_profiler()->disengage();
  1582        ResourceMark rm;
  1583        get_thread_profiler()->print(get_thread_name());
  1586      if (active_handles() != NULL) {
  1587       JNIHandleBlock* block = active_handles();
  1588       set_active_handles(NULL);
  1589       JNIHandleBlock::release_block(block);
  1592      if (free_handle_block() != NULL) {
  1593        JNIHandleBlock* block = free_handle_block();
  1594        set_free_handle_block(NULL);
  1595        JNIHandleBlock::release_block(block);
  1598      if (UseTLAB) {
  1599        tlab().make_parsable(true);  // retire TLAB, if any
  1602      Threads::remove(this);
  1603      delete this;
  1607 JavaThread* JavaThread::active() {
  1608   Thread* thread = ThreadLocalStorage::thread();
  1609   assert(thread != NULL, "just checking");
  1610   if (thread->is_Java_thread()) {
  1611     return (JavaThread*) thread;
  1612   } else {
  1613     assert(thread->is_VM_thread(), "this must be a vm thread");
  1614     VM_Operation* op = ((VMThread*) thread)->vm_operation();
  1615     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
  1616     assert(ret->is_Java_thread(), "must be a Java thread");
  1617     return ret;
  1621 bool JavaThread::is_lock_owned(address adr) const {
  1622   if (lock_is_in_stack(adr)) return true;
  1624   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
  1625     if (chunk->contains(adr)) return true;
  1628   return false;
  1632 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
  1633   chunk->set_next(monitor_chunks());
  1634   set_monitor_chunks(chunk);
  1637 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
  1638   guarantee(monitor_chunks() != NULL, "must be non empty");
  1639   if (monitor_chunks() == chunk) {
  1640     set_monitor_chunks(chunk->next());
  1641   } else {
  1642     MonitorChunk* prev = monitor_chunks();
  1643     while (prev->next() != chunk) prev = prev->next();
  1644     prev->set_next(chunk->next());
  1648 // JVM support.
  1650 // Note: this function shouldn't block if it's called in
  1651 // _thread_in_native_trans state (such as from
  1652 // check_special_condition_for_native_trans()).
  1653 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
  1655   if (has_last_Java_frame() && has_async_condition()) {
  1656     // If we are at a polling page safepoint (not a poll return)
  1657     // then we must defer async exception because live registers
  1658     // will be clobbered by the exception path. Poll return is
  1659     // ok because the call we a returning from already collides
  1660     // with exception handling registers and so there is no issue.
  1661     // (The exception handling path kills call result registers but
  1662     //  this is ok since the exception kills the result anyway).
  1664     if (is_at_poll_safepoint()) {
  1665       // if the code we are returning to has deoptimized we must defer
  1666       // the exception otherwise live registers get clobbered on the
  1667       // exception path before deoptimization is able to retrieve them.
  1668       //
  1669       RegisterMap map(this, false);
  1670       frame caller_fr = last_frame().sender(&map);
  1671       assert(caller_fr.is_compiled_frame(), "what?");
  1672       if (caller_fr.is_deoptimized_frame()) {
  1673         if (TraceExceptions) {
  1674           ResourceMark rm;
  1675           tty->print_cr("deferred async exception at compiled safepoint");
  1677         return;
  1682   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
  1683   if (condition == _no_async_condition) {
  1684     // Conditions have changed since has_special_runtime_exit_condition()
  1685     // was called:
  1686     // - if we were here only because of an external suspend request,
  1687     //   then that was taken care of above (or cancelled) so we are done
  1688     // - if we were here because of another async request, then it has
  1689     //   been cleared between the has_special_runtime_exit_condition()
  1690     //   and now so again we are done
  1691     return;
  1694   // Check for pending async. exception
  1695   if (_pending_async_exception != NULL) {
  1696     // Only overwrite an already pending exception, if it is not a threadDeath.
  1697     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) {
  1699       // We cannot call Exceptions::_throw(...) here because we cannot block
  1700       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
  1702       if (TraceExceptions) {
  1703         ResourceMark rm;
  1704         tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
  1705         if (has_last_Java_frame() ) {
  1706           frame f = last_frame();
  1707           tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
  1709         tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
  1711       _pending_async_exception = NULL;
  1712       clear_has_async_exception();
  1716   if (check_unsafe_error &&
  1717       condition == _async_unsafe_access_error && !has_pending_exception()) {
  1718     condition = _no_async_condition;  // done
  1719     switch (thread_state()) {
  1720     case _thread_in_vm:
  1722         JavaThread* THREAD = this;
  1723         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
  1725     case _thread_in_native:
  1727         ThreadInVMfromNative tiv(this);
  1728         JavaThread* THREAD = this;
  1729         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
  1731     case _thread_in_Java:
  1733         ThreadInVMfromJava tiv(this);
  1734         JavaThread* THREAD = this;
  1735         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
  1737     default:
  1738       ShouldNotReachHere();
  1742   assert(condition == _no_async_condition || has_pending_exception() ||
  1743          (!check_unsafe_error && condition == _async_unsafe_access_error),
  1744          "must have handled the async condition, if no exception");
  1747 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
  1748   //
  1749   // Check for pending external suspend. Internal suspend requests do
  1750   // not use handle_special_runtime_exit_condition().
  1751   // If JNIEnv proxies are allowed, don't self-suspend if the target
  1752   // thread is not the current thread. In older versions of jdbx, jdbx
  1753   // threads could call into the VM with another thread's JNIEnv so we
  1754   // can be here operating on behalf of a suspended thread (4432884).
  1755   bool do_self_suspend = is_external_suspend_with_lock();
  1756   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
  1757     //
  1758     // Because thread is external suspended the safepoint code will count
  1759     // thread as at a safepoint. This can be odd because we can be here
  1760     // as _thread_in_Java which would normally transition to _thread_blocked
  1761     // at a safepoint. We would like to mark the thread as _thread_blocked
  1762     // before calling java_suspend_self like all other callers of it but
  1763     // we must then observe proper safepoint protocol. (We can't leave
  1764     // _thread_blocked with a safepoint in progress). However we can be
  1765     // here as _thread_in_native_trans so we can't use a normal transition
  1766     // constructor/destructor pair because they assert on that type of
  1767     // transition. We could do something like:
  1768     //
  1769     // JavaThreadState state = thread_state();
  1770     // set_thread_state(_thread_in_vm);
  1771     // {
  1772     //   ThreadBlockInVM tbivm(this);
  1773     //   java_suspend_self()
  1774     // }
  1775     // set_thread_state(_thread_in_vm_trans);
  1776     // if (safepoint) block;
  1777     // set_thread_state(state);
  1778     //
  1779     // but that is pretty messy. Instead we just go with the way the
  1780     // code has worked before and note that this is the only path to
  1781     // java_suspend_self that doesn't put the thread in _thread_blocked
  1782     // mode.
  1784     frame_anchor()->make_walkable(this);
  1785     java_suspend_self();
  1787     // We might be here for reasons in addition to the self-suspend request
  1788     // so check for other async requests.
  1791   if (check_asyncs) {
  1792     check_and_handle_async_exceptions();
  1796 void JavaThread::send_thread_stop(oop java_throwable)  {
  1797   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
  1798   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
  1799   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
  1801   // Do not throw asynchronous exceptions against the compiler thread
  1802   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
  1803   if (is_Compiler_thread()) return;
  1805   // This is a change from JDK 1.1, but JDK 1.2 will also do it:
  1806   if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) {
  1807     java_lang_Thread::set_stillborn(threadObj());
  1811     // Actually throw the Throwable against the target Thread - however
  1812     // only if there is no thread death exception installed already.
  1813     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) {
  1814       // If the topmost frame is a runtime stub, then we are calling into
  1815       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
  1816       // must deoptimize the caller before continuing, as the compiled  exception handler table
  1817       // may not be valid
  1818       if (has_last_Java_frame()) {
  1819         frame f = last_frame();
  1820         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
  1821           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
  1822           RegisterMap reg_map(this, UseBiasedLocking);
  1823           frame compiled_frame = f.sender(&reg_map);
  1824           if (compiled_frame.can_be_deoptimized()) {
  1825             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
  1830       // Set async. pending exception in thread.
  1831       set_pending_async_exception(java_throwable);
  1833       if (TraceExceptions) {
  1834        ResourceMark rm;
  1835        tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
  1837       // for AbortVMOnException flag
  1838       NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
  1843   // Interrupt thread so it will wake up from a potential wait()
  1844   Thread::interrupt(this);
  1847 // External suspension mechanism.
  1848 //
  1849 // Tell the VM to suspend a thread when ever it knows that it does not hold on
  1850 // to any VM_locks and it is at a transition
  1851 // Self-suspension will happen on the transition out of the vm.
  1852 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
  1853 //
  1854 // Guarantees on return:
  1855 //   + Target thread will not execute any new bytecode (that's why we need to
  1856 //     force a safepoint)
  1857 //   + Target thread will not enter any new monitors
  1858 //
  1859 void JavaThread::java_suspend() {
  1860   { MutexLocker mu(Threads_lock);
  1861     if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
  1862        return;
  1866   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
  1867     if (!is_external_suspend()) {
  1868       // a racing resume has cancelled us; bail out now
  1869       return;
  1872     // suspend is done
  1873     uint32_t debug_bits = 0;
  1874     // Warning: is_ext_suspend_completed() may temporarily drop the
  1875     // SR_lock to allow the thread to reach a stable thread state if
  1876     // it is currently in a transient thread state.
  1877     if (is_ext_suspend_completed(false /* !called_by_wait */,
  1878                                  SuspendRetryDelay, &debug_bits) ) {
  1879       return;
  1883   VM_ForceSafepoint vm_suspend;
  1884   VMThread::execute(&vm_suspend);
  1887 // Part II of external suspension.
  1888 // A JavaThread self suspends when it detects a pending external suspend
  1889 // request. This is usually on transitions. It is also done in places
  1890 // where continuing to the next transition would surprise the caller,
  1891 // e.g., monitor entry.
  1892 //
  1893 // Returns the number of times that the thread self-suspended.
