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.
22 #include <folly/AtomicIntrusiveLinkedList.h>
23 #include <folly/CPortability.h>
24 #include <folly/Function.h>
25 #include <folly/IntrusiveList.h>
26 #include <folly/Portability.h>
27 #include <folly/fibers/BoostContextCompatibility.h>
28 #include <folly/io/async/Request.h>
38 * @brief Fiber object used by FiberManager to execute tasks.
40 * Each Fiber object can be executing at most one task at a time. In active
41 * phase it is running the task function and keeps its context.
42 * Fiber is also used to pass data to blocked task and thus unblock it.
43 * Each Fiber may be associated with a single FiberManager.
48 * Resume the blocked task
52 Fiber(const Fiber&) = delete;
53 Fiber& operator=(const Fiber&) = delete;
58 * Retrieve this fiber's base stack and stack size.
60 * @return This fiber's stack pointer and stack size.
62 std::pair<void*, size_t> getStack() const {
64 std::min<void*>(fcontext_.stackLimit(), fcontext_.stackBase());
65 const size_t size = std::abs(
66 reinterpret_cast<intptr_t>(fcontext_.stackBase()) -
67 reinterpret_cast<intptr_t>(fcontext_.stackLimit()));
73 INVALID, /**< Does't have task function */
74 NOT_STARTED, /**< Has task function, not started */
75 READY_TO_RUN, /**< Was started, blocked, then unblocked */
76 RUNNING, /**< Is running right now */
77 AWAITING, /**< Is currently blocked */
78 AWAITING_IMMEDIATE, /**< Was preempted to run an immediate function,
79 and will be resumed right away */
80 YIELDED, /**< The fiber yielded execution voluntarily */
83 State state_{INVALID}; /**< current Fiber state */
86 friend class FiberManager;
88 explicit Fiber(FiberManager& fiberManager);
90 void init(bool recordStackUsed);
93 void setFunction(F&& func);
95 template <typename F, typename G>
96 void setFunctionFinally(F&& func, G&& finally);
98 static void fiberFuncHelper(intptr_t fiber);
102 * Switch out of fiber context into the main context,
103 * performing necessary housekeeping for the new state.
105 * @param state New state, must not be RUNNING.
107 void preempt(State state);
110 * Examines how much of the stack we used at this moment and
111 * registers with the FiberManager (for monitoring).
113 void recordStackPosition();
115 FiberManager& fiberManager_; /**< Associated FiberManager */
116 FContext fcontext_; /**< current task execution context */
117 std::shared_ptr<RequestContext> rcontext_; /**< current RequestContext */
118 folly::Function<void()> func_; /**< task function */
119 bool recordStackUsed_{false};
120 bool stackFilledWithMagic_{false};
123 * Points to next fiber in remote ready list
125 folly::AtomicIntrusiveLinkedListHook<Fiber> nextRemoteReady_;
127 static constexpr size_t kUserBufferSize = 256;
128 std::aligned_storage<kUserBufferSize>::type userBuffer_;
130 void* getUserBuffer();
132 folly::Function<void()> resultFunc_;
133 folly::Function<void()> finallyFunc_;
138 LocalData(const LocalData& other);
139 LocalData& operator=(const LocalData& other);
141 template <typename T>
144 assert(*dataType_ == typeid(T));
145 return *reinterpret_cast<T*>(data_);
153 template <typename T>
154 FOLLY_NOINLINE T& getSlow();
156 static void* allocateHeapBuffer(size_t size);
157 static void freeHeapBuffer(void* buffer);
159 template <typename T>
160 static void dataCopyConstructor(void*, const void*);
161 template <typename T>
162 static void dataBufferDestructor(void*);
163 template <typename T>
164 static void dataHeapDestructor(void*);
166 static constexpr size_t kBufferSize = 128;
167 std::aligned_storage<kBufferSize>::type buffer_;
170 const std::type_info* dataType_;
171 void (*dataDestructor_)(void*);
172 void (*dataCopyConstructor_)(void*, const void*);
173 void* data_{nullptr};
176 LocalData localData_;
178 folly::IntrusiveListHook listHook_; /**< list hook for different FiberManager
180 folly::IntrusiveListHook globalListHook_; /**< list hook for global list */
181 std::thread::id threadId_{};
183 #ifdef FOLLY_SANITIZE_ADDRESS
184 void* asanFakeStack_{nullptr};
185 const void* asanMainStackBase_{nullptr};
186 size_t asanMainStackSize_{0};
192 #include <folly/fibers/Fiber-inl.h>