| /* |
| * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "jvm.h" |
| #include "aot/aotLoader.hpp" |
| #include "classfile/classLoader.hpp" |
| #include "classfile/javaClasses.hpp" |
| #include "classfile/moduleEntry.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "classfile/vmSymbols.hpp" |
| #include "code/codeCache.hpp" |
| #include "code/scopeDesc.hpp" |
| #include "compiler/compileBroker.hpp" |
| #include "compiler/compileTask.hpp" |
| #include "gc/shared/barrierSet.hpp" |
| #include "gc/shared/gcId.hpp" |
| #include "gc/shared/gcLocker.inline.hpp" |
| #include "gc/shared/workgroup.hpp" |
| #include "interpreter/interpreter.hpp" |
| #include "interpreter/linkResolver.hpp" |
| #include "interpreter/oopMapCache.hpp" |
| #include "jfr/jfrEvents.hpp" |
| #include "jvmtifiles/jvmtiEnv.hpp" |
| #include "logging/log.hpp" |
| #include "logging/logConfiguration.hpp" |
| #include "logging/logStream.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "memory/metaspaceShared.hpp" |
| #include "memory/oopFactory.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "memory/universe.hpp" |
| #include "oops/access.inline.hpp" |
| #include "oops/instanceKlass.hpp" |
| #include "oops/objArrayOop.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "oops/symbol.hpp" |
| #include "oops/typeArrayOop.inline.hpp" |
| #include "oops/verifyOopClosure.hpp" |
| #include "prims/jvm_misc.hpp" |
| #include "prims/jvmtiExport.hpp" |
| #include "prims/jvmtiThreadState.hpp" |
| #include "runtime/arguments.hpp" |
| #include "runtime/atomic.hpp" |
| #include "runtime/biasedLocking.hpp" |
| #include "runtime/fieldDescriptor.inline.hpp" |
| #include "runtime/flags/jvmFlagConstraintList.hpp" |
| #include "runtime/flags/jvmFlagRangeList.hpp" |
| #include "runtime/flags/jvmFlagWriteableList.hpp" |
| #include "runtime/deoptimization.hpp" |
| #include "runtime/frame.inline.hpp" |
| #include "runtime/handles.inline.hpp" |
| #include "runtime/handshake.hpp" |
| #include "runtime/init.hpp" |
| #include "runtime/interfaceSupport.inline.hpp" |
| #include "runtime/java.hpp" |
| #include "runtime/javaCalls.hpp" |
| #include "runtime/jniHandles.inline.hpp" |
| #include "runtime/jniPeriodicChecker.hpp" |
| #include "runtime/memprofiler.hpp" |
| #include "runtime/mutexLocker.hpp" |
| #include "runtime/objectMonitor.hpp" |
| #include "runtime/orderAccess.hpp" |
| #include "runtime/osThread.hpp" |
| #include "runtime/prefetch.inline.hpp" |
| #include "runtime/safepoint.hpp" |
| #include "runtime/safepointMechanism.inline.hpp" |
| #include "runtime/safepointVerifiers.hpp" |
| #include "runtime/sharedRuntime.hpp" |
| #include "runtime/statSampler.hpp" |
| #include "runtime/stubRoutines.hpp" |
| #include "runtime/sweeper.hpp" |
| #include "runtime/task.hpp" |
| #include "runtime/thread.inline.hpp" |
| #include "runtime/threadCritical.hpp" |
| #include "runtime/threadSMR.inline.hpp" |
| #include "runtime/threadStatisticalInfo.hpp" |
| #include "runtime/timer.hpp" |
| #include "runtime/timerTrace.hpp" |
| #include "runtime/vframe.inline.hpp" |
| #include "runtime/vframeArray.hpp" |
| #include "runtime/vframe_hp.hpp" |
| #include "runtime/vmThread.hpp" |
| #include "runtime/vmOperations.hpp" |
| #include "runtime/vm_version.hpp" |
| #include "services/attachListener.hpp" |
| #include "services/management.hpp" |
| #include "services/memTracker.hpp" |
| #include "services/threadService.hpp" |
| #include "utilities/align.hpp" |
| #include "utilities/copy.hpp" |
| #include "utilities/defaultStream.hpp" |
| #include "utilities/dtrace.hpp" |
| #include "utilities/events.hpp" |
| #include "utilities/macros.hpp" |
| #include "utilities/preserveException.hpp" |
| #include "utilities/singleWriterSynchronizer.hpp" |
| #include "utilities/vmError.hpp" |
| #if INCLUDE_JVMCI |
| #include "jvmci/jvmci.hpp" |
| #include "jvmci/jvmciEnv.hpp" |
| #endif |
| #ifdef COMPILER1 |
| #include "c1/c1_Compiler.hpp" |
| #endif |
| #ifdef COMPILER2 |
| #include "opto/c2compiler.hpp" |
| #include "opto/idealGraphPrinter.hpp" |
| #endif |
| #if INCLUDE_RTM_OPT |
| #include "runtime/rtmLocking.hpp" |
| #endif |
| #if INCLUDE_JFR |
| #include "jfr/jfr.hpp" |
| #endif |
| |
| // Initialization after module runtime initialization |
| void universe_post_module_init(); // must happen after call_initPhase2 |
| |
| #ifdef DTRACE_ENABLED |
| |
| // Only bother with this argument setup if dtrace is available |
| |
| #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START |
| #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP |
| |
| #define DTRACE_THREAD_PROBE(probe, javathread) \ |
| { \ |
| ResourceMark rm(this); \ |
| int len = 0; \ |
| const char* name = (javathread)->get_thread_name(); \ |
| len = strlen(name); \ |
| HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ |
| (char *) name, len, \ |
| java_lang_Thread::thread_id((javathread)->threadObj()), \ |
| (uintptr_t) (javathread)->osthread()->thread_id(), \ |
| java_lang_Thread::is_daemon((javathread)->threadObj())); \ |
| } |
| |
| #else // ndef DTRACE_ENABLED |
| |
| #define DTRACE_THREAD_PROBE(probe, javathread) |
| |
| #endif // ndef DTRACE_ENABLED |
| |
| #ifndef USE_LIBRARY_BASED_TLS_ONLY |
| // Current thread is maintained as a thread-local variable |
| THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; |
| #endif |
| |
| // ======= Thread ======== |
| // Support for forcing alignment of thread objects for biased locking |
| void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { |
| if (UseBiasedLocking) { |
| const int alignment = markOopDesc::biased_lock_alignment; |
| size_t aligned_size = size + (alignment - sizeof(intptr_t)); |
| void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) |
| : AllocateHeap(aligned_size, flags, CURRENT_PC, |
| AllocFailStrategy::RETURN_NULL); |
| void* aligned_addr = align_up(real_malloc_addr, alignment); |
| assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= |
| ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), |
| "JavaThread alignment code overflowed allocated storage"); |
| if (aligned_addr != real_malloc_addr) { |
| log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, |
| p2i(real_malloc_addr), |
| p2i(aligned_addr)); |
| } |
| ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; |
| return aligned_addr; |
| } else { |
| return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) |
| : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); |
| } |
| } |
| |
| void Thread::operator delete(void* p) { |
| if (UseBiasedLocking) { |
| FreeHeap(((Thread*) p)->_real_malloc_address); |
| } else { |
| FreeHeap(p); |
| } |
| } |
| |
| void JavaThread::smr_delete() { |
| if (_on_thread_list) { |
| ThreadsSMRSupport::smr_delete(this); |
| } else { |
| delete this; |
| } |
| } |
| |
| // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, |
| // JavaThread |
| |
| DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;) |
| |
| Thread::Thread() { |
| |
| DEBUG_ONLY(_run_state = PRE_CALL_RUN;) |
| |
| // stack and get_thread |
| set_stack_base(NULL); |
| set_stack_size(0); |
| set_self_raw_id(0); |
| set_lgrp_id(-1); |
| DEBUG_ONLY(clear_suspendible_thread();) |
| |
| // allocated data structures |
| set_osthread(NULL); |
| set_resource_area(new (mtThread)ResourceArea()); |
| DEBUG_ONLY(_current_resource_mark = NULL;) |
| set_handle_area(new (mtThread) HandleArea(NULL)); |
| set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); |
| set_active_handles(NULL); |
| set_free_handle_block(NULL); |
| set_last_handle_mark(NULL); |
| DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL); |
| |
| // Initial value of zero ==> never claimed. |
| _threads_do_token = 0; |
| _threads_hazard_ptr = NULL; |
| _threads_list_ptr = NULL; |
| _nested_threads_hazard_ptr_cnt = 0; |
| _rcu_counter = 0; |
| |
| // the handle mark links itself to last_handle_mark |
| new HandleMark(this); |
| |
| // plain initialization |
| debug_only(_owned_locks = NULL;) |
| debug_only(_allow_allocation_count = 0;) |
| NOT_PRODUCT(_allow_safepoint_count = 0;) |
| NOT_PRODUCT(_skip_gcalot = false;) |
| _jvmti_env_iteration_count = 0; |
| set_allocated_bytes(0); |
| _vm_operation_started_count = 0; |
| _vm_operation_completed_count = 0; |
| _current_pending_monitor = NULL; |
| _current_pending_monitor_is_from_java = true; |
| _current_waiting_monitor = NULL; |
| _num_nested_signal = 0; |
| omFreeList = NULL; |
| omFreeCount = 0; |
| omFreeProvision = 32; |
| omInUseList = NULL; |
| omInUseCount = 0; |
| |
| #ifdef ASSERT |
| _visited_for_critical_count = false; |
| #endif |
| |
| _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, |
| Monitor::_safepoint_check_sometimes); |
| _suspend_flags = 0; |
| |
| // thread-specific hashCode stream generator state - Marsaglia shift-xor form |
| _hashStateX = os::random(); |
| _hashStateY = 842502087; |
| _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; |
| _hashStateW = 273326509; |
| |
| _OnTrap = 0; |
| _Stalled = 0; |
| _TypeTag = 0x2BAD; |
| |
| // Many of the following fields are effectively final - immutable |
| // Note that nascent threads can't use the Native Monitor-Mutex |
| // construct until the _MutexEvent is initialized ... |
| // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents |
| // we might instead use a stack of ParkEvents that we could provision on-demand. |
| // The stack would act as a cache to avoid calls to ParkEvent::Allocate() |
| // and ::Release() |
| _ParkEvent = ParkEvent::Allocate(this); |
| _SleepEvent = ParkEvent::Allocate(this); |
| _MuxEvent = ParkEvent::Allocate(this); |
| |
| #ifdef CHECK_UNHANDLED_OOPS |
| if (CheckUnhandledOops) { |
| _unhandled_oops = new UnhandledOops(this); |
| } |
| #endif // CHECK_UNHANDLED_OOPS |
| #ifdef ASSERT |
| if (UseBiasedLocking) { |
| assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); |
| assert(this == _real_malloc_address || |
| this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment), |
| "bug in forced alignment of thread objects"); |
| } |
| #endif // ASSERT |
| |
| // Notify the barrier set that a thread is being created. The initial |
| // thread is created before the barrier set is available. The call to |
| // BarrierSet::on_thread_create() for this thread is therefore deferred |
| // to BarrierSet::set_barrier_set(). |
| BarrierSet* const barrier_set = BarrierSet::barrier_set(); |
| if (barrier_set != NULL) { |
| barrier_set->on_thread_create(this); |
| } else { |
| // Only the main thread should be created before the barrier set |
| // and that happens just before Thread::current is set. No other thread |
| // can attach as the VM is not created yet, so they can't execute this code. |
| // If the main thread creates other threads before the barrier set that is an error. |
| assert(Thread::current_or_null() == NULL, "creating thread before barrier set"); |
| } |
| } |
| |
| void Thread::initialize_thread_current() { |
| #ifndef USE_LIBRARY_BASED_TLS_ONLY |
| assert(_thr_current == NULL, "Thread::current already initialized"); |
| _thr_current = this; |
| #endif |
| assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); |
| ThreadLocalStorage::set_thread(this); |
| assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); |
| } |
| |
| void Thread::clear_thread_current() { |
| assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); |
| #ifndef USE_LIBRARY_BASED_TLS_ONLY |
| _thr_current = NULL; |
| #endif |
| ThreadLocalStorage::set_thread(NULL); |
| } |
| |
| void Thread::record_stack_base_and_size() { |
| // Note: at this point, Thread object is not yet initialized. Do not rely on |
| // any members being initialized. Do not rely on Thread::current() being set. |
| // If possible, refrain from doing anything which may crash or assert since |
| // quite probably those crash dumps will be useless. |
| set_stack_base(os::current_stack_base()); |
| set_stack_size(os::current_stack_size()); |
| |
| #ifdef SOLARIS |
| if (os::is_primordial_thread()) { |
| os::Solaris::correct_stack_boundaries_for_primordial_thread(this); |
| } |
| #endif |
| |
| // Set stack limits after thread is initialized. |
| if (is_Java_thread()) { |
| ((JavaThread*) this)->set_stack_overflow_limit(); |
| ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); |
| } |
| } |
| |
| #if INCLUDE_NMT |
| void Thread::register_thread_stack_with_NMT() { |
| MemTracker::record_thread_stack(stack_end(), stack_size()); |
| } |
| #endif // INCLUDE_NMT |
| |
| void Thread::call_run() { |
| DEBUG_ONLY(_run_state = CALL_RUN;) |
| |
| // At this point, Thread object should be fully initialized and |
| // Thread::current() should be set. |
| |
| assert(Thread::current_or_null() != NULL, "current thread is unset"); |
| assert(Thread::current_or_null() == this, "current thread is wrong"); |
| |
| // Perform common initialization actions |
| |
| register_thread_stack_with_NMT(); |
| |
| JFR_ONLY(Jfr::on_thread_start(this);) |
| |
| log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " |
| PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", |
| os::current_thread_id(), p2i(stack_base() - stack_size()), |
| p2i(stack_base()), stack_size()/1024); |
| |
| // Perform <ChildClass> initialization actions |
| DEBUG_ONLY(_run_state = PRE_RUN;) |
| this->pre_run(); |
| |
| // Invoke <ChildClass>::run() |
| DEBUG_ONLY(_run_state = RUN;) |
| this->run(); |
| // Returned from <ChildClass>::run(). Thread finished. |
| |
| // Perform common tear-down actions |
| |
| assert(Thread::current_or_null() != NULL, "current thread is unset"); |
| assert(Thread::current_or_null() == this, "current thread is wrong"); |
| |
| // Perform <ChildClass> tear-down actions |
| DEBUG_ONLY(_run_state = POST_RUN;) |
| this->post_run(); |
| |
| // Note: at this point the thread object may already have deleted itself, |
| // so from here on do not dereference *this*. Not all thread types currently |
| // delete themselves when they terminate. But no thread should ever be deleted |
| // asynchronously with respect to its termination - that is what _run_state can |
| // be used to check. |
| |
| assert(Thread::current_or_null() == NULL, "current thread still present"); |
| } |
| |
| Thread::~Thread() { |
| |
| // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually |
| // get started due to errors etc. Any active thread should at least reach post_run |
| // before it is deleted (usually in post_run()). |
| assert(_run_state == PRE_CALL_RUN || |
| _run_state == POST_RUN, "Active Thread deleted before post_run(): " |
| "_run_state=%d", (int)_run_state); |
| |
| // Notify the barrier set that a thread is being destroyed. Note that a barrier |
| // set might not be available if we encountered errors during bootstrapping. |
| BarrierSet* const barrier_set = BarrierSet::barrier_set(); |
| if (barrier_set != NULL) { |
| barrier_set->on_thread_destroy(this); |
| } |
| |
| // stack_base can be NULL if the thread is never started or exited before |
| // record_stack_base_and_size called. Although, we would like to ensure |
| // that all started threads do call record_stack_base_and_size(), there is |
| // not proper way to enforce that. |
| #if INCLUDE_NMT |
| if (_stack_base != NULL) { |
| MemTracker::release_thread_stack(stack_end(), stack_size()); |
| #ifdef ASSERT |
| set_stack_base(NULL); |
| #endif |
| } |
| #endif // INCLUDE_NMT |
| |
| // deallocate data structures |
| delete resource_area(); |
| // since the handle marks are using the handle area, we have to deallocated the root |
| // handle mark before deallocating the thread's handle area, |
| assert(last_handle_mark() != NULL, "check we have an element"); |
| delete last_handle_mark(); |
| assert(last_handle_mark() == NULL, "check we have reached the end"); |
| |
| // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. |
| // We NULL out the fields for good hygiene. |
| ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; |
| ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; |
| ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; |
| |
| delete handle_area(); |
| delete metadata_handles(); |
| |
| // SR_handler uses this as a termination indicator - |
| // needs to happen before os::free_thread() |
| delete _SR_lock; |
| _SR_lock = NULL; |
| |
| // osthread() can be NULL, if creation of thread failed. |
| if (osthread() != NULL) os::free_thread(osthread()); |
| |
| // Clear Thread::current if thread is deleting itself and it has not |
| // already been done. This must be done before the memory is deallocated. |
| // Needed to ensure JNI correctly detects non-attached threads. |
| if (this == Thread::current_or_null()) { |
| Thread::clear_thread_current(); |
| } |
| |
| CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) |
| } |
| |
| #ifdef ASSERT |
| // A JavaThread is considered "dangling" if it is not the current |
| // thread, has been added the Threads list, the system is not at a |
| // safepoint and the Thread is not "protected". |
| // |
| void Thread::check_for_dangling_thread_pointer(Thread *thread) { |
| assert(!thread->is_Java_thread() || Thread::current() == thread || |
| !((JavaThread *) thread)->on_thread_list() || |
| SafepointSynchronize::is_at_safepoint() || |
| ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread), |
| "possibility of dangling Thread pointer"); |
| } |
| #endif |
| |
| ThreadPriority Thread::get_priority(const Thread* const thread) { |
| ThreadPriority priority; |
| // Can return an error! |
| (void)os::get_priority(thread, priority); |
| assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); |
| return priority; |
| } |
| |
| void Thread::set_priority(Thread* thread, ThreadPriority priority) { |
| debug_only(check_for_dangling_thread_pointer(thread);) |
| // Can return an error! |
| (void)os::set_priority(thread, priority); |
| } |
| |
| |
| void Thread::start(Thread* thread) { |
| // Start is different from resume in that its safety is guaranteed by context or |
| // being called from a Java method synchronized on the Thread object. |
| if (!DisableStartThread) { |
| if (thread->is_Java_thread()) { |
| // Initialize the thread state to RUNNABLE before starting this thread. |
| // Can not set it after the thread started because we do not know the |
| // exact thread state at that time. It could be in MONITOR_WAIT or |
| // in SLEEPING or some other state. |
| java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), |
| java_lang_Thread::RUNNABLE); |
| } |
| os::start_thread(thread); |
| } |
| } |
| |
| // Enqueue a VM_Operation to do the job for us - sometime later |
| void Thread::send_async_exception(oop java_thread, oop java_throwable) { |
| VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); |
| VMThread::execute(vm_stop); |
| } |
| |
| |
| // Check if an external suspend request has completed (or has been |
| // cancelled). Returns true if the thread is externally suspended and |
| // false otherwise. |
| // |
| // The bits parameter returns information about the code path through |
| // the routine. Useful for debugging: |
| // |
| // set in is_ext_suspend_completed(): |
| // 0x00000001 - routine was entered |
| // 0x00000010 - routine return false at end |
| // 0x00000100 - thread exited (return false) |
| // 0x00000200 - suspend request cancelled (return false) |
| // 0x00000400 - thread suspended (return true) |
| // 0x00001000 - thread is in a suspend equivalent state (return true) |
| // 0x00002000 - thread is native and walkable (return true) |
| // 0x00004000 - thread is native_trans and walkable (needed retry) |
| // |
| // set in wait_for_ext_suspend_completion(): |
| // 0x00010000 - routine was entered |
| // 0x00020000 - suspend request cancelled before loop (return false) |
| // 0x00040000 - thread suspended before loop (return true) |
| // 0x00080000 - suspend request cancelled in loop (return false) |
| // 0x00100000 - thread suspended in loop (return true) |
| // 0x00200000 - suspend not completed during retry loop (return false) |
| |
| // Helper class for tracing suspend wait debug bits. |
| // |
| // 0x00000100 indicates that the target thread exited before it could |
| // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and |
| // 0x00080000 each indicate a cancelled suspend request so they don't |
| // count as wait failures either. |
| #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) |
| |
| class TraceSuspendDebugBits : public StackObj { |
| private: |
| JavaThread * jt; |
| bool is_wait; |
| bool called_by_wait; // meaningful when !is_wait |
| uint32_t * bits; |
| |
| public: |
| TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, |
| uint32_t *_bits) { |
| jt = _jt; |
| is_wait = _is_wait; |
| called_by_wait = _called_by_wait; |
| bits = _bits; |
| } |
| |
| ~TraceSuspendDebugBits() { |
| if (!is_wait) { |
| #if 1 |
| // By default, don't trace bits for is_ext_suspend_completed() calls. |
| // That trace is very chatty. |
| return; |
| #else |
| if (!called_by_wait) { |
| // If tracing for is_ext_suspend_completed() is enabled, then only |
| // trace calls to it from wait_for_ext_suspend_completion() |
| return; |
| } |
| #endif |
| } |
| |
| if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { |
| if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { |
| MutexLocker ml(Threads_lock); // needed for get_thread_name() |
| ResourceMark rm; |
| |
| tty->print_cr( |
| "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", |
| jt->get_thread_name(), *bits); |
| |
| guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); |
| } |
| } |
| } |
| }; |
| #undef DEBUG_FALSE_BITS |
| |
| |
| bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, |
| uint32_t *bits) { |
| TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); |
| |
| bool did_trans_retry = false; // only do thread_in_native_trans retry once |
| bool do_trans_retry; // flag to force the retry |
| |
| *bits |= 0x00000001; |
| |
| do { |
| do_trans_retry = false; |
| |
| if (is_exiting()) { |
| // Thread is in the process of exiting. This is always checked |
| // first to reduce the risk of dereferencing a freed JavaThread. |
| *bits |= 0x00000100; |
| return false; |
| } |
| |
| if (!is_external_suspend()) { |
| // Suspend request is cancelled. This is always checked before |
| // is_ext_suspended() to reduce the risk of a rogue resume |
| // confusing the thread that made the suspend request. |
| *bits |= 0x00000200; |
| return false; |
| } |
| |
| if (is_ext_suspended()) { |
| // thread is suspended |
| *bits |= 0x00000400; |
| return true; |
| } |
| |
| // Now that we no longer do hard suspends of threads running |
| // native code, the target thread can be changing thread state |