  1894 //
  1895 // Note: DO NOT call java_suspend_self() when you just want to block current
  1896 //       thread. java_suspend_self() is the second stage of cooperative
  1897 //       suspension for external suspend requests and should only be used
  1898 //       to complete an external suspend request.
  1899 //
  1900 int JavaThread::java_suspend_self() {
  1901   int ret = 0;
  1903   // we are in the process of exiting so don't suspend
  1904   if (is_exiting()) {
  1905      clear_external_suspend();
  1906      return ret;
  1909   assert(_anchor.walkable() ||
  1910     (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
  1911     "must have walkable stack");
  1913   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
  1915   assert(!this->is_any_suspended(),
  1916     "a thread trying to self-suspend should not already be suspended");
  1918   if (this->is_suspend_equivalent()) {
  1919     // If we are self-suspending as a result of the lifting of a
  1920     // suspend equivalent condition, then the suspend_equivalent
  1921     // flag is not cleared until we set the ext_suspended flag so
  1922     // that wait_for_ext_suspend_completion() returns consistent
  1923     // results.
  1924     this->clear_suspend_equivalent();
  1927   // A racing resume may have cancelled us before we grabbed SR_lock
  1928   // above. Or another external suspend request could be waiting for us
  1929   // by the time we return from SR_lock()->wait(). The thread
  1930   // that requested the suspension may already be trying to walk our
  1931   // stack and if we return now, we can change the stack out from under
  1932   // it. This would be a "bad thing (TM)" and cause the stack walker
  1933   // to crash. We stay self-suspended until there are no more pending
  1934   // external suspend requests.
  1935   while (is_external_suspend()) {
  1936     ret++;
  1937     this->set_ext_suspended();
  1939     // _ext_suspended flag is cleared by java_resume()
  1940     while (is_ext_suspended()) {
  1941       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
  1945   return ret;
  1948 #ifdef ASSERT
  1949 // verify the JavaThread has not yet been published in the Threads::list, and
  1950 // hence doesn't need protection from concurrent access at this stage
  1951 void JavaThread::verify_not_published() {
  1952   if (!Threads_lock->owned_by_self()) {
  1953    MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
  1954    assert( !Threads::includes(this),
  1955            "java thread shouldn't have been published yet!");
  1957   else {
  1958    assert( !Threads::includes(this),
  1959            "java thread shouldn't have been published yet!");
  1962 #endif
  1964 // Slow path when the native==>VM/Java barriers detect a safepoint is in
  1965 // progress or when _suspend_flags is non-zero.
  1966 // Current thread needs to self-suspend if there is a suspend request and/or
  1967 // block if a safepoint is in progress.
  1968 // Async exception ISN'T checked.
  1969 // Note only the ThreadInVMfromNative transition can call this function
  1970 // directly and when thread state is _thread_in_native_trans
  1971 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
  1972   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
  1974   JavaThread *curJT = JavaThread::current();
  1975   bool do_self_suspend = thread->is_external_suspend();
  1977   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
  1979   // If JNIEnv proxies are allowed, don't self-suspend if the target
  1980   // thread is not the current thread. In older versions of jdbx, jdbx
  1981   // threads could call into the VM with another thread's JNIEnv so we
  1982   // can be here operating on behalf of a suspended thread (4432884).
  1983   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
  1984     JavaThreadState state = thread->thread_state();
  1986     // We mark this thread_blocked state as a suspend-equivalent so
  1987     // that a caller to is_ext_suspend_completed() won't be confused.
  1988     // The suspend-equivalent state is cleared by java_suspend_self().
  1989     thread->set_suspend_equivalent();
  1991     // If the safepoint code sees the _thread_in_native_trans state, it will
  1992     // wait until the thread changes to other thread state. There is no
  1993     // guarantee on how soon we can obtain the SR_lock and complete the
  1994     // self-suspend request. It would be a bad idea to let safepoint wait for
  1995     // too long. Temporarily change the state to _thread_blocked to
  1996     // let the VM thread know that this thread is ready for GC. The problem
  1997     // of changing thread state is that safepoint could happen just after
  1998     // java_suspend_self() returns after being resumed, and VM thread will
  1999     // see the _thread_blocked state. We must check for safepoint
  2000     // after restoring the state and make sure we won't leave while a safepoint
  2001     // is in progress.
  2002     thread->set_thread_state(_thread_blocked);
  2003     thread->java_suspend_self();
  2004     thread->set_thread_state(state);
  2005     // Make sure new state is seen by VM thread
  2006     if (os::is_MP()) {
  2007       if (UseMembar) {
  2008         // Force a fence between the write above and read below
  2009         OrderAccess::fence();
  2010       } else {
  2011         // Must use this rather than serialization page in particular on Windows
  2012         InterfaceSupport::serialize_memory(thread);
  2017   if (SafepointSynchronize::do_call_back()) {
  2018     // If we are safepointing, then block the caller which may not be
  2019     // the same as the target thread (see above).
  2020     SafepointSynchronize::block(curJT);
  2023   if (thread->is_deopt_suspend()) {
  2024     thread->clear_deopt_suspend();
  2025     RegisterMap map(thread, false);
  2026     frame f = thread->last_frame();
  2027     while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
  2028       f = f.sender(&map);
  2030     if (f.id() == thread->must_deopt_id()) {
  2031       thread->clear_must_deopt_id();
  2032       // Since we know we're safe to deopt the current state is a safe state
  2033       f.deoptimize(thread, true);
  2034     } else {
  2035       fatal("missed deoptimization!");
  2040 // Slow path when the native==>VM/Java barriers detect a safepoint is in
  2041 // progress or when _suspend_flags is non-zero.
  2042 // Current thread needs to self-suspend if there is a suspend request and/or
  2043 // block if a safepoint is in progress.
  2044 // Also check for pending async exception (not including unsafe access error).
  2045 // Note only the native==>VM/Java barriers can call this function and when
  2046 // thread state is _thread_in_native_trans.
  2047 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
  2048   check_safepoint_and_suspend_for_native_trans(thread);
  2050   if (thread->has_async_exception()) {
  2051     // We are in _thread_in_native_trans state, don't handle unsafe
  2052     // access error since that may block.
  2053     thread->check_and_handle_async_exceptions(false);
  2057 // We need to guarantee the Threads_lock here, since resumes are not
  2058 // allowed during safepoint synchronization
  2059 // Can only resume from an external suspension
  2060 void JavaThread::java_resume() {
  2061   assert_locked_or_safepoint(Threads_lock);
  2063   // Sanity check: thread is gone, has started exiting or the thread
  2064   // was not externally suspended.
  2065   if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
  2066     return;
  2069   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
  2071   clear_external_suspend();
  2073   if (is_ext_suspended()) {
  2074     clear_ext_suspended();
  2075     SR_lock()->notify_all();
  2079 void JavaThread::create_stack_guard_pages() {
  2080   if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
  2081   address low_addr = stack_base() - stack_size();
  2082   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
  2084   int allocate = os::allocate_stack_guard_pages();
  2085   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
  2087   if (allocate && !os::commit_memory((char *) low_addr, len)) {
  2088     warning("Attempt to allocate stack guard pages failed.");
  2089     return;
  2092   if (os::guard_memory((char *) low_addr, len)) {
  2093     _stack_guard_state = stack_guard_enabled;
  2094   } else {
  2095     warning("Attempt to protect stack guard pages failed.");
  2096     if (os::uncommit_memory((char *) low_addr, len)) {
  2097       warning("Attempt to deallocate stack guard pages failed.");
  2102 void JavaThread::remove_stack_guard_pages() {
  2103   if (_stack_guard_state == stack_guard_unused) return;
  2104   address low_addr = stack_base() - stack_size();
  2105   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
  2107   if (os::allocate_stack_guard_pages()) {
  2108     if (os::uncommit_memory((char *) low_addr, len)) {
  2109       _stack_guard_state = stack_guard_unused;
  2110     } else {
  2111       warning("Attempt to deallocate stack guard pages failed.");
  2113   } else {
  2114     if (_stack_guard_state == stack_guard_unused) return;
  2115     if (os::unguard_memory((char *) low_addr, len)) {
  2116       _stack_guard_state = stack_guard_unused;
  2117     } else {
  2118         warning("Attempt to unprotect stack guard pages failed.");
  2123 void JavaThread::enable_stack_yellow_zone() {
  2124   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
  2125   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
  2127   // The base notation is from the stacks point of view, growing downward.
  2128   // We need to adjust it to work correctly with guard_memory()
  2129   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
  2131   guarantee(base < stack_base(),"Error calculating stack yellow zone");
  2132   guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
  2134   if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
  2135     _stack_guard_state = stack_guard_enabled;
  2136   } else {
  2137     warning("Attempt to guard stack yellow zone failed.");
  2139   enable_register_stack_guard();
  2142 void JavaThread::disable_stack_yellow_zone() {
  2143   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
  2144   assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
  2146   // Simply return if called for a thread that does not use guard pages.
  2147   if (_stack_guard_state == stack_guard_unused) return;
  2149   // The base notation is from the stacks point of view, growing downward.
  2150   // We need to adjust it to work correctly with guard_memory()
  2151   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
  2153   if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
  2154     _stack_guard_state = stack_guard_yellow_disabled;
  2155   } else {
  2156     warning("Attempt to unguard stack yellow zone failed.");
  2158   disable_register_stack_guard();
  2161 void JavaThread::enable_stack_red_zone() {
  2162   // The base notation is from the stacks point of view, growing downward.
  2163   // We need to adjust it to work correctly with guard_memory()
  2164   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
  2165   address base = stack_red_zone_base() - stack_red_zone_size();
  2167   guarantee(base < stack_base(),"Error calculating stack red zone");
  2168   guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
  2170   if(!os::guard_memory((char *) base, stack_red_zone_size())) {
  2171     warning("Attempt to guard stack red zone failed.");
  2175 void JavaThread::disable_stack_red_zone() {
  2176   // The base notation is from the stacks point of view, growing downward.
