2 * Copyright 2016 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/fibers/Baton.h>
29 #include <folly/fibers/Fiber.h>
30 #include <folly/fibers/LoopController.h>
31 #include <folly/fibers/Promise.h>
32 #include <folly/Try.h>
39 inline FiberManager::Options preprocessOptions(FiberManager::Options opts) {
40 #ifdef FOLLY_SANITIZE_ADDRESS
41 /* ASAN needs a lot of extra stack space.
42 16x is a conservative estimate, 8x also worked with tests
43 where it mattered. Note that overallocating here does not necessarily
44 increase RSS, since unused memory is pretty much free. */
52 inline void FiberManager::ensureLoopScheduled() {
53 if (isLoopScheduled_) {
57 isLoopScheduled_ = true;
58 loopController_->schedule();
61 inline void FiberManager::activateFiber(Fiber* fiber) {
62 DCHECK_EQ(activeFiber_, (Fiber*)nullptr);
64 #ifdef FOLLY_SANITIZE_ADDRESS
65 DCHECK(!fiber->asanMainStackBase_);
66 DCHECK(!fiber->asanMainStackSize_);
67 auto stack = fiber->getStack();
69 registerStartSwitchStackWithAsan(&asanFakeStack, stack.first, stack.second);
71 registerFinishSwitchStackWithAsan(asanFakeStack, nullptr, nullptr);
72 fiber->asanMainStackBase_ = nullptr;
73 fiber->asanMainStackSize_ = 0;
78 fiber->fiberImpl_.activate();
81 inline void FiberManager::deactivateFiber(Fiber* fiber) {
82 DCHECK_EQ(activeFiber_, fiber);
84 #ifdef FOLLY_SANITIZE_ADDRESS
85 DCHECK(fiber->asanMainStackBase_);
86 DCHECK(fiber->asanMainStackSize_);
88 // Release fake stack if fiber is completed
89 auto saveFakeStackPtr =
90 fiber->state_ == Fiber::INVALID ? nullptr : &fiber->asanFakeStack_;
91 registerStartSwitchStackWithAsan(
92 saveFakeStackPtr, fiber->asanMainStackBase_, fiber->asanMainStackSize_);
94 registerFinishSwitchStackWithAsan(
95 fiber->asanFakeStack_,
96 &fiber->asanMainStackBase_,
97 &fiber->asanMainStackSize_);
98 fiber->asanFakeStack_ = nullptr;
102 activeFiber_ = nullptr;
103 fiber->fiberImpl_.deactivate();
106 inline void FiberManager::runReadyFiber(Fiber* fiber) {
108 assert(currentFiber_ == nullptr);
109 assert(activeFiber_ == nullptr);
113 fiber->state_ == Fiber::NOT_STARTED ||
114 fiber->state_ == Fiber::READY_TO_RUN);
115 currentFiber_ = fiber;
116 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
118 observer_->starting(reinterpret_cast<uintptr_t>(fiber));
121 while (fiber->state_ == Fiber::NOT_STARTED ||
122 fiber->state_ == Fiber::READY_TO_RUN) {
123 activateFiber(fiber);
124 if (fiber->state_ == Fiber::AWAITING_IMMEDIATE) {
128 exceptionCallback_(std::current_exception(), "running immediateFunc_");
130 immediateFunc_ = nullptr;
131 fiber->state_ = Fiber::READY_TO_RUN;
135 if (fiber->state_ == Fiber::AWAITING) {
137 awaitFunc_ = nullptr;
139 observer_->stopped(reinterpret_cast<uintptr_t>(fiber));
141 currentFiber_ = nullptr;
142 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
143 } else if (fiber->state_ == Fiber::INVALID) {
144 assert(fibersActive_ > 0);
146 // Making sure that task functor is deleted once task is complete.
147 // NOTE: we must do it on main context, as the fiber is not
148 // running at this point.