| // while we are in this routine: |
| // |
| // _thread_in_native -> _thread_in_native_trans -> _thread_blocked |
| // |
| // We save a copy of the thread state as observed at this moment |
| // and make our decision about suspend completeness based on the |
| // copy. This closes the race where the thread state is seen as |
| // _thread_in_native_trans in the if-thread_blocked check, but is |
| // seen as _thread_blocked in if-thread_in_native_trans check. |
| JavaThreadState save_state = thread_state(); |
| |
| if (save_state == _thread_blocked && is_suspend_equivalent()) { |
| // If the thread's state is _thread_blocked and this blocking |
| // condition is known to be equivalent to a suspend, then we can |
| // consider the thread to be externally suspended. This means that |
| // the code that sets _thread_blocked has been modified to do |
| // self-suspension if the blocking condition releases. We also |
| // used to check for CONDVAR_WAIT here, but that is now covered by |
| // the _thread_blocked with self-suspension check. |
| // |
| // Return true since we wouldn't be here unless there was still an |
| // external suspend request. |
| *bits |= 0x00001000; |
| return true; |
| } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { |
| // Threads running native code will self-suspend on native==>VM/Java |
| // transitions. If its stack is walkable (should always be the case |
| // unless this function is called before the actual java_suspend() |
| // call), then the wait is done. |
| *bits |= 0x00002000; |
| return true; |
| } else if (!called_by_wait && !did_trans_retry && |
| save_state == _thread_in_native_trans && |
| frame_anchor()->walkable()) { |
| // The thread is transitioning from thread_in_native to another |
| // thread state. check_safepoint_and_suspend_for_native_trans() |
| // will force the thread to self-suspend. If it hasn't gotten |
| // there yet we may have caught the thread in-between the native |
| // code check above and the self-suspend. Lucky us. If we were |
| // called by wait_for_ext_suspend_completion(), then it |
| // will be doing the retries so we don't have to. |
| // |
| // Since we use the saved thread state in the if-statement above, |
| // there is a chance that the thread has already transitioned to |
| // _thread_blocked by the time we get here. In that case, we will |
| // make a single unnecessary pass through the logic below. This |
| // doesn't hurt anything since we still do the trans retry. |
| |
| *bits |= 0x00004000; |
| |
| // Once the thread leaves thread_in_native_trans for another |
| // thread state, we break out of this retry loop. We shouldn't |
| // need this flag to prevent us from getting back here, but |
| // sometimes paranoia is good. |
| did_trans_retry = true; |
| |
| // We wait for the thread to transition to a more usable state. |
| for (int i = 1; i <= SuspendRetryCount; i++) { |
| // We used to do an "os::yield_all(i)" call here with the intention |
| // that yielding would increase on each retry. However, the parameter |
| // is ignored on Linux which means the yield didn't scale up. Waiting |
| // on the SR_lock below provides a much more predictable scale up for |
| // the delay. It also provides a simple/direct point to check for any |
| // safepoint requests from the VMThread |
| |
| // temporarily drops SR_lock while doing wait with safepoint check |
| // (if we're a JavaThread - the WatcherThread can also call this) |
| // and increase delay with each retry |
| if (Thread::current()->is_Java_thread()) { |
| SR_lock()->wait(i * delay); |
| } else { |
| SR_lock()->wait_without_safepoint_check(i * delay); |
| } |
| |
| // check the actual thread state instead of what we saved above |
| if (thread_state() != _thread_in_native_trans) { |
| // the thread has transitioned to another thread state so |
| // try all the checks (except this one) one more time. |
| do_trans_retry = true; |
| break; |
| } |
| } // end retry loop |
| |
| |
| } |
| } while (do_trans_retry); |
| |
| *bits |= 0x00000010; |
| return false; |
| } |
| |
| // Wait for an external suspend request to complete (or be cancelled). |
| // Returns true if the thread is externally suspended and false otherwise. |
| // |
| bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, |
| uint32_t *bits) { |
| TraceSuspendDebugBits tsdb(this, true /* is_wait */, |
| false /* !called_by_wait */, bits); |
| |
| // local flag copies to minimize SR_lock hold time |
| bool is_suspended; |
| bool pending; |
| uint32_t reset_bits; |
| |
| // set a marker so is_ext_suspend_completed() knows we are the caller |
| *bits |= 0x00010000; |
| |
| // We use reset_bits to reinitialize the bits value at the top of |
| // each retry loop. This allows the caller to make use of any |
| // unused bits for their own marking purposes. |
| reset_bits = *bits; |
| |
| { |
| MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); |
| is_suspended = is_ext_suspend_completed(true /* called_by_wait */, |
| delay, bits); |
| pending = is_external_suspend(); |
| } |
| // must release SR_lock to allow suspension to complete |
| |
| if (!pending) { |
| // A cancelled suspend request is the only false return from |
| // is_ext_suspend_completed() that keeps us from entering the |
| // retry loop. |
| *bits |= 0x00020000; |
| return false; |
| } |
| |
| if (is_suspended) { |
| *bits |= 0x00040000; |
| return true; |
| } |
| |
| for (int i = 1; i <= retries; i++) { |
| *bits = reset_bits; // reinit to only track last retry |
| |
| // We used to do an "os::yield_all(i)" call here with the intention |
| // that yielding would increase on each retry. However, the parameter |
| // is ignored on Linux which means the yield didn't scale up. Waiting |
| // on the SR_lock below provides a much more predictable scale up for |
| // the delay. It also provides a simple/direct point to check for any |
| // safepoint requests from the VMThread |
| |
| { |
| Thread* t = Thread::current(); |
| MonitorLocker ml(SR_lock(), |
| t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag); |
| // wait with safepoint check (if we're a JavaThread - the WatcherThread |
| // can also call this) and increase delay with each retry |
| ml.wait(i * delay); |
| |
| is_suspended = is_ext_suspend_completed(true /* called_by_wait */, |
| delay, bits); |
| |
| // It is possible for the external suspend request to be cancelled |
| // (by a resume) before the actual suspend operation is completed. |
| // Refresh our local copy to see if we still need to wait. |
| pending = is_external_suspend(); |
| } |
| |
| if (!pending) { |
| // A cancelled suspend request is the only false return from |
| // is_ext_suspend_completed() that keeps us from staying in the |
| // retry loop. |
| *bits |= 0x00080000; |
| return false; |
| } |
| |
| if (is_suspended) { |
| *bits |= 0x00100000; |
| return true; |
| } |
| } // end retry loop |
| |
| // thread did not suspend after all our retries |
| *bits |= 0x00200000; |
| return false; |
| } |
| |
| // Called from API entry points which perform stack walking. If the |
| // associated JavaThread is the current thread, then wait_for_suspend |
| // is not used. Otherwise, it determines if we should wait for the |
| // "other" thread to complete external suspension. (NOTE: in future |
| // releases the suspension mechanism should be reimplemented so this |
| // is not necessary.) |
| // |
| bool |
| JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) { |
| if (this != JavaThread::current()) { |
| // "other" threads require special handling. |
| if (wait_for_suspend) { |
| // We are allowed to wait for the external suspend to complete |
| // so give the other thread a chance to get suspended. |
| if (!wait_for_ext_suspend_completion(SuspendRetryCount, |
| SuspendRetryDelay, bits)) { |
| // Didn't make it so let the caller know. |
| return false; |
| } |
| } |
| // We aren't allowed to wait for the external suspend to complete |
| // so if the other thread isn't externally suspended we need to |
| // let the caller know. |
| else if (!is_ext_suspend_completed_with_lock(bits)) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| #ifndef PRODUCT |
| void JavaThread::record_jump(address target, address instr, const char* file, |
| int line) { |
| |
| // This should not need to be atomic as the only way for simultaneous |
| // updates is via interrupts. Even then this should be rare or non-existent |
| // and we don't care that much anyway. |
| |
| int index = _jmp_ring_index; |
| _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); |
| _jmp_ring[index]._target = (intptr_t) target; |
| _jmp_ring[index]._instruction = (intptr_t) instr; |
| _jmp_ring[index]._file = file; |
| _jmp_ring[index]._line = line; |
| } |
| #endif // PRODUCT |
| |
| void Thread::interrupt(Thread* thread) { |
| debug_only(check_for_dangling_thread_pointer(thread);) |
| os::interrupt(thread); |
| } |
| |
| bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { |
| debug_only(check_for_dangling_thread_pointer(thread);) |
| // Note: If clear_interrupted==false, this simply fetches and |
| // returns the value of the field osthread()->interrupted(). |
| return os::is_interrupted(thread, clear_interrupted); |
| } |
| |
| |
| // GC Support |
| bool Thread::claim_par_threads_do(uintx claim_token) { |
| uintx token = _threads_do_token; |
| if (token != claim_token) { |
| uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token); |
| if (res == token) { |
| return true; |
| } |
| guarantee(res == claim_token, "invariant"); |
| } |
| return false; |
| } |
| |
| void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { |
| active_handles()->oops_do(f); |
| // Do oop for ThreadShadow |
| f->do_oop((oop*)&_pending_exception); |
| handle_area()->oops_do(f); |
| |
| // We scan thread local monitor lists here, and the remaining global |
| // monitors in ObjectSynchronizer::oops_do(). |
| ObjectSynchronizer::thread_local_used_oops_do(this, f); |
| } |
| |
| void Thread::metadata_handles_do(void f(Metadata*)) { |
| // Only walk the Handles in Thread. |
| if (metadata_handles() != NULL) { |
| for (int i = 0; i< metadata_handles()->length(); i++) { |
| f(metadata_handles()->at(i)); |
| } |
| } |
| } |
| |
| void Thread::print_on(outputStream* st, bool print_extended_info) const { |
| // get_priority assumes osthread initialized |
| if (osthread() != NULL) { |
| int os_prio; |
| if (os::get_native_priority(this, &os_prio) == OS_OK) { |
| st->print("os_prio=%d ", os_prio); |
| } |
| |
| st->print("cpu=%.2fms ", |
| os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0 |
| ); |
| st->print("elapsed=%.2fs ", |
| _statistical_info.getElapsedTime() / 1000.0 |
| ); |
| if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) { |
| size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes(); |
| st->print("allocated=" SIZE_FORMAT "%s ", |
| byte_size_in_proper_unit(allocated_bytes), |
| proper_unit_for_byte_size(allocated_bytes) |
| ); |
| st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount()); |
| } |
| |
| st->print("tid=" INTPTR_FORMAT " ", p2i(this)); |
| osthread()->print_on(st); |
| } |
| ThreadsSMRSupport::print_info_on(this, st); |
| st->print(" "); |
| debug_only(if (WizardMode) print_owned_locks_on(st);) |
| } |
| |
| void Thread::print() const { print_on(tty); } |
| |
| // Thread::print_on_error() is called by fatal error handler. Don't use |
| // any lock or allocate memory. |
| void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { |
| assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates"); |
| |
| if (is_VM_thread()) { st->print("VMThread"); } |
| else if (is_GC_task_thread()) { st->print("GCTaskThread"); } |
| else if (is_Watcher_thread()) { st->print("WatcherThread"); } |
| else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); } |
| else { st->print("Thread"); } |
| |
| if (is_Named_thread()) { |
| st->print(" \"%s\"", name()); |
| } |
| |
| st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", |
| p2i(stack_end()), p2i(stack_base())); |
| |
| if (osthread()) { |
| st->print(" [id=%d]", osthread()->thread_id()); |
| } |
| |
| ThreadsSMRSupport::print_info_on(this, st); |
| } |
| |
| void Thread::print_value_on(outputStream* st) const { |
| if (is_Named_thread()) { |
| st->print(" \"%s\" ", name()); |
| } |
| st->print(INTPTR_FORMAT, p2i(this)); // print address |
| } |
| |
| #ifdef ASSERT |
| void Thread::print_owned_locks_on(outputStream* st) const { |
| Monitor *cur = _owned_locks; |
| if (cur == NULL) { |
| st->print(" (no locks) "); |
| } else { |
| st->print_cr(" Locks owned:"); |
| while (cur) { |
| cur->print_on(st); |
| cur = cur->next(); |
| } |
| } |
| } |
| |
| static int ref_use_count = 0; |
| |
| bool Thread::owns_locks_but_compiled_lock() const { |
| for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { |
| if (cur != Compile_lock) return true; |
| } |
| return false; |
| } |
| |
| |
| #endif |
| |
| #ifndef PRODUCT |
| |
| // The flag: potential_vm_operation notifies if this particular safepoint state could potentially |
| // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that |
| // no locks which allow_vm_block's are held |
| void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { |
| // Check if current thread is allowed to block at a safepoint |
| if (!(_allow_safepoint_count == 0)) { |
| fatal("Possible safepoint reached by thread that does not allow it"); |
| } |
| if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { |
| fatal("LEAF method calling lock?"); |
| } |
| |
| #ifdef ASSERT |
| if (potential_vm_operation && is_Java_thread() |
| && !Universe::is_bootstrapping()) { |
| // Make sure we do not hold any locks that the VM thread also uses. |
| // This could potentially lead to deadlocks |
| for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { |
| // Threads_lock is special, since the safepoint synchronization will not start before this is |
| // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, |
| // since it is used to transfer control between JavaThreads and the VMThread |
| // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! |
| if ((cur->allow_vm_block() && |
| cur != Threads_lock && |
| cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation |
| cur != VMOperationRequest_lock && |
| cur != VMOperationQueue_lock) || |
| cur->rank() == Mutex::special) { |
| fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); |
| } |
| } |
| } |
| |
| if (GCALotAtAllSafepoints) { |
| // We could enter a safepoint here and thus have a gc |
| InterfaceSupport::check_gc_alot(); |
| } |
| #endif |
| } |
| #endif |
| |
| bool Thread::is_in_stack(address adr) const { |
| assert(Thread::current() == this, "is_in_stack can only be called from current thread"); |
| address end = os::current_stack_pointer(); |
| // Allow non Java threads to call this without stack_base |
| if (_stack_base == NULL) return true; |
| if (stack_base() >= adr && adr >= end) return true; |
| |
| return false; |
| } |
| |
| bool Thread::is_in_usable_stack(address adr) const { |
| size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; |
| size_t usable_stack_size = _stack_size - stack_guard_size; |
| |
| return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); |
| } |
| |
| |
| // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter |
| // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being |
| // used for compilation in the future. If that change is made, the need for these methods |
| // should be revisited, and they should be removed if possible. |
| |
| bool Thread::is_lock_owned(address adr) const { |
| return on_local_stack(adr); |
| } |
| |
| bool Thread::set_as_starting_thread() { |
| assert(_starting_thread == NULL, "already initialized: " |
| "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread)); |
| // NOTE: this must be called inside the main thread. |
| DEBUG_ONLY(_starting_thread = this;) |
| return os::create_main_thread((JavaThread*)this); |
| } |
| |
| static void initialize_class(Symbol* class_name, TRAPS) { |
| Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); |
| InstanceKlass::cast(klass)->initialize(CHECK); |
| } |
| |
| |
| // Creates the initial ThreadGroup |
| static Handle create_initial_thread_group(TRAPS) { |
| Handle system_instance = JavaCalls::construct_new_instance( |
| SystemDictionary::ThreadGroup_klass(), |
| vmSymbols::void_method_signature(), |
| CHECK_NH); |
| Universe::set_system_thread_group(system_instance()); |
| |
| Handle string = java_lang_String::create_from_str("main", CHECK_NH); |
| Handle main_instance = JavaCalls::construct_new_instance( |
| SystemDictionary::ThreadGroup_klass(), |
| vmSymbols::threadgroup_string_void_signature(), |
| system_instance, |
| string, |
| CHECK_NH); |
| return main_instance; |
| } |
| |
| // Creates the initial Thread |
| static oop create_initial_thread(Handle thread_group, JavaThread* thread, |
| TRAPS) { |
| InstanceKlass* ik = SystemDictionary::Thread_klass(); |
| assert(ik->is_initialized(), "must be"); |
| instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL); |
| |
| // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread |
| // constructor calls Thread.current(), which must be set here for the |
| // initial thread. |
| java_lang_Thread::set_thread(thread_oop(), thread); |
| java_lang_Thread::set_priority(thread_oop(), NormPriority); |
| thread->set_threadObj(thread_oop()); |
| |
| Handle string = java_lang_String::create_from_str("main", CHECK_NULL); |
| |
| JavaValue result(T_VOID); |
| JavaCalls::call_special(&result, thread_oop, |
| ik, |
| vmSymbols::object_initializer_name(), |
| vmSymbols::threadgroup_string_void_signature(), |
| thread_group, |
| string, |
| CHECK_NULL); |
| return thread_oop(); |
| } |
| |
| char java_runtime_name[128] = ""; |
| char java_runtime_version[128] = ""; |
| |
| // extract the JRE name from java.lang.VersionProps.java_runtime_name |
| static const char* get_java_runtime_name(TRAPS) { |
| Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), |
| Handle(), Handle(), CHECK_AND_CLEAR_NULL); |
| fieldDescriptor fd; |
| bool found = k != NULL && |
| InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), |
| vmSymbols::string_signature(), &fd); |
| if (found) { |
| oop name_oop = k->java_mirror()->obj_field(fd.offset()); |
| if (name_oop == NULL) { |
| return NULL; |
| } |
| const char* name = java_lang_String::as_utf8_string(name_oop, |
| java_runtime_name, |
| sizeof(java_runtime_name)); |
| return name; |
| } else { |
| return NULL; |
| } |
| } |
| |
| // extract the JRE version from java.lang.VersionProps.java_runtime_version |
| static const char* get_java_runtime_version(TRAPS) { |
| Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), |
| Handle(), Handle(), CHECK_AND_CLEAR_NULL); |
| fieldDescriptor fd; |
| bool found = k != NULL && |
| InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), |
| vmSymbols::string_signature(), &fd); |
| if (found) { |
| oop name_oop = k->java_mirror()->obj_field(fd.offset()); |
| if (name_oop == NULL) { |
| return NULL; |
| } |
| const char* name = java_lang_String::as_utf8_string(name_oop, |
| java_runtime_version, |
| sizeof(java_runtime_version)); |
| return name; |
| } else { |
| return NULL; |
| } |
| } |
| |
| // General purpose hook into Java code, run once when the VM is initialized. |
| // The Java library method itself may be changed independently from the VM. |
| static void call_postVMInitHook(TRAPS) { |
| Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD); |
| if (klass != NULL) { |
| JavaValue result(T_VOID); |
| JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), |
| vmSymbols::void_method_signature(), |
| CHECK); |
| } |
| } |
| |
| void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, |
| bool daemon, TRAPS) { |
| assert(thread_group.not_null(), "thread group should be specified"); |
| assert(threadObj() == NULL, "should only create Java thread object once"); |
| |
| InstanceKlass* ik = SystemDictionary::Thread_klass(); |
| assert(ik->is_initialized(), "must be"); |
| instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); |
| |
| // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon. |
| // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread |
| // constructor calls Thread.current(), which must be set here. |
| java_lang_Thread::set_thread(thread_oop(), this); |
| java_lang_Thread::set_priority(thread_oop(), NormPriority); |
| set_threadObj(thread_oop()); |
| |
| JavaValue result(T_VOID); |
| if (thread_name != NULL) { |
| Handle name = java_lang_String::create_from_str(thread_name, CHECK); |
| // Thread gets assigned specified name and null target |
| JavaCalls::call_special(&result, |
| thread_oop, |
| ik, |
| vmSymbols::object_initializer_name(), |
| vmSymbols::threadgroup_string_void_signature(), |
| thread_group, |
| name, |
| THREAD); |
| } else { |
| // Thread gets assigned name "Thread-nnn" and null target |
| // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) |
| JavaCalls::call_special(&result, |
| thread_oop, |
| ik, |
| vmSymbols::object_initializer_name(), |
| vmSymbols::threadgroup_runnable_void_signature(), |
| thread_group, |
| Handle(), |
| THREAD); |
| } |
| |
| |
| if (daemon) { |
| java_lang_Thread::set_daemon(thread_oop()); |
| } |
| |
| if (HAS_PENDING_EXCEPTION) { |
| return; |
| } |
| |
| Klass* group = SystemDictionary::ThreadGroup_klass(); |
| Handle threadObj(THREAD, this->threadObj()); |
| |
| JavaCalls::call_special(&result, |
| thread_group, |
| group, |
| vmSymbols::add_method_name(), |
| vmSymbols::thread_void_signature(), |
| threadObj, // Arg 1 |
| THREAD); |
| } |
| |
| // List of all NonJavaThreads and safe iteration over that list. |
| |
| class NonJavaThread::List { |
| public: |
| NonJavaThread* volatile _head; |
| SingleWriterSynchronizer _protect; |
| |
| List() : _head(NULL), _protect() {} |
| }; |
| |
| NonJavaThread::List NonJavaThread::_the_list; |
| |
| NonJavaThread::Iterator::Iterator() : |
| _protect_enter(_the_list._protect.enter()), |
| _current(OrderAccess::load_acquire(&_the_list._head)) |
| {} |
| |
| NonJavaThread::Iterator::~Iterator() { |
| _the_list._protect.exit(_protect_enter); |
| } |
| |
| void NonJavaThread::Iterator::step() { |
| assert(!end(), "precondition"); |
| _current = OrderAccess::load_acquire(&_current->_next); |
| } |
| |
| NonJavaThread::NonJavaThread() : Thread(), _next(NULL) { |
| assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!"); |
| } |
| |
| NonJavaThread::~NonJavaThread() { } |
| |
| void NonJavaThread::add_to_the_list() { |
| MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); |
| // Initialize BarrierSet-related data before adding to list. |
| BarrierSet::barrier_set()->on_thread_attach(this); |
| OrderAccess::release_store(&_next, _the_list._head); |
| OrderAccess::release_store(&_the_list._head, this); |
| } |
| |
| void NonJavaThread::remove_from_the_list() { |
| { |
| MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); |
| // Cleanup BarrierSet-related data before removing from list. |
| BarrierSet::barrier_set()->on_thread_detach(this); |
| NonJavaThread* volatile* p = &_the_list._head; |
| for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) { |
| if (t == this) { |
| *p = _next; |
| break; |
| } |
| } |
| } |
| // Wait for any in-progress iterators. Concurrent synchronize is not |
| // allowed, so do it while holding a dedicated lock. Outside and distinct |
| // from NJTList_lock in case an iteration attempts to lock it. |
| MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag); |
| _the_list._protect.synchronize(); |
| _next = NULL; // Safe to drop the link now. |
| } |
| |
| void NonJavaThread::pre_run() { |
| add_to_the_list(); |
| |
| // This is slightly odd in that NamedThread is a subclass, but |
| // in fact name() is defined in Thread |
| assert(this->name() != NULL, "thread name was not set before it was started"); |
| this->set_native_thread_name(this->name()); |
| } |
| |
| void NonJavaThread::post_run() { |
| JFR_ONLY(Jfr::on_thread_exit(this);) |
| remove_from_the_list(); |
| // Ensure thread-local-storage is cleared before termination. |
| Thread::clear_thread_current(); |
| } |
| |
| // NamedThread -- non-JavaThread subclasses with multiple |
| // uniquely named instances should derive from this. |
| NamedThread::NamedThread() : |
| NonJavaThread(), |
| _name(NULL), |
| _processed_thread(NULL), |
| _gc_id(GCId::undefined()) |
| {} |
| |
| NamedThread::~NamedThread() { |
| if (_name != NULL) { |
| FREE_C_HEAP_ARRAY(char, _name); |
| _name = NULL; |
| } |
| } |
| |
| void NamedThread::set_name(const char* format, ...) { |
| guarantee(_name == NULL, "Only get to set name once."); |
| _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); |
| guarantee(_name != NULL, "alloc failure"); |
| va_list ap; |
| va_start(ap, format); |
| jio_vsnprintf(_name, max_name_len, format, ap); |
| va_end(ap); |
| } |
| |
| void NamedThread::print_on(outputStream* st) const { |
| st->print("\"%s\" ", name()); |
| Thread::print_on(st); |
| st->cr(); |
| } |
| |
| |
| // ======= WatcherThread ======== |
| |
| // The watcher thread exists to simulate timer interrupts. It should |
| // be replaced by an abstraction over whatever native support for |
| // timer interrupts exists on the platform. |
| |
| WatcherThread* WatcherThread::_watcher_thread = NULL; |
| bool WatcherThread::_startable = false; |
| volatile bool WatcherThread::_should_terminate = false; |
| |
| WatcherThread::WatcherThread() : NonJavaThread() { |
| assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); |
| if (os::create_thread(this, os::watcher_thread)) { |
| _watcher_thread = this; |
| |
| // Set the watcher thread to the highest OS priority which should not be |
| // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY |
| // is created. The only normal thread using this priority is the reference |
| // handler thread, which runs for very short intervals only. |
| // If the VMThread's priority is not lower than the WatcherThread profiling |
| // will be inaccurate. |
| os::set_priority(this, MaxPriority); |
| if (!DisableStartThread) { |
| os::start_thread(this); |
| } |
| } |
| } |
| |
| int WatcherThread::sleep() const { |
| // The WatcherThread does not participate in the safepoint protocol |
| // for the PeriodicTask_lock because it is not a JavaThread. |
| MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); |
| |
| if (_should_terminate) { |
| // check for termination before we do any housekeeping or wait |
| return 0; // we did not sleep. |
| } |
| |
| // remaining will be zero if there are no tasks, |
| // causing the WatcherThread to sleep until a task is |
| // enrolled |
| int remaining = PeriodicTask::time_to_wait(); |
| int time_slept = 0; |
| |
| // we expect this to timeout - we only ever get unparked when |
| // we should terminate or when a new task has been enrolled |
| OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); |
| |
| jlong time_before_loop = os::javaTimeNanos(); |
| |
| while (true) { |
| bool timedout = ml.wait(remaining); |
| jlong now = os::javaTimeNanos(); |
| |
| if (remaining == 0) { |
| // if we didn't have any tasks we could have waited for a long time |
| // consider the time_slept zero and reset time_before_loop |
| time_slept = 0; |
| time_before_loop = now; |
| } else { |
| // need to recalculate since we might have new tasks in _tasks |
| time_slept = (int) ((now - time_before_loop) / 1000000); |
| } |
| |
| // Change to task list or spurious wakeup of some kind |
| if (timedout || _should_terminate) { |
| break; |
| } |
| |
| remaining = PeriodicTask::time_to_wait(); |
| if (remaining == 0) { |
| // Last task was just disenrolled so loop around and wait until |
| // another task gets enrolled |
| continue; |
| } |
| |
| remaining -= time_slept; |
| if (remaining <= 0) { |
| break; |
| } |
| } |
| |
| return time_slept; |
| } |
| |
| void WatcherThread::run() { |
| assert(this == watcher_thread(), "just checking"); |
| |
| this->set_active_handles(JNIHandleBlock::allocate_block()); |
| while (true) { |
| assert(watcher_thread() == Thread::current(), "thread consistency check"); |
| assert(watcher_thread() == this, "thread consistency check"); |
| |
| // Calculate how long it'll be until the next PeriodicTask work |
| // should be done, and sleep that amount of time. |
| int time_waited = sleep(); |
| |
| if (VMError::is_error_reported()) { |
| // A fatal error has happened, the error handler(VMError::report_and_die) |
| // should abort JVM after creating an error log file. However in some |
| // rare cases, the error handler itself might deadlock. Here periodically |
| // check for error reporting timeouts, and if it happens, just proceed to |
| // abort the VM. |
| |
| // This code is in WatcherThread because WatcherThread wakes up |
| // periodically so the fatal error handler doesn't need to do anything; |
| // also because the WatcherThread is less likely to crash than other |
| // threads. |
| |
| for (;;) { |
| // Note: we use naked sleep in this loop because we want to avoid using |
| // any kind of VM infrastructure which may be broken at this point. |
| if (VMError::check_timeout()) { |
| // We hit error reporting timeout. Error reporting was interrupted and |
| // will be wrapping things up now (closing files etc). Give it some more |
| // time, then quit the VM. |
| os::naked_short_sleep(200); |
| // Print a message to stderr. |
| fdStream err(defaultStream::output_fd()); |
| err.print_raw_cr("# [ timer expired, abort... ]"); |
| // skip atexit/vm_exit/vm_abort hooks |
| os::die(); |
| } |
| |
| // Wait a second, then recheck for timeout. |
| os::naked_short_sleep(999); |
| } |
| } |
| |
| if (_should_terminate) { |
| // check for termination before posting the next tick |
| break; |
| } |
| |
| PeriodicTask::real_time_tick(time_waited); |
| } |
| |
| // Signal that it is terminated |
| { |
| MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag); |
| _watcher_thread = NULL; |
| Terminator_lock->notify_all(); |
| } |
| } |
| |
| void WatcherThread::start() { |
| assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); |
| |
| if (watcher_thread() == NULL && _startable) { |
| _should_terminate = false; |
| // Create the single instance of WatcherThread |
| new WatcherThread(); |
| } |
| } |
| |
| void WatcherThread::make_startable() { |
| assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); |
| _startable = true; |
| } |
| |
| void WatcherThread::stop() { |
| { |
| // Follow normal safepoint aware lock enter protocol since the |
| // WatcherThread is stopped by another JavaThread. |
| MutexLocker ml(PeriodicTask_lock); |
| _should_terminate = true; |
| |
| WatcherThread* watcher = watcher_thread(); |
| if (watcher != NULL) { |
| // unpark the WatcherThread so it can see that it should terminate |
| watcher->unpark(); |
| } |
| } |
| |
| MonitorLocker mu(Terminator_lock); |
| |
| while (watcher_thread() != NULL) { |
| // This wait should make safepoint checks, wait without a timeout, |
| // and wait as a suspend-equivalent condition. |
| mu.wait(0, Mutex::_as_suspend_equivalent_flag); |
| } |
| } |
| |
| void WatcherThread::unpark() { |
| assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); |
| PeriodicTask_lock->notify(); |
| } |
| |
| void WatcherThread::print_on(outputStream* st) const { |
| st->print("\"%s\" ", name()); |
| Thread::print_on(st); |
| st->cr(); |
| } |
| |
| // ======= JavaThread ======== |
| |
| #if INCLUDE_JVMCI |
| |
| jlong* JavaThread::_jvmci_old_thread_counters; |
| |
| bool jvmci_counters_include(JavaThread* thread) { |
| return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); |
| } |
| |
| void JavaThread::collect_counters(jlong* array, int length) { |
| assert(length == JVMCICounterSize, "wrong value"); |
| for (int i = 0; i < length; i++) { |
| array[i] = _jvmci_old_thread_counters[i]; |
| } |
| for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) { |
| if (jvmci_counters_include(tp)) { |
| for (int i = 0; i < length; i++) { |
| array[i] += tp->_jvmci_counters[i]; |
| } |
| } |
| } |
| } |
| |
| // Attempt to enlarge the array for per thread counters. |
| jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) { |
| jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI); |
| if (new_counters == NULL) { |
| return NULL; |
| } |
| if (old_counters == NULL) { |
| old_counters = new_counters; |
| memset(old_counters, 0, sizeof(jlong) * new_size); |
| } else { |
| for (int i = 0; i < MIN2((int) current_size, new_size); i++) { |
| new_counters[i] = old_counters[i]; |
| } |
| if (new_size > current_size) { |
| memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size)); |
| } |
| FREE_C_HEAP_ARRAY(jlong, old_counters); |
| } |
| return new_counters; |
| } |
| |
| // Attempt to enlarge the array for per thread counters. |
| bool JavaThread::resize_counters(int current_size, int new_size) { |
| jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size); |
| if (new_counters == NULL) { |
| return false; |
| } else { |
| _jvmci_counters = new_counters; |
| return true; |
| } |
| } |
| |
| class VM_JVMCIResizeCounters : public VM_Operation { |
| private: |
| int _new_size; |
| bool _failed; |
| |
| public: |
| VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { } |
| VMOp_Type type() const { return VMOp_JVMCIResizeCounters; } |
| bool allow_nested_vm_operations() const { return true; } |
| void doit() { |
| // Resize the old thread counters array |
| jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size); |
| if (new_counters == NULL) { |
| _failed = true; |
| return; |
| } else { |
| JavaThread::_jvmci_old_thread_counters = new_counters; |
| } |
| |
| // Now resize each threads array |
| for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) { |
| if (!tp->resize_counters(JVMCICounterSize, _new_size)) { |
| _failed = true; |
| break; |
| } |
| } |
| if (!_failed) { |
| JVMCICounterSize = _new_size; |
| } |
| } |
| |
| bool failed() { return _failed; } |
| }; |
| |
| bool JavaThread::resize_all_jvmci_counters(int new_size) { |
| VM_JVMCIResizeCounters op(new_size); |
| VMThread::execute(&op); |
| return !op.failed(); |
| } |
| |
| #endif // INCLUDE_JVMCI |
| |
| // A JavaThread is a normal Java thread |
| |
| void JavaThread::initialize() { |
| // Initialize fields |
| |
| set_saved_exception_pc(NULL); |
| set_threadObj(NULL); |
| _anchor.clear(); |
| set_entry_point(NULL); |
| set_jni_functions(jni_functions()); |
| set_callee_target(NULL); |
| set_vm_result(NULL); |
| set_vm_result_2(NULL); |
| set_vframe_array_head(NULL); |
| set_vframe_array_last(NULL); |
| set_deferred_locals(NULL); |
| set_deopt_mark(NULL); |
| set_deopt_compiled_method(NULL); |
| clear_must_deopt_id(); |
| set_monitor_chunks(NULL); |
| _on_thread_list = false; |
| set_thread_state(_thread_new); |
| _terminated = _not_terminated; |
| _array_for_gc = NULL; |
| _suspend_equivalent = false; |
| _in_deopt_handler = 0; |
| _doing_unsafe_access = false; |
| _stack_guard_state = stack_guard_unused; |
| #if INCLUDE_JVMCI |
| _pending_monitorenter = false; |
| _pending_deoptimization = -1; |
| _pending_failed_speculation = 0; |
| _pending_transfer_to_interpreter = false; |
| _in_retryable_allocation = false; |
| _jvmci._alternate_call_target = NULL; |
| assert(_jvmci._implicit_exception_pc == NULL, "must be"); |
| _jvmci_counters = NULL; |
| if (JVMCICounterSize > 0) { |
| resize_counters(0, (int) JVMCICounterSize); |
| } |
| #endif // INCLUDE_JVMCI |
| _reserved_stack_activation = NULL; // stack base not known yet |
| (void)const_cast<oop&>(_exception_oop = oop(NULL)); |
| _exception_pc = 0; |
| _exception_handler_pc = 0; |
| _is_method_handle_return = 0; |
| _jvmti_thread_state= NULL; |
| _should_post_on_exceptions_flag = JNI_FALSE; |
| _interp_only_mode = 0; |
| _special_runtime_exit_condition = _no_async_condition; |
| _pending_async_exception = NULL; |
| _thread_stat = NULL; |
| _thread_stat = new ThreadStatistics(); |
| _blocked_on_compilation = false; |
| _jni_active_critical = 0; |
| _pending_jni_exception_check_fn = NULL; |
| _do_not_unlock_if_synchronized = false; |
| _cached_monitor_info = NULL; |
| _parker = Parker::Allocate(this); |
| |
| #ifndef PRODUCT |
| _jmp_ring_index = 0; |
| for (int ji = 0; ji < jump_ring_buffer_size; ji++) { |
| record_jump(NULL, NULL, NULL, 0); |
| } |
| #endif // PRODUCT |
| |
| // Setup safepoint state info for this thread |
| ThreadSafepointState::create(this); |
| |
| debug_only(_java_call_counter = 0); |
| |
| // JVMTI PopFrame support |
| _popframe_condition = popframe_inactive; |
| _popframe_preserved_args = NULL; |
| _popframe_preserved_args_size = 0; |
| _frames_to_pop_failed_realloc = 0; |
| |
| if (SafepointMechanism::uses_thread_local_poll()) { |
| SafepointMechanism::initialize_header(this); |
| } |
| |
| _class_to_be_initialized = NULL; |
| |
| pd_initialize(); |
| } |
| |
| JavaThread::JavaThread(bool is_attaching_via_jni) : |
| Thread() { |
| initialize(); |
| if (is_attaching_via_jni) { |
| _jni_attach_state = _attaching_via_jni; |
| } else { |
| _jni_attach_state = _not_attaching_via_jni; |
| } |
| assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); |
| } |
| |
| bool JavaThread::reguard_stack(address cur_sp) { |
| if (_stack_guard_state != stack_guard_yellow_reserved_disabled |
| && _stack_guard_state != stack_guard_reserved_disabled) { |
| return true; // Stack already guarded or guard pages not needed. |
| } |
| |
| if (register_stack_overflow()) { |
| // For those architectures which have separate register and |
| // memory stacks, we must check the register stack to see if |
| // it has overflowed. |
| return false; |
| } |
| |
| // Java code never executes within the yellow zone: the latter is only |
| // there to provoke an exception during stack banging. If java code |
| // is executing there, either StackShadowPages should be larger, or |
| // some exception code in c1, c2 or the interpreter isn't unwinding |
| // when it should. |
| guarantee(cur_sp > stack_reserved_zone_base(), |
| "not enough space to reguard - increase StackShadowPages"); |
| if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { |
| enable_stack_yellow_reserved_zone(); |
| if (reserved_stack_activation() != stack_base()) { |
| set_reserved_stack_activation(stack_base()); |
| } |
| } else if (_stack_guard_state == stack_guard_reserved_disabled) { |
| set_reserved_stack_activation(stack_base()); |
| enable_stack_reserved_zone(); |
| } |
| return true; |
| } |
| |
| bool JavaThread::reguard_stack(void) { |
| return reguard_stack(os::current_stack_pointer()); |
| } |
| |
| |
| void JavaThread::block_if_vm_exited() { |
| if (_terminated == _vm_exited) { |
| // _vm_exited is set at safepoint, and Threads_lock is never released |
| // we will block here forever |
| Threads_lock->lock_without_safepoint_check(); |
| ShouldNotReachHere(); |
| } |
| } |
| |
| |
| // Remove this ifdef when C1 is ported to the compiler interface. |
| static void compiler_thread_entry(JavaThread* thread, TRAPS); |
| static void sweeper_thread_entry(JavaThread* thread, TRAPS); |
| |
| JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : |
| Thread() { |
| initialize(); |
| _jni_attach_state = _not_attaching_via_jni; |
| set_entry_point(entry_point); |
| // Create the native thread itself. |
| // %note runtime_23 |
| os::ThreadType thr_type = os::java_thread; |
| thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : |
| os::java_thread; |
| os::create_thread(this, thr_type, stack_sz); |
| // The _osthread may be NULL here because we ran out of memory (too many threads active). |
| // We need to throw and OutOfMemoryError - however we cannot do this here because the caller |
| // may hold a lock and all locks must be unlocked before throwing the exception (throwing |
| // the exception consists of creating the exception object & initializing it, initialization |
| // will leave the VM via a JavaCall and then all locks must be unlocked). |
| // |
| // The thread is still suspended when we reach here. Thread must be explicit started |
| // by creator! Furthermore, the thread must also explicitly be added to the Threads list |
| // by calling Threads:add. The reason why this is not done here, is because the thread |
| // object must be fully initialized (take a look at JVM_Start) |
| } |
| |
| JavaThread::~JavaThread() { |
| |
| // JSR166 -- return the parker to the free list |
| Parker::Release(_parker); |
| _parker = NULL; |
| |
| // Free any remaining previous UnrollBlock |
| vframeArray* old_array = vframe_array_last(); |
| |
| if (old_array != NULL) { |
| Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); |
| old_array->set_unroll_block(NULL); |
| delete old_info; |
| delete old_array; |
| } |
| |
| GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); |
| if (deferred != NULL) { |
| // This can only happen if thread is destroyed before deoptimization occurs. |
| assert(deferred->length() != 0, "empty array!"); |
| do { |
| jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); |
| deferred->remove_at(0); |
| // individual jvmtiDeferredLocalVariableSet are CHeapObj's |
| delete dlv; |
| } while (deferred->length() != 0); |
| delete deferred; |
| } |
| |
| // All Java related clean up happens in exit |
| ThreadSafepointState::destroy(this); |
| if (_thread_stat != NULL) delete _thread_stat; |
| |
| #if INCLUDE_JVMCI |
| if (JVMCICounterSize > 0) { |
| if (jvmci_counters_include(this)) { |
| for (int i = 0; i < JVMCICounterSize; i++) { |
| _jvmci_old_thread_counters[i] += _jvmci_counters[i]; |
| } |
| } |
| FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); |
| } |
| #endif // INCLUDE_JVMCI |
| } |
| |
| |
| // First JavaThread specific code executed by a new Java thread. |
| void JavaThread::pre_run() { |
| // empty - see comments in run() |
| } |
| |
| // The main routine called by a new Java thread. This isn't overridden |
| // by subclasses, instead different subclasses define a different "entry_point" |
| // which defines the actual logic for that kind of thread. |
| void JavaThread::run() { |
| // initialize thread-local alloc buffer related fields |
| this->initialize_tlab(); |
| |
| // Used to test validity of stack trace backs. |
| // This can't be moved into pre_run() else we invalidate |
| // the requirement that thread_main_inner is lower on |
| // the stack. Consequently all the initialization logic |
| // stays here in run() rather than pre_run(). |
| this->record_base_of_stack_pointer(); |
| |
| this->create_stack_guard_pages(); |
| |
| this->cache_global_variables(); |
| |
| // Thread is now sufficiently initialized to be handled by the safepoint code as being |
| // in the VM. Change thread state from _thread_new to _thread_in_vm |
| ThreadStateTransition::transition(this, _thread_new, _thread_in_vm); |
| // Before a thread is on the threads list it is always safe, so after leaving the |
| // _thread_new we should emit a instruction barrier. The distance to modified code |
| // from here is probably far enough, but this is consistent and safe. |
| OrderAccess::cross_modify_fence(); |
| |
| assert(JavaThread::current() == this, "sanity check"); |
| assert(!Thread::current()->owns_locks(), "sanity check"); |
| |
| DTRACE_THREAD_PROBE(start, this); |
| |
| // This operation might block. We call that after all safepoint checks for a new thread has |
| // been completed. |
| this->set_active_handles(JNIHandleBlock::allocate_block()); |
| |
| if (JvmtiExport::should_post_thread_life()) { |
| JvmtiExport::post_thread_start(this); |
| |
| } |
| |
| // We call another function to do the rest so we are sure that the stack addresses used |
| // from there will be lower than the stack base just computed. |
| thread_main_inner(); |
| } |
| |
| void JavaThread::thread_main_inner() { |
| assert(JavaThread::current() == this, "sanity check"); |
| assert(this->threadObj() != NULL, "just checking"); |
| |
| // Execute thread entry point unless this thread has a pending exception |
| // or has been stopped before starting. |
| // Note: Due to JVM_StopThread we can have pending exceptions already! |
| if (!this->has_pending_exception() && |
| !java_lang_Thread::is_stillborn(this->threadObj())) { |
| { |
| ResourceMark rm(this); |
| this->set_native_thread_name(this->get_thread_name()); |
| } |
| HandleMark hm(this); |
| this->entry_point()(this, this); |
| } |
| |
| DTRACE_THREAD_PROBE(stop, this); |
| |
| // Cleanup is handled in post_run() |
| } |
| |
| // Shared teardown for all JavaThreads |
| void JavaThread::post_run() { |
| this->exit(false); |
| // Defer deletion to here to ensure 'this' is still referenceable in call_run |
| // for any shared tear-down. |
| this->smr_delete(); |
| } |
| |
| static void ensure_join(JavaThread* thread) { |
| // We do not need to grab the Threads_lock, since we are operating on ourself. |
| Handle threadObj(thread, thread->threadObj()); |
| assert(threadObj.not_null(), "java thread object must exist"); |
| ObjectLocker lock(threadObj, thread); |
| // Ignore pending exception (ThreadDeath), since we are exiting anyway |
| thread->clear_pending_exception(); |
| // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. |