  2177   // We need to adjust it to work correctly with guard_memory()
  2178   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
  2179   address base = stack_red_zone_base() - stack_red_zone_size();
  2180   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
  2181     warning("Attempt to unguard stack red zone failed.");
  2185 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
  2186   // ignore is there is no stack
  2187   if (!has_last_Java_frame()) return;
  2188   // traverse the stack frames. Starts from top frame.
  2189   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
  2190     frame* fr = fst.current();
  2191     f(fr, fst.register_map());
  2196 #ifndef PRODUCT
  2197 // Deoptimization
  2198 // Function for testing deoptimization
  2199 void JavaThread::deoptimize() {
  2200   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
  2201   StackFrameStream fst(this, UseBiasedLocking);
  2202   bool deopt = false;           // Dump stack only if a deopt actually happens.
  2203   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
  2204   // Iterate over all frames in the thread and deoptimize
  2205   for(; !fst.is_done(); fst.next()) {
  2206     if(fst.current()->can_be_deoptimized()) {
  2208       if (only_at) {
  2209         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
  2210         // consists of comma or carriage return separated numbers so
  2211         // search for the current bci in that string.
  2212         address pc = fst.current()->pc();
  2213         nmethod* nm =  (nmethod*) fst.current()->cb();
  2214         ScopeDesc* sd = nm->scope_desc_at( pc);
  2215         char buffer[8];
  2216         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
  2217         size_t len = strlen(buffer);
  2218         const char * found = strstr(DeoptimizeOnlyAt, buffer);
  2219         while (found != NULL) {
  2220           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
  2221               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
  2222             // Check that the bci found is bracketed by terminators.
  2223             break;
  2225           found = strstr(found + 1, buffer);
  2227         if (!found) {
  2228           continue;
  2232       if (DebugDeoptimization && !deopt) {
  2233         deopt = true; // One-time only print before deopt
  2234         tty->print_cr("[BEFORE Deoptimization]");
  2235         trace_frames();
  2236         trace_stack();
  2238       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
  2242   if (DebugDeoptimization && deopt) {
  2243     tty->print_cr("[AFTER Deoptimization]");
  2244     trace_frames();
  2249 // Make zombies
  2250 void JavaThread::make_zombies() {
  2251   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
  2252     if (fst.current()->can_be_deoptimized()) {
  2253       // it is a Java nmethod
  2254       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
  2255       nm->make_not_entrant();
  2259 #endif // PRODUCT
  2262 void JavaThread::deoptimized_wrt_marked_nmethods() {
  2263   if (!has_last_Java_frame()) return;
  2264   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
  2265   StackFrameStream fst(this, UseBiasedLocking);
  2266   for(; !fst.is_done(); fst.next()) {
  2267     if (fst.current()->should_be_deoptimized()) {
  2268       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
  2274 // GC support
  2275 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
  2277 void JavaThread::gc_epilogue() {
  2278   frames_do(frame_gc_epilogue);
  2282 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
  2284 void JavaThread::gc_prologue() {
  2285   frames_do(frame_gc_prologue);
  2289 void JavaThread::oops_do(OopClosure* f) {
  2290   // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
  2291   // since there may be more than one thread using each ThreadProfiler.
  2293   // Traverse the GCHandles
  2294   Thread::oops_do(f);
  2296   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
  2297           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
  2299   if (has_last_Java_frame()) {
  2301     // Traverse the privileged stack
  2302     if (_privileged_stack_top != NULL) {
  2303       _privileged_stack_top->oops_do(f);
  2306     // traverse the registered growable array
  2307     if (_array_for_gc != NULL) {
  2308       for (int index = 0; index < _array_for_gc->length(); index++) {
  2309         f->do_oop(_array_for_gc->adr_at(index));
  2313     // Traverse the monitor chunks
  2314     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
  2315       chunk->oops_do(f);
  2318     // Traverse the execution stack
  2319     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
  2320       fst.current()->oops_do(f, fst.register_map());
  2324   // callee_target is never live across a gc point so NULL it here should
  2325   // it still contain a methdOop.
  2327   set_callee_target(NULL);
  2329   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
  2330   // If we have deferred set_locals there might be oops waiting to be
  2331   // written
  2332   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
  2333   if (list != NULL) {
  2334     for (int i = 0; i < list->length(); i++) {
  2335       list->at(i)->oops_do(f);
  2339   // Traverse instance variables at the end since the GC may be moving things
  2340   // around using this function
  2341   f->do_oop((oop*) &_threadObj);
  2342   f->do_oop((oop*) &_vm_result);
  2343   f->do_oop((oop*) &_vm_result_2);
  2344   f->do_oop((oop*) &_exception_oop);
  2345   f->do_oop((oop*) &_pending_async_exception);
  2347   if (jvmti_thread_state() != NULL) {
  2348     jvmti_thread_state()->oops_do(f);
  2352 void JavaThread::nmethods_do() {
  2353   // Traverse the GCHandles
  2354   Thread::nmethods_do();
  2356   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
  2357           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
  2359   if (has_last_Java_frame()) {
  2360     // Traverse the execution stack
  2361     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
  2362       fst.current()->nmethods_do();
  2367 // Printing
  2368 const char* _get_thread_state_name(JavaThreadState _thread_state) {
  2369   switch (_thread_state) {
  2370   case _thread_uninitialized:     return "_thread_uninitialized";
  2371   case _thread_new:               return "_thread_new";
  2372   case _thread_new_trans:         return "_thread_new_trans";
  2373   case _thread_in_native:         return "_thread_in_native";
  2374   case _thread_in_native_trans:   return "_thread_in_native_trans";
  2375   case _thread_in_vm:             return "_thread_in_vm";
  2376   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
  2377   case _thread_in_Java:           return "_thread_in_Java";
  2378   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
  2379   case _thread_blocked:           return "_thread_blocked";
  2380   case _thread_blocked_trans:     return "_thread_blocked_trans";
  2381   default:                        return "unknown thread state";
  2385 #ifndef PRODUCT
  2386 void JavaThread::print_thread_state_on(outputStream *st) const {
  2387   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
  2388 };
  2389 void JavaThread::print_thread_state() const {
  2390   print_thread_state_on(tty);
  2391 };
  2392 #endif // PRODUCT
  2394 // Called by Threads::print() for VM_PrintThreads operation
  2395 void JavaThread::print_on(outputStream *st) const {
  2396   st->print("\"%s\" ", get_thread_name());
  2397   oop thread_oop = threadObj();
  2398   if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
  2399   Thread::print_on(st);
  2400   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
  2401   st->print_cr("[" INTPTR_FORMAT ".." INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12), highest_lock());
  2402   if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
  2403     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
  2405 #ifndef PRODUCT
  2406   print_thread_state_on(st);
  2407   _safepoint_state->print_on(st);
  2408 #endif // PRODUCT
  2411 // Called by fatal error handler. The difference between this and
  2412 // JavaThread::print() is that we can't grab lock or allocate memory.
  2413 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
  2414   st->print("JavaThread \"%s\"",  get_thread_name_string(buf, buflen));
  2415   oop thread_obj = threadObj();
  2416   if (thread_obj != NULL) {
  2417      if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
  2419   st->print(" [");
  2420   st->print("%s", _get_thread_state_name(_thread_state));
  2421   if (osthread()) {
  2422     st->print(", id=%d", osthread()->thread_id());
  2424   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
  2425             _stack_base - _stack_size, _stack_base);
  2426   st->print("]");
  2427   return;
  2430 // Verification
  2432 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
  2434 void JavaThread::verify() {
  2435   // Verify oops in the thread.
  2436   oops_do(&VerifyOopClosure::verify_oop);
  2438   // Verify the stack frames.
  2439   frames_do(frame_verify);
  2442 // CR 6300358 (sub-CR 2137150)
  2443 // Most callers of this method assume that it can't return NULL but a
  2444 // thread may not have a name whilst it is in the process of attaching to
  2445 // the VM - see CR 6412693, and there are places where a JavaThread can be
  2446 // seen prior to having it's threadObj set (eg JNI attaching threads and
  2447 // if vm exit occurs during initialization). These cases can all be accounted
  2448 // for such that this method never returns NULL.
  2449 const char* JavaThread::get_thread_name() const {
  2450 #ifdef ASSERT
  2451   // early safepoints can hit while current thread does not yet have TLS
  2452   if (!SafepointSynchronize::is_at_safepoint()) {
  2453     Thread *cur = Thread::current();
  2454     if (!(cur->is_Java_thread() && cur == this)) {
  2455       // Current JavaThreads are allowed to get their own name without
  2456       // the Threads_lock.
  2457       assert_locked_or_safepoint(Threads_lock);
  2460 #endif // ASSERT
  2461     return get_thread_name_string();
  2464 // Returns a non-NULL representation of this thread's name, or a suitable
  2465 // descriptive string if there is no set name
  2466 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
  2467   const char* name_str;
  2468   oop thread_obj = threadObj();
  2469   if (thread_obj != NULL) {
  2470     typeArrayOop name = java_lang_Thread::name(thread_obj);
  2471     if (name != NULL) {
  2472       if (buf == NULL) {
  2473         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
  2475       else {
  2476         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
  2479     else if (is_attaching()) { // workaround for 6412693 - see 6404306
  2480       name_str = "<no-name - thread is attaching>";
  2482     else {
  2483       name_str = Thread::name();
  2486   else {
  2487     name_str = Thread::name();
  2489   assert(name_str != NULL, "unexpected NULL thread name");
  2490   return name_str;
  2494 const char* JavaThread::get_threadgroup_name() const {
  2495   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
  2496   oop thread_obj = threadObj();
  2497   if (thread_obj != NULL) {
  2498     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
  2499     if (thread_group != NULL) {
  2500       typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
  2501       // ThreadGroup.name can be null
  2502       if (name != NULL) {
  2503         const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
  2504         return str;
  2508   return NULL;
  2511 const char* JavaThread::get_parent_name() const {
  2512   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
  2513   oop thread_obj = threadObj();
  2514   if (thread_obj != NULL) {
  2515     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
  2516     if (thread_group != NULL) {
  2517       oop parent = java_lang_ThreadGroup::parent(thread_group);
  2518       if (parent != NULL) {
  2519         typeArrayOop name = java_lang_ThreadGroup::name(parent);
  2520         // ThreadGroup.name can be null
  2521         if (name != NULL) {
  2522           const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
  2523           return str;
  2528   return NULL;
  2531 ThreadPriority JavaThread::java_priority() const {
  2532   oop thr_oop = threadObj();
  2533   if (thr_oop == NULL) return NormPriority; // Bootstrapping
  2534   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
  2535   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
  2536   return priority;
  2539 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
  2541   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
  2542   // Link Java Thread object <-> C++ Thread
  2544   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
  2545   // and put it into a new Handle.  The Handle "thread_oop" can then
  2546   // be used to pass the C++ thread object to other methods.
