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/*
* Copyright (c) 1997, 2022, 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/classLoaderDataGraph.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/codeCache.hpp"
#include "compiler/compileBroker.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "gc/shared/isGCActiveMark.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "logging/logConfiguration.hpp"
#include "memory/heapInspection.hpp"
#include "memory/metaspace/metaspaceReporter.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "oops/symbol.hpp"
#include "runtime/arguments.hpp"
#include "runtime/deoptimization.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/javaThread.inline.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/stackFrameStream.inline.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/threads.hpp"
#include "runtime/threadSMR.inline.hpp"
#include "runtime/vmOperations.hpp"
#include "services/threadService.hpp"
#define VM_OP_NAME_INITIALIZE(name) #name,
const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
{ VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
void VM_Operation::set_calling_thread(Thread* thread) {
_calling_thread = thread;
}
void VM_Operation::evaluate() {
ResourceMark rm;
LogTarget(Debug, vmoperation) lt;
if (lt.is_enabled()) {
LogStream ls(lt);
ls.print("begin ");
print_on_error(&ls);
ls.cr();
}
doit();
if (lt.is_enabled()) {
LogStream ls(lt);
ls.print("end ");
print_on_error(&ls);
ls.cr();
}
}
// Called by fatal error handler.
void VM_Operation::print_on_error(outputStream* st) const {
st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
st->print("%s", name());
st->print(", mode: %s", evaluate_at_safepoint() ? "safepoint" : "no safepoint");
if (calling_thread()) {
st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
}
}
void VM_ClearICs::doit() {
if (_preserve_static_stubs) {
CodeCache::cleanup_inline_caches_whitebox();
} else {
CodeCache::clear_inline_caches();
}
}
void VM_CleanClassLoaderDataMetaspaces::doit() {
ClassLoaderDataGraph::walk_metadata_and_clean_metaspaces();
}
VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
_thread = thread;
_id = id;
_reason = reason;
}
void VM_DeoptimizeFrame::doit() {
assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
}
#ifndef PRODUCT
void VM_DeoptimizeAll::doit() {
JavaThreadIteratorWithHandle jtiwh;
// deoptimize all java threads in the system
if (DeoptimizeALot) {
for (; JavaThread *thread = jtiwh.next(); ) {
if (thread->has_last_Java_frame()) {
thread->deoptimize();
}
}
} else if (DeoptimizeRandom) {
// Deoptimize some selected threads and frames
int tnum = os::random() & 0x3;
int fnum = os::random() & 0x3;
int tcount = 0;
for (; JavaThread *thread = jtiwh.next(); ) {
if (thread->has_last_Java_frame()) {
if (tcount++ == tnum) {
tcount = 0;
int fcount = 0;
// Deoptimize some selected frames.
for(StackFrameStream fst(thread, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
if (fst.current()->can_be_deoptimized()) {
if (fcount++ == fnum) {
fcount = 0;
Deoptimization::deoptimize(thread, *fst.current());
}
}
}
}
}
}
}
}
void VM_ZombieAll::doit() {
JavaThread::cast(calling_thread())->make_zombies();
}
#endif // !PRODUCT
bool VM_PrintThreads::doit_prologue() {
// Get Heap_lock if concurrent locks will be dumped
if (_print_concurrent_locks) {
Heap_lock->lock();
}
return true;
}
void VM_PrintThreads::doit() {
Threads::print_on(_out, true, false, _print_concurrent_locks, _print_extended_info);
if (_print_jni_handle_info) {
JNIHandles::print_on(_out);
}
}
void VM_PrintThreads::doit_epilogue() {
if (_print_concurrent_locks) {
// Release Heap_lock
Heap_lock->unlock();
}
}
void VM_PrintMetadata::doit() {
metaspace::MetaspaceReporter::print_report(_out, _scale, _flags);
}
VM_FindDeadlocks::~VM_FindDeadlocks() {
if (_deadlocks != NULL) {
DeadlockCycle* cycle = _deadlocks;
while (cycle != NULL) {
DeadlockCycle* d = cycle;
cycle = cycle->next();
delete d;
}
}
}
void VM_FindDeadlocks::doit() {
// Update the hazard ptr in the originating thread to the current
// list of threads. This VM operation needs the current list of
// threads for proper deadlock detection and those are the
// JavaThreads we need to be protected when we return info to the
// originating thread.
