2 * Copyright 2015 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
20 #include <folly/CPortability.h>
21 #include <folly/Memory.h>
22 #include <folly/Optional.h>
23 #include <folly/Portability.h>
24 #include <folly/ScopeGuard.h>
26 #include <folly/ThreadLocal.h>
28 #include <folly/experimental/fibers/Baton.h>
29 #include <folly/experimental/fibers/Fiber.h>
30 #include <folly/experimental/fibers/LoopController.h>
31 #include <folly/experimental/fibers/Promise.h>
32 #include <folly/futures/Try.h>
34 namespace folly { namespace fibers {
38 inline FiberManager::Options preprocessOptions(FiberManager::Options opts) {
39 #ifdef FOLLY_SANITIZE_ADDRESS
40 /* ASAN needs a lot of extra stack space.
41 16x is a conservative estimate, 8x also worked with tests
42 where it mattered. Note that overallocating here does not necessarily
43 increase RSS, since unused memory is pretty much free. */
51 inline void FiberManager::ensureLoopScheduled() {
52 if (isLoopScheduled_) {
56 isLoopScheduled_ = true;
57 loopController_->schedule();
60 inline void FiberManager::runReadyFiber(Fiber* fiber) {
62 assert(currentFiber_ == nullptr);
63 assert(activeFiber_ == nullptr);
66 assert(fiber->state_ == Fiber::NOT_STARTED ||
67 fiber->state_ == Fiber::READY_TO_RUN);
68 currentFiber_ = fiber;
69 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
71 observer_->starting(reinterpret_cast<uintptr_t>(fiber));
74 while (fiber->state_ == Fiber::NOT_STARTED ||
75 fiber->state_ == Fiber::READY_TO_RUN) {
77 jumpContext(&mainContext_, &fiber->fcontext_, fiber->data_);
78 if (fiber->state_ == Fiber::AWAITING_IMMEDIATE) {
82 exceptionCallback_(std::current_exception(), "running immediateFunc_");
84 immediateFunc_ = nullptr;
85 fiber->state_ = Fiber::READY_TO_RUN;
89 if (fiber->state_ == Fiber::AWAITING) {
93 observer_->stopped(reinterpret_cast<uintptr_t>(fiber));
95 currentFiber_ = nullptr;
96 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
97 } else if (fiber->state_ == Fiber::INVALID) {
98 assert(fibersActive_ > 0);
100 // Making sure that task functor is deleted once task is complete.
101 // NOTE: we must do it on main context, as the fiber is not
102 // running at this point.
103 fiber->func_ = nullptr;
104 fiber->resultFunc_ = nullptr;
105 if (fiber->finallyFunc_) {
107 fiber->finallyFunc_();
109 exceptionCallback_(std::current_exception(), "running finallyFunc_");
111 fiber->finallyFunc_ = nullptr;
113 // Make sure LocalData is not accessible from its destructor
115 observer_->stopped(reinterpret_cast<uintptr_t>(fiber));
117 currentFiber_ = nullptr;
118 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
119 fiber->localData_.reset();
120 fiber->rcontext_.reset();
122 if (fibersPoolSize_ < options_.maxFibersPoolSize) {
123 fibersPool_.push_front(*fiber);
127 assert(fibersAllocated_ > 0);
130 } else if (fiber->state_ == Fiber::YIELDED) {
132 observer_->stopped(reinterpret_cast<uintptr_t>(fiber));
134 currentFiber_ = nullptr;
135 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
136 fiber->state_ = Fiber::READY_TO_RUN;
137 yieldedFibers_.push_back(*fiber);
141 inline bool FiberManager::loopUntilNoReady() {
143 isLoopScheduled_ = false;
144 if (!readyFibers_.empty()) {
145 ensureLoopScheduled();
147 currentFiberManager_ = nullptr;
150 currentFiberManager_ = this;
152 bool hadRemoteFiber = true;
153 while (hadRemoteFiber) {
154 hadRemoteFiber = false;
156 while (!readyFibers_.empty()) {
157 auto& fiber = readyFibers_.front();
158 readyFibers_.pop_front();
159 runReadyFiber(&fiber);
162 remoteReadyQueue_.sweep(
163 [this, &hadRemoteFiber] (Fiber* fiber) {
164 runReadyFiber(fiber);
165 hadRemoteFiber = true;
169 remoteTaskQueue_.sweep(
170 [this, &hadRemoteFiber] (RemoteTask* taskPtr) {
171 std::unique_ptr<RemoteTask> task(taskPtr);
172 auto fiber = getFiber();
173 if (task->localData) {
174 fiber->localData_ = *task->localData;
176 fiber->rcontext_ = std::move(task->rcontext);