  2548   // Set the Java level thread object (jthread) field of the
  2549   // new thread (a JavaThread *) to C++ thread object using the
  2550   // "thread_oop" handle.
  2552   // Set the thread field (a JavaThread *) of the
  2553   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
  2555   Handle thread_oop(Thread::current(),
  2556                     JNIHandles::resolve_non_null(jni_thread));
  2557   assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
  2558     "must be initialized");
  2559   set_threadObj(thread_oop());
  2560   java_lang_Thread::set_thread(thread_oop(), this);
  2562   if (prio == NoPriority) {
  2563     prio = java_lang_Thread::priority(thread_oop());
  2564     assert(prio != NoPriority, "A valid priority should be present");
  2567   // Push the Java priority down to the native thread; needs Threads_lock
  2568   Thread::set_priority(this, prio);
  2570   // Add the new thread to the Threads list and set it in motion.
  2571   // We must have threads lock in order to call Threads::add.
  2572   // It is crucial that we do not block before the thread is
  2573   // added to the Threads list for if a GC happens, then the java_thread oop
  2574   // will not be visited by GC.
  2575   Threads::add(this);
  2578 oop JavaThread::current_park_blocker() {
  2579   // Support for JSR-166 locks
  2580   oop thread_oop = threadObj();
  2581   if (thread_oop != NULL && JDK_Version::supports_thread_park_blocker()) {
  2582     return java_lang_Thread::park_blocker(thread_oop);
  2584   return NULL;
  2588 void JavaThread::print_stack_on(outputStream* st) {
  2589   if (!has_last_Java_frame()) return;
  2590   ResourceMark rm;
  2591   HandleMark   hm;
  2593   RegisterMap reg_map(this);
  2594   vframe* start_vf = last_java_vframe(&reg_map);
  2595   int count = 0;
  2596   for (vframe* f = start_vf; f; f = f->sender() ) {
  2597     if (f->is_java_frame()) {
  2598       javaVFrame* jvf = javaVFrame::cast(f);
  2599       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
  2601       // Print out lock information
  2602       if (JavaMonitorsInStackTrace) {
  2603         jvf->print_lock_info_on(st, count);
  2605     } else {
  2606       // Ignore non-Java frames
  2609     // Bail-out case for too deep stacks
  2610     count++;
  2611     if (MaxJavaStackTraceDepth == count) return;
  2616 // JVMTI PopFrame support
  2617 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
  2618   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
  2619   if (in_bytes(size_in_bytes) != 0) {
  2620     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
  2621     _popframe_preserved_args_size = in_bytes(size_in_bytes);
  2622     Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
  2626 void* JavaThread::popframe_preserved_args() {
  2627   return _popframe_preserved_args;
  2630 ByteSize JavaThread::popframe_preserved_args_size() {
  2631   return in_ByteSize(_popframe_preserved_args_size);
  2634 WordSize JavaThread::popframe_preserved_args_size_in_words() {
  2635   int sz = in_bytes(popframe_preserved_args_size());
  2636   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
  2637   return in_WordSize(sz / wordSize);
  2640 void JavaThread::popframe_free_preserved_args() {
  2641   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
  2642   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
  2643   _popframe_preserved_args = NULL;
  2644   _popframe_preserved_args_size = 0;
  2647 #ifndef PRODUCT
  2649 void JavaThread::trace_frames() {
  2650   tty->print_cr("[Describe stack]");
  2651   int frame_no = 1;
  2652   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
  2653     tty->print("  %d. ", frame_no++);
  2654     fst.current()->print_value_on(tty,this);
  2655     tty->cr();
  2660 void JavaThread::trace_stack_from(vframe* start_vf) {
  2661   ResourceMark rm;
  2662   int vframe_no = 1;
  2663   for (vframe* f = start_vf; f; f = f->sender() ) {
  2664     if (f->is_java_frame()) {
  2665       javaVFrame::cast(f)->print_activation(vframe_no++);
  2666     } else {
  2667       f->print();
  2669     if (vframe_no > StackPrintLimit) {
  2670       tty->print_cr("...<more frames>...");
  2671       return;
  2677 void JavaThread::trace_stack() {
  2678   if (!has_last_Java_frame()) return;
  2679   ResourceMark rm;
  2680   HandleMark   hm;
  2681   RegisterMap reg_map(this);
  2682   trace_stack_from(last_java_vframe(&reg_map));
  2686 #endif // PRODUCT
  2689 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
  2690   assert(reg_map != NULL, "a map must be given");
  2691   frame f = last_frame();
  2692   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
  2693     if (vf->is_java_frame()) return javaVFrame::cast(vf);
  2695   return NULL;
  2699 klassOop JavaThread::security_get_caller_class(int depth) {
  2700   vframeStream vfst(this);
  2701   vfst.security_get_caller_frame(depth);
  2702   if (!vfst.at_end()) {
  2703     return vfst.method()->method_holder();
  2705   return NULL;
  2708 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
  2709   assert(thread->is_Compiler_thread(), "must be compiler thread");
  2710   CompileBroker::compiler_thread_loop();
  2713 // Create a CompilerThread
  2714 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
  2715 : JavaThread(&compiler_thread_entry) {
  2716   _env   = NULL;
  2717   _log   = NULL;
  2718   _task  = NULL;
  2719   _queue = queue;
  2720   _counters = counters;
  2722 #ifndef PRODUCT
  2723   _ideal_graph_printer = NULL;
  2724 #endif
  2728 // ======= Threads ========
  2730 // The Threads class links together all active threads, and provides
  2731 // operations over all threads.  It is protected by its own Mutex
  2732 // lock, which is also used in other contexts to protect thread
  2733 // operations from having the thread being operated on from exiting
  2734 // and going away unexpectedly (e.g., safepoint synchronization)
  2736 JavaThread* Threads::_thread_list = NULL;
  2737 int         Threads::_number_of_threads = 0;
  2738 int         Threads::_number_of_non_daemon_threads = 0;
  2739 int         Threads::_return_code = 0;
  2740 size_t      JavaThread::_stack_size_at_create = 0;
  2742 // All JavaThreads
  2743 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
  2745 void os_stream();
  2747 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
  2748 void Threads::threads_do(ThreadClosure* tc) {
  2749   assert_locked_or_safepoint(Threads_lock);
  2750   // ALL_JAVA_THREADS iterates through all JavaThreads
  2751   ALL_JAVA_THREADS(p) {
  2752     tc->do_thread(p);
  2754   // Someday we could have a table or list of all non-JavaThreads.
  2755   // For now, just manually iterate through them.
  2756   tc->do_thread(VMThread::vm_thread());
  2757   Universe::heap()->gc_threads_do(tc);
  2758   tc->do_thread(WatcherThread::watcher_thread());
  2759   // If CompilerThreads ever become non-JavaThreads, add them here
  2762 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
  2764   // Check version
  2765   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
  2767   // Initialize the output stream module
  2768   ostream_init();
  2770   // Process java launcher properties.
  2771   Arguments::process_sun_java_launcher_properties(args);
  2773   // Initialize the os module before using TLS
  2774   os::init();
  2776   // Initialize system properties.
  2777   Arguments::init_system_properties();
  2779   // Parse arguments
  2780   jint parse_result = Arguments::parse(args);
  2781   if (parse_result != JNI_OK) return parse_result;
  2783   if (PauseAtStartup) {
  2784     os::pause();
  2787   HS_DTRACE_PROBE(hotspot, vm__init__begin);
  2789   // Record VM creation timing statistics
  2790   TraceVmCreationTime create_vm_timer;
  2791   create_vm_timer.start();
  2793   // Timing (must come after argument parsing)
  2794   TraceTime timer("Create VM", TraceStartupTime);
  2796   // Initialize the os module after parsing the args
  2797   jint os_init_2_result = os::init_2();
  2798   if (os_init_2_result != JNI_OK) return os_init_2_result;
  2800   // Initialize output stream logging
  2801   ostream_init_log();
  2803   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
  2804   // Must be before create_vm_init_agents()
  2805   if (Arguments::init_libraries_at_startup()) {
  2806     convert_vm_init_libraries_to_agents();
  2809   // Launch -agentlib/-agentpath and converted -Xrun agents
  2810   if (Arguments::init_agents_at_startup()) {
  2811     create_vm_init_agents();
  2814   // Initialize Threads state
  2815   _thread_list = NULL;
  2816   _number_of_threads = 0;
  2817   _number_of_non_daemon_threads = 0;
  2819   // Initialize TLS
  2820   ThreadLocalStorage::init();
  2822   // Initialize global data structures and create system classes in heap
  2823   vm_init_globals();
  2825   // Attach the main thread to this os thread
  2826   JavaThread* main_thread = new JavaThread();
  2827   main_thread->set_thread_state(_thread_in_vm);
  2828   // must do this before set_active_handles and initialize_thread_local_storage
  2829   // Note: on solaris initialize_thread_local_storage() will (indirectly)
  2830   // change the stack size recorded here to one based on the java thread
  2831   // stacksize. This adjusted size is what is used to figure the placement
  2832   // of the guard pages.
