diff -r 000000000000 -r f90c822e73f8 src/share/vm/runtime/thread.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/runtime/thread.cpp Wed Apr 27 01:25:04 2016 +0800 @@ -0,0 +1,4686 @@ +/* + * Copyright (c) 1997, 2014, 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 "classfile/classLoader.hpp" +#include "classfile/javaClasses.hpp" +#include "classfile/systemDictionary.hpp" +#include "classfile/vmSymbols.hpp" +#include "code/scopeDesc.hpp" +#include "compiler/compileBroker.hpp" +#include "interpreter/interpreter.hpp" +#include "interpreter/linkResolver.hpp" +#include "interpreter/oopMapCache.hpp" +#include "jvmtifiles/jvmtiEnv.hpp" +#include "memory/gcLocker.inline.hpp" +#include "memory/metaspaceShared.hpp" +#include "memory/oopFactory.hpp" +#include "memory/universe.inline.hpp" +#include "oops/instanceKlass.hpp" +#include "oops/objArrayOop.hpp" +#include "oops/oop.inline.hpp" +#include "oops/symbol.hpp" +#include "prims/jvm_misc.hpp" +#include "prims/jvmtiExport.hpp" +#include "prims/jvmtiThreadState.hpp" +#include "prims/privilegedStack.hpp" +#include "runtime/arguments.hpp" +#include "runtime/biasedLocking.hpp" +#include "runtime/deoptimization.hpp" +#include "runtime/fprofiler.hpp" +#include "runtime/frame.inline.hpp" +#include "runtime/init.hpp" +#include "runtime/interfaceSupport.hpp" +#include "runtime/java.hpp" +#include "runtime/javaCalls.hpp" +#include "runtime/jniPeriodicChecker.hpp" +#include "runtime/memprofiler.hpp" +#include "runtime/mutexLocker.hpp" +#include "runtime/objectMonitor.hpp" +#include "runtime/osThread.hpp" +#include "runtime/safepoint.hpp" +#include "runtime/sharedRuntime.hpp" +#include "runtime/statSampler.hpp" +#include "runtime/stubRoutines.hpp" +#include "runtime/task.hpp" +#include "runtime/thread.inline.hpp" +#include "runtime/threadCritical.hpp" +#include "runtime/threadLocalStorage.hpp" +#include "runtime/vframe.hpp" +#include "runtime/vframeArray.hpp" +#include "runtime/vframe_hp.hpp" +#include "runtime/vmThread.hpp" +#include "runtime/vm_operations.hpp" +#include "services/attachListener.hpp" +#include "services/management.hpp" +#include "services/memTracker.hpp" +#include "services/threadService.hpp" +#include "trace/tracing.hpp" +#include "trace/traceMacros.hpp" +#include "utilities/defaultStream.hpp" +#include "utilities/dtrace.hpp" +#include "utilities/events.hpp" +#include "utilities/preserveException.hpp" +#include "utilities/macros.hpp" +#ifdef TARGET_OS_FAMILY_linux +# include "os_linux.inline.hpp" +#endif +#ifdef TARGET_OS_FAMILY_solaris +# include "os_solaris.inline.hpp" +#endif +#ifdef TARGET_OS_FAMILY_windows +# include "os_windows.inline.hpp" +#endif +#ifdef TARGET_OS_FAMILY_bsd +# include "os_bsd.inline.hpp" +#endif +#if INCLUDE_ALL_GCS +#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" +#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" +#include "gc_implementation/parallelScavenge/pcTasks.hpp" +#endif // INCLUDE_ALL_GCS +#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 + +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC + +#ifdef DTRACE_ENABLED + +// Only bother with this argument setup if dtrace is available + +#ifndef USDT2 +HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); +HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); +HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, + intptr_t, intptr_t, bool); +HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, + intptr_t, intptr_t, bool); + +#define DTRACE_THREAD_PROBE(probe, javathread) \ + { \ + ResourceMark rm(this); \ + int len = 0; \ + const char* name = (javathread)->get_thread_name(); \ + len = strlen(name); \ + HS_DTRACE_PROBE5(hotspot, thread__##probe, \ + name, len, \ + java_lang_Thread::thread_id((javathread)->threadObj()), \ + (javathread)->osthread()->thread_id(), \ + java_lang_Thread::is_daemon((javathread)->threadObj())); \ + } + +#else /* USDT2 */ + +#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START +#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_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())); \ + } + +#endif /* USDT2 */ + +#else // ndef DTRACE_ENABLED + +#define DTRACE_THREAD_PROBE(probe, javathread) + +#endif // ndef DTRACE_ENABLED + + +// Class hierarchy +// - Thread +// - VMThread +// - WatcherThread +// - ConcurrentMarkSweepThread +// - JavaThread +// - CompilerThread + +// ======= 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 = (void*) align_size_up((intptr_t) 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 (TraceBiasedLocking) { + if (aligned_addr != real_malloc_addr) + tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, + real_malloc_addr, 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) { + void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; + FreeHeap(real_malloc_addr, mtThread); + } else { + FreeHeap(p, mtThread); + } +} + + +// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, +// JavaThread + + +Thread::Thread() { + // stack and get_thread + set_stack_base(NULL); + set_stack_size(0); + set_self_raw_id(0); + set_lgrp_id(-1); + + // 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(30, true)); + set_active_handles(NULL); + set_free_handle_block(NULL); + set_last_handle_mark(NULL); + + // This initial value ==> never claimed. + _oops_do_parity = 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); + _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 ; + _schedctl = NULL ; + _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) ; + _MutexEvent = 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 == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), + "bug in forced alignment of thread objects"); + } +#endif /* ASSERT */ +} + +void Thread::initialize_thread_local_storage() { + // Note: Make sure this method only calls + // non-blocking operations. Otherwise, it might not work + // with the thread-startup/safepoint interaction. + + // During Java thread startup, safepoint code should allow this + // method to complete because it may need to allocate memory to + // store information for the new thread. + + // initialize structure dependent on thread local storage + ThreadLocalStorage::set_thread(this); +} + +void Thread::record_stack_base_and_size() { + set_stack_base(os::current_stack_base()); + set_stack_size(os::current_stack_size()); + if (is_Java_thread()) { + ((JavaThread*) this)->set_stack_overflow_limit(); + } + // CR 7190089: on Solaris, primordial thread's stack is adjusted + // in initialize_thread(). Without the adjustment, stack size is + // incorrect if stack is set to unlimited (ulimit -s unlimited). + // So far, only Solaris has real implementation of initialize_thread(). + // + // set up any platform-specific state. + os::initialize_thread(this); + +#if INCLUDE_NMT + // record thread's native stack, stack grows downward + address stack_low_addr = stack_base() - stack_size(); + MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, + CURRENT_PC); +#endif // INCLUDE_NMT +} + + +Thread::~Thread() { + // Reclaim the objectmonitors from the omFreeList of the moribund thread. + ObjectSynchronizer::omFlush (this) ; + + EVENT_THREAD_DESTRUCT(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) { + address low_stack_addr = stack_base() - stack_size(); + MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); +#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 (_MutexEvent) ; _MutexEvent = NULL ; + ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; + + delete handle_area(); + delete metadata_handles(); + + // osthread() can be NULL, if creation of thread failed. + if (osthread() != NULL) os::free_thread(osthread()); + + delete _SR_lock; + + // clear thread local storage if the Thread is deleting itself + if (this == Thread::current()) { + ThreadLocalStorage::set_thread(NULL); + } else { + // In the case where we're not the current thread, invalidate all the + // caches in case some code tries to get the current thread or the + // thread that was destroyed, and gets stale information. + ThreadLocalStorage::invalidate_all(); + } + CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) +} + +// NOTE: dummy function for assertion purpose. +void Thread::run() { + ShouldNotReachHere(); +} + +#ifdef ASSERT +// Private method to check for dangling thread pointer +void check_for_dangling_thread_pointer(Thread *thread) { + assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), + "possibility of dangling Thread pointer"); +} +#endif + + +#ifndef PRODUCT +// Tracing method for basic thread operations +void Thread::trace(const char* msg, const