178 fiber->setFunction(std::move(task->func));
179 fiber->data_ = reinterpret_cast<intptr_t>(fiber);
181 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
183 runReadyFiber(fiber);
184 hadRemoteFiber = true;
190 for (auto& yielded : yieldedFibers_) {
191 observer_->runnable(reinterpret_cast<uintptr_t>(&yielded));
194 readyFibers_.splice(readyFibers_.end(), yieldedFibers_);
196 return fibersActive_ > 0;
199 // We need this to be in a struct, not inlined in addTask, because clang crashes
201 template <typename F>
202 struct FiberManager::AddTaskHelper {
205 static constexpr bool allocateInBuffer =
206 sizeof(Func) <= Fiber::kUserBufferSize;
210 Func(F&& func, FiberManager& fm) :
211 func_(std::forward<F>(func)), fm_(fm) {}
217 fm_.exceptionCallback_(std::current_exception(),
218 "running Func functor");
220 if (allocateInBuffer) {
233 template <typename F>
234 void FiberManager::addTask(F&& func) {
235 typedef AddTaskHelper<F> Helper;
237 auto fiber = getFiber();
238 initLocalData(*fiber);
240 if (Helper::allocateInBuffer) {
241 auto funcLoc = static_cast<typename Helper::Func*>(fiber->getUserBuffer());
242 new (funcLoc) typename Helper::Func(std::forward<F>(func), *this);
244 fiber->setFunction(std::ref(*funcLoc));
246 auto funcLoc = new typename Helper::Func(std::forward<F>(func), *this);
248 fiber->setFunction(std::ref(*funcLoc));
251 fiber->data_ = reinterpret_cast<intptr_t>(fiber);
252 readyFibers_.push_back(*fiber);
254 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
257 ensureLoopScheduled();
260 template <typename F>
261 void FiberManager::addTaskRemote(F&& func) {
263 auto currentFm = getFiberManagerUnsafe();
265 currentFm->currentFiber_ &&
266 currentFm->localType_ == localType_) {
267 return folly::make_unique<RemoteTask>(
268 std::forward<F>(func),
269 currentFm->currentFiber_->localData_);
271 return folly::make_unique<RemoteTask>(std::forward<F>(func));
273 if (remoteTaskQueue_.insertHead(task.release())) {
274 loopController_->scheduleThreadSafe();
278 template <typename X>
279 struct IsRvalueRefTry { static const bool value = false; };
280 template <typename T>
281 struct IsRvalueRefTry<folly::Try<T>&&> { static const bool value = true; };
283 // We need this to be in a struct, not inlined in addTaskFinally, because clang
284 // crashes otherwise.
285 template <typename F, typename G>
286 struct FiberManager::AddTaskFinallyHelper {
290 typedef typename std::result_of<F()>::type Result;
292 static constexpr bool allocateInBuffer =
293 sizeof(Func) + sizeof(Finally) <= Fiber::kUserBufferSize;
299 finally_(std::move(finally)),
305 finally_(std::move(*result_));
307 fm_.exceptionCallback_(std::current_exception(),
308 "running Finally functor");
311 if (allocateInBuffer) {
322 folly::Optional<folly::Try<Result>> result_;
328 Func(F&& func, Finally& finally) :
329 func_(std::move(func)), result_(finally.result_) {}
332 result_ = folly::makeTryWith(std::move(func_));
334 if (allocateInBuffer) {
343 folly::Optional<folly::Try<Result>>& result_;
347 template <typename F, typename G>
348 void FiberManager::addTaskFinally(F&& func, G&& finally) {
349 typedef typename std::result_of<F()>::type Result;
352 IsRvalueRefTry<typename FirstArgOf<G>::type>::value,
353 "finally(arg): arg must be Try<T>&&");
357 typename std::remove_reference<
358 typename FirstArgOf<G>::type
359 >::type::element_type
361 "finally(Try<T>&&): T must be convertible from func()'s return type");
363 auto fiber = getFiber();
364 initLocalData(*fiber);
366 typedef AddTaskFinallyHelper<F,G> Helper;
368 if (Helper::allocateInBuffer) {
369 auto funcLoc = static_cast<typename Helper::Func*>(
370 fiber->getUserBuffer());
371 auto finallyLoc = static_cast<typename Helper::Finally*>(
372 static_cast<void*>(funcLoc + 1));
374 new (finallyLoc) typename Helper::Finally(std::move(finally), *this);
375 new (funcLoc) typename Helper::Func(std::move(func), *finallyLoc);