| java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); |
| // Clear the native thread instance - this makes isAlive return false and allows the join() |
| // to complete once we've done the notify_all below |
| java_lang_Thread::set_thread(threadObj(), NULL); |
| lock.notify_all(thread); |
| // Ignore pending exception (ThreadDeath), since we are exiting anyway |
| thread->clear_pending_exception(); |
| } |
| |
| static bool is_daemon(oop threadObj) { |
| return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)); |
| } |
| |
| // For any new cleanup additions, please check to see if they need to be applied to |
| // cleanup_failed_attach_current_thread as well. |
| void JavaThread::exit(bool destroy_vm, ExitType exit_type) { |
| assert(this == JavaThread::current(), "thread consistency check"); |
| |
| elapsedTimer _timer_exit_phase1; |
| elapsedTimer _timer_exit_phase2; |
| elapsedTimer _timer_exit_phase3; |
| elapsedTimer _timer_exit_phase4; |
| |
| if (log_is_enabled(Debug, os, thread, timer)) { |
| _timer_exit_phase1.start(); |
| } |
| |
| HandleMark hm(this); |
| Handle uncaught_exception(this, this->pending_exception()); |
| this->clear_pending_exception(); |
| Handle threadObj(this, this->threadObj()); |
| assert(threadObj.not_null(), "Java thread object should be created"); |
| |
| // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place |
| { |
| EXCEPTION_MARK; |
| |
| CLEAR_PENDING_EXCEPTION; |
| } |
| if (!destroy_vm) { |
| if (uncaught_exception.not_null()) { |
| EXCEPTION_MARK; |
| // Call method Thread.dispatchUncaughtException(). |
| Klass* thread_klass = SystemDictionary::Thread_klass(); |
| JavaValue result(T_VOID); |
| JavaCalls::call_virtual(&result, |
| threadObj, thread_klass, |
| vmSymbols::dispatchUncaughtException_name(), |
| vmSymbols::throwable_void_signature(), |
| uncaught_exception, |
| THREAD); |
| if (HAS_PENDING_EXCEPTION) { |
| ResourceMark rm(this); |
| jio_fprintf(defaultStream::error_stream(), |
| "\nException: %s thrown from the UncaughtExceptionHandler" |
| " in thread \"%s\"\n", |
| pending_exception()->klass()->external_name(), |
| get_thread_name()); |
| CLEAR_PENDING_EXCEPTION; |
| } |
| } |
| JFR_ONLY(Jfr::on_java_thread_dismantle(this);) |
| |
| // Call Thread.exit(). We try 3 times in case we got another Thread.stop during |
| // the execution of the method. If that is not enough, then we don't really care. Thread.stop |
| // is deprecated anyhow. |
| if (!is_Compiler_thread()) { |
| int count = 3; |
| while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { |
| EXCEPTION_MARK; |
| JavaValue result(T_VOID); |
| Klass* thread_klass = SystemDictionary::Thread_klass(); |
| JavaCalls::call_virtual(&result, |
| threadObj, thread_klass, |
| vmSymbols::exit_method_name(), |
| vmSymbols::void_method_signature(), |
| THREAD); |
| CLEAR_PENDING_EXCEPTION; |
| } |
| } |
| // notify JVMTI |
| if (JvmtiExport::should_post_thread_life()) { |
| JvmtiExport::post_thread_end(this); |
| } |
| |
| // We have notified the agents that we are exiting, before we go on, |
| // we must check for a pending external suspend request and honor it |
| // in order to not surprise the thread that made the suspend request. |
| while (true) { |
| { |
| MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); |
| if (!is_external_suspend()) { |
| set_terminated(_thread_exiting); |
| ThreadService::current_thread_exiting(this, is_daemon(threadObj())); |
| break; |
| } |
| // Implied else: |
| // Things get a little tricky here. We have a pending external |
| // suspend request, but we are holding the SR_lock so we |
| // can't just self-suspend. So we temporarily drop the lock |
| // and then self-suspend. |
| } |
| |
| ThreadBlockInVM tbivm(this); |
| java_suspend_self(); |
| |
| // We're done with this suspend request, but we have to loop around |
| // and check again. Eventually we will get SR_lock without a pending |
| // external suspend request and will be able to mark ourselves as |
| // exiting. |
| } |
| // no more external suspends are allowed at this point |
| } else { |
| assert(!is_terminated() && !is_exiting(), "must not be exiting"); |
| // before_exit() has already posted JVMTI THREAD_END events |
| } |
| |
| if (log_is_enabled(Debug, os, thread, timer)) { |
| _timer_exit_phase1.stop(); |
| _timer_exit_phase2.start(); |
| } |
| |
| // Capture daemon status before the thread is marked as terminated. |
| bool daemon = is_daemon(threadObj()); |
| |
| // Notify waiters on thread object. This has to be done after exit() is called |
| // on the thread (if the thread is the last thread in a daemon ThreadGroup the |
| // group should have the destroyed bit set before waiters are notified). |
| ensure_join(this); |
| assert(!this->has_pending_exception(), "ensure_join should have cleared"); |
| |
| if (log_is_enabled(Debug, os, thread, timer)) { |
| _timer_exit_phase2.stop(); |
| _timer_exit_phase3.start(); |
| } |
| // 6282335 JNI DetachCurrentThread spec states that all Java monitors |
| // held by this thread must be released. The spec does not distinguish |
| // between JNI-acquired and regular Java monitors. We can only see |
| // regular Java monitors here if monitor enter-exit matching is broken. |
| // |
| // ensure_join() ignores IllegalThreadStateExceptions, and so does |
| // ObjectSynchronizer::release_monitors_owned_by_thread(). |
| if (exit_type == jni_detach) { |
| // Sanity check even though JNI DetachCurrentThread() would have |
| // returned JNI_ERR if there was a Java frame. JavaThread exit |
| // should be done executing Java code by the time we get here. |
| assert(!this->has_last_Java_frame(), |
| "should not have a Java frame when detaching or exiting"); |
| ObjectSynchronizer::release_monitors_owned_by_thread(this); |
| assert(!this->has_pending_exception(), "release_monitors should have cleared"); |
| } |
| |
| // These things needs to be done while we are still a Java Thread. Make sure that thread |
| // is in a consistent state, in case GC happens |
| JFR_ONLY(Jfr::on_thread_exit(this);) |
| |
| if (active_handles() != NULL) { |
| JNIHandleBlock* block = active_handles(); |
| set_active_handles(NULL); |
| JNIHandleBlock::release_block(block); |
| } |
| |
| if (free_handle_block() != NULL) { |
| JNIHandleBlock* block = free_handle_block(); |
| set_free_handle_block(NULL); |
| JNIHandleBlock::release_block(block); |
| } |
| |
| // These have to be removed while this is still a valid thread. |
| remove_stack_guard_pages(); |
| |
| if (UseTLAB) { |
| tlab().retire(); |
| } |
| |
| if (JvmtiEnv::environments_might_exist()) { |
| JvmtiExport::cleanup_thread(this); |
| } |
| |
| // We must flush any deferred card marks and other various GC barrier |
| // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer) |
| // before removing a thread from the list of active threads. |
| BarrierSet::barrier_set()->on_thread_detach(this); |
| |
| log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", |
| exit_type == JavaThread::normal_exit ? "exiting" : "detaching", |
| os::current_thread_id()); |
| |
| if (log_is_enabled(Debug, os, thread, timer)) { |
| _timer_exit_phase3.stop(); |
| _timer_exit_phase4.start(); |
| } |
| // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread |
| Threads::remove(this, daemon); |
| |
| if (log_is_enabled(Debug, os, thread, timer)) { |
| _timer_exit_phase4.stop(); |
| ResourceMark rm(this); |
| log_debug(os, thread, timer)("name='%s'" |
| ", exit-phase1=" JLONG_FORMAT |
| ", exit-phase2=" JLONG_FORMAT |
| ", exit-phase3=" JLONG_FORMAT |
| ", exit-phase4=" JLONG_FORMAT, |
| get_thread_name(), |
| _timer_exit_phase1.milliseconds(), |
| _timer_exit_phase2.milliseconds(), |
| _timer_exit_phase3.milliseconds(), |
| _timer_exit_phase4.milliseconds()); |
| } |
| } |
| |
| void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) { |
| if (active_handles() != NULL) { |
| JNIHandleBlock* block = active_handles(); |
| set_active_handles(NULL); |
| JNIHandleBlock::release_block(block); |
| } |
| |
| if (free_handle_block() != NULL) { |
| JNIHandleBlock* block = free_handle_block(); |
| set_free_handle_block(NULL); |
| JNIHandleBlock::release_block(block); |
| } |
| |
| // These have to be removed while this is still a valid thread. |
| remove_stack_guard_pages(); |
| |
| if (UseTLAB) { |
| tlab().retire(); |
| } |
| |
| BarrierSet::barrier_set()->on_thread_detach(this); |
| |
| Threads::remove(this, is_daemon); |
| this->smr_delete(); |
| } |
| |
| JavaThread* JavaThread::active() { |
| Thread* thread = Thread::current(); |
| if (thread->is_Java_thread()) { |
| return (JavaThread*) thread; |
| } else { |
| assert(thread->is_VM_thread(), "this must be a vm thread"); |
| VM_Operation* op = ((VMThread*) thread)->vm_operation(); |
| JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); |
| assert(ret->is_Java_thread(), "must be a Java thread"); |
| return ret; |
| } |
| } |
| |
| bool JavaThread::is_lock_owned(address adr) const { |
| if (Thread::is_lock_owned(adr)) return true; |
| |
| for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { |
| if (chunk->contains(adr)) return true; |
| } |
| |
| return false; |
| } |
| |
| |
| void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { |
| chunk->set_next(monitor_chunks()); |
| set_monitor_chunks(chunk); |
| } |
| |
| void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { |
| guarantee(monitor_chunks() != NULL, "must be non empty"); |
| if (monitor_chunks() == chunk) { |
| set_monitor_chunks(chunk->next()); |
| } else { |
| MonitorChunk* prev = monitor_chunks(); |
| while (prev->next() != chunk) prev = prev->next(); |
| prev->set_next(chunk->next()); |
| } |
| } |
| |
| // JVM support. |
| |
| // Note: this function shouldn't block if it's called in |
| // _thread_in_native_trans state (such as from |
| // check_special_condition_for_native_trans()). |
| void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { |
| |
| if (has_last_Java_frame() && has_async_condition()) { |
| // If we are at a polling page safepoint (not a poll return) |
| // then we must defer async exception because live registers |
| // will be clobbered by the exception path. Poll return is |
| // ok because the call we a returning from already collides |
| // with exception handling registers and so there is no issue. |
| // (The exception handling path kills call result registers but |
| // this is ok since the exception kills the result anyway). |
| |
| if (is_at_poll_safepoint()) { |
| // if the code we are returning to has deoptimized we must defer |
| // the exception otherwise live registers get clobbered on the |
| // exception path before deoptimization is able to retrieve them. |
| // |
| RegisterMap map(this, false); |
| frame caller_fr = last_frame().sender(&map); |
| assert(caller_fr.is_compiled_frame(), "what?"); |
| if (caller_fr.is_deoptimized_frame()) { |
| log_info(exceptions)("deferred async exception at compiled safepoint"); |
| return; |
| } |
| } |
| } |
| |
| JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); |
| if (condition == _no_async_condition) { |
| // Conditions have changed since has_special_runtime_exit_condition() |
| // was called: |
| // - if we were here only because of an external suspend request, |
| // then that was taken care of above (or cancelled) so we are done |
| // - if we were here because of another async request, then it has |
| // been cleared between the has_special_runtime_exit_condition() |
| // and now so again we are done |
| return; |
| } |
| |
| // Check for pending async. exception |
| if (_pending_async_exception != NULL) { |
| // Only overwrite an already pending exception, if it is not a threadDeath. |
| if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { |
| |
| // We cannot call Exceptions::_throw(...) here because we cannot block |
| set_pending_exception(_pending_async_exception, __FILE__, __LINE__); |
| |
| LogTarget(Info, exceptions) lt; |
| if (lt.is_enabled()) { |
| ResourceMark rm; |
| LogStream ls(lt); |
| ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); |
| if (has_last_Java_frame()) { |
| frame f = last_frame(); |
| ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); |
| } |
| ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); |
| } |
| _pending_async_exception = NULL; |
| clear_has_async_exception(); |
| } |
| } |
| |
| if (check_unsafe_error && |
| condition == _async_unsafe_access_error && !has_pending_exception()) { |
| condition = _no_async_condition; // done |
| switch (thread_state()) { |
| case _thread_in_vm: { |
| JavaThread* THREAD = this; |
| THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); |
| } |
| case _thread_in_native: { |
| ThreadInVMfromNative tiv(this); |
| JavaThread* THREAD = this; |
| THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); |
| } |
| case _thread_in_Java: { |
| ThreadInVMfromJava tiv(this); |
| JavaThread* THREAD = this; |
| THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); |
| } |
| default: |
| ShouldNotReachHere(); |
| } |
| } |
| |
| assert(condition == _no_async_condition || has_pending_exception() || |
| (!check_unsafe_error && condition == _async_unsafe_access_error), |
| "must have handled the async condition, if no exception"); |
| } |
| |
| void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { |
| // |
| // Check for pending external suspend. |
| // If JNIEnv proxies are allowed, don't self-suspend if the target |
| // thread is not the current thread. In older versions of jdbx, jdbx |
| // threads could call into the VM with another thread's JNIEnv so we |
| // can be here operating on behalf of a suspended thread (4432884). |
| bool do_self_suspend = is_external_suspend_with_lock(); |
| if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { |
| frame_anchor()->make_walkable(this); |
| java_suspend_self_with_safepoint_check(); |
| } |
| |
| // We might be here for reasons in addition to the self-suspend request |
| // so check for other async requests. |
| if (check_asyncs) { |
| check_and_handle_async_exceptions(); |
| } |
| |
| JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);) |
| } |
| |
| void JavaThread::send_thread_stop(oop java_throwable) { |
| assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); |
| assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); |
| assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); |
| |
| // Do not throw asynchronous exceptions against the compiler thread |
| // (the compiler thread should not be a Java thread -- fix in 1.4.2) |
| if (!can_call_java()) return; |
| |
| { |
| // Actually throw the Throwable against the target Thread - however |
| // only if there is no thread death exception installed already. |
| if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { |
| // If the topmost frame is a runtime stub, then we are calling into |
| // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) |
| // must deoptimize the caller before continuing, as the compiled exception handler table |
| // may not be valid |
| if (has_last_Java_frame()) { |
| frame f = last_frame(); |
| if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { |
| // BiasedLocking needs an updated RegisterMap for the revoke monitors pass |
| RegisterMap reg_map(this, UseBiasedLocking); |
| frame compiled_frame = f.sender(®_map); |
| if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { |
| Deoptimization::deoptimize(this, compiled_frame, ®_map); |
| } |
| } |
| } |
| |
| // Set async. pending exception in thread. |
| set_pending_async_exception(java_throwable); |
| |
| if (log_is_enabled(Info, exceptions)) { |
| ResourceMark rm; |
| log_info(exceptions)("Pending Async. exception installed of type: %s", |
| InstanceKlass::cast(_pending_async_exception->klass())->external_name()); |
| } |
| // for AbortVMOnException flag |
| Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); |
| } |
| } |
| |
| |
| // Interrupt thread so it will wake up from a potential wait() |
| Thread::interrupt(this); |
| } |
| |
| // External suspension mechanism. |
| // |
| // Tell the VM to suspend a thread when ever it knows that it does not hold on |
| // to any VM_locks and it is at a transition |
| // Self-suspension will happen on the transition out of the vm. |
| // Catch "this" coming in from JNIEnv pointers when the thread has been freed |
| // |
| // Guarantees on return: |
| // + Target thread will not execute any new bytecode (that's why we need to |
| // force a safepoint) |
| // + Target thread will not enter any new monitors |
| // |
| void JavaThread::java_suspend() { |
| ThreadsListHandle tlh; |
| if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) { |
| return; |
| } |
| |
| { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); |
| if (!is_external_suspend()) { |
| // a racing resume has cancelled us; bail out now |
| return; |
| } |
| |
| // suspend is done |
| uint32_t debug_bits = 0; |
| // Warning: is_ext_suspend_completed() may temporarily drop the |
| // SR_lock to allow the thread to reach a stable thread state if |
| // it is currently in a transient thread state. |
| if (is_ext_suspend_completed(false /* !called_by_wait */, |
| SuspendRetryDelay, &debug_bits)) { |
| return; |
| } |
| } |
| |
| if (Thread::current() == this) { |
| // Safely self-suspend. |
| // If we don't do this explicitly it will implicitly happen |
| // before we transition back to Java, and on some other thread-state |
| // transition paths, but not as we exit a JVM TI SuspendThread call. |
| // As SuspendThread(current) must not return (until resumed) we must |
| // self-suspend here. |
| ThreadBlockInVM tbivm(this); |
| java_suspend_self(); |
| } else { |
| VM_ThreadSuspend vm_suspend; |
| VMThread::execute(&vm_suspend); |
| } |
| } |
| |
| // Part II of external suspension. |
| // A JavaThread self suspends when it detects a pending external suspend |
| // request. This is usually on transitions. It is also done in places |
| // where continuing to the next transition would surprise the caller, |
| // e.g., monitor entry. |
| // |
| // Returns the number of times that the thread self-suspended. |
| // |
| // Note: DO NOT call java_suspend_self() when you just want to block current |
| // thread. java_suspend_self() is the second stage of cooperative |
| // suspension for external suspend requests and should only be used |
| // to complete an external suspend request. |
| // |
| int JavaThread::java_suspend_self() { |
| assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()"); |
| int ret = 0; |
| |
| // we are in the process of exiting so don't suspend |
| if (is_exiting()) { |
| clear_external_suspend(); |
| return ret; |
| } |
| |
| assert(_anchor.walkable() || |
| (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), |
| "must have walkable stack"); |
| |
| MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); |
| |
| assert(!this->is_ext_suspended(), |
| "a thread trying to self-suspend should not already be suspended"); |
| |
| if (this->is_suspend_equivalent()) { |
| // If we are self-suspending as a result of the lifting of a |
| // suspend equivalent condition, then the suspend_equivalent |
| // flag is not cleared until we set the ext_suspended flag so |
| // that wait_for_ext_suspend_completion() returns consistent |
| // results. |
| this->clear_suspend_equivalent(); |
| } |
| |
| // A racing resume may have cancelled us before we grabbed SR_lock |
| // above. Or another external suspend request could be waiting for us |
| // by the time we return from SR_lock()->wait(). The thread |
| // that requested the suspension may already be trying to walk our |
| // stack and if we return now, we can change the stack out from under |
| // it. This would be a "bad thing (TM)" and cause the stack walker |
| // to crash. We stay self-suspended until there are no more pending |
| // external suspend requests. |
| while (is_external_suspend()) { |
| ret++; |
| this->set_ext_suspended(); |
| |
| // _ext_suspended flag is cleared by java_resume() |
| while (is_ext_suspended()) { |
| ml.wait(); |
| } |
| } |
| return ret; |
| } |
| |
| // Helper routine to set up the correct thread state before calling java_suspend_self. |
| // This is called when regular thread-state transition helpers can't be used because |
| // we can be in various states, in particular _thread_in_native_trans. |
| // Because this thread is external suspended the safepoint code will count it as at |
| // a safepoint, regardless of what its actual current thread-state is. But |
| // is_ext_suspend_completed() may be waiting to see a thread transition from |
| // _thread_in_native_trans to _thread_blocked. So we set the thread state directly |
| // to _thread_blocked. The problem with setting thread state directly is that a |
| // safepoint could happen just after java_suspend_self() returns after being resumed, |
| // and the VM thread will see the _thread_blocked state. So we must check for a safepoint |
| // after restoring the state to make sure we won't leave while a safepoint is in progress. |
| // However, not all initial-states are allowed when performing a safepoint check, as we |
| // should never be blocking at a safepoint whilst in those states. Of these 'bad' states |
| // only _thread_in_native is possible when executing this code (based on our two callers). |
| // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter |
| // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state, |
| // and so we don't need the explicit safepoint check. |
| |
| void JavaThread::java_suspend_self_with_safepoint_check() { |
| assert(this == Thread::current(), "invariant"); |
| JavaThreadState state = thread_state(); |
| set_thread_state(_thread_blocked); |
| java_suspend_self(); |
| set_thread_state_fence(state); |
| // Since we are not using a regular thread-state transition helper here, |
| // we must manually emit the instruction barrier after leaving a safe state. |
| OrderAccess::cross_modify_fence(); |
| if (state != _thread_in_native) { |
| SafepointMechanism::block_if_requested(this); |
| } |
| } |
| |
| #ifdef ASSERT |
| // Verify the JavaThread has not yet been published in the Threads::list, and |
| // hence doesn't need protection from concurrent access at this stage. |
| void JavaThread::verify_not_published() { |
| // Cannot create a ThreadsListHandle here and check !tlh.includes(this) |
| // since an unpublished JavaThread doesn't participate in the |
| // Thread-SMR protocol for keeping a ThreadsList alive. |
| assert(!on_thread_list(), "JavaThread shouldn't have been published yet!"); |
| } |
| #endif |
