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arangodb/lib/Basics/Thread.cpp

377 lines
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C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
/// @author Achim Brandt
////////////////////////////////////////////////////////////////////////////////
#include "Thread.h"
#include <errno.h>
#include <signal.h>
#include "ApplicationFeatures/ApplicationServer.h"
#include "Basics/ConditionLocker.h"
#include "Basics/Exceptions.h"
#include "Logger/Logger.h"
#include <velocypack/Builder.h>
#include <velocypack/velocypack-aliases.h>
#include <thread>
#include <chrono>
using namespace arangodb;
using namespace arangodb::application_features;
using namespace arangodb::basics;
/// @brief local thread number
static thread_local uint64_t LOCAL_THREAD_NUMBER = 0;
static thread_local char const* LOCAL_THREAD_NAME = nullptr;
#if !defined(ARANGODB_HAVE_GETTID) && !defined(_WIN32)
namespace {
std::atomic<uint64_t> NEXT_THREAD_ID(1);
}
#endif
/// @brief static started with access to the private variables
void Thread::startThread(void* arg) {
#if defined(ARANGODB_HAVE_GETTID)
LOCAL_THREAD_NUMBER = (uint64_t)gettid();
#elif defined(_WIN32)
LOCAL_THREAD_NUMBER = (uint64_t)GetCurrentThreadId();
#else
LOCAL_THREAD_NUMBER = NEXT_THREAD_ID.fetch_add(1, std::memory_order_seq_cst);
#endif
TRI_ASSERT(arg != nullptr);
Thread* ptr = static_cast<Thread*>(arg);
TRI_ASSERT(ptr != nullptr);
ptr->_threadNumber = LOCAL_THREAD_NUMBER;
LOCAL_THREAD_NAME = ptr->name().c_str();
if (0 <= ptr->_affinity) {
TRI_SetProcessorAffinity(&ptr->_thread, ptr->_affinity);
}
auto guard = scopeGuard([&ptr]() {
ptr->cleanupMe();
});
try {
ptr->runMe();
} catch (std::exception const& ex) {
LOG_TOPIC(WARN, Logger::THREADS)
<< "caught exception in thread '" << ptr->_name << "': " << ex.what();
ptr->crashNotification(ex);
throw;
}
}
/// @brief returns the process id
TRI_pid_t Thread::currentProcessId() {
#ifdef _WIN32
return _getpid();
#else
return getpid();
#endif
}
/// @brief returns the thread process id
uint64_t Thread::currentThreadNumber() { return LOCAL_THREAD_NUMBER; }
/// @brief returns the name of the current thread, if set
/// note that this function may return a nullptr
char const* Thread::currentThreadName() { return LOCAL_THREAD_NAME; }
/// @brief returns the thread id
TRI_tid_t Thread::currentThreadId() {
#ifdef TRI_HAVE_WIN32_THREADS
return GetCurrentThreadId();
#else
#ifdef TRI_HAVE_POSIX_THREADS
return pthread_self();
#else
#error "Thread::currentThreadId not implemented"
#endif
#endif
}
std::string Thread::stringify(ThreadState state) {
switch (state) {
case ThreadState::CREATED:
return "created";
case ThreadState::STARTED:
return "started";
case ThreadState::STOPPING:
return "stopping";
case ThreadState::STOPPED:
return "stopped";
case ThreadState::DETACHED:
return "detached";
}
return "unknown";
}
/// @brief constructs a thread
Thread::Thread(std::string const& name, bool deleteOnExit)
: _deleteOnExit(deleteOnExit),
_threadStructInitialized(false),
_name(name),
_thread(),
_threadNumber(0),
_threadId(),
_finishedCondition(nullptr),
_state(ThreadState::CREATED),
_affinity(-1) {
TRI_InitThread(&_thread);
}
/// @brief deletes the thread
Thread::~Thread() {
auto state = _state.load();
LOG_TOPIC(TRACE, Logger::THREADS)
<< "delete(" << _name << "), state: " << stringify(state);
if (state == ThreadState::STOPPED) {
if (_threadStructInitialized) {
if (TRI_IsSelfThread(&_thread)) {
// we must ignore any errors here, but TRI_DetachThread will log them
TRI_DetachThread(&_thread);
} else {
// we must ignore any errors here, but TRI_JoinThread will log them
TRI_JoinThread(&_thread);
}
}
_state.store(ThreadState::DETACHED);
return;
}
state = _state.load();
if (state != ThreadState::DETACHED && state != ThreadState::CREATED) {
LOG_TOPIC(FATAL, arangodb::Logger::FIXME)
<< "thread '" << _name << "' is not detached but " << stringify(state)
<< ". shutting down hard";
FATAL_ERROR_ABORT();
}
LOCAL_THREAD_NAME = nullptr;
}
/// @brief flags the thread as stopping
void Thread::beginShutdown() {
LOG_TOPIC(TRACE, Logger::THREADS)
<< "beginShutdown(" << _name << ") in state " << stringify(_state.load());
ThreadState state = _state.load();
while (state == ThreadState::CREATED) {