Thread* const thread) { + if (!TraceThreadEvents) return; + ResourceMark rm; + ThreadCritical tc; + const char *name = "non-Java thread"; + int prio = -1; + if (thread->is_Java_thread() + && !thread->is_Compiler_thread()) { + // The Threads_lock must be held to get information about + // this thread but may not be in some situations when + // tracing thread events. + bool release_Threads_lock = false; + if (!Threads_lock->owned_by_self()) { + Threads_lock->lock(); + release_Threads_lock = true; + } + JavaThread* jt = (JavaThread *)thread; + name = (char *)jt->get_thread_name(); + oop thread_oop = jt->threadObj(); + if (thread_oop != NULL) { + prio = java_lang_Thread::priority(thread_oop); + } + if (release_Threads_lock) { + Threads_lock->unlock(); + } + } + tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); +} +#endif + + +ThreadPriority Thread::get_priority(const Thread* const thread) { + trace("get priority", 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) { + trace("set priority", thread); + debug_only(check_for_dangling_thread_pointer(thread);) + // Can return an error! + (void)os::set_priority(thread, priority); +} + + +void Thread::start(Thread* thread) { + trace("start", 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 + SR_lock()->wait(!Thread::current()->is_Java_thread(), 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; + + { + MutexLockerEx 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 + + { + MutexLocker ml(SR_lock()); + // wait with safepoint check (if we're a JavaThread - the WatcherThread + // can also call this) and increase delay with each retry + SR_lock()->wait(!Thread::current()->is_Java_thread(), 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; +} + +#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-existant + // 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 */ + +// Called by flat profiler +// Callers have already called wait_for_ext_suspend_completion +// The assertion for that is currently too complex to put here: +bool JavaThread::profile_last_Java_frame(frame* _fr) { + bool gotframe = false; + // self suspension saves needed state. + if (has_last_Java_frame() && _anchor.walkable()) { + *_fr = pd_last_frame(); + gotframe = true; + } + return gotframe; +} + +void Thread::interrupt(Thread* thread) { + trace("interrupt", thread); + debug_only(check_for_dangling_thread_pointer(thread);) + os::interrupt(thread); +} + +bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { + trace("is_interrupted", thread); + 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_oops_do_par_case(int strong_roots_parity) { + jint thread_parity = _oops_do_parity; + if (thread_parity != strong_roots_parity) { + jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); + if (res == thread_parity) { + return true; + } else { + guarantee(res == strong_roots_parity, "Or else what?"); + assert(SharedHeap::heap()->workers()->active_workers() > 0, + "Should only fail when parallel."); + return false; + } + } + assert(SharedHeap::heap()->workers()->active_workers() > 0, + "Should only fail when parallel."); + return false; +} + +void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { + active_handles()->oops_do(f); + // Do oop for ThreadShadow + f->do_oop((oop*)&_pending_exception); + handle_area()->oops_do(f); +} + +void Thread::nmethods_do(CodeBlobClosure* cf) { + // no nmethods in a generic thread... +} + +void Thread::metadata_do(void f(Metadata*)) { + if (metadata_handles() != NULL) { + for (int i = 0; i< metadata_handles()->length(); i++) { + f(metadata_handles()->at(i)); + } + } +} + +void Thread::print_on(outputStream* st) 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("tid=" INTPTR_FORMAT " ", this); + osthread()->print_on(st); + } + debug_only(if (WizardMode) print_owned_locks_on(st);) +} + +// 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 { + if (is_VM_thread()) st->print("VMThread"); + else if (is_Compiler_thread()) st->print("CompilerThread"); + else if (is_Java_thread()) st->print("JavaThread"); + 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"); + + st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", + _stack_base - _stack_size, _stack_base); + + if (osthread()) { + st->print(" [id=%d]", osthread()->thread_id()); + } +} + +#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 potential +// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that +// no threads 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 absolutly 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 spearate compilation + cur != VMOperationRequest_lock && + cur != VMOperationQueue_lock) || + cur->rank() == Mutex::special) { + warning("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() ? (StackYellowPages + StackRedPages) * os::vm_page_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() { + // NOTE: this must be called inside the main thread. + 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) { + Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); + instanceKlassHandle klass (THREAD, k); + + Handle system_instance = klass->allocate_instance_handle(CHECK_NH); + { + JavaValue result(T_VOID); + JavaCalls::call_special(&result, + system_instance, + klass, + vmSymbols::object_initializer_name(), + vmSymbols::void_method_signature(), + CHECK_NH); + } + Universe::set_system_thread_group(system_instance()); + + Handle main_instance = klass->allocate_instance_handle(CHECK_NH); + { + JavaValue result(T_VOID); + Handle string = java_lang_String::create_from_str("main", CHECK_NH); + JavaCalls::call_special(&result, + main_instance, + klass, + vmSymbols::object_initializer_name(), + 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) { + Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); + instanceKlassHandle klass (THREAD, k); + instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); + + 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, + klass, + vmSymbols::object_initializer_name(), + vmSymbols::threadgroup_string_void_signature(), + thread_group, + string, + CHECK_NULL); + return thread_oop(); +} + +static void call_initializeSystemClass(TRAPS) { + Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); + instanceKlassHandle klass (THREAD, k); + + JavaValue result(T_VOID); + JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), + vmSymbols::void_method_signature(), CHECK); +} + +char java_runtime_name[128] = ""; +char java_runtime_version[128] = ""; + +// extract the JRE name from sun.misc.Version.java_runtime_name +static const char* get_java_runtime_name(TRAPS) { + Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), + 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 sun.misc.Version.java_runtime_version +static const char* get_java_runtime_version(TRAPS) { + Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), + 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* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); + instanceKlassHandle klass (THREAD, k); + if (klass.not_null()) { + JavaValue result(T_VOID); + JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), + vmSymbols::void_method_signature(), + CHECK); + } +} + +static void reset_vm_info_property(TRAPS) { + // the vm info string + ResourceMark rm(THREAD); + const char *vm_info = VM_Version::vm_info_string(); + + // java.lang.System class + Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); + instanceKlassHandle klass (THREAD, k); + + // setProperty arguments + Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); + Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); + + // return value + JavaValue r(T_OBJECT); + + // public static String setProperty(String key, String value); + JavaCalls::call_static(&r, + klass, + vmSymbols::setProperty_name(), + vmSymbols::string_string_string_signature(), + key_str, + value_str, + CHECK); +} + + +void JavaThread::allocate_threadObj(Handle thread_group, 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"); + + Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); + instanceKlassHandle klass (THREAD, k); + instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); + + 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, + klass, + vmSymbols::object_initializer_name(), + vmSymbols::threadgroup_string_void_signature(), + thread_group, // Argument 1 + name, // Argument 2 + 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, + klass, + vmSymbols::object_initializer_name(), + vmSymbols::threadgroup_runnable_void_signature(), + thread_group, // Argument 1 + Handle(), // Argument 2 + THREAD); + } + + + if (daemon) { + java_lang_Thread::set_daemon(thread_oop()); + } + + if (HAS_PENDING_EXCEPTION) { + return; + } + + KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); + Handle threadObj(this, this->threadObj()); + + JavaCalls::call_special(&result, + thread_group, + group, + vmSymbols::add_method_name(), + vmSymbols::thread_void_signature(), + threadObj, // Arg 1 + THREAD); + + +} + +// NamedThread -- non-JavaThread subclasses with multiple +// uniquely named instances should derive from this. +NamedThread::NamedThread() : Thread() { + _name = NULL; + _processed_thread = NULL; +} + +NamedThread::~NamedThread() { + if (_name != NULL) { + FREE_C_HEAP_ARRAY(char, _name, mtThread); + _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); +} + +// ======= 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() : Thread(), _crash_protection(NULL) { + 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 { + MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); + + // 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(); + + for (;;) { + bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 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 recalulate 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->record_stack_base_and_size(); + this->initialize_thread_local_storage(); + this->set_active_handles(JNIHandleBlock::allocate_block()); + while(!_should_terminate) { + 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 (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 we try to + // kill JVM if the fatal error handler fails to abort in 2 minutes. + // + // 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 (;;) { + if (!ShowMessageBoxOnError + && (OnError == NULL || OnError[0] == '\0') + && Arguments::abort_hook() == NULL) { + os::sleep(this, 2 * 60 * 1000, false); + fdStream err(defaultStream::output_fd()); + err.print_raw_cr("# [ timer expired, abort... ]"); + // skip atexit/vm_exit/vm_abort hooks + os::die(); + } + + // Wake up 5 seconds later, the fatal handler may reset OnError or + // ShowMessageBoxOnError when it is ready to abort. + os::sleep(this, 5 * 1000, false); + } + } + + PeriodicTask::real_time_tick(time_waited); + } + + // Signal that it is terminated + { + MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); + _watcher_thread = NULL; + Terminator_lock->notify(); + } + + // Thread destructor usually does this.. + ThreadLocalStorage::set_thread(NULL); +} + +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() { + { + MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); + _should_terminate = true; + OrderAccess::fence(); // ensure WatcherThread sees update in main loop + + WatcherThread* watcher = watcher_thread(); + if (watcher != NULL) + watcher->unpark(); + } + + // it is ok to take late safepoints here, if needed + MutexLocker mu(Terminator_lock); + + while(watcher_thread() != NULL) { + // This wait should make safepoint checks, wait without a timeout, + // and wait as a suspend-equivalent condition. + // + // Note: If the FlatProfiler is running, then this thread is waiting + // for the WatcherThread to terminate and the WatcherThread, via the + // FlatProfiler task, is waiting for the external suspend request on + // this thread to complete. wait_for_ext_suspend_completion() will + // eventually timeout, but that takes time. Making this wait a + // suspend-equivalent condition solves that timeout problem. + // + Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, + Mutex::_as_suspend_equivalent_flag); + } +} + +void WatcherThread::unpark() { + MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); + PeriodicTask_lock->notify(); +} + +void WatcherThread::print_on(outputStream* st) const { + st->print("\"%s\" ", name()); + Thread::print_on(st); + st->cr(); +} + +// ======= JavaThread ======== + +// A JavaThread is a normal Java thread + +void JavaThread::initialize() { + // Initialize fields + + // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) + set_claimed_par_id(UINT_MAX); + + 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_nmethod(NULL); + clear_must_deopt_id(); + set_monitor_chunks(NULL); + set_next(NULL); + set_thread_state(_thread_new); +#if INCLUDE_NMT + set_recorder(NULL); +#endif + _terminated = _not_terminated; + _privileged_stack_top = NULL; + _array_for_gc = NULL; + _suspend_equivalent = false; + _in_deopt_handler = 0; + _doing_unsafe_access = false; + _stack_guard_state = stack_guard_unused; + (void)const_cast(_exception_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; + _jvmti_get_loaded_classes_closure = NULL; + _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; + _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 */ + + set_thread_profiler(NULL); + if (FlatProfiler::is_active()) { + // This is where we would decide to either give each thread it's own profiler + // or use one global one from FlatProfiler, + // or up to some count of the number of profiled threads, etc. + ThreadProfiler* pp = new ThreadProfiler(); + pp->engage(); + set_thread_profiler(pp); + } + + // 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; + + pd_initialize(); +} + +#if INCLUDE_ALL_GCS +SATBMarkQueueSet JavaThread::_satb_mark_queue_set; +DirtyCardQueueSet JavaThread::_dirty_card_queue_set; +#endif // INCLUDE_ALL_GCS + +JavaThread::JavaThread(bool is_attaching_via_jni) : + Thread() +#if INCLUDE_ALL_GCS + , _satb_mark_queue(&_satb_mark_queue_set), + _dirty_card_queue(&_dirty_card_queue_set) +#endif // INCLUDE_ALL_GCS +{ + 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"); + _safepoint_visible = false; +} + +bool JavaThread::reguard_stack(address cur_sp) { + if (_stack_guard_state != stack_guard_yellow_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_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); + + enable_stack_yellow_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); + +JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : + Thread() +#if INCLUDE_ALL_GCS + , _satb_mark_queue(&_satb_mark_queue_set), + _dirty_card_queue(&_dirty_card_queue_set) +#endif // INCLUDE_ALL_GCS +{ + if (TraceThreadEvents) { + tty->print_cr("creating thread %p", this); + } + 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); + _safepoint_visible = false; + // 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() { + if (TraceThreadEvents) { + tty->print_cr("terminate thread %p", this); + } + + // By now, this thread should already be invisible to safepoint, + // and its per-thread recorder also collected. + assert(!is_safepoint_visible(), "wrong state"); +#if INCLUDE_NMT + assert(get_recorder() == NULL, "Already collected"); +#endif // INCLUDE_NMT + + // 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* 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_profiler != NULL) delete _thread_profiler; + if (_thread_stat != NULL) delete _thread_stat; +} + + +// The first routine called by a new Java thread +void JavaThread::run() { + // initialize thread-local alloc buffer related fields + this->initialize_tlab(); + + // used to test validitity of stack trace backs + this->record_base_of_stack_pointer(); + + // Record real stack base and size. + this->record_stack_base_and_size(); + + // Initialize thread local storage; set before calling MutexLocker + this->initialize_thread_local_storage(); + + this->create_stack_guard_pages(); + + this->cache_global_variables(); + + // Thread is now sufficient 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_and_fence(this, _thread_new, _thread_in_vm); + + 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); + } + + EventThreadStart event; + if (event.should_commit()) { + event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); + event.commit(); + } + + // 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(); + + // Note, thread is no longer valid at this point! +} + + +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); + + this->exit(false); + delete this; +} + + +static void ensure_join(JavaThread* thread) { + // We do not need to grap 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(); +} + + +// 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"); + + 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"); + + if (get_thread_profiler() != NULL) { + get_thread_profiler()->disengage(); + ResourceMark rm; + get_thread_profiler()->print(get_thread_name()); + } + + + // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place + { + EXCEPTION_MARK; + + CLEAR_PENDING_EXCEPTION; + } + // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This + // has