| |
| // Slow path when the native==>VM/Java barriers detect a safepoint is in |
| // progress or when _suspend_flags is non-zero. |
| // Current thread needs to self-suspend if there is a suspend request and/or |
| // block if a safepoint is in progress. |
| // Async exception ISN'T checked. |
| // Note only the ThreadInVMfromNative transition can call this function |
| // directly and when thread state is _thread_in_native_trans |
| void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { |
| assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); |
| |
| JavaThread *curJT = JavaThread::current(); |
| bool do_self_suspend = thread->is_external_suspend(); |
| |
| assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); |
| |
| // If JNIEnv proxies are allowed, don't self-suspend if the target |
| // thread is not the current thread. In older versions of jdbx, jdbx |
| // threads could call into the VM with another thread's JNIEnv so we |
| // can be here operating on behalf of a suspended thread (4432884). |
| if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { |
| thread->java_suspend_self_with_safepoint_check(); |
| } else { |
| SafepointMechanism::block_if_requested(curJT); |
| } |
| |
| JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);) |
| } |
| |
| // Slow path when the native==>VM/Java barriers detect a safepoint is in |
| // progress or when _suspend_flags is non-zero. |
| // Current thread needs to self-suspend if there is a suspend request and/or |
| // block if a safepoint is in progress. |
| // Also check for pending async exception (not including unsafe access error). |
| // Note only the native==>VM/Java barriers can call this function and when |
| // thread state is _thread_in_native_trans. |
| void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { |
| check_safepoint_and_suspend_for_native_trans(thread); |
| |
| if (thread->has_async_exception()) { |
| // We are in _thread_in_native_trans state, don't handle unsafe |
| // access error since that may block. |
| thread->check_and_handle_async_exceptions(false); |
| } |
| } |
| |
| // This is a variant of the normal |
| // check_special_condition_for_native_trans with slightly different |
| // semantics for use by critical native wrappers. It does all the |
| // normal checks but also performs the transition back into |
| // thread_in_Java state. This is required so that critical natives |
| // can potentially block and perform a GC if they are the last thread |
| // exiting the GCLocker. |
| void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { |
| check_special_condition_for_native_trans(thread); |
| |
| // Finish the transition |
| thread->set_thread_state(_thread_in_Java); |
| |
| if (thread->do_critical_native_unlock()) { |
| ThreadInVMfromJavaNoAsyncException tiv(thread); |
| GCLocker::unlock_critical(thread); |
| thread->clear_critical_native_unlock(); |
| } |
| } |
| |
| // We need to guarantee the Threads_lock here, since resumes are not |
| // allowed during safepoint synchronization |
| // Can only resume from an external suspension |
| void JavaThread::java_resume() { |
| assert_locked_or_safepoint(Threads_lock); |
| |
| // Sanity check: thread is gone, has started exiting or the thread |
| // was not externally suspended. |
| ThreadsListHandle tlh; |
| if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) { |
| return; |
| } |
| |
| MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); |
| |
| clear_external_suspend(); |
| |
| if (is_ext_suspended()) { |
| clear_ext_suspended(); |
| SR_lock()->notify_all(); |
| } |
| } |
| |
| size_t JavaThread::_stack_red_zone_size = 0; |
| size_t JavaThread::_stack_yellow_zone_size = 0; |
| size_t JavaThread::_stack_reserved_zone_size = 0; |
| size_t JavaThread::_stack_shadow_zone_size = 0; |
| |
| void JavaThread::create_stack_guard_pages() { |
| if (!os::uses_stack_guard_pages() || |
| _stack_guard_state != stack_guard_unused || |
| (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) { |
| log_info(os, thread)("Stack guard page creation for thread " |
| UINTX_FORMAT " disabled", os::current_thread_id()); |
| return; |
| } |
| address low_addr = stack_end(); |
| size_t len = stack_guard_zone_size(); |
| |
| assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page"); |
| assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size"); |
| |
| int must_commit = os::must_commit_stack_guard_pages(); |
| // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); |
| |
| if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) { |
| log_warning(os, thread)("Attempt to allocate stack guard pages failed."); |
| return; |
| } |
| |
| if (os::guard_memory((char *) low_addr, len)) { |
| _stack_guard_state = stack_guard_enabled; |
| } else { |
| log_warning(os, thread)("Attempt to protect stack guard pages failed (" |
| PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); |
| if (os::uncommit_memory((char *) low_addr, len)) { |
| log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); |
| } |
| return; |
| } |
| |
| log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " |
| PTR_FORMAT "-" PTR_FORMAT ".", |
| os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); |
| } |
| |
| void JavaThread::remove_stack_guard_pages() { |
| assert(Thread::current() == this, "from different thread"); |
| if (_stack_guard_state == stack_guard_unused) return; |
| address low_addr = stack_end(); |
| size_t len = stack_guard_zone_size(); |
| |
| if (os::must_commit_stack_guard_pages()) { |
| if (os::remove_stack_guard_pages((char *) low_addr, len)) { |
| _stack_guard_state = stack_guard_unused; |
| } else { |
| log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" |
| PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); |
| return; |
| } |
| } else { |
| if (_stack_guard_state == stack_guard_unused) return; |
| if (os::unguard_memory((char *) low_addr, len)) { |
| _stack_guard_state = stack_guard_unused; |
| } else { |
| log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" |
| PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); |
| return; |
| } |
| } |
| |
| log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " |
| PTR_FORMAT "-" PTR_FORMAT ".", |
| os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); |
| } |
| |
| void JavaThread::enable_stack_reserved_zone() { |
| assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state"); |
| |
| // The base notation is from the stack's point of view, growing downward. |
| // We need to adjust it to work correctly with guard_memory() |
| address base = stack_reserved_zone_base() - stack_reserved_zone_size(); |
| |
| guarantee(base < stack_base(),"Error calculating stack reserved zone"); |
| guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); |
| |
| if (os::guard_memory((char *) base, stack_reserved_zone_size())) { |
| _stack_guard_state = stack_guard_enabled; |
| } else { |
| warning("Attempt to guard stack reserved zone failed."); |
| } |
| enable_register_stack_guard(); |
| } |
| |
| void JavaThread::disable_stack_reserved_zone() { |
| assert(_stack_guard_state == stack_guard_enabled, "inconsistent state"); |
| |
| // Simply return if called for a thread that does not use guard pages. |
| if (_stack_guard_state != stack_guard_enabled) return; |
| |
| // The base notation is from the stack's point of view, growing downward. |
| // We need to adjust it to work correctly with guard_memory() |
| address base = stack_reserved_zone_base() - stack_reserved_zone_size(); |
| |
| if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { |
| _stack_guard_state = stack_guard_reserved_disabled; |
| } else { |
| warning("Attempt to unguard stack reserved zone failed."); |
| } |
| disable_register_stack_guard(); |
| } |
| |
| void JavaThread::enable_stack_yellow_reserved_zone() { |
| assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); |
| assert(_stack_guard_state != stack_guard_enabled, "already enabled"); |
| |
| // The base notation is from the stacks point of view, growing downward. |
| // We need to adjust it to work correctly with guard_memory() |
| address base = stack_red_zone_base(); |
| |
| guarantee(base < stack_base(), "Error calculating stack yellow zone"); |
| guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); |
| |
| if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { |
| _stack_guard_state = stack_guard_enabled; |
| } else { |
| warning("Attempt to guard stack yellow zone failed."); |
| } |
| enable_register_stack_guard(); |
| } |
| |
| void JavaThread::disable_stack_yellow_reserved_zone() { |
| assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); |
| assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); |
| |
| // Simply return if called for a thread that does not use guard pages. |
| if (_stack_guard_state == stack_guard_unused) return; |
| |
| // The base notation is from the stacks point of view, growing downward. |
| // We need to adjust it to work correctly with guard_memory() |
| address base = stack_red_zone_base(); |
| |
| if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { |
| _stack_guard_state = stack_guard_yellow_reserved_disabled; |
| } else { |
| warning("Attempt to unguard stack yellow zone failed."); |
| } |
| disable_register_stack_guard(); |
| } |
| |
| void JavaThread::enable_stack_red_zone() { |
| // The base notation is from the stacks point of view, growing downward. |
| // We need to adjust it to work correctly with guard_memory() |
| assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); |
| address base = stack_red_zone_base() - stack_red_zone_size(); |
| |
| guarantee(base < stack_base(), "Error calculating stack red zone"); |
| guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); |
| |
| if (!os::guard_memory((char *) base, stack_red_zone_size())) { |
| warning("Attempt to guard stack red zone failed."); |
| } |
| } |
| |
| void JavaThread::disable_stack_red_zone() { |
| // The base notation is from the stacks point of view, growing downward. |
| // We need to adjust it to work correctly with guard_memory() |
| assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); |
| address base = stack_red_zone_base() - stack_red_zone_size(); |
| if (!os::unguard_memory((char *)base, stack_red_zone_size())) { |
| warning("Attempt to unguard stack red zone failed."); |
| } |
| } |
| |
| void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { |
| // ignore is there is no stack |
| if (!has_last_Java_frame()) return; |
| // traverse the stack frames. Starts from top frame. |
| for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { |
| frame* fr = fst.current(); |
| f(fr, fst.register_map()); |
| } |
| } |
| |
| |
| #ifndef PRODUCT |
| // Deoptimization |
| // Function for testing deoptimization |
| void JavaThread::deoptimize() { |
| // BiasedLocking needs an updated RegisterMap for the revoke monitors pass |
| StackFrameStream fst(this, UseBiasedLocking); |
| bool deopt = false; // Dump stack only if a deopt actually happens. |
| bool only_at = strlen(DeoptimizeOnlyAt) > 0; |
| // Iterate over all frames in the thread and deoptimize |
| for (; !fst.is_done(); fst.next()) { |
| if (fst.current()->can_be_deoptimized()) { |
| |
| if (only_at) { |
| // Deoptimize only at particular bcis. DeoptimizeOnlyAt |
| // consists of comma or carriage return separated numbers so |
| // search for the current bci in that string. |
| address pc = fst.current()->pc(); |
| nmethod* nm = (nmethod*) fst.current()->cb(); |
| ScopeDesc* sd = nm->scope_desc_at(pc); |
| char buffer[8]; |
| jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); |
| size_t len = strlen(buffer); |
| const char * found = strstr(DeoptimizeOnlyAt, buffer); |
| while (found != NULL) { |
| if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && |
| (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { |
| // Check that the bci found is bracketed by terminators. |
| break; |
| } |
| found = strstr(found + 1, buffer); |
| } |
| if (!found) { |
| continue; |
| } |
| } |
| |
| if (DebugDeoptimization && !deopt) { |
| deopt = true; // One-time only print before deopt |
| tty->print_cr("[BEFORE Deoptimization]"); |
| trace_frames(); |
| trace_stack(); |
| } |
| Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); |
| } |
| } |
| |
| if (DebugDeoptimization && deopt) { |
| tty->print_cr("[AFTER Deoptimization]"); |
| trace_frames(); |
| } |
| } |
| |
| |
| // Make zombies |
| void JavaThread::make_zombies() { |
| for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { |
| if (fst.current()->can_be_deoptimized()) { |
| // it is a Java nmethod |
| nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); |
| nm->make_not_entrant(); |
| } |
| } |
| } |
| #endif // PRODUCT |
| |
| |
| void JavaThread::deoptimized_wrt_marked_nmethods() { |
| if (!has_last_Java_frame()) return; |
| // BiasedLocking needs an updated RegisterMap for the revoke monitors pass |
| StackFrameStream fst(this, UseBiasedLocking); |
| for (; !fst.is_done(); fst.next()) { |
| if (fst.current()->should_be_deoptimized()) { |
| Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); |
| } |
| } |
| } |
| |
| |
| // If the caller is a NamedThread, then remember, in the current scope, |
| // the given JavaThread in its _processed_thread field. |
| class RememberProcessedThread: public StackObj { |
| NamedThread* _cur_thr; |
| public: |
| RememberProcessedThread(JavaThread* jthr) { |
| Thread* thread = Thread::current(); |
| if (thread->is_Named_thread()) { |
| _cur_thr = (NamedThread *)thread; |
| _cur_thr->set_processed_thread(jthr); |
| } else { |
| _cur_thr = NULL; |
| } |
| } |
| |
| ~RememberProcessedThread() { |
| if (_cur_thr) { |
| _cur_thr->set_processed_thread(NULL); |
| } |
| } |
| }; |
| |
| void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { |
| // Verify that the deferred card marks have been flushed. |
| assert(deferred_card_mark().is_empty(), "Should be empty during GC"); |
| |
| // Traverse the GCHandles |
| Thread::oops_do(f, cf); |
| |
| assert((!has_last_Java_frame() && java_call_counter() == 0) || |
| (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); |
| |
| if (has_last_Java_frame()) { |
| // Record JavaThread to GC thread |
| RememberProcessedThread rpt(this); |
| |
| // traverse the registered growable array |
| if (_array_for_gc != NULL) { |
| for (int index = 0; index < _array_for_gc->length(); index++) { |
| f->do_oop(_array_for_gc->adr_at(index)); |
| } |
| } |
| |
| // Traverse the monitor chunks |
| for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { |
| chunk->oops_do(f); |
| } |
| |
| // Traverse the execution stack |
| for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { |
| fst.current()->oops_do(f, cf, fst.register_map()); |
| } |
| } |
| |
| // callee_target is never live across a gc point so NULL it here should |
| // it still contain a methdOop. |
| |
| set_callee_target(NULL); |
| |
| assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); |
| // If we have deferred set_locals there might be oops waiting to be |
| // written |
| GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); |
| if (list != NULL) { |
| for (int i = 0; i < list->length(); i++) { |
| list->at(i)->oops_do(f); |
| } |
| } |
| |
| // Traverse instance variables at the end since the GC may be moving things |
| // around using this function |
| f->do_oop((oop*) &_threadObj); |
| f->do_oop((oop*) &_vm_result); |
| f->do_oop((oop*) &_exception_oop); |
| f->do_oop((oop*) &_pending_async_exception); |
| |
| if (jvmti_thread_state() != NULL) { |
| jvmti_thread_state()->oops_do(f); |
| } |
| } |
| |
| #ifdef ASSERT |
| void JavaThread::verify_states_for_handshake() { |
| // This checks that the thread has a correct frame state during a handshake. |
| assert((!has_last_Java_frame() && java_call_counter() == 0) || |
| (has_last_Java_frame() && java_call_counter() > 0), |
| "unexpected frame info: has_last_frame=%d, java_call_counter=%d", |
| has_last_Java_frame(), java_call_counter()); |
| } |
| #endif |
| |
| void JavaThread::nmethods_do(CodeBlobClosure* cf) { |
| assert((!has_last_Java_frame() && java_call_counter() == 0) || |
| (has_last_Java_frame() && java_call_counter() > 0), |
| "unexpected frame info: has_last_frame=%d, java_call_counter=%d", |
| has_last_Java_frame(), java_call_counter()); |
| |
| if (has_last_Java_frame()) { |
| // Traverse the execution stack |
| for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { |
| fst.current()->nmethods_do(cf); |
| } |
| } |
| } |
| |
| void JavaThread::metadata_do(MetadataClosure* f) { |
| if (has_last_Java_frame()) { |
| // Traverse the execution stack to call f() on the methods in the stack |
| for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { |
| fst.current()->metadata_do(f); |
| } |
| } else if (is_Compiler_thread()) { |
| // need to walk ciMetadata in current compile tasks to keep alive. |
| CompilerThread* ct = (CompilerThread*)this; |
| if (ct->env() != NULL) { |
| ct->env()->metadata_do(f); |
| } |
| CompileTask* task = ct->task(); |
| if (task != NULL) { |
| task->metadata_do(f); |
| } |
| } |
| } |
| |
| // Printing |
| const char* _get_thread_state_name(JavaThreadState _thread_state) { |
| switch (_thread_state) { |
| case _thread_uninitialized: return "_thread_uninitialized"; |
| case _thread_new: return "_thread_new"; |
| case _thread_new_trans: return "_thread_new_trans"; |
| case _thread_in_native: return "_thread_in_native"; |
| case _thread_in_native_trans: return "_thread_in_native_trans"; |
| case _thread_in_vm: return "_thread_in_vm"; |
| case _thread_in_vm_trans: return "_thread_in_vm_trans"; |
| case _thread_in_Java: return "_thread_in_Java"; |
| case _thread_in_Java_trans: return "_thread_in_Java_trans"; |
| case _thread_blocked: return "_thread_blocked"; |
| case _thread_blocked_trans: return "_thread_blocked_trans"; |
| default: return "unknown thread state"; |
| } |
| } |
| |
| #ifndef PRODUCT |
| void JavaThread::print_thread_state_on(outputStream *st) const { |
| st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); |
| }; |
| void JavaThread::print_thread_state() const { |
| print_thread_state_on(tty); |
| } |
| #endif // PRODUCT |
| |
| // Called by Threads::print() for VM_PrintThreads operation |
| void JavaThread::print_on(outputStream *st, bool print_extended_info) const { |
| st->print_raw("\""); |
| st->print_raw(get_thread_name()); |
| st->print_raw("\" "); |
| oop thread_oop = threadObj(); |
| if (thread_oop != NULL) { |
| st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop)); |
| if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); |
| st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); |
| } |
| Thread::print_on(st, print_extended_info); |
| // print guess for valid stack memory region (assume 4K pages); helps lock debugging |
| st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); |
| if (thread_oop != NULL) { |
| st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); |
| } |
| #ifndef PRODUCT |
| _safepoint_state->print_on(st); |
| #endif // PRODUCT |
| if (is_Compiler_thread()) { |
| CompileTask *task = ((CompilerThread*)this)->task(); |
| if (task != NULL) { |
| st->print(" Compiling: "); |
| task->print(st, NULL, true, false); |
| } else { |
| st->print(" No compile task"); |
| } |
| st->cr(); |
| } |
| } |
| |
| void JavaThread::print() const { print_on(tty); } |
| |
| void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { |
| st->print("%s", get_thread_name_string(buf, buflen)); |
| } |
| |
| // Called by fatal error handler. The difference between this and |
| // JavaThread::print() is that we can't grab lock or allocate memory. |
| void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { |
| st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); |
| oop thread_obj = threadObj(); |
| if (thread_obj != NULL) { |
| if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); |
| } |
| st->print(" ["); |
| st->print("%s", _get_thread_state_name(_thread_state)); |
| if (osthread()) { |
| st->print(", id=%d", osthread()->thread_id()); |
| } |
| st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", |
| p2i(stack_end()), p2i(stack_base())); |
| st->print("]"); |
| |
| ThreadsSMRSupport::print_info_on(this, st); |
| return; |
| } |
| |
| // Verification |
| |
| static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } |
| |
| void JavaThread::verify() { |
| // Verify oops in the thread. |
| oops_do(&VerifyOopClosure::verify_oop, NULL); |
| |
| // Verify the stack frames. |
| frames_do(frame_verify); |
| } |
| |
| // CR 6300358 (sub-CR 2137150) |
| // Most callers of this method assume that it can't return NULL but a |
| // thread may not have a name whilst it is in the process of attaching to |
| // the VM - see CR 6412693, and there are places where a JavaThread can be |
| // seen prior to having it's threadObj set (eg JNI attaching threads and |
| // if vm exit occurs during initialization). These cases can all be accounted |
| // for such that this method never returns NULL. |
| const char* JavaThread::get_thread_name() const { |
| #ifdef ASSERT |
| // early safepoints can hit while current thread does not yet have TLS |
| if (!SafepointSynchronize::is_at_safepoint()) { |
| Thread *cur = Thread::current(); |
| if (!(cur->is_Java_thread() && cur == this)) { |
| // Current JavaThreads are allowed to get their own name without |
| // the Threads_lock. |
| assert_locked_or_safepoint(Threads_lock); |
| } |
| } |
| #endif // ASSERT |
| return get_thread_name_string(); |
| } |
| |
| // Returns a non-NULL representation of this thread's name, or a suitable |
| // descriptive string if there is no set name |
| const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { |
| const char* name_str; |
| oop thread_obj = threadObj(); |
| if (thread_obj != NULL) { |
| oop name = java_lang_Thread::name(thread_obj); |
| if (name != NULL) { |
| if (buf == NULL) { |
| name_str = java_lang_String::as_utf8_string(name); |
| } else { |
| name_str = java_lang_String::as_utf8_string(name, buf, buflen); |
| } |
| } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 |
| name_str = "<no-name - thread is attaching>"; |
| } else { |
| name_str = Thread::name(); |
| } |
| } else { |
| name_str = Thread::name(); |
| } |
| assert(name_str != NULL, "unexpected NULL thread name"); |
| return name_str; |
| } |
| |
| |
| const char* JavaThread::get_threadgroup_name() const { |
| debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) |
| oop thread_obj = threadObj(); |
| if (thread_obj != NULL) { |
| oop thread_group = java_lang_Thread::threadGroup(thread_obj); |