  2833   main_thread->record_stack_base_and_size();
  2834   main_thread->initialize_thread_local_storage();
  2836   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
  2838   if (!main_thread->set_as_starting_thread()) {
  2839     vm_shutdown_during_initialization(
  2840       "Failed necessary internal allocation. Out of swap space");
  2841     delete main_thread;
  2842     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
  2843     return JNI_ENOMEM;
  2846   // Enable guard page *after* os::create_main_thread(), otherwise it would
  2847   // crash Linux VM, see notes in os_linux.cpp.
  2848   main_thread->create_stack_guard_pages();
  2850   // Initialize Java-Leve synchronization subsystem
  2851   ObjectSynchronizer::Initialize() ;
  2853   // Initialize global modules
  2854   jint status = init_globals();
  2855   if (status != JNI_OK) {
  2856     delete main_thread;
  2857     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
  2858     return status;
  2861   HandleMark hm;
  2863   { MutexLocker mu(Threads_lock);
  2864     Threads::add(main_thread);
  2867   // Any JVMTI raw monitors entered in onload will transition into
  2868   // real raw monitor. VM is setup enough here for raw monitor enter.
  2869   JvmtiExport::transition_pending_onload_raw_monitors();
  2871   if (VerifyBeforeGC &&
  2872       Universe::heap()->total_collections() >= VerifyGCStartAt) {
  2873     Universe::heap()->prepare_for_verify();
  2874     Universe::verify();   // make sure we're starting with a clean slate
  2877   // Create the VMThread
  2878   { TraceTime timer("Start VMThread", TraceStartupTime);
  2879     VMThread::create();
  2880     Thread* vmthread = VMThread::vm_thread();
  2882     if (!os::create_thread(vmthread, os::vm_thread))
  2883       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
  2885     // Wait for the VM thread to become ready, and VMThread::run to initialize
  2886     // Monitors can have spurious returns, must always check another state flag
  2888       MutexLocker ml(Notify_lock);
  2889       os::start_thread(vmthread);
  2890       while (vmthread->active_handles() == NULL) {
  2891         Notify_lock->wait();
  2896   assert (Universe::is_fully_initialized(), "not initialized");
  2897   EXCEPTION_MARK;
  2899   // At this point, the Universe is initialized, but we have not executed
  2900   // any byte code.  Now is a good time (the only time) to dump out the
  2901   // internal state of the JVM for sharing.
  2903   if (DumpSharedSpaces) {
  2904     Universe::heap()->preload_and_dump(CHECK_0);
  2905     ShouldNotReachHere();
  2908   // Always call even when there are not JVMTI environments yet, since environments
  2909   // may be attached late and JVMTI must track phases of VM execution
  2910   JvmtiExport::enter_start_phase();
  2912   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
  2913   JvmtiExport::post_vm_start();
  2916     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
  2918     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
  2919       create_vm_init_libraries();
  2922     if (InitializeJavaLangString) {
  2923       initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
  2924     } else {
  2925       warning("java.lang.String not initialized");
  2928     if (AggressiveOpts) {
  2929       // Forcibly initialize java/util/HashMap and mutate the private
  2930       // static final "frontCacheEnabled" field before we start creating instances
  2931 #ifdef ASSERT
  2932       klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
  2933       assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
  2934 #endif
  2935       klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
  2936       KlassHandle k = KlassHandle(THREAD, k_o);
  2937       guarantee(k.not_null(), "Must find java/util/HashMap");
  2938       instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
  2939       ik->initialize(CHECK_0);
  2940       fieldDescriptor fd;
  2941       // Possible we might not find this field; if so, don't break
  2942       if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
  2943         k()->bool_field_put(fd.offset(), true);
  2947     // Initialize java_lang.System (needed before creating the thread)
  2948     if (InitializeJavaLangSystem) {
  2949       initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
  2950       initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
  2951       Handle thread_group = create_initial_thread_group(CHECK_0);
  2952       Universe::set_main_thread_group(thread_group());
  2953       initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
  2954       oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
  2955       main_thread->set_threadObj(thread_object);
  2956       // Set thread status to running since main thread has
  2957       // been started and running.
  2958       java_lang_Thread::set_thread_status(thread_object,
  2959                                           java_lang_Thread::RUNNABLE);
  2961       // The VM preresolve methods to these classes. Make sure that get initialized
  2962       initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
  2963       initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(),  CHECK_0);
  2964       // The VM creates & returns objects of this class. Make sure it's initialized.
  2965       initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
  2966       call_initializeSystemClass(CHECK_0);
  2967     } else {
  2968       warning("java.lang.System not initialized");
  2971     // an instance of OutOfMemory exception has been allocated earlier
  2972     if (InitializeJavaLangExceptionsErrors) {
  2973       initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
  2974       initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
  2975       initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
  2976       initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
  2977       initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
  2978       initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
  2979       initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
  2980     } else {
  2981       warning("java.lang.OutOfMemoryError has not been initialized");
  2982       warning("java.lang.NullPointerException has not been initialized");
  2983       warning("java.lang.ClassCastException has not been initialized");
  2984       warning("java.lang.ArrayStoreException has not been initialized");
  2985       warning("java.lang.ArithmeticException has not been initialized");
  2986       warning("java.lang.StackOverflowError has not been initialized");
  2990   // See        : bugid 4211085.
  2991   // Background : the static initializer of java.lang.Compiler tries to read
  2992   //              property"java.compiler" and read & write property "java.vm.info".
  2993   //              When a security manager is installed through the command line
  2994   //              option "-Djava.security.manager", the above properties are not
  2995   //              readable and the static initializer for java.lang.Compiler fails
  2996   //              resulting in a NoClassDefFoundError.  This can happen in any
  2997   //              user code which calls methods in java.lang.Compiler.
  2998   // Hack :       the hack is to pre-load and initialize this class, so that only
  2999   //              system domains are on the stack when the properties are read.
  3000   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
  3001   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
  3002   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
  3003   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
  3004   //              Once that is done, we should remove this hack.
  3005   initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
  3007   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
  3008   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
  3009   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
  3010   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
  3011   // This should also be taken out as soon as 4211383 gets fixed.
  3012   reset_vm_info_property(CHECK_0);
  3014   quicken_jni_functions();
  3016   // Set flag that basic initialization has completed. Used by exceptions and various
  3017   // debug stuff, that does not work until all basic classes have been initialized.
  3018   set_init_completed();
  3020   HS_DTRACE_PROBE(hotspot, vm__init__end);
  3022   // record VM initialization completion time
  3023   Management::record_vm_init_completed();
  3025   // Compute system loader. Note that this has to occur after set_init_completed, since
  3026   // valid exceptions may be thrown in the process.
  3027   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
  3028   // set_init_completed has just been called, causing exceptions not to be shortcut
  3029   // anymore. We call vm_exit_during_initialization directly instead.
  3030   SystemDictionary::compute_java_system_loader(THREAD);
  3031   if (HAS_PENDING_EXCEPTION) {
  3032     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
  3035 #ifndef SERIALGC
  3036   // Support for ConcurrentMarkSweep. This should be cleaned up
  3037   // and better encapsulated. XXX YSR
  3038   if (UseConcMarkSweepGC) {
  3039     ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
  3040     if (HAS_PENDING_EXCEPTION) {
  3041       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
  3044 #endif // SERIALGC
  3046   // Always call even when there are not JVMTI environments yet, since environments
  3047   // may be attached late and JVMTI must track phases of VM execution
  3048   JvmtiExport::enter_live_phase();
  3050   // Signal Dispatcher needs to be started before VMInit event is posted
  3051   os::signal_init();
  3053   // Start Attach Listener if +StartAttachListener or it can't be started lazily
  3054   if (!DisableAttachMechanism) {
  3055     if (StartAttachListener || AttachListener::init_at_startup()) {
  3056       AttachListener::init();
  3060   // Launch -Xrun agents
  3061   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
  3062   // back-end can launch with -Xdebug -Xrunjdwp.
  3063   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
  3064     create_vm_init_libraries();
  3067   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
  3068   JvmtiExport::post_vm_initialized();
  3070   Chunk::start_chunk_pool_cleaner_task();
  3072   // initialize compiler(s)
  3073   CompileBroker::compilation_init();
  3075   Management::initialize(THREAD);
  3076   if (HAS_PENDING_EXCEPTION) {
  3077     // management agent fails to start possibly due to
  3078     // configuration problem and is responsible for printing
  3079     // stack trace if appropriate. Simply exit VM.
  3080     vm_exit(1);
  3083   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
  3084   if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
  3085   if (MemProfiling)                   MemProfiler::engage();
  3086   StatSampler::engage();
  3087   if (CheckJNICalls)                  JniPeriodicChecker::engage();
  3089   BiasedLocking::init();
  3092   // Start up the WatcherThread if there are any periodic tasks
  3093   // NOTE:  All PeriodicTasks should be registered by now. If they
  3094   //   aren't, late joiners might appear to start slowly (we might
  3095   //   take a while to process their first tick).
  3096   if (PeriodicTask::num_tasks() > 0) {
  3097     WatcherThread::start();
  3100   create_vm_timer.end();
  3101   return JNI_OK;
  3104 // type for the Agent_OnLoad and JVM_OnLoad entry points
  3105 extern "C" {
  3106   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
  3108 // Find a command line agent library and return its entry point for
  3109 //         -agentlib:  -agentpath:   -Xrun
  3110 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
  3111 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
  3112   OnLoadEntry_t on_load_entry = NULL;
  3113   void *library = agent->os_lib();  // check if we have looked it up before
  3115   if (library == NULL) {
  3116     char buffer[JVM_MAXPATHLEN];
  3117     char ebuf[1024];
  3118     const char *name = agent->name();
  3120     if (agent->is_absolute_path()) {
  3121       library = hpi::dll_load(name, ebuf, sizeof ebuf);
  3122       if (library == NULL) {
  3123         // If we can't find the agent, exit.