to be fixed by a runtime query method + if (!destroy_vm || JDK_Version::is_jdk12x_version()) { + // JSR-166: change call from from ThreadGroup.uncaughtException to + // java.lang.Thread.dispatchUncaughtException + if (uncaught_exception.not_null()) { + Handle group(this, java_lang_Thread::threadGroup(threadObj())); + { + EXCEPTION_MARK; + // Check if the method Thread.dispatchUncaughtException() exists. If so + // call it. Otherwise we have an older library without the JSR-166 changes, + // so call ThreadGroup.uncaughtException() + KlassHandle recvrKlass(THREAD, threadObj->klass()); + CallInfo callinfo; + KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); + LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, + vmSymbols::dispatchUncaughtException_name(), + vmSymbols::throwable_void_signature(), + KlassHandle(), false, false, THREAD); + CLEAR_PENDING_EXCEPTION; + methodHandle method = callinfo.selected_method(); + if (method.not_null()) { + JavaValue result(T_VOID); + JavaCalls::call_virtual(&result, + threadObj, thread_klass, + vmSymbols::dispatchUncaughtException_name(), + vmSymbols::throwable_void_signature(), + uncaught_exception, + THREAD); + } else { + KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); + JavaValue result(T_VOID); + JavaCalls::call_virtual(&result, + group, thread_group, + vmSymbols::uncaughtException_name(), + vmSymbols::thread_throwable_void_signature(), + threadObj, // Arg 1 + uncaught_exception, // Arg 2 + 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; + } + } + } + + // Called before the java thread exit since we want to read info + // from java_lang_Thread object + EventThreadEnd event; + if (event.should_commit()) { + event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); + event.commit(); + } + + // Call after last event on thread + EVENT_THREAD_EXIT(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); + KlassHandle thread_klass(THREAD, 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) { + { + MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); + if (!is_external_suspend()) { + set_terminated(_thread_exiting); + ThreadService::current_thread_exiting(this); + 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 { + // before_exit() has already posted JVMTI THREAD_END events + } + + // 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"); + + // 6282335 JNI DetachCurrentThread spec states that all Java monitors + // held by this thread must be released. A detach operation must only + // get here if there are no Java frames on the stack. Therefore, any + // owned monitors at this point MUST be JNI-acquired monitors which are + // pre-inflated and in the monitor cache. + // + // ensure_join() ignores IllegalThreadStateExceptions, and so does this. + if (exit_type == jni_detach && JNIDetachReleasesMonitors) { + assert(!this->has_last_Java_frame(), "detaching with Java frames?"); + 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 + assert(_privileged_stack_top == NULL, "must be NULL when we get here"); + + 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().make_parsable(true); // retire TLAB + } + + if (JvmtiEnv::environments_might_exist()) { + JvmtiExport::cleanup_thread(this); + } + + // We must flush any deferred card marks before removing a thread from + // the list of active threads. + Universe::heap()->flush_deferred_store_barrier(this); + assert(deferred_card_mark().is_empty(), "Should have been flushed"); + +#if INCLUDE_ALL_GCS + // We must flush the G1-related buffers before removing a thread + // from the list of active threads. We must do this after any deferred + // card marks have been flushed (above) so that any entries that are + // added to the thread's dirty card queue as a result are not lost. + if (UseG1GC) { + flush_barrier_queues(); + } +#endif // INCLUDE_ALL_GCS + + // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread + Threads::remove(this); +} + +#if INCLUDE_ALL_GCS +// Flush G1-related queues. +void JavaThread::flush_barrier_queues() { + satb_mark_queue().flush(); + dirty_card_queue().flush(); +} + +void JavaThread::initialize_queues() { + assert(!SafepointSynchronize::is_at_safepoint(), + "we should not be at a safepoint"); + + ObjPtrQueue& satb_queue = satb_mark_queue(); + SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); + // The SATB queue should have been constructed with its active + // field set to false. + assert(!satb_queue.is_active(), "SATB queue should not be active"); + assert(satb_queue.is_empty(), "SATB queue should be empty"); + // If we are creating the thread during a marking cycle, we should + // set the active field of the SATB queue to true. + if (satb_queue_set.is_active()) { + satb_queue.set_active(true); + } + + DirtyCardQueue& dirty_queue = dirty_card_queue(); + // The dirty card queue should have been constructed with its + // active field set to true. + assert(dirty_queue.is_active(), "dirty card queue should be active"); +} +#endif // INCLUDE_ALL_GCS + +void JavaThread::cleanup_failed_attach_current_thread() { + if (get_thread_profiler() != NULL) { + get_thread_profiler()->disengage(); + ResourceMark rm; + get_thread_profiler()->print(get_thread_name()); + } + + 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().make_parsable(true); // retire TLAB, if any + } + +#if INCLUDE_ALL_GCS + if (UseG1GC) { + flush_barrier_queues(); + } +#endif // INCLUDE_ALL_GCS + + Threads::remove(this); + delete this; +} + + + + +JavaThread* JavaThread::active() { + Thread* thread = ThreadLocalStorage::thread(); + assert(thread != NULL, "just checking"); + 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()) { + if (TraceExceptions) { + ResourceMark rm; + tty->print_cr("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__); + + if (TraceExceptions) { + ResourceMark rm; + tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); + if (has_last_Java_frame() ) { + frame f = last_frame(); + tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); + } + tty->print_cr(" of type: %s", InstanceKlass::cast(_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. Internal suspend requests do + // not use handle_special_runtime_exit_condition(). + // 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())) { + // + // Because thread is external suspended the safepoint code will count + // thread as at a safepoint. This can be odd because we can be here + // as _thread_in_Java which would normally transition to _thread_blocked + // at a safepoint. We would like to mark the thread as _thread_blocked + // before calling java_suspend_self like all other callers of it but + // we must then observe proper safepoint protocol. (We can't leave + // _thread_blocked with a safepoint in progress). However we can be + // here as _thread_in_native_trans so we can't use a normal transition + // constructor/destructor pair because they assert on that type of + // transition. We could do something like: + // + // JavaThreadState state = thread_state(); + // set_thread_state(_thread_in_vm); + // { + // ThreadBlockInVM tbivm(this); + // java_suspend_self() + // } + // set_thread_state(_thread_in_vm_trans); + // if (safepoint) block; + // set_thread_state(state); + // + // but that is pretty messy. Instead we just go with the way the + // code has worked before and note that this is the only path to + // java_suspend_self that doesn't put the thread in _thread_blocked + // mode. + + frame_anchor()->make_walkable(this); + java_suspend_self(); + + // 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(); + } +} + +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 (is_Compiler_thread()) 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 (TraceExceptions) { + ResourceMark rm; + tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); + } + // for AbortVMOnException flag + NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_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() { + { MutexLocker mu(Threads_lock); + if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { + return; + } + } + + { MutexLockerEx 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; + } + } + + VM_ForceSafepoint 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() { + 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"); + + MutexLockerEx 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()) { + this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); + } + } + + return ret; +} + +#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() { + if (!Threads_lock->owned_by_self()) { + MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); + assert( !Threads::includes(this), + "java thread shouldn't have been published yet!"); + } + else { + assert( !Threads::includes(this), + "java thread 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)) { + JavaThreadState state = thread->thread_state(); + + // We mark this thread_blocked state as a suspend-equivalent so + // that a caller to is_ext_suspend_completed() won't be confused. + // The suspend-equivalent state is cleared by java_suspend_self(). + thread->set_suspend_equivalent(); + + // If the safepoint code sees the _thread_in_native_trans state, it will + // wait until the thread changes to other thread state. There is no + // guarantee on how soon we can obtain the SR_lock and complete the + // self-suspend request. It would be a bad idea to let safepoint wait for + // too long. Temporarily change the state to _thread_blocked to + // let the VM thread know that this thread is ready for GC. The problem + // of changing thread state is that safepoint could happen just after + // java_suspend_self() returns after being resumed, and VM thread will + // see the _thread_blocked state. We must check for safepoint + // after restoring the state and make sure we won't leave while a safepoint + // is in progress. + thread->set_thread_state(_thread_blocked); + thread->java_suspend_self(); + thread->set_thread_state(state); + // Make sure new state is seen by VM thread + if (os::is_MP()) { + if (UseMembar) { + // Force a fence between the write above and read below + OrderAccess::fence(); + } else { + // Must use this rather than serialization page in particular on Windows + InterfaceSupport::serialize_memory(thread); + } + } + } + + if (SafepointSynchronize::do_call_back()) { + // If we are safepointing, then block the caller which may not be + // the same as the target thread (see above). + SafepointSynchronize::block(curJT); + } + + if (thread->is_deopt_suspend()) { + thread->clear_deopt_suspend(); + RegisterMap map(thread, false); + frame f = thread->last_frame(); + while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { + f = f.sender(&map); + } + if (f.id() == thread->must_deopt_id()) { + thread->clear_must_deopt_id(); + f.deoptimize(thread); + } else { + fatal("missed deoptimization!"); + } + } +} + +// 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 GC_locker. +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); + GC_locker::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. + if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { + return; + } + + MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); + + clear_external_suspend(); + + if (is_ext_suspended()) { + clear_ext_suspended(); + SR_lock()->notify_all(); + } +} + +void JavaThread::create_stack_guard_pages() { + if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; + address low_addr = stack_base() - stack_size(); + size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); + + int allocate = os::allocate_stack_guard_pages(); + // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); + + if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { + warning("Attempt to allocate stack guard pages failed."); + return; + } + + if (os::guard_memory((char *) low_addr, len)) { + _stack_guard_state = stack_guard_enabled; + } else { + warning("Attempt to protect stack guard pages failed."); + if (os::uncommit_memory((char *) low_addr, len)) { + warning("Attempt to deallocate stack guard pages failed."); + } + } +} + +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_base() - stack_size(); + size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); + + if (os::allocate_stack_guard_pages()) { + if (os::remove_stack_guard_pages((char *) low_addr, len)) { + _stack_guard_state = stack_guard_unused; + } else { + warning("Attempt to deallocate stack guard pages failed."); + } + } else { + if (_stack_guard_state == stack_guard_unused) return; + if (os::unguard_memory((char *) low_addr, len)) { + _stack_guard_state = stack_guard_unused; + } else { + warning("Attempt to unprotect stack guard pages failed."); + } + } +} + +void JavaThread::enable_stack_yellow_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_yellow_zone_base() - stack_yellow_zone_size(); + + 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_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_zone() { + assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); + assert(_stack_guard_state != stack_guard_yellow_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_yellow_zone_base() - stack_yellow_zone_size(); + + if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { + _stack_guard_state = stack_guard_yellow_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()) { + if (LogCompilation && xtty != NULL) { + nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); + xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", + this->name(), nm != NULL ? nm->compile_id() : -1); + } + + Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); + } + } +} + + +// GC support +static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } + +void JavaThread::gc_epilogue() { + frames_do(frame_gc_epilogue); +} + + +static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } + +void JavaThread::gc_prologue() { + frames_do(frame_gc_prologue); +} + +// 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, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { + // Verify that the deferred card marks have been flushed. + assert(deferred_card_mark().is_empty(), "Should be empty during GC"); + + // The ThreadProfiler oops_do is done from FlatProfiler::oops_do + // since there may be more than one thread using each ThreadProfiler. + + // Traverse the GCHandles + Thread::oops_do(f, cld_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 privileged stack + if (_privileged_stack_top != NULL) { + _privileged_stack_top->oops_do(f); + } + + // 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, cld_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* 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); + } +} + +void JavaThread::nmethods_do(CodeBlobClosure* cf) { + Thread::nmethods_do(cf); // (super method is a no-op) + + 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()) { + // Traverse the execution stack + for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { + fst.current()->nmethods_do(cf); + } + } +} + +void JavaThread::metadata_do(void f(Metadata*)) { + Thread::metadata_do(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); + } + } +} + +// 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) const { + st->print("\"%s\" ", get_thread_name()); + oop thread_oop = threadObj(); + if (thread_oop != NULL) { + st->print("#" INT64_FORMAT " ", 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 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 && JDK_Version::is_gte_jdk15x_version()) { + st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); + } +#ifndef PRODUCT + print_thread_state_on(st); + _safepoint_state->print_on(st); +#endif // PRODUCT +} + +// 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 ")", + _stack_base - _stack_size, _stack_base); + st->print("]"); + 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, 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) { + typeArrayOop name = java_lang_Thread::name(thread_obj); + if (name != NULL) { + if (buf == NULL) { + name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); + } + else { + name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); + } + } + else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 + name_str = ""; + } + 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) { + typeArrayOop name = java_lang_ThreadGroup::name(thread_group); + // ThreadGroup.name can be null + if (name != NULL) { + const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); + return str; + } + } + } + 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) { + typeArrayOop name = java_lang_ThreadGroup::name(parent); + // ThreadGroup.name can be null + if (name != NULL) { + const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); + return str; + } + } + } + } + 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 && + JDK_Version::current().supports_thread_park_blocker()) { + 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; 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 + count++; + if (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, mtThread); + _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 inline void do_oop_work(T* p) { + oop