377 fiber->setFunctionFinally(std::ref(*funcLoc), std::ref(*finallyLoc));
379 auto finallyLoc = new typename Helper::Finally(std::move(finally), *this);
380 auto funcLoc = new typename Helper::Func(std::move(func), *finallyLoc);
382 fiber->setFunctionFinally(std::ref(*funcLoc), std::ref(*finallyLoc));
385 fiber->data_ = reinterpret_cast<intptr_t>(fiber);
386 readyFibers_.push_back(*fiber);
388 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
391 ensureLoopScheduled();
394 template <typename F>
395 typename std::result_of<F()>::type
396 FiberManager::runInMainContext(F&& func) {
397 return runInMainContextHelper(std::forward<F>(func));
400 template <typename F>
401 inline typename std::enable_if<
402 !std::is_same<typename std::result_of<F()>::type, void>::value,
403 typename std::result_of<F()>::type>::type
404 FiberManager::runInMainContextHelper(F&& func) {
405 if (UNLIKELY(activeFiber_ == nullptr)) {
409 typedef typename std::result_of<F()>::type Result;
411 folly::Try<Result> result;
412 auto f = [&func, &result]() mutable {
413 result = folly::makeTryWith(std::forward<F>(func));
416 immediateFunc_ = std::ref(f);
417 activeFiber_->preempt(Fiber::AWAITING_IMMEDIATE);
419 return std::move(result.value());
422 template <typename F>
423 inline typename std::enable_if<
424 std::is_same<typename std::result_of<F()>::type, void>::value,
426 FiberManager::runInMainContextHelper(F&& func) {
427 if (UNLIKELY(activeFiber_ == nullptr)) {
432 immediateFunc_ = std::ref(func);
433 activeFiber_->preempt(Fiber::AWAITING_IMMEDIATE);
436 inline FiberManager& FiberManager::getFiberManager() {
437 assert(currentFiberManager_ != nullptr);
438 return *currentFiberManager_;
441 inline FiberManager* FiberManager::getFiberManagerUnsafe() {
442 return currentFiberManager_;
445 inline bool FiberManager::hasActiveFiber() const {
446 return activeFiber_ != nullptr;
449 inline void FiberManager::yield() {
450 assert(currentFiberManager_ == this);
451 assert(activeFiber_ != nullptr);
452 assert(activeFiber_->state_ == Fiber::RUNNING);
453 activeFiber_->preempt(Fiber::YIELDED);
456 template <typename T>
457 T& FiberManager::local() {
458 if (std::type_index(typeid(T)) == localType_ && currentFiber_) {
459 return currentFiber_->localData_.get<T>();
461 return localThread<T>();
464 template <typename T>
465 T& FiberManager::localThread() {
467 static thread_local T t;
469 #else // osx doesn't support thread_local
470 static ThreadLocal<T> t;
475 inline void FiberManager::initLocalData(Fiber& fiber) {
476 auto fm = getFiberManagerUnsafe();
477 if (fm && fm->currentFiber_ && fm->localType_ == localType_) {
478 fiber.localData_ = fm->currentFiber_->localData_;
480 fiber.rcontext_ = RequestContext::saveContext();
483 template <typename LocalT>
484 FiberManager::FiberManager(
486 std::unique_ptr<LoopController> loopController__,
488 loopController_(std::move(loopController__)),
489 stackAllocator_(options.useGuardPages),
490 options_(preprocessOptions(std::move(options))),
491 exceptionCallback_([](std::exception_ptr eptr, std::string context) {
493 std::rethrow_exception(eptr);
494 } catch (const std::exception& e) {
495 LOG(DFATAL) << "Exception " << typeid(e).name()
496 << " with message '" << e.what() << "' was thrown in "
497 << "FiberManager with context '" << context << "'";
500 LOG(DFATAL) << "Unknown exception was thrown in FiberManager with "
501 << "context '" << context << "'";
505 timeoutManager_(std::make_shared<TimeoutController>(*loopController_)),
506 localType_(typeid(LocalT)) {
507 loopController_->setFiberManager(this);
510 template <typename F>
511 typename FirstArgOf<F>::type::value_type
512 inline await(F&& func) {
513 typedef typename FirstArgOf<F>::type::value_type Result;
515 folly::Try<Result> result;
518 baton.wait([&func, &result, &baton]() mutable {
519 func(Promise<Result>(result, baton));
522 return folly::moveFromTry(std::move(result));