  3124         vm_exit_during_initialization("Could not find agent library in absolute path", name);
  3126     } else {
  3127       // Try to load the agent from the standard dll directory
  3128       hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
  3129       library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
  3130 #ifdef KERNEL
  3131       // Download instrument dll
  3132       if (library == NULL && strcmp(name, "instrument") == 0) {
  3133         char *props = Arguments::get_kernel_properties();
  3134         char *home  = Arguments::get_java_home();
  3135         const char *fmt   = "%s/bin/java %s -Dkernel.background.download=false"
  3136                       " sun.jkernel.DownloadManager -download client_jvm";
  3137         int length = strlen(props) + strlen(home) + strlen(fmt) + 1;
  3138         char *cmd = AllocateHeap(length);
  3139         jio_snprintf(cmd, length, fmt, home, props);
  3140         int status = os::fork_and_exec(cmd);
  3141         FreeHeap(props);
  3142         FreeHeap(cmd);
  3143         if (status == -1) {
  3144           warning(cmd);
  3145           vm_exit_during_initialization("fork_and_exec failed: %s",
  3146                                          strerror(errno));
  3148         // when this comes back the instrument.dll should be where it belongs.
  3149         library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
  3151 #endif // KERNEL
  3152       if (library == NULL) { // Try the local directory
  3153         char ns[1] = {0};
  3154         hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
  3155         library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
  3156         if (library == NULL) {
  3157           // If we can't find the agent, exit.
  3158           vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name);
  3162     agent->set_os_lib(library);
  3165   // Find the OnLoad function.
  3166   for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
  3167     on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
  3168     if (on_load_entry != NULL) break;
  3170   return on_load_entry;
  3173 // Find the JVM_OnLoad entry point
  3174 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
  3175   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
  3176   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
  3179 // Find the Agent_OnLoad entry point
  3180 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
  3181   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
  3182   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
  3185 // For backwards compatibility with -Xrun
  3186 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
  3187 // treated like -agentpath:
  3188 // Must be called before agent libraries are created
  3189 void Threads::convert_vm_init_libraries_to_agents() {
  3190   AgentLibrary* agent;
  3191   AgentLibrary* next;
  3193   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
  3194     next = agent->next();  // cache the next agent now as this agent may get moved off this list
  3195     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
  3197     // If there is an JVM_OnLoad function it will get called later,
  3198     // otherwise see if there is an Agent_OnLoad
  3199     if (on_load_entry == NULL) {
  3200       on_load_entry = lookup_agent_on_load(agent);
  3201       if (on_load_entry != NULL) {
  3202         // switch it to the agent list -- so that Agent_OnLoad will be called,
  3203         // JVM_OnLoad won't be attempted and Agent_OnUnload will
  3204         Arguments::convert_library_to_agent(agent);
  3205       } else {
  3206         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
  3212 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
  3213 // Invokes Agent_OnLoad
  3214 // Called very early -- before JavaThreads exist
  3215 void Threads::create_vm_init_agents() {
  3216   extern struct JavaVM_ main_vm;
  3217   AgentLibrary* agent;
  3219   JvmtiExport::enter_onload_phase();
  3220   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
  3221     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
  3223     if (on_load_entry != NULL) {
  3224       // Invoke the Agent_OnLoad function
  3225       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
  3226       if (err != JNI_OK) {
  3227         vm_exit_during_initialization("agent library failed to init", agent->name());
  3229     } else {
  3230       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
  3233   JvmtiExport::enter_primordial_phase();
  3236 extern "C" {
  3237   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
  3240 void Threads::shutdown_vm_agents() {
  3241   // Send any Agent_OnUnload notifications
  3242   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
  3243   extern struct JavaVM_ main_vm;
  3244   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
  3246     // Find the Agent_OnUnload function.
  3247     for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
  3248       Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
  3249                hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
  3251       // Invoke the Agent_OnUnload function
  3252       if (unload_entry != NULL) {
  3253         JavaThread* thread = JavaThread::current();
  3254         ThreadToNativeFromVM ttn(thread);
  3255         HandleMark hm(thread);
  3256         (*unload_entry)(&main_vm);
  3257         break;
  3263 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
  3264 // Invokes JVM_OnLoad
  3265 void Threads::create_vm_init_libraries() {
  3266   extern struct JavaVM_ main_vm;
  3267   AgentLibrary* agent;
  3269   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
  3270     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
  3272     if (on_load_entry != NULL) {
  3273       // Invoke the JVM_OnLoad function
  3274       JavaThread* thread = JavaThread::current();
  3275       ThreadToNativeFromVM ttn(thread);
  3276       HandleMark hm(thread);
  3277       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
  3278       if (err != JNI_OK) {
  3279         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
  3281     } else {
  3282       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
  3287 // Last thread running calls java.lang.Shutdown.shutdown()
  3288 void JavaThread::invoke_shutdown_hooks() {
  3289   HandleMark hm(this);
  3291   // We could get here with a pending exception, if so clear it now.
  3292   if (this->has_pending_exception()) {
  3293     this->clear_pending_exception();
  3296   EXCEPTION_MARK;
  3297   klassOop k =
  3298     SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
  3299                                       THREAD);
  3300   if (k != NULL) {
  3301     // SystemDictionary::resolve_or_null will return null if there was
  3302     // an exception.  If we cannot load the Shutdown class, just don't
  3303     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
  3304     // and finalizers (if runFinalizersOnExit is set) won't be run.
  3305     // Note that if a shutdown hook was registered or runFinalizersOnExit
  3306     // was called, the Shutdown class would have already been loaded
  3307     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
  3308     instanceKlassHandle shutdown_klass (THREAD, k);
  3309     JavaValue result(T_VOID);
  3310     JavaCalls::call_static(&result,
  3311                            shutdown_klass,
  3312                            vmSymbolHandles::shutdown_method_name(),
  3313                            vmSymbolHandles::void_method_signature(),
  3314                            THREAD);
  3316   CLEAR_PENDING_EXCEPTION;
  3319 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
  3320 // the program falls off the end of main(). Another VM exit path is through
  3321 // vm_exit() when the program calls System.exit() to return a value or when
  3322 // there is a serious error in VM. The two shutdown paths are not exactly
  3323 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
  3324 // and VM_Exit op at VM level.
  3325 //
  3326 // Shutdown sequence:
  3327 //   + Wait until we are the last non-daemon thread to execute
  3328 //     <-- every thing is still working at this moment -->
  3329 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
  3330 //        shutdown hooks, run finalizers if finalization-on-exit
  3331 //   + Call before_exit(), prepare for VM exit
  3332 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
  3333 //        currently the only user of this mechanism is File.deleteOnExit())
  3334 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
  3335 //        post thread end and vm death events to JVMTI,
  3336 //        stop signal thread
  3337 //   + Call JavaThread::exit(), it will:
  3338 //      > release JNI handle blocks, remove stack guard pages
  3339 //      > remove this thread from Threads list
  3340 //     <-- no more Java code from this thread after this point -->
  3341 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
  3342 //     the compiler threads at safepoint
  3343 //     <-- do not use anything that could get blocked by Safepoint -->
  3344 //   + Disable tracing at JNI/JVM barriers
  3345 //   + Set _vm_exited flag for threads that are still running native code
  3346 //   + Delete this thread
  3347 //   + Call exit_globals()
  3348 //      > deletes tty
  3349 //      > deletes PerfMemory resources
  3350 //   + Return to caller
  3352 bool Threads::destroy_vm() {
  3353   JavaThread* thread = JavaThread::current();
  3355   // Wait until we are the last non-daemon thread to execute
  3356   { MutexLocker nu(Threads_lock);
  3357     while (Threads::number_of_non_daemon_threads() > 1 )
  3358       // This wait should make safepoint checks, wait without a timeout,
  3359       // and wait as a suspend-equivalent condition.
  3360       //
  3361       // Note: If the FlatProfiler is running and this thread is waiting
  3362       // for another non-daemon thread to finish, then the FlatProfiler
  3363       // is waiting for the external suspend request on this thread to
  3364       // complete. wait_for_ext_suspend_completion() will eventually
  3365       // timeout, but that takes time. Making this wait a suspend-
  3366       // equivalent condition solves that timeout problem.
  3367       //
  3368       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
  3369                          Mutex::_as_suspend_equivalent_flag);
  3372   // Hang forever on exit if we are reporting an error.
  3373   if (ShowMessageBoxOnError && is_error_reported()) {
  3374     os::infinite_sleep();
  3377   if (JDK_Version::is_jdk12x_version()) {
  3378     // We are the last thread running, so check if finalizers should be run.
  3379     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
  3380     HandleMark rm(thread);
  3381     Universe::run_finalizers_on_exit();
  3382   } else {
  3383     // run Java level shutdown hooks
  3384     thread->invoke_shutdown_hooks();
  3387   before_exit(thread);
  3389   thread->exit(true);
  3391   // Stop VM thread.
  3393     // 4945125 The vm thread comes to a safepoint during exit.
  3394     // GC vm_operations can get caught at the safepoint, and the
  3395     // heap is unparseable if they are caught. Grab the Heap_lock
  3396     // to prevent this. The GC vm_operations will not be able to
  3397     // queue until after the vm thread is dead.
  3398     MutexLocker ml(Heap_lock);
  3400     VMThread::wait_for_vm_thread_exit();
  3401     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
  3402     VMThread::destroy();
  3405   // clean up ideal graph printers
  3406 #if defined(COMPILER2) && !defined(PRODUCT)
  3407   IdealGraphPrinter::clean_up();
  3408 #endif
  3410   // Now, all Java threads are gone except daemon threads. Daemon threads
  3411   // running Java code or in VM are stopped by the Safepoint. However,
  3412   // daemon threads executing native code are still running.  But they
  3413   // will be stopped at native=>Java/VM barriers. Note that we can't
  3414   // simply kill or suspend them, as it is inherently deadlock-prone.