obj = oopDesc::load_decode_heap_oop(p); + if (obj == NULL) return; + tty->print(INTPTR_FORMAT ": ", p); + if (obj->is_oop_or_null()) { + if (obj->is_objArray()) { + tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); + } else { + obj->print(); + } + } else { + tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) 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, 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("......"); + 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(); +} + +// 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; + _scanned_nmethod = NULL; + _compiler = NULL; + +#ifndef PRODUCT + _ideal_graph_printer = NULL; +#endif +} + +void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { + JavaThread::oops_do(f, cld_f, cf); + if (_scanned_nmethod != 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_nmethod); + } +} + + +// ======= Threads ======== + +// The Threads class links together all active threads, and provides +// operations over all threads. It is protected by its own Mutex +// lock, which is also used in other contexts to protect thread +// operations from having the thread being operated on from exiting +// and going away unexpectedly (e.g., safepoint synchronization) + +JavaThread* Threads::_thread_list = NULL; +int Threads::_number_of_threads = 0; +int Threads::_number_of_non_daemon_threads = 0; +int Threads::_return_code = 0; +size_t JavaThread::_stack_size_at_create = 0; +#ifdef ASSERT +bool Threads::_vm_complete = false; +#endif + +// All JavaThreads +#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) + +// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) +void Threads::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); + } + // Someday we could have a table or list of all non-JavaThreads. + // For now, just manually iterate through them. + tc->do_thread(VMThread::vm_thread()); + Universe::heap()->gc_threads_do(tc); + WatcherThread *wt = WatcherThread::watcher_thread(); + // Strictly speaking, the following NULL check isn't sufficient to make sure + // the data for WatcherThread is still valid upon being examined. However, + // considering that WatchThread terminates when the VM is on the way to + // exit at safepoint, the chance of the above is extremely small. The right + // way to prevent termination of WatcherThread would be to acquire + // Terminator_lock, but we can't do that without violating the lock rank + // checking in some cases. + if (wt != NULL) + tc->do_thread(wt); + + // If CompilerThreads ever become non-JavaThreads, add them here +} + +jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { + + extern void JDK_Version_init(); + + // Check version + if (!is_supported_jni_version(args->version)) return JNI_EVERSION; + + // Initialize the output stream module + ostream_init(); + + // Process java launcher properties. + Arguments::process_sun_java_launcher_properties(args); + + // Initialize the os module before using TLS + os::init(); + + // Initialize system properties. + Arguments::init_system_properties(); + + // So that JDK version can be used as a discrimintor when parsing arguments + JDK_Version_init(); + + // Update/Initialize System properties after JDK version number is known + Arguments::init_version_specific_system_properties(); + + // Parse arguments + 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; + + if (PauseAtStartup) { + os::pause(); + } + +#ifndef USDT2 + HS_DTRACE_PROBE(hotspot, vm__init__begin); +#else /* USDT2 */ + HOTSPOT_VM_INIT_BEGIN(); +#endif /* USDT2 */ + + // Record VM creation timing statistics + TraceVmCreationTime create_vm_timer; + create_vm_timer.start(); + + // Timing (must come after argument parsing) + TraceTime timer("Create VM", TraceStartupTime); + + // 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; + + jint adjust_after_os_result = Arguments::adjust_after_os(); + if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; + + // intialize TLS + ThreadLocalStorage::init(); + + // Bootstrap native memory tracking, so it can start recording memory + // activities before worker thread is started. This is the first phase + // of bootstrapping, VM is currently running in single-thread mode. + MemTracker::bootstrap_single_thread(); + + // 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 + _thread_list = NULL; + _number_of_threads = 0; + _number_of_non_daemon_threads = 0; + + // Initialize global data structures and create system classes in heap + vm_init_globals(); + + // Attach the main thread to this os thread + JavaThread* main_thread = new JavaThread(); + main_thread->set_thread_state(_thread_in_vm); + // must do this before set_active_handles and initialize_thread_local_storage + // Note: on solaris initialize_thread_local_storage() will (indirectly) + // change the stack size recorded here to one based on the java thread + // stacksize. This adjusted size is what is used to figure the placement + // of the guard pages. + main_thread->record_stack_base_and_size(); + main_thread->initialize_thread_local_storage(); + + 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"); + delete main_thread; + *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() ; + + // Second phase of bootstrapping, VM is about entering multi-thread mode + MemTracker::bootstrap_multi_thread(); + + // Initialize global modules + jint status = init_globals(); + if (status != JNI_OK) { + delete main_thread; + *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again + return status; + } + + // 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(); + + // Fully start NMT + MemTracker::start(); + + // Create the VMThread + { TraceTime timer("Start VMThread", TraceStartupTime); + 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 + { + MutexLocker ml(Notify_lock); + os::start_thread(vmthread); + while (vmthread->active_handles() == NULL) { + Notify_lock->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); + } + + EXCEPTION_MARK; + + // At this point, the Universe is initialized, but we have not executed + // any byte code. Now is a good time (the only time) to dump out the + // internal state of the JVM for sharing. + if (DumpSharedSpaces) { + MetaspaceShared::preload_and_dump(CHECK_0); + ShouldNotReachHere(); + } + + // 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(); + + { + TraceTime timer("Initialize java.lang classes", TraceStartupTime); + + if (EagerXrunInit && Arguments::init_libraries_at_startup()) { + create_vm_init_libraries(); + } + + initialize_class(vmSymbols::java_lang_String(), CHECK_0); + + // Initialize java_lang.System (needed before creating the thread) + initialize_class(vmSymbols::java_lang_System(), CHECK_0); + initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); + Handle thread_group = create_initial_thread_group(CHECK_0); + Universe::set_main_thread_group(thread_group()); + initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); + oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); + 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 & returns objects of this class. Make sure it's initialized. + initialize_class(vmSymbols::java_lang_Class(), CHECK_0); + + // The VM preresolves methods to these classes. Make sure that they get initialized + initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); + initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); + call_initializeSystemClass(CHECK_0); + + // 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_0); + initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); + initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); + initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); + initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); + initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); + initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); + initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); + } + + // See : bugid 4211085. + // Background : the static initializer of java.lang.Compiler tries to read + // property"java.compiler" and read & write property "java.vm.info". + // When a security manager is installed through the command line + // option "-Djava.security.manager", the above properties are not + // readable and the static initializer for java.lang.Compiler fails + // resulting in a NoClassDefFoundError. This can happen in any + // user code which calls methods in java.lang.Compiler. + // Hack : the hack is to pre-load and initialize this class, so that only + // system domains are on the stack when the properties are