| if (thread_group != NULL) { |
| // ThreadGroup.name can be null |
| return java_lang_ThreadGroup::name(thread_group); |
| } |
| } |
| return NULL; |
| } |
| |
| const char* JavaThread::get_parent_name() const { |
| debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) |
| oop thread_obj = threadObj(); |
| if (thread_obj != NULL) { |
| oop thread_group = java_lang_Thread::threadGroup(thread_obj); |
| if (thread_group != NULL) { |
| oop parent = java_lang_ThreadGroup::parent(thread_group); |
| if (parent != NULL) { |
| // ThreadGroup.name can be null |
| return java_lang_ThreadGroup::name(parent); |
| } |
| } |
| } |
| return NULL; |
| } |
| |
| ThreadPriority JavaThread::java_priority() const { |
| oop thr_oop = threadObj(); |
| if (thr_oop == NULL) return NormPriority; // Bootstrapping |
| ThreadPriority priority = java_lang_Thread::priority(thr_oop); |
| assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); |
| return priority; |
| } |
| |
| void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { |
| |
| assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); |
| // Link Java Thread object <-> C++ Thread |
| |
| // Get the C++ thread object (an oop) from the JNI handle (a jthread) |
| // and put it into a new Handle. The Handle "thread_oop" can then |
| // be used to pass the C++ thread object to other methods. |
| |
| // Set the Java level thread object (jthread) field of the |
| // new thread (a JavaThread *) to C++ thread object using the |
| // "thread_oop" handle. |
| |
| // Set the thread field (a JavaThread *) of the |
| // oop representing the java_lang_Thread to the new thread (a JavaThread *). |
| |
| Handle thread_oop(Thread::current(), |
| JNIHandles::resolve_non_null(jni_thread)); |
| assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), |
| "must be initialized"); |
| set_threadObj(thread_oop()); |
| java_lang_Thread::set_thread(thread_oop(), this); |
| |
| if (prio == NoPriority) { |
| prio = java_lang_Thread::priority(thread_oop()); |
| assert(prio != NoPriority, "A valid priority should be present"); |
| } |
| |
| // Push the Java priority down to the native thread; needs Threads_lock |
| Thread::set_priority(this, prio); |
| |
| // Add the new thread to the Threads list and set it in motion. |
| // We must have threads lock in order to call Threads::add. |
| // It is crucial that we do not block before the thread is |
| // added to the Threads list for if a GC happens, then the java_thread oop |
| // will not be visited by GC. |
| Threads::add(this); |
| } |
| |
| oop JavaThread::current_park_blocker() { |
| // Support for JSR-166 locks |
| oop thread_oop = threadObj(); |
| if (thread_oop != NULL) { |
| return java_lang_Thread::park_blocker(thread_oop); |
| } |
| return NULL; |
| } |
| |
| |
| void JavaThread::print_stack_on(outputStream* st) { |
| if (!has_last_Java_frame()) return; |
| ResourceMark rm; |
| HandleMark hm; |
| |
| RegisterMap reg_map(this); |
| vframe* start_vf = last_java_vframe(®_map); |
| int count = 0; |
| for (vframe* f = start_vf; f != NULL; f = f->sender()) { |
| if (f->is_java_frame()) { |
| javaVFrame* jvf = javaVFrame::cast(f); |
| java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); |
| |
| // Print out lock information |
| if (JavaMonitorsInStackTrace) { |
| jvf->print_lock_info_on(st, count); |
| } |
| } else { |
| // Ignore non-Java frames |
| } |
| |
| // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0 |
| count++; |
| if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return; |
| } |
| } |
| |
| |
| // JVMTI PopFrame support |
| void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { |
| assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); |
| if (in_bytes(size_in_bytes) != 0) { |
| _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); |
| _popframe_preserved_args_size = in_bytes(size_in_bytes); |
| Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); |
| } |
| } |
| |
| void* JavaThread::popframe_preserved_args() { |
| return _popframe_preserved_args; |
| } |
| |
| ByteSize JavaThread::popframe_preserved_args_size() { |
| return in_ByteSize(_popframe_preserved_args_size); |
| } |
| |
| WordSize JavaThread::popframe_preserved_args_size_in_words() { |
| int sz = in_bytes(popframe_preserved_args_size()); |
| assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); |
| return in_WordSize(sz / wordSize); |
| } |
| |
| void JavaThread::popframe_free_preserved_args() { |
| assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); |
| FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); |
| _popframe_preserved_args = NULL; |
| _popframe_preserved_args_size = 0; |
| } |
| |
| #ifndef PRODUCT |
| |
| void JavaThread::trace_frames() { |
| tty->print_cr("[Describe stack]"); |
| int frame_no = 1; |
| for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { |
| tty->print(" %d. ", frame_no++); |
| fst.current()->print_value_on(tty, this); |
| tty->cr(); |
| } |
| } |
| |
| class PrintAndVerifyOopClosure: public OopClosure { |
| protected: |
| template <class T> inline void do_oop_work(T* p) { |
| oop obj = RawAccess<>::oop_load(p); |
| if (obj == NULL) return; |
| tty->print(INTPTR_FORMAT ": ", p2i(p)); |
| if (oopDesc::is_oop_or_null(obj)) { |
| if (obj->is_objArray()) { |
| tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); |
| } else { |
| obj->print(); |
| } |
| } else { |
| tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); |
| } |
| tty->cr(); |
| } |
| public: |
| virtual void do_oop(oop* p) { do_oop_work(p); } |
| virtual void do_oop(narrowOop* p) { do_oop_work(p); } |
| }; |
| |
| |
| static void oops_print(frame* f, const RegisterMap *map) { |
| PrintAndVerifyOopClosure print; |
| f->print_value(); |
| f->oops_do(&print, NULL, (RegisterMap*)map); |
| } |
| |
| // Print our all the locations that contain oops and whether they are |
| // valid or not. This useful when trying to find the oldest frame |
| // where an oop has gone bad since the frame walk is from youngest to |
| // oldest. |
| void JavaThread::trace_oops() { |
| tty->print_cr("[Trace oops]"); |
| frames_do(oops_print); |
| } |
| |
| |
| #ifdef ASSERT |
| // Print or validate the layout of stack frames |
| void JavaThread::print_frame_layout(int depth, bool validate_only) { |
| ResourceMark rm; |
| PRESERVE_EXCEPTION_MARK; |
| FrameValues values; |
| int frame_no = 0; |
| for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { |
| fst.current()->describe(values, ++frame_no); |
| if (depth == frame_no) break; |
| } |
| if (validate_only) { |
| values.validate(); |
| } else { |
| tty->print_cr("[Describe stack layout]"); |
| values.print(this); |
| } |
| } |
| #endif |
| |
| void JavaThread::trace_stack_from(vframe* start_vf) { |
| ResourceMark rm; |
| int vframe_no = 1; |
| for (vframe* f = start_vf; f; f = f->sender()) { |
| if (f->is_java_frame()) { |
| javaVFrame::cast(f)->print_activation(vframe_no++); |
| } else { |
| f->print(); |
| } |
| if (vframe_no > StackPrintLimit) { |
| tty->print_cr("...<more frames>..."); |
| return; |
| } |
| } |
| } |
| |
| |
| void JavaThread::trace_stack() { |
| if (!has_last_Java_frame()) return; |
| ResourceMark rm; |
| HandleMark hm; |
| RegisterMap reg_map(this); |
| trace_stack_from(last_java_vframe(®_map)); |
| } |
| |
| |
| #endif // PRODUCT |
| |
| |
| javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { |
| assert(reg_map != NULL, "a map must be given"); |
| frame f = last_frame(); |
| for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { |
| if (vf->is_java_frame()) return javaVFrame::cast(vf); |
| } |
| return NULL; |
| } |
| |
| |
| Klass* JavaThread::security_get_caller_class(int depth) { |
| vframeStream vfst(this); |
| vfst.security_get_caller_frame(depth); |
| if (!vfst.at_end()) { |
| return vfst.method()->method_holder(); |
| } |
| return NULL; |
| } |
| |
| static void compiler_thread_entry(JavaThread* thread, TRAPS) { |
| assert(thread->is_Compiler_thread(), "must be compiler thread"); |
| CompileBroker::compiler_thread_loop(); |
| } |
| |
| static void sweeper_thread_entry(JavaThread* thread, TRAPS) { |
| NMethodSweeper::sweeper_loop(); |
| } |
| |
| // Create a CompilerThread |
| CompilerThread::CompilerThread(CompileQueue* queue, |
| CompilerCounters* counters) |
| : JavaThread(&compiler_thread_entry) { |
| _env = NULL; |
| _log = NULL; |
| _task = NULL; |
| _queue = queue; |
| _counters = counters; |
| _buffer_blob = NULL; |
| _compiler = NULL; |
| |
| // Compiler uses resource area for compilation, let's bias it to mtCompiler |
| resource_area()->bias_to(mtCompiler); |
| |
| #ifndef PRODUCT |
| _ideal_graph_printer = NULL; |
| #endif |
| } |
| |
| CompilerThread::~CompilerThread() { |
| // Delete objects which were allocated on heap. |
| delete _counters; |
| } |
| |
| bool CompilerThread::can_call_java() const { |
| return _compiler != NULL && _compiler->is_jvmci(); |
| } |
| |
| // Create sweeper thread |
| CodeCacheSweeperThread::CodeCacheSweeperThread() |
| : JavaThread(&sweeper_thread_entry) { |
| _scanned_compiled_method = NULL; |
| } |
| |
| void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { |
| JavaThread::oops_do(f, cf); |
| if (_scanned_compiled_method != NULL && cf != NULL) { |
| // Safepoints can occur when the sweeper is scanning an nmethod so |
| // process it here to make sure it isn't unloaded in the middle of |
| // a scan. |
| cf->do_code_blob(_scanned_compiled_method); |
| } |
| } |
| |
| void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) { |
| JavaThread::nmethods_do(cf); |
| if (_scanned_compiled_method != NULL && cf != NULL) { |
| // Safepoints can occur when the sweeper is scanning an nmethod so |
| // process it here to make sure it isn't unloaded in the middle of |
| // a scan. |
| cf->do_code_blob(_scanned_compiled_method); |
| } |
| } |
| |
| |
| // ======= Threads ======== |
| |
| // The Threads class links together all active threads, and provides |
| // operations over all threads. It is protected by the Threads_lock, |
| // which is also used in other global contexts like safepointing. |
| // ThreadsListHandles are used to safely perform operations on one |
| // or more threads without the risk of the thread exiting during the |
| // operation. |
| // |
| // Note: The Threads_lock is currently more widely used than we |
| // would like. We are actively migrating Threads_lock uses to other |
| // mechanisms in order to reduce Threads_lock contention. |
| |
| int Threads::_number_of_threads = 0; |
| int Threads::_number_of_non_daemon_threads = 0; |
| int Threads::_return_code = 0; |
| uintx Threads::_thread_claim_token = 1; // Never zero. |
| size_t JavaThread::_stack_size_at_create = 0; |
| |
| #ifdef ASSERT |
| bool Threads::_vm_complete = false; |
| #endif |
| |
| static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) { |
| Prefetch::read((void*)addr, prefetch_interval); |
| return *addr; |
| } |
| |
| // Possibly the ugliest for loop the world has seen. C++ does not allow |
| // multiple types in the declaration section of the for loop. In this case |
| // we are only dealing with pointers and hence can cast them. It looks ugly |
| // but macros are ugly and therefore it's fine to make things absurdly ugly. |
| #define DO_JAVA_THREADS(LIST, X) \ |
| for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \ |
| *MACRO_list = (JavaThread*)(LIST), \ |
| **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \ |
| **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \ |
| *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \ |
| MACRO_current_p != MACRO_end; \ |
| MACRO_current_p++, \ |
| X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval)) |
| |
| // All JavaThreads |
| #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X) |
| |
| // All NonJavaThreads (i.e., every non-JavaThread in the system). |
| void Threads::non_java_threads_do(ThreadClosure* tc) { |
| NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false); |
| for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) { |
| tc->do_thread(njti.current()); |
| } |
| } |
| |
| // All JavaThreads |
| void Threads::java_threads_do(ThreadClosure* tc) { |
| assert_locked_or_safepoint(Threads_lock); |
| // ALL_JAVA_THREADS iterates through all JavaThreads. |
| ALL_JAVA_THREADS(p) { |
| tc->do_thread(p); |
| } |
| } |
| |
| void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) { |
| assert_locked_or_safepoint(Threads_lock); |
| java_threads_do(tc); |
| tc->do_thread(VMThread::vm_thread()); |
| } |
| |
| // All JavaThreads + all non-JavaThreads (i.e., every thread in the system). |
| void Threads::threads_do(ThreadClosure* tc) { |
| assert_locked_or_safepoint(Threads_lock); |
| java_threads_do(tc); |
| non_java_threads_do(tc); |
| } |
| |
| void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) { |
| uintx claim_token = Threads::thread_claim_token(); |
| ALL_JAVA_THREADS(p) { |
| if (p->claim_threads_do(is_par, claim_token)) { |
| tc->do_thread(p); |
| } |
| } |
| VMThread* vmt = VMThread::vm_thread(); |
| if (vmt->claim_threads_do(is_par, claim_token)) { |
| tc->do_thread(vmt); |
| } |
| } |
| |
| // The system initialization in the library has three phases. |
| // |
| // Phase 1: java.lang.System class initialization |
| // java.lang.System is a primordial class loaded and initialized |
| // by the VM early during startup. java.lang.System.<clinit> |
| // only does registerNatives and keeps the rest of the class |
| // initialization work later until thread initialization completes. |
| // |
| // System.initPhase1 initializes the system properties, the static |
| // fields in, out, and err. Set up java signal handlers, OS-specific |
| // system settings, and thread group of the main thread. |
| static void call_initPhase1(TRAPS) { |
| Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); |
| JavaValue result(T_VOID); |
| JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(), |
| vmSymbols::void_method_signature(), CHECK); |
| } |
| |
| // Phase 2. Module system initialization |
| // This will initialize the module system. Only java.base classes |
| // can be loaded until phase 2 completes. |
| // |
| // Call System.initPhase2 after the compiler initialization and jsr292 |
| // classes get initialized because module initialization runs a lot of java |
| // code, that for performance reasons, should be compiled. Also, this will |
| // enable the startup code to use lambda and other language features in this |
| // phase and onward. |
| // |
| // After phase 2, The VM will begin search classes from -Xbootclasspath/a. |
| static void call_initPhase2(TRAPS) { |
| TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime)); |
| |
| Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); |
| |
| JavaValue result(T_INT); |
| JavaCallArguments args; |
| args.push_int(DisplayVMOutputToStderr); |
| args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown |
| JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(), |
| vmSymbols::boolean_boolean_int_signature(), &args, CHECK); |
| if (result.get_jint() != JNI_OK) { |
| vm_exit_during_initialization(); // no message or exception |
| } |
| |
| universe_post_module_init(); |
| } |
| |
| // Phase 3. final setup - set security manager, system class loader and TCCL |
| // |
| // This will instantiate and set the security manager, set the system class |
| // loader as well as the thread context class loader. The security manager |
| // and system class loader may be a custom class loaded from -Xbootclasspath/a, |
| // other modules or the application's classpath. |
| static void call_initPhase3(TRAPS) { |
| Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); |
| JavaValue result(T_VOID); |
| JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(), |
| vmSymbols::void_method_signature(), CHECK); |
| } |
| |
| void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { |
| TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime)); |
| |
| if (EagerXrunInit && Arguments::init_libraries_at_startup()) { |
| create_vm_init_libraries(); |
| } |
| |
| initialize_class(vmSymbols::java_lang_String(), CHECK); |
| |
| // Inject CompactStrings value after the static initializers for String ran. |
| java_lang_String::set_compact_strings(CompactStrings); |
| |
| // Initialize java_lang.System (needed before creating the thread) |
| initialize_class(vmSymbols::java_lang_System(), CHECK); |
| // The VM creates & returns objects of this class. Make sure it's initialized. |
| initialize_class(vmSymbols::java_lang_Class(), CHECK); |
| initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); |
| Handle thread_group = create_initial_thread_group(CHECK); |
| Universe::set_main_thread_group(thread_group()); |
| initialize_class(vmSymbols::java_lang_Thread(), CHECK); |
| oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); |
| main_thread->set_threadObj(thread_object); |
| |
| // Set thread status to running since main thread has |
| // been started and running. |
| java_lang_Thread::set_thread_status(thread_object, |
| java_lang_Thread::RUNNABLE); |
| |
| // The VM creates objects of this class. |
| initialize_class(vmSymbols::java_lang_Module(), CHECK); |
| |
| #ifdef ASSERT |
| InstanceKlass *k = SystemDictionary::UnsafeConstants_klass(); |
| assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized"); |
| #endif |
| |
| // initialize the hardware-specific constants needed by Unsafe |
| initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK); |
| jdk_internal_misc_UnsafeConstants::set_unsafe_constants(); |
| |
| // The VM preresolves methods to these classes. Make sure that they get initialized |
| initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); |
| initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); |
| |
| // Phase 1 of the system initialization in the library, java.lang.System class initialization |
| call_initPhase1(CHECK); |
| |
| // get the Java runtime name after java.lang.System is initialized |
| JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); |
| JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); |
| |
| // an instance of OutOfMemory exception has been allocated earlier |
| initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); |
| initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); |
| initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); |
| initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); |
| initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); |
| initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); |
| initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); |
| initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); |
| |
| // Eager box cache initialization only if AOT is on and any library is loaded. |
| AOTLoader::initialize_box_caches(CHECK); |
| } |
| |
| void Threads::initialize_jsr292_core_classes(TRAPS) { |
| TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime)); |
| |
| initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); |
| initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK); |
| initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); |
| initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); |
| } |
| |
| jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { |
| extern void JDK_Version_init(); |
| |
| // Preinitialize version info. |
| VM_Version::early_initialize(); |
| |
| // Check version |
| if (!is_supported_jni_version(args->version)) return JNI_EVERSION; |
| |
| // Initialize library-based TLS |
| ThreadLocalStorage::init(); |
| |
| // Initialize the output stream module |
| ostream_init(); |
| |
| // Process java launcher properties. |
| Arguments::process_sun_java_launcher_properties(args); |
| |
| // Initialize the os module |
| os::init(); |
| |
| // Record VM creation timing statistics |
| TraceVmCreationTime create_vm_timer; |
| create_vm_timer.start(); |
| |
| // Initialize system properties. |
| Arguments::init_system_properties(); |
| |
| // So that JDK version can be used as a discriminator when parsing arguments |
| JDK_Version_init(); |
| |
| // Update/Initialize System properties after JDK version number is known |
| Arguments::init_version_specific_system_properties(); |
| |
| // Make sure to initialize log configuration *before* parsing arguments |
| LogConfiguration::initialize(create_vm_timer.begin_time()); |
| |
| // Parse arguments |
| // Note: this internally calls os::init_container_support() |
| jint parse_result = Arguments::parse(args); |
| if (parse_result != JNI_OK) return parse_result; |
| |
| os::init_before_ergo(); |
| |
| jint ergo_result = Arguments::apply_ergo(); |
| if (ergo_result != JNI_OK) return ergo_result; |
| |
| // Final check of all ranges after ergonomics which may change values. |
| if (!JVMFlagRangeList::check_ranges()) { |
| return JNI_EINVAL; |
| } |
| |
| // Final check of all 'AfterErgo' constraints after ergonomics which may change values. |
| bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo); |
| if (!constraint_result) { |
| return JNI_EINVAL; |
| } |
| |
| JVMFlagWriteableList::mark_startup(); |
| |
| if (PauseAtStartup) { |
| os::pause(); |
| } |
| |
| HOTSPOT_VM_INIT_BEGIN(); |
| |
| // Timing (must come after argument parsing) |
| TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime)); |
| |
| // Initialize the os module after parsing the args |
| jint os_init_2_result = os::init_2(); |
| if (os_init_2_result != JNI_OK) return os_init_2_result; |
| |
| #ifdef CAN_SHOW_REGISTERS_ON_ASSERT |
| // Initialize assert poison page mechanism. |
| if (ShowRegistersOnAssert) { |
| initialize_assert_poison(); |
| } |
| #endif // CAN_SHOW_REGISTERS_ON_ASSERT |
| |
| SafepointMechanism::initialize(); |
| |
| jint adjust_after_os_result = Arguments::adjust_after_os(); |
| if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; |
| |
| // Initialize output stream logging |
| ostream_init_log(); |
| |
| // Convert -Xrun to -agentlib: if there is no JVM_OnLoad |
| // Must be before create_vm_init_agents() |
| if (Arguments::init_libraries_at_startup()) { |
| convert_vm_init_libraries_to_agents(); |
| } |
| |
| // Launch -agentlib/-agentpath and converted -Xrun agents |
| if (Arguments::init_agents_at_startup()) { |
| create_vm_init_agents(); |
| } |
| |
| // Initialize Threads state |
| _number_of_threads = 0; |
| _number_of_non_daemon_threads = 0; |
| |
| // Initialize global data structures and create system classes in heap |
| vm_init_globals(); |
| |
| #if INCLUDE_JVMCI |
| if (JVMCICounterSize > 0) { |
| JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI); |
| memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); |