  3416 #ifndef PRODUCT
  3417   // disable function tracing at JNI/JVM barriers
  3418   TraceHPI = false;
  3419   TraceJNICalls = false;
  3420   TraceJVMCalls = false;
  3421   TraceRuntimeCalls = false;
  3422 #endif
  3424   VM_Exit::set_vm_exited();
  3426   notify_vm_shutdown();
  3428   delete thread;
  3430   // exit_globals() will delete tty
  3431   exit_globals();
  3433   return true;
  3437 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
  3438   if (version == JNI_VERSION_1_1) return JNI_TRUE;
  3439   return is_supported_jni_version(version);
  3443 jboolean Threads::is_supported_jni_version(jint version) {
  3444   if (version == JNI_VERSION_1_2) return JNI_TRUE;
  3445   if (version == JNI_VERSION_1_4) return JNI_TRUE;
  3446   if (version == JNI_VERSION_1_6) return JNI_TRUE;
  3447   return JNI_FALSE;
  3451 void Threads::add(JavaThread* p, bool force_daemon) {
  3452   // The threads lock must be owned at this point
  3453   assert_locked_or_safepoint(Threads_lock);
  3454   p->set_next(_thread_list);
  3455   _thread_list = p;
  3456   _number_of_threads++;
  3457   oop threadObj = p->threadObj();
  3458   bool daemon = true;
  3459   // Bootstrapping problem: threadObj can be null for initial
  3460   // JavaThread (or for threads attached via JNI)
  3461   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
  3462     _number_of_non_daemon_threads++;
  3463     daemon = false;
  3466   ThreadService::add_thread(p, daemon);
  3468   // Possible GC point.
  3469   Events::log("Thread added: " INTPTR_FORMAT, p);
  3472 void Threads::remove(JavaThread* p) {
  3473   // Extra scope needed for Thread_lock, so we can check
  3474   // that we do not remove thread without safepoint code notice
  3475   { MutexLocker ml(Threads_lock);
  3477     assert(includes(p), "p must be present");
  3479     JavaThread* current = _thread_list;
  3480     JavaThread* prev    = NULL;
  3482     while (current != p) {
  3483       prev    = current;
  3484       current = current->next();
  3487     if (prev) {
  3488       prev->set_next(current->next());
  3489     } else {
  3490       _thread_list = p->next();
  3492     _number_of_threads--;
  3493     oop threadObj = p->threadObj();
  3494     bool daemon = true;
  3495     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
  3496       _number_of_non_daemon_threads--;
  3497       daemon = false;
  3499       // Only one thread left, do a notify on the Threads_lock so a thread waiting
  3500       // on destroy_vm will wake up.
  3501       if (number_of_non_daemon_threads() == 1)
  3502         Threads_lock->notify_all();
  3504     ThreadService::remove_thread(p, daemon);
  3506     // Make sure that safepoint code disregard this thread. This is needed since
  3507     // the thread might mess around with locks after this point. This can cause it
  3508     // to do callbacks into the safepoint code. However, the safepoint code is not aware
  3509     // of this thread since it is removed from the queue.
  3510     p->set_terminated_value();
  3511   } // unlock Threads_lock
  3513   // Since Events::log uses a lock, we grab it outside the Threads_lock
  3514   Events::log("Thread exited: " INTPTR_FORMAT, p);
  3517 // Threads_lock must be held when this is called (or must be called during a safepoint)
  3518 bool Threads::includes(JavaThread* p) {
  3519   assert(Threads_lock->is_locked(), "sanity check");
  3520   ALL_JAVA_THREADS(q) {
  3521     if (q == p ) {
  3522       return true;
  3525   return false;
  3528 // Operations on the Threads list for GC.  These are not explicitly locked,
  3529 // but the garbage collector must provide a safe context for them to run.
  3530 // In particular, these things should never be called when the Threads_lock
  3531 // is held by some other thread. (Note: the Safepoint abstraction also
  3532 // uses the Threads_lock to gurantee this property. It also makes sure that
  3533 // all threads gets blocked when exiting or starting).
  3535 void Threads::oops_do(OopClosure* f) {
  3536   ALL_JAVA_THREADS(p) {
  3537     p->oops_do(f);
  3539   VMThread::vm_thread()->oops_do(f);
  3542 void Threads::possibly_parallel_oops_do(OopClosure* f) {
  3543   // Introduce a mechanism allowing parallel threads to claim threads as
  3544   // root groups.  Overhead should be small enough to use all the time,
  3545   // even in sequential code.
  3546   SharedHeap* sh = SharedHeap::heap();
  3547   bool is_par = (sh->n_par_threads() > 0);
  3548   int cp = SharedHeap::heap()->strong_roots_parity();
  3549   ALL_JAVA_THREADS(p) {
  3550     if (p->claim_oops_do(is_par, cp)) {
  3551       p->oops_do(f);
  3554   VMThread* vmt = VMThread::vm_thread();
  3555   if (vmt->claim_oops_do(is_par, cp))
  3556     vmt->oops_do(f);
  3559 #ifndef SERIALGC
  3560 // Used by ParallelScavenge
  3561 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
  3562   ALL_JAVA_THREADS(p) {
  3563     q->enqueue(new ThreadRootsTask(p));
  3565   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
  3568 // Used by Parallel Old
  3569 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
  3570   ALL_JAVA_THREADS(p) {
  3571     q->enqueue(new ThreadRootsMarkingTask(p));
  3573   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
  3575 #endif // SERIALGC
  3577 void Threads::nmethods_do() {
  3578   ALL_JAVA_THREADS(p) {
  3579     p->nmethods_do();
  3581   VMThread::vm_thread()->nmethods_do();
  3584 void Threads::gc_epilogue() {
  3585   ALL_JAVA_THREADS(p) {
  3586     p->gc_epilogue();
  3590 void Threads::gc_prologue() {
  3591   ALL_JAVA_THREADS(p) {
  3592     p->gc_prologue();
  3596 void Threads::deoptimized_wrt_marked_nmethods() {
  3597   ALL_JAVA_THREADS(p) {
  3598     p->deoptimized_wrt_marked_nmethods();
  3603 // Get count Java threads that are waiting to enter the specified monitor.
  3604 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
  3605   address monitor, bool doLock) {
  3606   assert(doLock || SafepointSynchronize::is_at_safepoint(),
  3607     "must grab Threads_lock or be at safepoint");
  3608   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
  3610   int i = 0;
  3612     MutexLockerEx ml(doLock ? Threads_lock : NULL);
  3613     ALL_JAVA_THREADS(p) {
  3614       if (p->is_Compiler_thread()) continue;
  3616       address pending = (address)p->current_pending_monitor();
  3617       if (pending == monitor) {             // found a match
  3618         if (i < count) result->append(p);   // save the first count matches
  3619         i++;
  3623   return result;
  3627 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
  3628   assert(doLock ||
  3629          Threads_lock->owned_by_self() ||
  3630          SafepointSynchronize::is_at_safepoint(),
  3631          "must grab Threads_lock or be at safepoint");
  3633   // NULL owner means not locked so we can skip the search
  3634   if (owner == NULL) return NULL;
  3637     MutexLockerEx ml(doLock ? Threads_lock : NULL);
  3638     ALL_JAVA_THREADS(p) {
  3639       // first, see if owner is the address of a Java thread
  3640       if (owner == (address)p) return p;
  3643   assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
  3644   if (UseHeavyMonitors) return NULL;
  3646   //
  3647   // If we didn't find a matching Java thread and we didn't force use of
  3648   // heavyweight monitors, then the owner is the stack address of the
  3649   // Lock Word in the owning Java thread's stack.
  3650   //
  3651   // We can't use Thread::is_lock_owned() or Thread::lock_is_in_stack() because
  3652   // those routines rely on the "current" stack pointer. That would be our
  3653   // stack pointer which is not relevant to the question. Instead we use the
  3654   // highest lock ever entered by the thread and find the thread that is
  3655   // higher than and closest to our target stack address.
  3656   //
  3657   address    least_diff = 0;
  3658   bool       least_diff_initialized = false;
  3659   JavaThread* the_owner = NULL;
  3661     MutexLockerEx ml(doLock ? Threads_lock : NULL);
  3662     ALL_JAVA_THREADS(q) {
  3663       address addr = q->highest_lock();
  3664       if (addr == NULL || addr < owner) continue;  // thread has entered no monitors or is too low
  3665       address diff = (address)(addr - owner);
  3666       if (!least_diff_initialized || diff < least_diff) {
  3667         least_diff_initialized = true;
  3668         least_diff = diff;
  3669         the_owner = q;
  3673   assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
  3674   return the_owner;
  3677 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
  3678 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
  3679   char buf[32];
  3680   st->print_cr(os::local_time_string(buf, sizeof(buf)));
  3682   st->print_cr("Full thread dump %s (%s %s):",
  3683                 Abstract_VM_Version::vm_name(),
  3684                 Abstract_VM_Version::vm_release(),
  3685                 Abstract_VM_Version::vm_info_string()
  3686                );
  3687   st->cr();
  3689 #ifndef SERIALGC
  3690   // Dump concurrent locks
  3691   ConcurrentLocksDump concurrent_locks;
  3692   if (print_concurrent_locks) {
  3693     concurrent_locks.dump_at_safepoint();
  3695 #endif // SERIALGC
  3697   ALL_JAVA_THREADS(p) {
  3698     ResourceMark rm;
  3699     p->print_on(st);
  3700     if (print_stacks) {
  3701       if (internal_format) {
  3702         p->trace_stack();
  3703       } else {
  3704         p->print_stack_on(st);
  3707     st->cr();
  3708 #ifndef SERIALGC
  3709     if (print_concurrent_locks) {
  3710       concurrent_locks.print_locks_on(p, st);
  3712 #endif // SERIALGC
  3715   VMThread::vm_thread()->print_on(st);
  3716   st->cr();
  3717   Universe::heap()->print_gc_threads_on(st);
  3718   WatcherThread* wt = WatcherThread::watcher_thread();
  3719   if (wt != NULL) wt->print_on(st);
  3720   st->cr();
  3721   CompileBroker::print_compiler_threads_on(st);
  3722   st->flush();
  3725 // Threads::print_on_error() is called by fatal error handler. It's possible
  3726 // that VM is not at safepoint and/or current thread is inside signal handler.
  3727 // Don't print stack trace, as the stack may not be walkable. Don't allocate
  3728 // memory (even in resource area), it might deadlock the error handler.