read. + // Currently even the AWT code has calls to methods in java.lang.Compiler. + // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. + // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and + // read and write"java.vm.info" in the default policy file. See bugid 4211383 + // Once that is done, we should remove this hack. + initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); + + // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to + // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot + // compiler does not get loaded through java.lang.Compiler). "java -version" with the + // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. + // This should also be taken out as soon as 4211383 gets fixed. + reset_vm_info_property(CHECK_0); + + quicken_jni_functions(); + + // Must be run after init_ft which initializes ft_enabled + if (TRACE_INITIALIZE() != JNI_OK) { + vm_exit_during_initialization("Failed to initialize tracing backend"); + } + + // 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(); + + Metaspace::post_initialize(); + +#ifndef USDT2 + HS_DTRACE_PROBE(hotspot, vm__init__end); +#else /* USDT2 */ + HOTSPOT_VM_INIT_END(); +#endif /* USDT2 */ + + // record VM initialization completion time +#if INCLUDE_MANAGEMENT + Management::record_vm_init_completed(); +#endif // INCLUDE_MANAGEMENT + + // Compute system loader. Note that this has to occur after set_init_completed, since + // valid exceptions may be thrown in the process. + // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and + // set_init_completed has just been called, causing exceptions not to be shortcut + // anymore. We call vm_exit_during_initialization directly instead. + SystemDictionary::compute_java_system_loader(THREAD); + if (HAS_PENDING_EXCEPTION) { + vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); + } + +#if INCLUDE_ALL_GCS + // Support for ConcurrentMarkSweep. This should be cleaned up + // and better encapsulated. The ugly nested if test would go away + // once things are properly refactored. XXX YSR + if (UseConcMarkSweepGC || UseG1GC) { + if (UseConcMarkSweepGC) { + ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); + } else { + ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); + } + if (HAS_PENDING_EXCEPTION) { + vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); + } + } +#endif // INCLUDE_ALL_GCS + + // 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(); + + // Signal Dispatcher needs to be started before VMInit event is posted + os::signal_init(); + + // 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(); + } + + // Notify JVMTI agents that VM initialization is complete - nop if no agents. + JvmtiExport::post_vm_initialized(); + + if (TRACE_START() != JNI_OK) { + vm_exit_during_initialization("Failed to start tracing backend."); + } + + if (CleanChunkPoolAsync) { + Chunk::start_chunk_pool_cleaner_task(); + } + + // initialize compiler(s) +#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) + CompileBroker::compilation_init(); +#endif + + if (EnableInvokeDynamic) { + // 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_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0); + initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0); + initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0); + } + +#if INCLUDE_MANAGEMENT + Management::initialize(THREAD); +#endif // INCLUDE_MANAGEMENT + + 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); + } + + if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); + if (MemProfiling) MemProfiler::engage(); + StatSampler::engage(); + if (CheckJNICalls) JniPeriodicChecker::engage(); + + BiasedLocking::init(); + +#if INCLUDE_RTM_OPT + RTMLockingCounters::init(); +#endif + + if (JDK_Version::current().post_vm_init_hook_enabled()) { + 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; + } + } + + { + MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); + // Make sure the watcher thread 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(); + } + } + + // Give os specific code one last chance to start + os::init_3(); + + create_vm_timer.end(); +#ifdef ASSERT + _vm_complete = true; +#endif + 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, mtThread); + } + } else { + // Try to load the agent from the standard dll directory + if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), + name)) { + library = os::dll_load(buffer, ebuf, sizeof ebuf); + } + if (library == NULL) { // Try the local directory + char ns[1] = {0}; + if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { + library = os::dll_load(buffer, ebuf, sizeof ebuf); + } + if (library == NULL) { + const char *sub_msg = " on the library 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, mtThread); + } + } + } + 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()) { + 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* k = + SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), + THREAD); + if (k != 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 + // and finalizers (if runFinalizersOnExit is set) won't be run. + // Note that if a shutdown hook was registered or runFinalizersOnExit + // was called, the Shutdown class would have already been loaded + // (Runtime.addShutdownHook and runFinalizersOnExit will load it). + instanceKlassHandle shutdown_klass (THREAD, k); + JavaValue result(T_VOID); + JavaCalls::call_static(&result, + shutdown_klass, + vmSymbols::shutdown_method_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, run finalizers if finalization-on-exit +// + 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 flat profiler, 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 +// + Delete this thread +// + Call exit_globals() +// > deletes tty +// > deletes PerfMemory resources +// + 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 + { MutexLocker 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. + // + // Note: If the FlatProfiler is running and this thread is waiting + // for another non-daemon thread to finish, then the FlatProfiler + // is waiting for the external suspend request on this thread to + // complete. wait_for_ext_suspend_completion() will eventually + // timeout, but that takes time. Making this wait a suspend- + // equivalent condition solves that timeout problem. + // + Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, + Mutex::_as_suspend_equivalent_flag); + } + + // Hang forever on exit if we are reporting an error. + if (ShowMessageBoxOnError && is_error_reported()) { + os::infinite_sleep(); + } + os::wait_for_keypress_at_exit(); + + if (JDK_Version::is_jdk12x_version()) { + // We are the last thread running, so check if finalizers should be run. + // For 1.3 or later this is done in thread->invoke_shutdown_hooks() + HandleMark rm(thread); + Universe::run_finalizers_on_exit(); + } else { + // 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); + + VMThread::wait_for_vm_thread_exit(); + assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); + VMThread::destroy(); + } + + // clean up ideal graph printers +#if defined(COMPILER2) && !defined(PRODUCT) + IdealGraphPrinter::clean_up(); +#endif + + // 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. + +#ifndef PRODUCT + // disable function tracing at JNI/JVM barriers + TraceJNICalls = false; + TraceJVMCalls = false; + TraceRuntimeCalls = false; +#endif + + VM_Exit::set_vm_exited(); + + notify_vm_shutdown(); + + delete thread; + + // exit_globals() will delete tty + exit_globals(); + + 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; + return JNI_FALSE; +} + + +void Threads::add(JavaThread* p, bool force_daemon) { + // The threads lock must be owned at this point + assert_locked_or_safepoint(Threads_lock); + + // See the comment for this method in thread.hpp for its purpose and + // why it is called here. + p->initialize_queues(); + p->set_next(_thread_list); + _thread_list = p; + _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) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { + _number_of_non_daemon_threads++; + daemon = false; + } + + p->set_safepoint_visible(true); + + ThreadService::add_thread(p, daemon); + + // Possible GC point. + Events::log(p, "Thread added: " INTPTR_FORMAT, p); +} + +void Threads::remove(JavaThread* p) { + // Extra scope needed for Thread_lock, so we can check + // that we do not remove thread without safepoint code notice + { MutexLocker ml(Threads_lock); + + assert(includes(p), "p must be present"); + + JavaThread* current = _thread_list; + JavaThread* prev = NULL; + + while (current != p) { + prev = current; + current = current->next(); + } + + if (prev) { + prev->set_next(current->next()); + } else { + _thread_list = p->next(); + } + _number_of_threads--; + oop threadObj = p->threadObj(); + bool daemon = true; + if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { + _number_of_non_daemon_threads--; + daemon = false; + + // 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) + Threads_lock->notify_all(); + } + ThreadService::remove_thread(p, 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(); + + // Now, this thread is not visible to safepoint + p->set_safepoint_visible(false); + // once the thread becomes safepoint invisible, we can not use its per-thread + // recorder. And Threads::do_threads() no longer walks this thread, so we have + // to release its per-thread recorder here. + MemTracker::thread_exiting(p); + } // unlock Threads_lock + + // Since Events::log uses a lock, we grab it outside the Threads_lock + Events::log(p, "Thread exited: " INTPTR_FORMAT, p); +} + +// Threads_lock must be held when this is called (or must be called during a safepoint) +bool Threads::includes(JavaThread* p) { + assert(Threads_lock->is_locked(), "sanity check"); + ALL_JAVA_THREADS(q) { + if (q == p ) { + return true; + } + } + return false; +} + +// 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 gurantee this property. It also makes sure that +// all threads gets blocked when exiting or starting). + +void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { + ALL_JAVA_THREADS(p) { + p->oops_do(f, cld_f, cf); + } + VMThread::vm_thread()->oops_do(f, cld_f, cf); +} + +void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { + // Introduce a mechanism allowing parallel threads to claim threads as + // root groups. Overhead should be small enough to use all the time, + // even in sequential code. + SharedHeap* sh = SharedHeap::heap(); + // Cannot yet substitute active_workers for n_par_threads + // because of G1CollectedHeap::verify() use of + // SharedHeap::process_strong_roots(). n_par_threads == 0 will + // turn off parallelism in process_strong_roots while active_workers + // is being used for parallelism elsewhere. + bool is_par = sh->n_par_threads() > 0; + assert(!is_par || + (SharedHeap::heap()->n_par_threads() == + SharedHeap::heap()->workers()->active_workers()), "Mismatch"); + int cp = SharedHeap::heap()->strong_roots_parity(); + ALL_JAVA_THREADS(p) { + if (p->claim_oops_do(is_par, cp)) { + p->oops_do(f, cld_f, cf); + } + } + VMThread* vmt = VMThread::vm_thread(); + if (vmt->claim_oops_do(is_par, cp)) { + vmt->oops_do(f, cld_f, cf); + } +} + +#if INCLUDE_ALL_GCS +// Used by ParallelScavenge +void Threads::create_thread_roots_tasks(GCTaskQueue* q) { + ALL_JAVA_THREADS(p) { + q->enqueue(new ThreadRootsTask(p)); + } + q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); +} + +// Used by Parallel Old +void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { + ALL_JAVA_THREADS(p) { + q->enqueue(new ThreadRootsMarkingTask(p)); + } + q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); +} +#endif // INCLUDE_ALL_GCS + +void Threads::nmethods_do(CodeBlobClosure* cf) { + ALL_JAVA_THREADS(p) { + p->nmethods_do(cf); + } + VMThread::vm_thread()->nmethods_do(cf); +} + +void Threads::metadata_do(void f(Metadata*)) { + ALL_JAVA_THREADS(p) { + p->metadata_do(f); + } +} + +void Threads::gc_epilogue() { + ALL_JAVA_THREADS(p) { + p->gc_epilogue(); + } +} + +void Threads::gc_prologue() { + ALL_JAVA_THREADS(p) { + p->gc_prologue(); + } +} + +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* Threads::get_pending_threads(int count, + address monitor, bool doLock) { + assert(doLock || SafepointSynchronize::is_at_safepoint(), + "must grab Threads_lock or be at safepoint"); + GrowableArray* result = new GrowableArray(count); + + int i = 0; + { + MutexLockerEx ml(doLock ? Threads_lock : NULL); + ALL_JAVA_THREADS(p) { + if (p->is_Compiler_thread()) 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(address owner, bool doLock) { + assert(doLock || + Threads_lock->owned_by_self() || + SafepointSynchronize::is_at_safepoint(), + "must grab Threads_lock or be at safepoint"); + + // NULL owner means not locked so we can skip the search + if (owner == NULL) return NULL; + + { + MutexLockerEx ml(doLock ? Threads_lock : NULL); + ALL_JAVA_THREADS(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; + { + MutexLockerEx ml(doLock ? Threads_lock : NULL); + ALL_JAVA_THREADS(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) { + char buf[32]; + st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); + + st->print_cr("Full thread dump %s (%s %s):", + Abstract_VM_Version::vm_name(), + Abstract_VM_Version::vm_release(), + Abstract_VM_Version::vm_info_string() + ); + st->cr(); + +#if INCLUDE_ALL_GCS + // Dump concurrent locks + ConcurrentLocksDump concurrent_locks; + if (print_concurrent_locks) { + concurrent_locks.dump_at_safepoint(); + } +#endif // INCLUDE_ALL_GCS + + ALL_JAVA_THREADS(p) { + ResourceMark rm; + p->print_on(st); + if (print_stacks) { + if (internal_format) { + p->trace_stack(); + } else { + p->print_stack_on(st); + } + } + st->cr(); +#if INCLUDE_ALL_GCS + if (print_concurrent_locks) { + concurrent_locks.print_locks_on(p, st); + } +#endif // INCLUDE_ALL_GCS + } + + 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(); + } + CompileBroker::print_compiler_threads_on(st); + st->flush(); +} + +// 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) { + bool found_current = false; + st->print_cr("Java Threads: ( => current thread )"); + ALL_JAVA_THREADS(thread) { + bool is_current = (current == thread); + found_current = found_current || is_current; + + st->print("%s", is_current ? "=>" : " "); + + st->print(PTR_FORMAT, thread); + st->print(" "); + thread->print_on_error(st, buf, buflen); + st->cr(); + } + st->cr(); + + st->print_cr("Other Threads:"); + if (VMThread::vm_thread()) { + bool is_current = (current == VMThread::vm_thread()); + found_current = found_current || is_current; + st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); + + st->print(PTR_FORMAT, VMThread::vm_thread()); + st->print(" "); + VMThread::vm_thread()->print_on_error(st, buf, buflen); + st->cr(); + } + WatcherThread* wt = WatcherThread::watcher_thread(); + if (wt != NULL) { + bool is_current = (current == wt); + found_current = found_current || is_current; + st->print("%s", is_current ? "=>" : " "); + + st->print(PTR_FORMAT, wt); + st->print(" "); + wt->print_on_error(st, buf, buflen); + st->cr(); + } + if (!found_current) { + st->cr(); + st->print("=>" PTR_FORMAT " (exited) ", current); + current->print_on_error(st, buf, buflen); + st->cr(); + } +} + +// 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. + TEVENT (SpinAcquire - ctx) ; + 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::NakedYield() ; + ++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. + *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. +// * Consider schedctl.sc_nopreempt to cover the critical section. +// + + +typedef volatile intptr_t MutexT ; // Mux Lock-word +enum MuxBits { LOCKBIT = 1 } ; + +void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { + intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; + if (w == 0) return ; + if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { + return ; + } + + TEVENT (muxAcquire - Contention) ; + 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_ptr (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_ptr (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_ptr (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_ptr (LOCKBIT, Lock, 0) ; + if (w == 0) return ; + if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { + return ; + } + + TEVENT (muxAcquire - Contention) ; + 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_ptr (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_ptr (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_ptr (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). + +void Thread::muxRelease (volatile intptr_t * Lock) { + for (;;) { + const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; + assert (w & LOCKBIT, "invariant") ; + if (w == LOCKBIT) return ; + ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; + assert (List != NULL, "invariant") ; + assert (List->OnList == intptr_t(Lock), "invariant") ; + ParkEvent * nxt = List->ListNext ; + + // The following CAS() releases the lock and pops the head element. + if (Atomic::cmpxchg_ptr (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(); +}