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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kExecutor;
#include "mongo/platform/basic.h"
#include "mongo/transport/service_executor_reserved.h"
#include "mongo/stdx/thread.h"
#include "mongo/transport/service_entry_point_utils.h"
#include "mongo/transport/service_executor_gen.h"
#include "mongo/transport/service_executor_task_names.h"
#include "mongo/util/log.h"
#include "mongo/util/processinfo.h"
namespace mongo {
namespace transport {
namespace {
constexpr auto kThreadsRunning = "threadsRunning"_sd;
constexpr auto kExecutorLabel = "executor"_sd;
constexpr auto kExecutorName = "reserved"_sd;
constexpr auto kReadyThreads = "readyThreads"_sd;
constexpr auto kStartingThreads = "startingThreads"_sd;
} // namespace
thread_local std::deque<ServiceExecutor::Task> ServiceExecutorReserved::_localWorkQueue = {};
thread_local int ServiceExecutorReserved::_localRecursionDepth = 0;
thread_local int64_t ServiceExecutorReserved::_localThreadIdleCounter = 0;
ServiceExecutorReserved::ServiceExecutorReserved(ServiceContext* ctx,
std::string name,
size_t reservedThreads)
: _name(std::move(name)), _reservedThreads(reservedThreads) {}
Status ServiceExecutorReserved::start() {
{
stdx::unique_lock<Latch> lk(_mutex);
_stillRunning.store(true);
_numStartingThreads = _reservedThreads;
}
for (size_t i = 0; i < _reservedThreads; i++) {
auto status = _startWorker();
if (!status.isOK()) {
return status;
}
}
return Status::OK();
}
Status ServiceExecutorReserved::_startWorker() {
log() << "Starting new worker thread for " << _name << " service executor";
return launchServiceWorkerThread([this] {
stdx::unique_lock<Latch> lk(_mutex);
_numRunningWorkerThreads.addAndFetch(1);
auto numRunningGuard = makeGuard([&] {
_numRunningWorkerThreads.subtractAndFetch(1);
_shutdownCondition.notify_one();
});
_numStartingThreads--;
_numReadyThreads++;
while (_stillRunning.load()) {
_threadWakeup.wait(lk, [&] { return (!_stillRunning.load() || !_readyTasks.empty()); });
if (!_stillRunning.loadRelaxed()) {
break;
}
if (_readyTasks.empty()) {
continue;
}
auto task = std::move(_readyTasks.front());
_readyTasks.pop_front();
_numReadyThreads -= 1;
bool launchReplacement = false;
if (_numReadyThreads + _numStartingThreads < _reservedThreads) {
_numStartingThreads++;
launchReplacement = true;
}
lk.unlock();
if (launchReplacement) {
auto threadStartStatus = _startWorker();
if (!threadStartStatus.isOK()) {
warning() << "Could not start new reserve worker thread: " << threadStartStatus;
}
}
_localWorkQueue.emplace_back(std::move(task));
while (!_localWorkQueue.empty() && _stillRunning.loadRelaxed()) {
_localRecursionDepth = 1;
_localWorkQueue.front()();
_localWorkQueue.pop_front();
}
lk.lock();
if (_numReadyThreads + 1 > _reservedThreads) {
break;
} else {
_numReadyThreads += 1;
}
}
LOG(3) << "Exiting worker thread in " << _name << " service executor";
});
}
Status ServiceExecutorReserved::shutdown(Milliseconds timeout) {
LOG(3) << "Shutting down reserved executor";
stdx::unique_lock<Latch> lock(_mutex);
_stillRunning.store(false);
_threadWakeup.notify_all();
bool result = _shutdownCondition.wait_for(lock, timeout.toSystemDuration(), [this]() {
return _numRunningWorkerThreads.load() == 0;
});
return result
? Status::OK()
: Status(ErrorCodes::Error::ExceededTimeLimit,
"reserved executor couldn't shutdown all worker threads within time limit.");
}
Status ServiceExecutorReserved::schedule(Task task,
ScheduleFlags flags,
ServiceExecutorTaskName taskName) {
if (!_stillRunning.load()) {
return Status{ErrorCodes::ShutdownInProgress, "Executor is not running"};
}
if (!_localWorkQueue.empty()) {
// Execute task directly (recurse) if allowed by the caller as it produced better
// performance in testing. Try to limit the amount of recursion so we don't blow up the
// stack, even though this shouldn't happen with this executor that uses blocking network
// I/O.
if ((flags & ScheduleFlags::kMayRecurse) &&
(_localRecursionDepth < reservedServiceExecutorRecursionLimit.loadRelaxed())) {
++_localRecursionDepth;
task();
} else {
_localWorkQueue.emplace_back(std::move(task));
}
return Status::OK();
}
stdx::lock_guard<Latch> lk(_mutex);
_readyTasks.push_back(std::move(task));
_threadWakeup.notify_one();
return Status::OK();
}
void ServiceExecutorReserved::appendStats(BSONObjBuilder* bob) const {
stdx::lock_guard<Latch> lk(_mutex);
*bob << kExecutorLabel << kExecutorName << kThreadsRunning
<< static_cast<int>(_numRunningWorkerThreads.loadRelaxed()) << kReadyThreads
<< static_cast<int>(_numReadyThreads) << kStartingThreads
<< static_cast<int>(_numStartingThreads);
}
} // namespace transport
} // namespace mongo
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