  3729 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
  3730   bool found_current = false;
  3731   st->print_cr("Java Threads: ( => current thread )");
  3732   ALL_JAVA_THREADS(thread) {
  3733     bool is_current = (current == thread);
  3734     found_current = found_current || is_current;
  3736     st->print("%s", is_current ? "=>" : "  ");
  3738     st->print(PTR_FORMAT, thread);
  3739     st->print(" ");
  3740     thread->print_on_error(st, buf, buflen);
  3741     st->cr();
  3743   st->cr();
  3745   st->print_cr("Other Threads:");
  3746   if (VMThread::vm_thread()) {
  3747     bool is_current = (current == VMThread::vm_thread());
  3748     found_current = found_current || is_current;
  3749     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
  3751     st->print(PTR_FORMAT, VMThread::vm_thread());
  3752     st->print(" ");
  3753     VMThread::vm_thread()->print_on_error(st, buf, buflen);
  3754     st->cr();
  3756   WatcherThread* wt = WatcherThread::watcher_thread();
  3757   if (wt != NULL) {
  3758     bool is_current = (current == wt);
  3759     found_current = found_current || is_current;
  3760     st->print("%s", is_current ? "=>" : "  ");
  3762     st->print(PTR_FORMAT, wt);
  3763     st->print(" ");
  3764     wt->print_on_error(st, buf, buflen);
  3765     st->cr();
  3767   if (!found_current) {
  3768     st->cr();
  3769     st->print("=>" PTR_FORMAT " (exited) ", current);
  3770     current->print_on_error(st, buf, buflen);
  3771     st->cr();
  3776 // Lifecycle management for TSM ParkEvents.
  3777 // ParkEvents are type-stable (TSM).
  3778 // In our particular implementation they happen to be immortal.
  3779 //
  3780 // We manage concurrency on the FreeList with a CAS-based
  3781 // detach-modify-reattach idiom that avoids the ABA problems
  3782 // that would otherwise be present in a simple CAS-based
  3783 // push-pop implementation.   (push-one and pop-all)
  3784 //
  3785 // Caveat: Allocate() and Release() may be called from threads
  3786 // other than the thread associated with the Event!
  3787 // If we need to call Allocate() when running as the thread in
  3788 // question then look for the PD calls to initialize native TLS.
  3789 // Native TLS (Win32/Linux/Solaris) can only be initialized or
  3790 // accessed by the associated thread.
  3791 // See also pd_initialize().
  3792 //
  3793 // Note that we could defer associating a ParkEvent with a thread
  3794 // until the 1st time the thread calls park().  unpark() calls to
  3795 // an unprovisioned thread would be ignored.  The first park() call
  3796 // for a thread would allocate and associate a ParkEvent and return
  3797 // immediately.
  3799 volatile int ParkEvent::ListLock = 0 ;
  3800 ParkEvent * volatile ParkEvent::FreeList = NULL ;
  3802 ParkEvent * ParkEvent::Allocate (Thread * t) {
  3803   // In rare cases -- JVM_RawMonitor* operations -- we can find t == null.
  3804   ParkEvent * ev ;
  3806   // Start by trying to recycle an existing but unassociated
  3807   // ParkEvent from the global free list.
  3808   for (;;) {
  3809     ev = FreeList ;
  3810     if (ev == NULL) break ;
  3811     // 1: Detach - sequester or privatize the list
  3812     // Tantamount to ev = Swap (&FreeList, NULL)
  3813     if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) {
  3814        continue ;
  3817     // We've detached the list.  The list in-hand is now
  3818     // local to this thread.   This thread can operate on the
  3819     // list without risk of interference from other threads.
  3820     // 2: Extract -- pop the 1st element from the list.
  3821     ParkEvent * List = ev->FreeNext ;
  3822     if (List == NULL) break ;
  3823     for (;;) {
  3824         // 3: Try to reattach the residual list
  3825         guarantee (List != NULL, "invariant") ;
  3826         ParkEvent * Arv =  (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
  3827         if (Arv == NULL) break ;
  3829         // New nodes arrived.  Try to detach the recent arrivals.
  3830         if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
  3831             continue ;
  3833         guarantee (Arv != NULL, "invariant") ;
  3834         // 4: Merge Arv into List
  3835         ParkEvent * Tail = List ;
  3836         while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
  3837         Tail->FreeNext = Arv ;
  3839     break ;
  3842   if (ev != NULL) {
  3843     guarantee (ev->AssociatedWith == NULL, "invariant") ;
  3844   } else {
  3845     // Do this the hard way -- materialize a new ParkEvent.
  3846     // In rare cases an allocating thread might detach a long list --
  3847     // installing null into FreeList -- and then stall or be obstructed.
  3848     // A 2nd thread calling Allocate() would see FreeList == null.
  3849     // The list held privately by the 1st thread is unavailable to the 2nd thread.
  3850     // In that case the 2nd thread would have to materialize a new ParkEvent,
  3851     // even though free ParkEvents existed in the system.  In this case we end up
  3852     // with more ParkEvents in circulation than we need, but the race is
  3853     // rare and the outcome is benign.  Ideally, the # of extant ParkEvents
  3854     // is equal to the maximum # of threads that existed at any one time.
  3855     // Because of the race mentioned above, segments of the freelist
  3856     // can be transiently inaccessible.  At worst we may end up with the
  3857     // # of ParkEvents in circulation slightly above the ideal.
  3858     // Note that if we didn't have the TSM/immortal constraint, then
  3859     // when reattaching, above, we could trim the list.
  3860     ev = new ParkEvent () ;
  3861     guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ;
  3863   ev->reset() ;                     // courtesy to caller
  3864   ev->AssociatedWith = t ;          // Associate ev with t
  3865   ev->FreeNext       = NULL ;
  3866   return ev ;
  3869 void ParkEvent::Release (ParkEvent * ev) {
  3870   if (ev == NULL) return ;
  3871   guarantee (ev->FreeNext == NULL      , "invariant") ;
  3872   ev->AssociatedWith = NULL ;
  3873   for (;;) {
  3874     // Push ev onto FreeList
  3875     // The mechanism is "half" lock-free.
  3876     ParkEvent * List = FreeList ;
  3877     ev->FreeNext = List ;
  3878     if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ;
  3882 // Override operator new and delete so we can ensure that the
  3883 // least significant byte of ParkEvent addresses is 0.
  3884 // Beware that excessive address alignment is undesirable
  3885 // as it can result in D$ index usage imbalance as
  3886 // well as bank access imbalance on Niagara-like platforms,
  3887 // although Niagara's hash function should help.
  3889 void * ParkEvent::operator new (size_t sz) {
  3890   return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ;
  3893 void ParkEvent::operator delete (void * a) {
  3894   // ParkEvents are type-stable and immortal ...
  3895   ShouldNotReachHere();
  3899 // 6399321 As a temporary measure we copied & modified the ParkEvent::
  3900 // allocate() and release() code for use by Parkers.  The Parker:: forms
  3901 // will eventually be removed as we consolide and shift over to ParkEvents
  3902 // for both builtin synchronization and JSR166 operations.
  3904 volatile int Parker::ListLock = 0 ;
  3905 Parker * volatile Parker::FreeList = NULL ;
  3907 Parker * Parker::Allocate (JavaThread * t) {
  3908   guarantee (t != NULL, "invariant") ;
  3909   Parker * p ;
  3911   // Start by trying to recycle an existing but unassociated
  3912   // Parker from the global free list.
  3913   for (;;) {
  3914     p = FreeList ;
  3915     if (p  == NULL) break ;
  3916     // 1: Detach
  3917     // Tantamount to p = Swap (&FreeList, NULL)
  3918     if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) {
  3919        continue ;
  3922     // We've detached the list.  The list in-hand is now
  3923     // local to this thread.   This thread can operate on the
  3924     // list without risk of interference from other threads.
  3925     // 2: Extract -- pop the 1st element from the list.
  3926     Parker * List = p->FreeNext ;
  3927     if (List == NULL) break ;
  3928     for (;;) {
  3929         // 3: Try to reattach the residual list
  3930         guarantee (List != NULL, "invariant") ;
  3931         Parker * Arv =  (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
  3932         if (Arv == NULL) break ;
  3934         // New nodes arrived.  Try to detach the recent arrivals.
  3935         if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
  3936             continue ;
  3938         guarantee (Arv != NULL, "invariant") ;
  3939         // 4: Merge Arv into List
  3940         Parker * Tail = List ;
  3941         while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
  3942         Tail->FreeNext = Arv ;
  3944     break ;
  3947   if (p != NULL) {
  3948     guarantee (p->AssociatedWith == NULL, "invariant") ;
  3949   } else {
  3950     // Do this the hard way -- materialize a new Parker..
  3951     // In rare cases an allocating thread might detach
  3952     // a long list -- installing null into FreeList --and
  3953     // then stall.  Another thread calling Allocate() would see
  3954     // FreeList == null and then invoke the ctor.  In this case we
  3955     // end up with more Parkers in circulation than we need, but
  3956     // the race is rare and the outcome is benign.
  3957     // Ideally, the # of extant Parkers is equal to the
  3958     // maximum # of threads that existed at any one time.
  3959     // Because of the race mentioned above, segments of the
  3960     // freelist can be transiently inaccessible.  At worst
  3961     // we may end up with the # of Parkers in circulation
  3962     // slightly above the ideal.
  3963     p = new Parker() ;
  3965   p->AssociatedWith = t ;          // Associate p with t
  3966   p->FreeNext       = NULL ;
  3967   return p ;
  3971 void Parker::Release (Parker * p) {
  3972   if (p == NULL) return ;
  3973   guarantee (p->AssociatedWith != NULL, "invariant") ;
  3974   guarantee (p->FreeNext == NULL      , "invariant") ;
  3975   p->AssociatedWith = NULL ;
  3976   for (;;) {
  3977     // Push p onto FreeList
  3978     Parker * List = FreeList ;
  3979     p->FreeNext = List ;
  3980     if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ;
  3984 void Threads::verify() {
  3985   ALL_JAVA_THREADS(p) {
  3986     p->verify();
  3988   VMThread* thread = VMThread::vm_thread();
  3989   if (thread != NULL) thread->verify();

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