| } else { |
| JavaThread::_jvmci_old_thread_counters = NULL; |
| } |
| #endif // INCLUDE_JVMCI |
| |
| // Attach the main thread to this os thread |
| JavaThread* main_thread = new JavaThread(); |
| main_thread->set_thread_state(_thread_in_vm); |
| main_thread->initialize_thread_current(); |
| // must do this before set_active_handles |
| main_thread->record_stack_base_and_size(); |
| main_thread->register_thread_stack_with_NMT(); |
| main_thread->set_active_handles(JNIHandleBlock::allocate_block()); |
| |
| if (!main_thread->set_as_starting_thread()) { |
| vm_shutdown_during_initialization( |
| "Failed necessary internal allocation. Out of swap space"); |
| main_thread->smr_delete(); |
| *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again |
| return JNI_ENOMEM; |
| } |
| |
| // Enable guard page *after* os::create_main_thread(), otherwise it would |
| // crash Linux VM, see notes in os_linux.cpp. |
| main_thread->create_stack_guard_pages(); |
| |
| // Initialize Java-Level synchronization subsystem |
| ObjectMonitor::Initialize(); |
| |
| // Initialize global modules |
| jint status = init_globals(); |
| if (status != JNI_OK) { |
| main_thread->smr_delete(); |
| *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again |
| return status; |
| } |
| |
| JFR_ONLY(Jfr::on_vm_init();) |
| |
| // Should be done after the heap is fully created |
| main_thread->cache_global_variables(); |
| |
| HandleMark hm; |
| |
| { MutexLocker mu(Threads_lock); |
| Threads::add(main_thread); |
| } |
| |
| // Any JVMTI raw monitors entered in onload will transition into |
| // real raw monitor. VM is setup enough here for raw monitor enter. |
| JvmtiExport::transition_pending_onload_raw_monitors(); |
| |
| // Create the VMThread |
| { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime)); |
| |
| VMThread::create(); |
| Thread* vmthread = VMThread::vm_thread(); |
| |
| if (!os::create_thread(vmthread, os::vm_thread)) { |
| vm_exit_during_initialization("Cannot create VM thread. " |
| "Out of system resources."); |
| } |
| |
| // Wait for the VM thread to become ready, and VMThread::run to initialize |
| // Monitors can have spurious returns, must always check another state flag |
| { |
| MonitorLocker ml(Notify_lock); |
| os::start_thread(vmthread); |
| while (vmthread->active_handles() == NULL) { |
| ml.wait(); |
| } |
| } |
| } |
| |
| assert(Universe::is_fully_initialized(), "not initialized"); |
| if (VerifyDuringStartup) { |
| // Make sure we're starting with a clean slate. |
| VM_Verify verify_op; |
| VMThread::execute(&verify_op); |
| } |
| |
| // We need this to update the java.vm.info property in case any flags used |
| // to initially define it have been changed. This is needed for both CDS and |
| // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info |
| // is initially computed. See Abstract_VM_Version::vm_info_string(). |
| // This update must happen before we initialize the java classes, but |
| // after any initialization logic that might modify the flags. |
| Arguments::update_vm_info_property(VM_Version::vm_info_string()); |
| |
| Thread* THREAD = Thread::current(); |
| |
| // Always call even when there are not JVMTI environments yet, since environments |
| // may be attached late and JVMTI must track phases of VM execution |
| JvmtiExport::enter_early_start_phase(); |
| |
| // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. |
| JvmtiExport::post_early_vm_start(); |
| |
| initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); |
| |
| quicken_jni_functions(); |
| |
| // No more stub generation allowed after that point. |
| StubCodeDesc::freeze(); |
| |
| // Set flag that basic initialization has completed. Used by exceptions and various |
| // debug stuff, that does not work until all basic classes have been initialized. |
| set_init_completed(); |
| |
| LogConfiguration::post_initialize(); |
| Metaspace::post_initialize(); |
| |
| HOTSPOT_VM_INIT_END(); |
| |
| // record VM initialization completion time |
| #if INCLUDE_MANAGEMENT |
| Management::record_vm_init_completed(); |
| #endif // INCLUDE_MANAGEMENT |
| |
| // Signal Dispatcher needs to be started before VMInit event is posted |
| os::initialize_jdk_signal_support(CHECK_JNI_ERR); |
| |
| // Start Attach Listener if +StartAttachListener or it can't be started lazily |
| if (!DisableAttachMechanism) { |
| AttachListener::vm_start(); |
| if (StartAttachListener || AttachListener::init_at_startup()) { |
| AttachListener::init(); |
| } |
| } |
| |
| // Launch -Xrun agents |
| // Must be done in the JVMTI live phase so that for backward compatibility the JDWP |
| // back-end can launch with -Xdebug -Xrunjdwp. |
| if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { |
| create_vm_init_libraries(); |
| } |
| |
| if (CleanChunkPoolAsync) { |
| Chunk::start_chunk_pool_cleaner_task(); |
| } |
| |
| |
| // initialize compiler(s) |
| #if defined(COMPILER1) || COMPILER2_OR_JVMCI |
| #if INCLUDE_JVMCI |
| bool force_JVMCI_intialization = false; |
| if (EnableJVMCI) { |
| // Initialize JVMCI eagerly when it is explicitly requested. |
| // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled. |
| force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig; |
| |
| if (!force_JVMCI_intialization) { |
| // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking |
| // compilations via JVMCI will not actually block until JVMCI is initialized. |
| force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation); |
| } |
| } |
| #endif |
| CompileBroker::compilation_init_phase1(CHECK_JNI_ERR); |
| // Postpone completion of compiler initialization to after JVMCI |
| // is initialized to avoid timeouts of blocking compilations. |
| if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) { |
| CompileBroker::compilation_init_phase2(); |
| } |
| #endif |
| |
| // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. |
| // It is done after compilers are initialized, because otherwise compilations of |
| // signature polymorphic MH intrinsics can be missed |
| // (see SystemDictionary::find_method_handle_intrinsic). |
| initialize_jsr292_core_classes(CHECK_JNI_ERR); |
| |
| // This will initialize the module system. Only java.base classes can be |
| // loaded until phase 2 completes |
| call_initPhase2(CHECK_JNI_ERR); |
| |
| // Always call even when there are not JVMTI environments yet, since environments |
| // may be attached late and JVMTI must track phases of VM execution |
| JvmtiExport::enter_start_phase(); |
| |
| // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. |
| JvmtiExport::post_vm_start(); |
| |
| // Final system initialization including security manager and system class loader |
| call_initPhase3(CHECK_JNI_ERR); |
| |
| // cache the system and platform class loaders |
| SystemDictionary::compute_java_loaders(CHECK_JNI_ERR); |
| |
| #if INCLUDE_CDS |
| // capture the module path info from the ModuleEntryTable |
| ClassLoader::initialize_module_path(THREAD); |
| #endif |
| |
| #if INCLUDE_JVMCI |
| if (force_JVMCI_intialization) { |
| JVMCI::initialize_compiler(CHECK_JNI_ERR); |
| CompileBroker::compilation_init_phase2(); |
| } |
| #endif |
| |
| // Always call even when there are not JVMTI environments yet, since environments |
| // may be attached late and JVMTI must track phases of VM execution |
| JvmtiExport::enter_live_phase(); |
| |
| // Make perfmemory accessible |
| PerfMemory::set_accessible(true); |
| |
| // Notify JVMTI agents that VM initialization is complete - nop if no agents. |
| JvmtiExport::post_vm_initialized(); |
| |
| JFR_ONLY(Jfr::on_vm_start();) |
| |
| #if INCLUDE_MANAGEMENT |
| Management::initialize(THREAD); |
| |
| if (HAS_PENDING_EXCEPTION) { |
| // management agent fails to start possibly due to |
| // configuration problem and is responsible for printing |
| // stack trace if appropriate. Simply exit VM. |
| vm_exit(1); |
| } |
| #endif // INCLUDE_MANAGEMENT |
| |
| if (MemProfiling) MemProfiler::engage(); |
| StatSampler::engage(); |
| if (CheckJNICalls) JniPeriodicChecker::engage(); |
| |
| BiasedLocking::init(); |
| |
| #if INCLUDE_RTM_OPT |
| RTMLockingCounters::init(); |
| #endif |
| |
| call_postVMInitHook(THREAD); |
| // The Java side of PostVMInitHook.run must deal with all |
| // exceptions and provide means of diagnosis. |
| if (HAS_PENDING_EXCEPTION) { |
| CLEAR_PENDING_EXCEPTION; |
| } |
| |
| { |
| MutexLocker ml(PeriodicTask_lock); |
| // Make sure the WatcherThread can be started by WatcherThread::start() |
| // or by dynamic enrollment. |
| WatcherThread::make_startable(); |
| // Start up the WatcherThread if there are any periodic tasks |
| // NOTE: All PeriodicTasks should be registered by now. If they |
| // aren't, late joiners might appear to start slowly (we might |
| // take a while to process their first tick). |
| if (PeriodicTask::num_tasks() > 0) { |
| WatcherThread::start(); |
| } |
| } |
| |
| create_vm_timer.end(); |
| #ifdef ASSERT |
| _vm_complete = true; |
| #endif |
| |
| if (DumpSharedSpaces) { |
| MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); |
| ShouldNotReachHere(); |
| } |
| |
| return JNI_OK; |
| } |
| |
| // type for the Agent_OnLoad and JVM_OnLoad entry points |
| extern "C" { |
| typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); |
| } |
| // Find a command line agent library and return its entry point for |
| // -agentlib: -agentpath: -Xrun |
| // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. |
| static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, |
| const char *on_load_symbols[], |
| size_t num_symbol_entries) { |
| OnLoadEntry_t on_load_entry = NULL; |
| void *library = NULL; |
| |
| if (!agent->valid()) { |
| char buffer[JVM_MAXPATHLEN]; |
| char ebuf[1024] = ""; |
| const char *name = agent->name(); |
| const char *msg = "Could not find agent library "; |
| |
| // First check to see if agent is statically linked into executable |
| if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { |
| library = agent->os_lib(); |
| } else if (agent->is_absolute_path()) { |
| library = os::dll_load(name, ebuf, sizeof ebuf); |
| if (library == NULL) { |
| const char *sub_msg = " in absolute path, with error: "; |
| size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; |
| char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); |
| jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); |
| // If we can't find the agent, exit. |
| vm_exit_during_initialization(buf, NULL); |
| FREE_C_HEAP_ARRAY(char, buf); |
| } |
| } else { |
| // Try to load the agent from the standard dll directory |
| if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), |
| name)) { |
| library = os::dll_load(buffer, ebuf, sizeof ebuf); |
| } |
| if (library == NULL) { // Try the library path directory. |
| if (os::dll_build_name(buffer, sizeof(buffer), name)) { |
| library = os::dll_load(buffer, ebuf, sizeof ebuf); |
| } |
| if (library == NULL) { |
| const char *sub_msg = " on the library path, with error: "; |
| const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image."; |
| |
| size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + |
| strlen(ebuf) + strlen(sub_msg2) + 1; |
| char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); |
| if (!agent->is_instrument_lib()) { |
| jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); |
| } else { |
| jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2); |
| } |
| // If we can't find the agent, exit. |
| vm_exit_during_initialization(buf, NULL); |
| FREE_C_HEAP_ARRAY(char, buf); |
| } |
| } |
| } |
| agent->set_os_lib(library); |
| agent->set_valid(); |
| } |
| |
| // Find the OnLoad function. |
| on_load_entry = |
| CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, |
| false, |
| on_load_symbols, |
| num_symbol_entries)); |
| return on_load_entry; |
| } |
| |
| // Find the JVM_OnLoad entry point |
| static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { |
| const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; |
| return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); |
| } |
| |
| // Find the Agent_OnLoad entry point |
| static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { |
| const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; |
| return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); |
| } |
| |
| // For backwards compatibility with -Xrun |
| // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be |
| // treated like -agentpath: |
| // Must be called before agent libraries are created |
| void Threads::convert_vm_init_libraries_to_agents() { |
| AgentLibrary* agent; |
| AgentLibrary* next; |
| |
| for (agent = Arguments::libraries(); agent != NULL; agent = next) { |
| next = agent->next(); // cache the next agent now as this agent may get moved off this list |
| OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); |
| |
| // If there is an JVM_OnLoad function it will get called later, |
| // otherwise see if there is an Agent_OnLoad |
| if (on_load_entry == NULL) { |
| on_load_entry = lookup_agent_on_load(agent); |
| if (on_load_entry != NULL) { |
| // switch it to the agent list -- so that Agent_OnLoad will be called, |
| // JVM_OnLoad won't be attempted and Agent_OnUnload will |
| Arguments::convert_library_to_agent(agent); |
| } else { |
| vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); |
| } |
| } |
| } |
| } |
| |
| // Create agents for -agentlib: -agentpath: and converted -Xrun |
| // Invokes Agent_OnLoad |
| // Called very early -- before JavaThreads exist |
| void Threads::create_vm_init_agents() { |
| extern struct JavaVM_ main_vm; |
| AgentLibrary* agent; |
| |
| JvmtiExport::enter_onload_phase(); |
| |
| for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { |
| // CDS dumping does not support native JVMTI agent. |
| // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified. |
| if (DumpSharedSpaces || DynamicDumpSharedSpaces) { |
| if(!agent->is_instrument_lib()) { |
| vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name()); |
| } else if (!AllowArchivingWithJavaAgent) { |
| vm_exit_during_cds_dumping( |
| "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping"); |
| } |
| } |
| |
| OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); |
| |
| if (on_load_entry != NULL) { |
| // Invoke the Agent_OnLoad function |
| jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); |
| if (err != JNI_OK) { |
| vm_exit_during_initialization("agent library failed to init", agent->name()); |
| } |
| } else { |
| vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); |
| } |
| } |
| |
| JvmtiExport::enter_primordial_phase(); |
| } |
| |
| extern "C" { |
| typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); |
| } |
| |
| void Threads::shutdown_vm_agents() { |
| // Send any Agent_OnUnload notifications |
| const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; |
| size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); |
| extern struct JavaVM_ main_vm; |
| for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { |
| |
| // Find the Agent_OnUnload function. |
| Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, |
| os::find_agent_function(agent, |
| false, |
| on_unload_symbols, |
| num_symbol_entries)); |
| |
| // Invoke the Agent_OnUnload function |
| if (unload_entry != NULL) { |
| JavaThread* thread = JavaThread::current(); |
| ThreadToNativeFromVM ttn(thread); |
| HandleMark hm(thread); |
| (*unload_entry)(&main_vm); |
| } |
| } |
| } |
| |
| // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries |
| // Invokes JVM_OnLoad |
| void Threads::create_vm_init_libraries() { |
| extern struct JavaVM_ main_vm; |
| AgentLibrary* agent; |
| |
| for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { |
| OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); |
| |
| if (on_load_entry != NULL) { |
| // Invoke the JVM_OnLoad function |
| JavaThread* thread = JavaThread::current(); |
| ThreadToNativeFromVM ttn(thread); |
| HandleMark hm(thread); |
| jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); |
| if (err != JNI_OK) { |
| vm_exit_during_initialization("-Xrun library failed to init", agent->name()); |
| } |
| } else { |
| vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); |
| } |
| } |
| } |
| |
| |
| // Last thread running calls java.lang.Shutdown.shutdown() |
| void JavaThread::invoke_shutdown_hooks() { |
| HandleMark hm(this); |
| |
| // We could get here with a pending exception, if so clear it now. |
| if (this->has_pending_exception()) { |
| this->clear_pending_exception(); |
| } |
| |
| EXCEPTION_MARK; |
| Klass* shutdown_klass = |
| SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), |
| THREAD); |
| if (shutdown_klass != NULL) { |
| // SystemDictionary::resolve_or_null will return null if there was |
| // an exception. If we cannot load the Shutdown class, just don't |
| // call Shutdown.shutdown() at all. This will mean the shutdown hooks |
| // won't be run. Note that if a shutdown hook was registered, |
| // the Shutdown class would have already been loaded |
| // (Runtime.addShutdownHook will load it). |
| JavaValue result(T_VOID); |
| JavaCalls::call_static(&result, |
| shutdown_klass, |
| vmSymbols::shutdown_name(), |
| vmSymbols::void_method_signature(), |
| THREAD); |
| } |
| CLEAR_PENDING_EXCEPTION; |
| } |
| |
| // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when |
| // the program falls off the end of main(). Another VM exit path is through |
| // vm_exit() when the program calls System.exit() to return a value or when |
| // there is a serious error in VM. The two shutdown paths are not exactly |
| // the same, but they share Shutdown.shutdown() at Java level and before_exit() |
| // and VM_Exit op at VM level. |
| // |
| // Shutdown sequence: |
| // + Shutdown native memory tracking if it is on |
| // + Wait until we are the last non-daemon thread to execute |
| // <-- every thing is still working at this moment --> |
| // + Call java.lang.Shutdown.shutdown(), which will invoke Java level |
| // shutdown hooks |
| // + Call before_exit(), prepare for VM exit |
| // > run VM level shutdown hooks (they are registered through JVM_OnExit(), |
| // currently the only user of this mechanism is File.deleteOnExit()) |
| // > stop StatSampler, watcher thread, CMS threads, |
| // post thread end and vm death events to JVMTI, |
| // stop signal thread |
| // + Call JavaThread::exit(), it will: |
| // > release JNI handle blocks, remove stack guard pages |
| // > remove this thread from Threads list |
| // <-- no more Java code from this thread after this point --> |
| // + Stop VM thread, it will bring the remaining VM to a safepoint and stop |
| // the compiler threads at safepoint |
| // <-- do not use anything that could get blocked by Safepoint --> |
| // + Disable tracing at JNI/JVM barriers |
| // + Set _vm_exited flag for threads that are still running native code |
| // + Call exit_globals() |
| // > deletes tty |
| // > deletes PerfMemory resources |
| // + Delete this thread |
| // + Return to caller |
| |
| bool Threads::destroy_vm() { |
| JavaThread* thread = JavaThread::current(); |
| |
| #ifdef ASSERT |
| _vm_complete = false; |
| #endif |
| // Wait until we are the last non-daemon thread to execute |
| { MonitorLocker nu(Threads_lock); |
| while (Threads::number_of_non_daemon_threads() > 1) |
| // This wait should make safepoint checks, wait without a timeout, |
| // and wait as a suspend-equivalent condition. |
| nu.wait(0, Mutex::_as_suspend_equivalent_flag); |
| } |
| |
| EventShutdown e; |
| if (e.should_commit()) { |
| e.set_reason("No remaining non-daemon Java threads"); |
| e.commit(); |
| } |
| |
| // Hang forever on exit if we are reporting an error. |
| if (ShowMessageBoxOnError && VMError::is_error_reported()) { |
| os::infinite_sleep(); |
| } |
| os::wait_for_keypress_at_exit(); |
| |
| // run Java level shutdown hooks |
| thread->invoke_shutdown_hooks(); |
| |
| before_exit(thread); |
| |
| thread->exit(true); |
| |
| // Stop VM thread. |
| { |
| // 4945125 The vm thread comes to a safepoint during exit. |
| // GC vm_operations can get caught at the safepoint, and the |
| // heap is unparseable if they are caught. Grab the Heap_lock |
| // to prevent this. The GC vm_operations will not be able to |
| // queue until after the vm thread is dead. After this point, |
| // we'll never emerge out of the safepoint before the VM exits. |
| |
| MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag); |
| |
| VMThread::wait_for_vm_thread_exit(); |
| assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); |
| VMThread::destroy(); |
| } |
| |
| // Now, all Java threads are gone except daemon threads. Daemon threads |
| // running Java code or in VM are stopped by the Safepoint. However, |
| // daemon threads executing native code are still running. But they |
| // will be stopped at native=>Java/VM barriers. Note that we can't |
| // simply kill or suspend them, as it is inherently deadlock-prone. |
| |
| VM_Exit::set_vm_exited(); |
| |
| // Clean up ideal graph printers after the VMThread has started |
| // the final safepoint which will block all the Compiler threads. |
| // Note that this Thread has already logically exited so the |
| // clean_up() function's use of a JavaThreadIteratorWithHandle |
| // would be a problem except set_vm_exited() has remembered the |
| // shutdown thread which is granted a policy exception. |
| #if defined(COMPILER2) && !defined(PRODUCT) |
| IdealGraphPrinter::clean_up(); |
| #endif |
| |
| notify_vm_shutdown(); |
| |
| // exit_globals() will delete tty |
| exit_globals(); |
| |
| // We are after VM_Exit::set_vm_exited() so we can't call |
| // thread->smr_delete() or we will block on the Threads_lock. |
| // Deleting the shutdown thread here is safe because another |
| // JavaThread cannot have an active ThreadsListHandle for |
| // this JavaThread. |
| delete thread; |
| |
| #if INCLUDE_JVMCI |
| if (JVMCICounterSize > 0) { |
| FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); |
| } |
| #endif |
| |
| LogConfiguration::finalize(); |
| |
| return true; |
| } |
| |
| |
| jboolean Threads::is_supported_jni_version_including_1_1(jint version) { |
| if (version == JNI_VERSION_1_1) return JNI_TRUE; |
| return is_supported_jni_version(version); |
| } |
| |
| |
| jboolean Threads::is_supported_jni_version(jint version) { |
| if (version == JNI_VERSION_1_2) return JNI_TRUE; |
| if (version == JNI_VERSION_1_4) return JNI_TRUE; |
| if (version == JNI_VERSION_1_6) return JNI_TRUE; |
| if (version == JNI_VERSION_1_8) return JNI_TRUE; |