_state.compare_exchange_strong(state, ThreadState::STOPPED);
}
while (state != ThreadState::STOPPING && state != ThreadState::STOPPED &&
state != ThreadState::DETACHED) {
_state.compare_exchange_strong(state, ThreadState::STOPPING);
}
LOG_TOPIC(TRACE, Logger::THREADS)
<< "beginShutdown(" << _name << ") reached state "
<< stringify(_state.load());
}
/// @brief derived class MUST call from its destructor
void Thread::shutdown() {
LOG_TOPIC(TRACE, Logger::THREADS) << "shutdown(" << _name << ")";
ThreadState state = _state.load();
while (state == ThreadState::CREATED) {
bool res = _state.compare_exchange_strong(state, ThreadState::DETACHED);
if (res) {
return;
}
}
if (_state.load() == ThreadState::STARTED) {
beginShutdown();
if (!isSilent() && _state.load() != ThreadState::STOPPING &&
_state.load() != ThreadState::STOPPED) {
LOG_TOPIC(WARN, Logger::THREADS)
<< "forcefully shutting down thread '" << _name << "' in state "
<< stringify(_state.load());
}
}
size_t n = 10 * 60 * 5; // * 100ms = 1s * 60 * 5
for (size_t i = 0; i < n; ++i) {
if (_state.load() == ThreadState::STOPPED) {
break;
}
std::this_thread::sleep_for(std::chrono::microseconds(100 * 1000));
}
if (_state.load() != ThreadState::STOPPED) {
LOG_TOPIC(FATAL, arangodb::Logger::FIXME)
<< "cannot shutdown thread, giving up";
FATAL_ERROR_ABORT();
}
}
/// @brief checks if the current thread was asked to stop
bool Thread::isStopping() const {
auto state = _state.load(std::memory_order_relaxed);
return state == ThreadState::STOPPING || state == ThreadState::STOPPED ||
state == ThreadState::DETACHED;
}
/// @brief starts the thread
bool Thread::start(ConditionVariable* finishedCondition) {
if (!isSystem() && !ApplicationServer::isPrepared()) {
LOG_TOPIC(FATAL, arangodb::Logger::FIXME)
<< "trying to start a thread '" << _name
<< "' before prepare has finished, current state: "
<< (ApplicationServer::server == nullptr
? -1
: (int)ApplicationServer::server->state());
FATAL_ERROR_ABORT();
}
_finishedCondition = finishedCondition;
ThreadState state = _state.load();
if (state != ThreadState::CREATED) {
LOG_TOPIC(FATAL, Logger::THREADS)
<< "called started on an already started thread, thread is in state "
<< stringify(state);
FATAL_ERROR_ABORT();
}
ThreadState expected = ThreadState::CREATED;
bool res = _state.compare_exchange_strong(expected, ThreadState::STARTED);
if (!res) {
LOG_TOPIC(WARN, Logger::THREADS)
<< "thread died before it could start, thread is in state "
<< stringify(expected);
return false;
}
TRI_ASSERT(!_threadStructInitialized);
memset(&_thread, 0, sizeof(thread_t));
bool ok =
TRI_StartThread(&_thread, &_threadId, _name.c_str(), &startThread, this);
if (!ok) {
// could not start the thread
_state.store(ThreadState::STOPPED);
LOG_TOPIC(ERR, Logger::THREADS)
<< "could not start thread '" << _name << "': " << TRI_last_error();
// must cleanup to prevent memleaks
cleanupMe();
}
_threadStructInitialized = true;
return ok;
}
/// @brief sets the process affinity
void Thread::setProcessorAffinity(size_t c) { _affinity = (int)c; }
/// @brief sets status
void Thread::addStatus(VPackBuilder* b) {
b->add("affinity", VPackValue(_affinity));
switch (_state.load()) {
case ThreadState::CREATED:
b->add("started", VPackValue("created"));
break;
case ThreadState::STARTED:
b->add("started", VPackValue("started"));
break;
case ThreadState::STOPPING:
b->add("started", VPackValue("stopping"));
break;
case ThreadState::STOPPED:
b->add("started", VPackValue("stopped"));
break;
case ThreadState::DETACHED:
b->add("started", VPackValue("detached"));
break;
}
}
void Thread::markAsStopped() {
_state.store(ThreadState::STOPPED);
if (_finishedCondition != nullptr) {
CONDITION_LOCKER(locker, *_finishedCondition);
locker.broadcast();
}
}
void Thread::runMe() {
// make sure the thread is marked as stopped under all circumstances
TRI_DEFER(markAsStopped());
try {
run();
} catch (std::exception const& ex) {
if (!isSilent()) {
LOG_TOPIC(ERR, Logger::THREADS)
<< "exception caught in thread '" << _name << "': " << ex.what();
Logger::flush();
}
throw;
} catch (...) {
if (!isSilent()) {
LOG_TOPIC(ERR, Logger::THREADS)
<< "unknown exception caught in thread '" << _name << "'";
Logger::flush();
}
throw;
}
}
void Thread::cleanupMe() {
if (_deleteOnExit) {
LOCAL_THREAD_NAME = nullptr;
delete this;
}
}