149 fiber->func_ = nullptr;
150 fiber->resultFunc_ = nullptr;
151 if (fiber->finallyFunc_) {
153 fiber->finallyFunc_();
155 exceptionCallback_(std::current_exception(), "running finallyFunc_");
157 fiber->finallyFunc_ = nullptr;
159 // Make sure LocalData is not accessible from its destructor
161 observer_->stopped(reinterpret_cast<uintptr_t>(fiber));
163 currentFiber_ = nullptr;
164 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
165 fiber->localData_.reset();
166 fiber->rcontext_.reset();
168 if (fibersPoolSize_ < options_.maxFibersPoolSize ||
169 options_.fibersPoolResizePeriodMs > 0) {
170 fibersPool_.push_front(*fiber);
174 assert(fibersAllocated_ > 0);
177 } else if (fiber->state_ == Fiber::YIELDED) {
179 observer_->stopped(reinterpret_cast<uintptr_t>(fiber));
181 currentFiber_ = nullptr;
182 fiber->rcontext_ = RequestContext::setContext(std::move(fiber->rcontext_));
183 fiber->state_ = Fiber::READY_TO_RUN;
184 yieldedFibers_.push_back(*fiber);
188 inline bool FiberManager::loopUntilNoReady() {
190 if (UNLIKELY(!alternateSignalStackRegistered_)) {
191 registerAlternateSignalStack();
195 // Support nested FiberManagers
196 auto originalFiberManager = this;
197 std::swap(currentFiberManager_, originalFiberManager);
200 isLoopScheduled_ = false;
201 if (!readyFibers_.empty()) {
202 ensureLoopScheduled();
204 std::swap(currentFiberManager_, originalFiberManager);
205 CHECK_EQ(this, originalFiberManager);
208 bool hadRemoteFiber = true;
209 while (hadRemoteFiber) {
210 hadRemoteFiber = false;
212 while (!readyFibers_.empty()) {
213 auto& fiber = readyFibers_.front();
214 readyFibers_.pop_front();
215 runReadyFiber(&fiber);
218 remoteReadyQueue_.sweep([this, &hadRemoteFiber](Fiber* fiber) {
219 runReadyFiber(fiber);
220 hadRemoteFiber = true;
223 remoteTaskQueue_.sweep([this, &hadRemoteFiber](RemoteTask* taskPtr) {
224 std::unique_ptr<RemoteTask> task(taskPtr);
225 auto fiber = getFiber();
226 if (task->localData) {
227 fiber->localData_ = *task->localData;
229 fiber->rcontext_ = std::move(task->rcontext);
231 fiber->setFunction(std::move(task->func));
233 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
235 runReadyFiber(fiber);
236 hadRemoteFiber = true;
241 for (auto& yielded : yieldedFibers_) {
242 observer_->runnable(reinterpret_cast<uintptr_t>(&yielded));
245 readyFibers_.splice(readyFibers_.end(), yieldedFibers_);
247 return fibersActive_ > 0;
250 // We need this to be in a struct, not inlined in addTask, because clang crashes
252 template <typename F>
253 struct FiberManager::AddTaskHelper {
256 static constexpr bool allocateInBuffer =
257 sizeof(Func) <= Fiber::kUserBufferSize;
261 Func(F&& func, FiberManager& fm) : func_(std::forward<F>(func)), fm_(fm) {}
267 fm_.exceptionCallback_(
268 std::current_exception(), "running Func functor");
270 if (allocateInBuffer) {
283 template <typename F>
284 void FiberManager::addTask(F&& func) {
285 typedef AddTaskHelper<F> Helper;
287 auto fiber = getFiber();
288 initLocalData(*fiber);
290 if (Helper::allocateInBuffer) {
291 auto funcLoc = static_cast<typename Helper::Func*>(fiber->getUserBuffer());
292 new (funcLoc) typename Helper::Func(std::forward<F>(func), *this);
294 fiber->setFunction(std::ref(*funcLoc));
296 auto funcLoc = new typename Helper::Func(std::forward<F>(func), *this);
298 fiber->setFunction(std::ref(*funcLoc));
301 readyFibers_.push_back(*fiber);
303 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
306 ensureLoopScheduled();
309 template <typename F>
310 void FiberManager::addTaskRemote(F&& func) {
312 auto currentFm = getFiberManagerUnsafe();
313 if (currentFm && currentFm->currentFiber_ &&
314 currentFm->localType_ == localType_) {
315 return folly::make_unique<RemoteTask>(
316 std::forward<F>(func), currentFm->currentFiber_->localData_);
318 return folly::make_unique<RemoteTask>(std::forward<F>(func));
320 auto insertHead = [&]() {
321 return remoteTaskQueue_.insertHead(task.release());
323 loopController_->scheduleThreadSafe(std::ref(insertHead));
326 template <typename X>
327 struct IsRvalueRefTry {
328 static const bool value = false;
330 template <typename T>
331 struct IsRvalueRefTry<folly::Try<T>&&> {
332 static const bool value = true;
335 // We need this to be in a struct, not inlined in addTaskFinally, because clang
336 // crashes otherwise.