_setter.set();
_deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
if (_out != NULL) {
int num_deadlocks = 0;
for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
num_deadlocks++;
cycle->print_on_with(_setter.list(), _out);
}
if (num_deadlocks == 1) {
_out->print_cr("\nFound 1 deadlock.\n");
_out->flush();
} else if (num_deadlocks > 1) {
_out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
_out->flush();
}
}
}
VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
int max_depth,
bool with_locked_monitors,
bool with_locked_synchronizers) {
_result = result;
_num_threads = 0; // 0 indicates all threads
_threads = NULL;
_result = result;
_max_depth = max_depth;
_with_locked_monitors = with_locked_monitors;
_with_locked_synchronizers = with_locked_synchronizers;
}
VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
GrowableArray<instanceHandle>* threads,
int num_threads,
int max_depth,
bool with_locked_monitors,
bool with_locked_synchronizers) {
_result = result;
_num_threads = num_threads;
_threads = threads;
_result = result;
_max_depth = max_depth;
_with_locked_monitors = with_locked_monitors;
_with_locked_synchronizers = with_locked_synchronizers;
}
bool VM_ThreadDump::doit_prologue() {
if (_with_locked_synchronizers) {
// Acquire Heap_lock to dump concurrent locks
Heap_lock->lock();
}
return true;
}
void VM_ThreadDump::doit_epilogue() {
if (_with_locked_synchronizers) {
// Release Heap_lock
Heap_lock->unlock();
}
}
void VM_ThreadDump::doit() {
ResourceMark rm;
// Set the hazard ptr in the originating thread to protect the
// current list of threads. This VM operation needs the current list
// of threads for a proper dump and those are the JavaThreads we need
// to be protected when we return info to the originating thread.
_result->set_t_list();
ConcurrentLocksDump concurrent_locks(true);
if (_with_locked_synchronizers) {
concurrent_locks.dump_at_safepoint();
}
ObjectMonitorsHashtable table;
ObjectMonitorsHashtable* tablep = nullptr;
if (_with_locked_monitors) {
// The caller wants locked monitor information and that's expensive to gather
// when there are a lot of inflated monitors. So we deflate idle monitors and
// gather information about owned monitors at the same time.
tablep = &table;
while (ObjectSynchronizer::deflate_idle_monitors(tablep) > 0) {
; /* empty */
}
}
if (_num_threads == 0) {
// Snapshot all live threads
for (uint i = 0; i < _result->t_list()->length(); i++) {
JavaThread* jt = _result->t_list()->thread_at(i);
if (jt->is_exiting() ||
jt->is_hidden_from_external_view()) {
// skip terminating threads and hidden threads
continue;
}
ThreadConcurrentLocks* tcl = NULL;
if (_with_locked_synchronizers) {
tcl = concurrent_locks.thread_concurrent_locks(jt);
}
snapshot_thread(jt, tcl, tablep);
}
} else {
// Snapshot threads in the given _threads array
// A dummy snapshot is created if a thread doesn't exist
for (int i = 0; i < _num_threads; i++) {
instanceHandle th = _threads->at(i);
if (th() == NULL) {
// skip if the thread doesn't exist
// Add a dummy snapshot
_result->add_thread_snapshot();
continue;
}
// Dump thread stack only if the thread is alive and not exiting
// and not VM internal thread.
JavaThread* jt = java_lang_Thread::thread(th());
if (jt != NULL && !_result->t_list()->includes(jt)) {
// _threads[i] doesn't refer to a valid JavaThread; this check
// is primarily for JVM_DumpThreads() which doesn't have a good
// way to validate the _threads array.
jt = NULL;
}
if (jt == NULL || /* thread not alive */
jt->is_exiting() ||
jt->is_hidden_from_external_view()) {
// add a NULL snapshot if skipped
_result->add_thread_snapshot();
continue;
}
ThreadConcurrentLocks* tcl = NULL;
if (_with_locked_synchronizers) {
tcl = concurrent_locks.thread_concurrent_locks(jt);
}
snapshot_thread(jt, tcl, tablep);
}
}
}
void VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl,
ObjectMonitorsHashtable* table) {
ThreadSnapshot* snapshot = _result->add_thread_snapshot(java_thread);
snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors, table, false);
snapshot->set_concurrent_locks(tcl);
}
volatile bool VM_Exit::_vm_exited = false;
Thread * volatile VM_Exit::_shutdown_thread = NULL;
int VM_Exit::set_vm_exited() {
Thread * thr_cur = Thread::current();
assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
int num_active = 0;
_shutdown_thread = thr_cur;
_vm_exited = true; // global flag
for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
if (thr != thr_cur && thr->thread_state() == _thread_in_native) {
++num_active;
thr->set_terminated(JavaThread::_vm_exited); // per-thread flag
}
}
return num_active;
}
int VM_Exit::wait_for_threads_in_native_to_block() {
// VM exits at safepoint. This function must be called at the final safepoint
// to wait for threads in _thread_in_native state to be quiescent.
assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
Thread * thr_cur = Thread::current();
Monitor timer(Mutex::nosafepoint, "VM_ExitTimer_lock");
// Compiler threads need longer wait because they can access VM data directly
// while in native. If they are active and some structures being used are
// deleted by the shutdown sequence, they will crash. On the other hand, user
// threads must go through native=>Java/VM transitions first to access VM
// data, and they will be stopped during state transition. In theory, we
// don't have to wait for user threads to be quiescent, but it's always
// better to terminate VM when current thread is the only active thread, so
// wait for user threads too. Numbers are in 10 milliseconds.
int max_wait_user_thread = 30; // at least 300 milliseconds
int max_wait_compiler_thread = 1000; // at least 10 seconds
int max_wait = max_wait_compiler_thread;
int attempts = 0;
JavaThreadIteratorWithHandle jtiwh;
while (true) {
int num_active = 0;
int num_active_compiler_thread = 0;
jtiwh.rewind();
for (; JavaThread *thr = jtiwh.next(); ) {
if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
num_active++;
if (thr->is_Compiler_thread()) {
#if INCLUDE_JVMCI
CompilerThread* ct = (CompilerThread*) thr;
if (ct->compiler() == NULL || !ct->compiler()->is_jvmci()) {
num_active_compiler_thread++;
} else {
// A JVMCI compiler thread never accesses VM data structures
// while in _thread_in_native state so there's no need to wait
// for it and potentially add a 300 millisecond delay to VM
// shutdown.
num_active--;
}
#else
num_active_compiler_thread++;
#endif
}
}
}
if (num_active == 0) {
return 0;
} else if (attempts > max_wait) {
return num_active;
} else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
return num_active;
}
attempts++;
MonitorLocker ml(&timer, Mutex::_no_safepoint_check_flag);
ml.wait(10);
}
}
void VM_Exit::doit() {
if (VerifyBeforeExit) {
HandleMark hm(VMThread::vm_thread());
// Among other things, this ensures that Eden top is correct.
Universe::heap()->prepare_for_verify();
// Silent verification so as not to pollute normal output,
// unless we really asked for it.
Universe::verify();
}
CompileBroker::set_should_block();
// Wait for a short period for threads in native to block. Any thread
// still executing native code after the wait will be stopped at
// native==>Java/VM barriers.
// Among 16276 JCK tests, 94% of them come here without any threads still
// running in native; the other 6% are quiescent within 250ms (Ultra 80).
wait_for_threads_in_native_to_block();
set_vm_exited();
// The ObjectMonitor subsystem uses perf counters so do this before
// we call exit_globals() so we don't run afoul of perfMemory_exit().
ObjectSynchronizer::do_final_audit_and_print_stats();
// We'd like to call IdealGraphPrinter::clean_up() to finalize the
// XML logging, but we can't safely do that here. The logic to make
// XML termination logging safe is tied to the termination of the
// VMThread, and it doesn't terminate on this exit path. See 8222534.
// cleanup globals resources before exiting. exit_globals() currently
// cleans up outputStream resources and PerfMemory resources.
exit_globals();
LogConfiguration::finalize();
// Check for exit hook
exit_hook_t exit_hook = Arguments::exit_hook();
if (exit_hook != NULL) {
// exit hook should exit.
exit_hook(_exit_code);
// ... but if it didn't, we must do it here
vm_direct_exit(_exit_code);
} else {
vm_direct_exit(_exit_code);
}
}
void VM_Exit::wait_if_vm_exited() {
if (_vm_exited &&
Thread::current_or_null() != _shutdown_thread) {
// _vm_exited is set at safepoint, and the Threads_lock is never released
// so we will block here until the process dies.
Threads_lock->lock();
ShouldNotReachHere();
}
}
void VM_PrintCompileQueue::doit() {
CompileBroker::print_compile_queues(_out);
}
#if INCLUDE_SERVICES
void VM_PrintClassHierarchy::doit() {
KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
}
#endif
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