| if (version == JNI_VERSION_9) return JNI_TRUE; |
| if (version == JNI_VERSION_10) return JNI_TRUE; |
| return JNI_FALSE; |
| } |
| |
| |
| void Threads::add(JavaThread* p, bool force_daemon) { |
| // The threads lock must be owned at this point |
| assert(Threads_lock->owned_by_self(), "must have threads lock"); |
| |
| BarrierSet::barrier_set()->on_thread_attach(p); |
| |
| // Once a JavaThread is added to the Threads list, smr_delete() has |
| // to be used to delete it. Otherwise we can just delete it directly. |
| p->set_on_thread_list(); |
| |
| _number_of_threads++; |
| oop threadObj = p->threadObj(); |
| bool daemon = true; |
| // Bootstrapping problem: threadObj can be null for initial |
| // JavaThread (or for threads attached via JNI) |
| if ((!force_daemon) && !is_daemon((threadObj))) { |
| _number_of_non_daemon_threads++; |
| daemon = false; |
| } |
| |
| ThreadService::add_thread(p, daemon); |
| |
| // Maintain fast thread list |
| ThreadsSMRSupport::add_thread(p); |
| |
| // Possible GC point. |
| Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); |
| } |
| |
| void Threads::remove(JavaThread* p, bool is_daemon) { |
| |
| // Reclaim the ObjectMonitors from the omInUseList and omFreeList of the moribund thread. |
| ObjectSynchronizer::omFlush(p); |
| |
| // Extra scope needed for Thread_lock, so we can check |
| // that we do not remove thread without safepoint code notice |
| { MonitorLocker ml(Threads_lock); |
| |
| assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present"); |
| |
| // Maintain fast thread list |
| ThreadsSMRSupport::remove_thread(p); |
| |
| _number_of_threads--; |
| if (!is_daemon) { |
| _number_of_non_daemon_threads--; |
| |
| // Only one thread left, do a notify on the Threads_lock so a thread waiting |
| // on destroy_vm will wake up. |
| if (number_of_non_daemon_threads() == 1) { |
| ml.notify_all(); |
| } |
| } |
| ThreadService::remove_thread(p, is_daemon); |
| |
| // Make sure that safepoint code disregard this thread. This is needed since |
| // the thread might mess around with locks after this point. This can cause it |
| // to do callbacks into the safepoint code. However, the safepoint code is not aware |
| // of this thread since it is removed from the queue. |
| p->set_terminated_value(); |
| } // unlock Threads_lock |
| |
| // Since Events::log uses a lock, we grab it outside the Threads_lock |
| Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); |
| } |
| |
| // Operations on the Threads list for GC. These are not explicitly locked, |
| // but the garbage collector must provide a safe context for them to run. |
| // In particular, these things should never be called when the Threads_lock |
| // is held by some other thread. (Note: the Safepoint abstraction also |
| // uses the Threads_lock to guarantee this property. It also makes sure that |
| // all threads gets blocked when exiting or starting). |
| |
| void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { |
| ALL_JAVA_THREADS(p) { |
| p->oops_do(f, cf); |
| } |
| VMThread::vm_thread()->oops_do(f, cf); |
| } |
| |
| void Threads::change_thread_claim_token() { |
| if (++_thread_claim_token == 0) { |
| // On overflow of the token counter, there is a risk of future |
| // collisions between a new global token value and a stale token |
| // for a thread, because not all iterations visit all threads. |
| // (Though it's pretty much a theoretical concern for non-trivial |
| // token counter sizes.) To deal with the possibility, reset all |
| // the thread tokens to zero on global token overflow. |
| struct ResetClaims : public ThreadClosure { |
| virtual void do_thread(Thread* t) { |
| t->claim_threads_do(false, 0); |
| } |
| } reset_claims; |
| Threads::threads_do(&reset_claims); |
| // On overflow, update the global token to non-zero, to |
| // avoid the special "never claimed" initial thread value. |
| _thread_claim_token = 1; |
| } |
| } |
| |
| #ifdef ASSERT |
| void assert_thread_claimed(const char* kind, Thread* t, uintx expected) { |
| const uintx token = t->threads_do_token(); |
| assert(token == expected, |
| "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != " |
| UINTX_FORMAT, kind, p2i(t), token, expected); |
| } |
| |
| void Threads::assert_all_threads_claimed() { |
| ALL_JAVA_THREADS(p) { |
| assert_thread_claimed("Thread", p, _thread_claim_token); |
| } |
| assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token); |
| } |
| #endif // ASSERT |
| |
| class ParallelOopsDoThreadClosure : public ThreadClosure { |
| private: |
| OopClosure* _f; |
| CodeBlobClosure* _cf; |
| public: |
| ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {} |
| void do_thread(Thread* t) { |
| t->oops_do(_f, _cf); |
| } |
| }; |
| |
| void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) { |
| ParallelOopsDoThreadClosure tc(f, cf); |
| possibly_parallel_threads_do(is_par, &tc); |
| } |
| |
| void Threads::nmethods_do(CodeBlobClosure* cf) { |
| ALL_JAVA_THREADS(p) { |
| // This is used by the code cache sweeper to mark nmethods that are active |
| // on the stack of a Java thread. Ignore the sweeper thread itself to avoid |
| // marking CodeCacheSweeperThread::_scanned_compiled_method as active. |
| if(!p->is_Code_cache_sweeper_thread()) { |
| p->nmethods_do(cf); |
| } |
| } |
| } |
| |
| void Threads::metadata_do(MetadataClosure* f) { |
| ALL_JAVA_THREADS(p) { |
| p->metadata_do(f); |
| } |
| } |
| |
| class ThreadHandlesClosure : public ThreadClosure { |
| void (*_f)(Metadata*); |
| public: |
| ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} |
| virtual void do_thread(Thread* thread) { |
| thread->metadata_handles_do(_f); |
| } |
| }; |
| |
| void Threads::metadata_handles_do(void f(Metadata*)) { |
| // Only walk the Handles in Thread. |
| ThreadHandlesClosure handles_closure(f); |
| threads_do(&handles_closure); |
| } |
| |
| void Threads::deoptimized_wrt_marked_nmethods() { |
| ALL_JAVA_THREADS(p) { |
| p->deoptimized_wrt_marked_nmethods(); |
| } |
| } |
| |
| |
| // Get count Java threads that are waiting to enter the specified monitor. |
| GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list, |
| int count, |
| address monitor) { |
| GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); |
| |
| int i = 0; |
| DO_JAVA_THREADS(t_list, p) { |
| if (!p->can_call_java()) continue; |
| |
| address pending = (address)p->current_pending_monitor(); |
| if (pending == monitor) { // found a match |
| if (i < count) result->append(p); // save the first count matches |
| i++; |
| } |
| } |
| |
| return result; |
| } |
| |
| |
| JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list, |
| address owner) { |
| // NULL owner means not locked so we can skip the search |
| if (owner == NULL) return NULL; |
| |
| DO_JAVA_THREADS(t_list, p) { |
| // first, see if owner is the address of a Java thread |
| if (owner == (address)p) return p; |
| } |
| |
| // Cannot assert on lack of success here since this function may be |
| // used by code that is trying to report useful problem information |
| // like deadlock detection. |
| if (UseHeavyMonitors) return NULL; |
| |
| // If we didn't find a matching Java thread and we didn't force use of |
| // heavyweight monitors, then the owner is the stack address of the |
| // Lock Word in the owning Java thread's stack. |
| // |
| JavaThread* the_owner = NULL; |
| DO_JAVA_THREADS(t_list, q) { |
| if (q->is_lock_owned(owner)) { |
| the_owner = q; |
| break; |
| } |
| } |
| |
| // cannot assert on lack of success here; see above comment |
| return the_owner; |
| } |
| |
| // Threads::print_on() is called at safepoint by VM_PrintThreads operation. |
| void Threads::print_on(outputStream* st, bool print_stacks, |
| bool internal_format, bool print_concurrent_locks, |
| bool print_extended_info) { |
| char buf[32]; |
| st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); |
| |
| st->print_cr("Full thread dump %s (%s %s):", |
| VM_Version::vm_name(), |
| VM_Version::vm_release(), |
| VM_Version::vm_info_string()); |
| st->cr(); |
| |
| #if INCLUDE_SERVICES |
| // Dump concurrent locks |
| ConcurrentLocksDump concurrent_locks; |
| if (print_concurrent_locks) { |
| concurrent_locks.dump_at_safepoint(); |
| } |
| #endif // INCLUDE_SERVICES |
| |
| ThreadsSMRSupport::print_info_on(st); |
| st->cr(); |
| |
| ALL_JAVA_THREADS(p) { |
| ResourceMark rm; |
| p->print_on(st, print_extended_info); |
| if (print_stacks) { |
| if (internal_format) { |
| p->trace_stack(); |
| } else { |
| p->print_stack_on(st); |
| } |
| } |
| st->cr(); |
| #if INCLUDE_SERVICES |
| if (print_concurrent_locks) { |
| concurrent_locks.print_locks_on(p, st); |
| } |
| #endif // INCLUDE_SERVICES |
| } |
| |
| VMThread::vm_thread()->print_on(st); |
| st->cr(); |
| Universe::heap()->print_gc_threads_on(st); |
| WatcherThread* wt = WatcherThread::watcher_thread(); |
| if (wt != NULL) { |
| wt->print_on(st); |
| st->cr(); |
| } |
| |
| st->flush(); |
| } |
| |
| void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf, |
| int buflen, bool* found_current) { |
| if (this_thread != NULL) { |
| bool is_current = (current == this_thread); |
| *found_current = *found_current || is_current; |
| st->print("%s", is_current ? "=>" : " "); |
| |
| st->print(PTR_FORMAT, p2i(this_thread)); |
| st->print(" "); |
| this_thread->print_on_error(st, buf, buflen); |
| st->cr(); |
| } |
| } |
| |
| class PrintOnErrorClosure : public ThreadClosure { |
| outputStream* _st; |
| Thread* _current; |
| char* _buf; |
| int _buflen; |
| bool* _found_current; |
| public: |
| PrintOnErrorClosure(outputStream* st, Thread* current, char* buf, |
| int buflen, bool* found_current) : |
| _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {} |
| |
| virtual void do_thread(Thread* thread) { |
| Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current); |
| } |
| }; |
| |
| // Threads::print_on_error() is called by fatal error handler. It's possible |
| // that VM is not at safepoint and/or current thread is inside signal handler. |
| // Don't print stack trace, as the stack may not be walkable. Don't allocate |
| // memory (even in resource area), it might deadlock the error handler. |
| void Threads::print_on_error(outputStream* st, Thread* current, char* buf, |
| int buflen) { |
| ThreadsSMRSupport::print_info_on(st); |
| st->cr(); |
| |
| bool found_current = false; |
| st->print_cr("Java Threads: ( => current thread )"); |
| ALL_JAVA_THREADS(thread) { |
| print_on_error(thread, st, current, buf, buflen, &found_current); |
| } |
| st->cr(); |
| |
| st->print_cr("Other Threads:"); |
| print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current); |
| print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current); |
| |
| PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current); |
| Universe::heap()->gc_threads_do(&print_closure); |
| |
| if (!found_current) { |
| st->cr(); |
| st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); |
| current->print_on_error(st, buf, buflen); |
| st->cr(); |
| } |
| st->cr(); |
| |
| st->print_cr("Threads with active compile tasks:"); |
| print_threads_compiling(st, buf, buflen); |
| } |
| |
| void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) { |
| ALL_JAVA_THREADS(thread) { |
| if (thread->is_Compiler_thread()) { |
| CompilerThread* ct = (CompilerThread*) thread; |
| |
| // Keep task in local variable for NULL check. |
| // ct->_task might be set to NULL by concurring compiler thread |
| // because it completed the compilation. The task is never freed, |
| // though, just returned to a free list. |
| CompileTask* task = ct->task(); |
| if (task != NULL) { |
| thread->print_name_on_error(st, buf, buflen); |
| st->print(" "); |
| task->print(st, NULL, short_form, true); |
| } |
| } |
| } |
| } |
| |
| |
| // Internal SpinLock and Mutex |
| // Based on ParkEvent |
| |
| // Ad-hoc mutual exclusion primitives: SpinLock and Mux |
| // |
| // We employ SpinLocks _only for low-contention, fixed-length |
| // short-duration critical sections where we're concerned |
| // about native mutex_t or HotSpot Mutex:: latency. |
| // The mux construct provides a spin-then-block mutual exclusion |
| // mechanism. |
| // |
| // Testing has shown that contention on the ListLock guarding gFreeList |
| // is common. If we implement ListLock as a simple SpinLock it's common |
| // for the JVM to devolve to yielding with little progress. This is true |
| // despite the fact that the critical sections protected by ListLock are |
| // extremely short. |
| // |
| // TODO-FIXME: ListLock should be of type SpinLock. |
| // We should make this a 1st-class type, integrated into the lock |
| // hierarchy as leaf-locks. Critically, the SpinLock structure |
| // should have sufficient padding to avoid false-sharing and excessive |
| // cache-coherency traffic. |
| |
| |
| typedef volatile int SpinLockT; |
| |
| void Thread::SpinAcquire(volatile int * adr, const char * LockName) { |
| if (Atomic::cmpxchg (1, adr, 0) == 0) { |
| return; // normal fast-path return |
| } |
| |
| // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. |
| int ctr = 0; |
| int Yields = 0; |
| for (;;) { |
| while (*adr != 0) { |
| ++ctr; |
| if ((ctr & 0xFFF) == 0 || !os::is_MP()) { |
| if (Yields > 5) { |
| os::naked_short_sleep(1); |
| } else { |
| os::naked_yield(); |
| ++Yields; |
| } |
| } else { |
| SpinPause(); |
| } |
| } |
| if (Atomic::cmpxchg(1, adr, 0) == 0) return; |
| } |
| } |
| |
| void Thread::SpinRelease(volatile int * adr) { |
| assert(*adr != 0, "invariant"); |
| OrderAccess::fence(); // guarantee at least release consistency. |
| // Roach-motel semantics. |
| // It's safe if subsequent LDs and STs float "up" into the critical section, |
| // but prior LDs and STs within the critical section can't be allowed |
| // to reorder or float past the ST that releases the lock. |
| // Loads and stores in the critical section - which appear in program |
| // order before the store that releases the lock - must also appear |
| // before the store that releases the lock in memory visibility order. |
| // Conceptually we need a #loadstore|#storestore "release" MEMBAR before |
| // the ST of 0 into the lock-word which releases the lock, so fence |
| // more than covers this on all platforms. |
| *adr = 0; |
| } |
| |
| // muxAcquire and muxRelease: |
| // |
| // * muxAcquire and muxRelease support a single-word lock-word construct. |
| // The LSB of the word is set IFF the lock is held. |
| // The remainder of the word points to the head of a singly-linked list |
| // of threads blocked on the lock. |
| // |
| // * The current implementation of muxAcquire-muxRelease uses its own |
| // dedicated Thread._MuxEvent instance. If we're interested in |
| // minimizing the peak number of extant ParkEvent instances then |
| // we could eliminate _MuxEvent and "borrow" _ParkEvent as long |
| // as certain invariants were satisfied. Specifically, care would need |
| // to be taken with regards to consuming unpark() "permits". |
| // A safe rule of thumb is that a thread would never call muxAcquire() |
| // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently |
| // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could |
| // consume an unpark() permit intended for monitorenter, for instance. |
| // One way around this would be to widen the restricted-range semaphore |
| // implemented in park(). Another alternative would be to provide |
| // multiple instances of the PlatformEvent() for each thread. One |
| // instance would be dedicated to muxAcquire-muxRelease, for instance. |
| // |
| // * Usage: |
| // -- Only as leaf locks |
| // -- for short-term locking only as muxAcquire does not perform |
| // thread state transitions. |
| // |
| // Alternatives: |
| // * We could implement muxAcquire and muxRelease with MCS or CLH locks |
| // but with parking or spin-then-park instead of pure spinning. |
| // * Use Taura-Oyama-Yonenzawa locks. |
| // * It's possible to construct a 1-0 lock if we encode the lockword as |
| // (List,LockByte). Acquire will CAS the full lockword while Release |
| // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so |
| // acquiring threads use timers (ParkTimed) to detect and recover from |
| // the stranding window. Thread/Node structures must be aligned on 256-byte |
| // boundaries by using placement-new. |
| // * Augment MCS with advisory back-link fields maintained with CAS(). |
| // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. |
| // The validity of the backlinks must be ratified before we trust the value. |
| // If the backlinks are invalid the exiting thread must back-track through the |
| // the forward links, which are always trustworthy. |
| // * Add a successor indication. The LockWord is currently encoded as |
| // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable |
| // to provide the usual futile-wakeup optimization. |
| // See RTStt for details. |
| // |
| |
| |
| const intptr_t LOCKBIT = 1; |
| |
| void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { |
| intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0); |
| if (w == 0) return; |
| if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { |
| return; |
| } |
| |
| ParkEvent * const Self = Thread::current()->_MuxEvent; |
| assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); |
| for (;;) { |
| int its = (os::is_MP() ? 100 : 0) + 1; |
| |
| // Optional spin phase: spin-then-park strategy |
| while (--its >= 0) { |
| w = *Lock; |
| if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { |
| return; |
| } |
| } |
| |
| Self->reset(); |
| Self->OnList = intptr_t(Lock); |
| // The following fence() isn't _strictly necessary as the subsequent |
| // CAS() both serializes execution and ratifies the fetched *Lock value. |
| OrderAccess::fence(); |
| for (;;) { |
| w = *Lock; |
| if ((w & LOCKBIT) == 0) { |
| if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { |
| Self->OnList = 0; // hygiene - allows stronger asserts |
| return; |
| } |
| continue; // Interference -- *Lock changed -- Just retry |
| } |
| assert(w & LOCKBIT, "invariant"); |
| Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); |
| if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; |
| } |
| |
| while (Self->OnList != 0) { |
| Self->park(); |
| } |
| } |
| } |
| |
| void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { |
| intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0); |
| if (w == 0) return; |
| if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { |
| return; |
| } |
| |
| ParkEvent * ReleaseAfter = NULL; |
| if (ev == NULL) { |
| ev = ReleaseAfter = ParkEvent::Allocate(NULL); |
| } |
| assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); |
| for (;;) { |
| guarantee(ev->OnList == 0, "invariant"); |
| int its = (os::is_MP() ? 100 : 0) + 1; |
| |
| // Optional spin phase: spin-then-park strategy |
| while (--its >= 0) { |
| w = *Lock; |
| if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { |
| if (ReleaseAfter != NULL) { |
| ParkEvent::Release(ReleaseAfter); |
| } |
| return; |
| } |
| } |
| |
| ev->reset(); |
| ev->OnList = intptr_t(Lock); |
| // The following fence() isn't _strictly necessary as the subsequent |
| // CAS() both serializes execution and ratifies the fetched *Lock value. |
| OrderAccess::fence(); |
| for (;;) { |
| w = *Lock; |
| if ((w & LOCKBIT) == 0) { |
| if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { |
| ev->OnList = 0; |
| // We call ::Release while holding the outer lock, thus |
| // artificially lengthening the critical section. |
| // Consider deferring the ::Release() until the subsequent unlock(), |
| // after we've dropped the outer lock. |
| if (ReleaseAfter != NULL) { |
| ParkEvent::Release(ReleaseAfter); |
| } |
| return; |
| } |
| continue; // Interference -- *Lock changed -- Just retry |
| } |
| assert(w & LOCKBIT, "invariant"); |
| ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); |
| if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; |
| } |
| |
| while (ev->OnList != 0) { |
| ev->park(); |
| } |
| } |
| } |
| |
| // Release() must extract a successor from the list and then wake that thread. |
| // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme |
| // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based |
| // Release() would : |
| // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. |
| // (B) Extract a successor from the private list "in-hand" |
| // (C) attempt to CAS() the residual back into *Lock over null. |
| // If there were any newly arrived threads and the CAS() would fail. |
| // In that case Release() would detach the RATs, re-merge the list in-hand |
| // with the RATs and repeat as needed. Alternately, Release() might |
| // detach and extract a successor, but then pass the residual list to the wakee. |
| // The wakee would be responsible for reattaching and remerging before it |
| // competed for the lock. |
| // |
| // Both "pop" and DMR are immune from ABA corruption -- there can be |
| // multiple concurrent pushers, but only one popper or detacher. |
| // This implementation pops from the head of the list. This is unfair, |
| // but tends to provide excellent throughput as hot threads remain hot. |
| // (We wake recently run threads first). |
| // |
| // All paths through muxRelease() will execute a CAS. |
| // Release consistency -- We depend on the CAS in muxRelease() to provide full |
| // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations |
| // executed within the critical section are complete and globally visible before the |
| // store (CAS) to the lock-word that releases the lock becomes globally visible. |
| void Thread::muxRelease(volatile intptr_t * Lock) { |
| for (;;) { |
| const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT); |
| assert(w & LOCKBIT, "invariant"); |
| if (w == LOCKBIT) return; |
| ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); |
| assert(List != NULL, "invariant"); |
| assert(List->OnList == intptr_t(Lock), "invariant"); |
| ParkEvent * const nxt = List->ListNext; |
| guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); |
| |
| // The following CAS() releases the lock and pops the head element. |
| // The CAS() also ratifies the previously fetched lock-word value. |
| if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) { |
| continue; |
| } |
| List->OnList = 0; |
| OrderAccess::fence(); |
| List->unpark(); |
| return; |
| } |
| } |
| |
| |
| void Threads::verify() { |
| ALL_JAVA_THREADS(p) { |
| p->verify(); |
| } |
| VMThread* thread = VMThread::vm_thread(); |
| if (thread != NULL) thread->verify(); |
| } |