337 template <typename F, typename G>
338 struct FiberManager::AddTaskFinallyHelper {
341 typedef typename std::result_of<F()>::type Result;
345 Finally(G finally, FiberManager& fm)
346 : finally_(std::move(finally)), fm_(fm) {}
350 finally_(std::move(*result_));
352 fm_.exceptionCallback_(
353 std::current_exception(), "running Finally functor");
356 if (allocateInBuffer) {
367 folly::Optional<folly::Try<Result>> result_;
373 Func(F func, Finally& finally)
374 : func_(std::move(func)), result_(finally.result_) {}
377 result_ = folly::makeTryWith(std::move(func_));
379 if (allocateInBuffer) {
388 folly::Optional<folly::Try<Result>>& result_;
391 static constexpr bool allocateInBuffer =
392 sizeof(Func) + sizeof(Finally) <= Fiber::kUserBufferSize;
395 template <typename F, typename G>
396 void FiberManager::addTaskFinally(F&& func, G&& finally) {
397 typedef typename std::result_of<F()>::type Result;
400 IsRvalueRefTry<typename FirstArgOf<G>::type>::value,
401 "finally(arg): arg must be Try<T>&&");
405 typename std::remove_reference<
406 typename FirstArgOf<G>::type>::type::element_type>::value,
407 "finally(Try<T>&&): T must be convertible from func()'s return type");
409 auto fiber = getFiber();
410 initLocalData(*fiber);
412 typedef AddTaskFinallyHelper<
413 typename std::decay<F>::type,
414 typename std::decay<G>::type>
417 if (Helper::allocateInBuffer) {
418 auto funcLoc = static_cast<typename Helper::Func*>(fiber->getUserBuffer());
420 static_cast<typename Helper::Finally*>(static_cast<void*>(funcLoc + 1));
422 new (finallyLoc) typename Helper::Finally(std::forward<G>(finally), *this);
423 new (funcLoc) typename Helper::Func(std::forward<F>(func), *finallyLoc);
425 fiber->setFunctionFinally(std::ref(*funcLoc), std::ref(*finallyLoc));
428 new typename Helper::Finally(std::forward<G>(finally), *this);
430 new typename Helper::Func(std::forward<F>(func), *finallyLoc);
432 fiber->setFunctionFinally(std::ref(*funcLoc), std::ref(*finallyLoc));
435 readyFibers_.push_back(*fiber);
437 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
440 ensureLoopScheduled();
443 template <typename F>
444 typename std::result_of<F()>::type FiberManager::runInMainContext(F&& func) {
445 if (UNLIKELY(activeFiber_ == nullptr)) {
449 typedef typename std::result_of<F()>::type Result;
451 folly::Try<Result> result;
452 auto f = [&func, &result]() mutable {
453 result = folly::makeTryWith(std::forward<F>(func));
456 immediateFunc_ = std::ref(f);
457 activeFiber_->preempt(Fiber::AWAITING_IMMEDIATE);
459 return std::move(result).value();
462 inline FiberManager& FiberManager::getFiberManager() {
463 assert(currentFiberManager_ != nullptr);
464 return *currentFiberManager_;
467 inline FiberManager* FiberManager::getFiberManagerUnsafe() {
468 return currentFiberManager_;
471 inline bool FiberManager::hasActiveFiber() const {
472 return activeFiber_ != nullptr;
475 inline void FiberManager::yield() {
476 assert(currentFiberManager_ == this);
477 assert(activeFiber_ != nullptr);
478 assert(activeFiber_->state_ == Fiber::RUNNING);
479 activeFiber_->preempt(Fiber::YIELDED);
482 template <typename T>
483 T& FiberManager::local() {
484 if (std::type_index(typeid(T)) == localType_ && currentFiber_) {
485 return currentFiber_->localData_.get<T>();
487 return localThread<T>();
490 template <typename T>
491 T& FiberManager::localThread() {
493 static thread_local T t;
495 #else // osx doesn't support thread_local
496 static ThreadLocal<T> t;
501 inline void FiberManager::initLocalData(Fiber& fiber) {
502 auto fm = getFiberManagerUnsafe();
503 if (fm && fm->currentFiber_ && fm->localType_ == localType_) {
504 fiber.localData_ = fm->currentFiber_->localData_;
506 fiber.rcontext_ = RequestContext::saveContext();
509 template <typename LocalT>
510 FiberManager::FiberManager(
512 std::unique_ptr<LoopController> loopController__,
514 : loopController_(std::move(loopController__)),
515 stackAllocator_(options.useGuardPages),
516 options_(preprocessOptions(std::move(options))),
517 exceptionCallback_([](std::exception_ptr eptr, std::string context) {
519 std::rethrow_exception(eptr);
520 } catch (const std::exception& e) {
521 LOG(DFATAL) << "Exception " << typeid(e).name() << " with message '"
522 << e.what() << "' was thrown in "
523 << "FiberManager with context '" << context << "'";
525 LOG(DFATAL) << "Unknown exception was thrown in FiberManager with "
526 << "context '" << context << "'";
529 timeoutManager_(std::make_shared<TimeoutController>(*loopController_)),
530 fibersPoolResizer_(*this),
531 localType_(typeid(LocalT)) {
532 loopController_->setFiberManager(this);
535 template <typename F>
536 typename FirstArgOf<F>::type::value_type inline await(F&& func) {
537 typedef typename FirstArgOf<F>::type::value_type Result;
538 typedef typename FirstArgOf<F>::type::baton_type BatonT;
540 return Promise<Result, BatonT>::await(std::forward<F>(func));