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.
16 #include "FiberManagerInternal.h"
23 #include <glog/logging.h>
25 #include <folly/fibers/Fiber.h>
26 #include <folly/fibers/LoopController.h>
28 #include <folly/SingletonThreadLocal.h>
29 #include <folly/portability/SysSyscall.h>
30 #include <folly/portability/Unistd.h>
32 #ifdef FOLLY_SANITIZE_ADDRESS
36 static void __sanitizer_start_switch_fiber_weak(
37 void** fake_stack_save,
38 void const* fiber_stack_base,
39 size_t fiber_stack_extent)
40 __attribute__((__weakref__("__sanitizer_start_switch_fiber")));
41 static void __sanitizer_finish_switch_fiber_weak(
42 void* fake_stack_save,
43 void const** old_stack_base,
44 size_t* old_stack_extent)
45 __attribute__((__weakref__("__sanitizer_finish_switch_fiber")));
46 static void __asan_unpoison_memory_region_weak(
47 void const /* nolint */ volatile* addr,
48 size_t size) __attribute__((__weakref__("__asan_unpoison_memory_region")));
50 typedef void (*AsanStartSwitchStackFuncPtr)(void**, void const*, size_t);
51 typedef void (*AsanFinishSwitchStackFuncPtr)(void*, void const**, size_t*);
52 typedef void (*AsanUnpoisonMemoryRegionFuncPtr)(
53 void const /* nolint */ volatile*,
59 static AsanStartSwitchStackFuncPtr getStartSwitchStackFunc();
60 static AsanFinishSwitchStackFuncPtr getFinishSwitchStackFunc();
61 static AsanUnpoisonMemoryRegionFuncPtr getUnpoisonMemoryRegionFunc();
70 FOLLY_TLS FiberManager* FiberManager::currentFiberManager_ = nullptr;
72 FiberManager::FiberManager(
73 std::unique_ptr<LoopController> loopController,
77 std::move(loopController),
78 std::move(options)) {}
80 FiberManager::~FiberManager() {
81 if (isLoopScheduled_) {
82 loopController_->cancel();
85 while (!fibersPool_.empty()) {
86 fibersPool_.pop_front_and_dispose([](Fiber* fiber) { delete fiber; });
88 assert(readyFibers_.empty());
89 assert(fibersActive_ == 0);
92 LoopController& FiberManager::loopController() {
93 return *loopController_;
96 const LoopController& FiberManager::loopController() const {
97 return *loopController_;
100 bool FiberManager::hasTasks() const {
101 return fibersActive_ > 0 || !remoteReadyQueue_.empty() ||
102 !remoteTaskQueue_.empty();
105 Fiber* FiberManager::getFiber() {
106 Fiber* fiber = nullptr;
108 if (options_.fibersPoolResizePeriodMs > 0 && !fibersPoolResizerScheduled_) {
109 fibersPoolResizer_();
110 fibersPoolResizerScheduled_ = true;
113 if (fibersPool_.empty()) {
114 fiber = new Fiber(*this);
117 fiber = &fibersPool_.front();
118 fibersPool_.pop_front();
119 assert(fibersPoolSize_ > 0);
123 if (++fibersActive_ > maxFibersActiveLastPeriod_) {
124 maxFibersActiveLastPeriod_ = fibersActive_;
127 bool recordStack = (options_.recordStackEvery != 0) &&
128 (fiberId_ % options_.recordStackEvery == 0);
129 fiber->init(recordStack);
133 void FiberManager::setExceptionCallback(FiberManager::ExceptionCallback ec) {
135 exceptionCallback_ = std::move(ec);
138 size_t FiberManager::fibersAllocated() const {
139 return fibersAllocated_;
142 size_t FiberManager::fibersPoolSize() const {
143 return fibersPoolSize_;
146 size_t FiberManager::stackHighWatermark() const {
147 return stackHighWatermark_;
150 void FiberManager::remoteReadyInsert(Fiber* fiber) {
152 observer_->runnable(reinterpret_cast<uintptr_t>(fiber));
154 auto insertHead = [&]() { return remoteReadyQueue_.insertHead(fiber); };
155 loopController_->scheduleThreadSafe(std::ref(insertHead));
158 void FiberManager::setObserver(ExecutionObserver* observer) {
159 observer_ = observer;
162 ExecutionObserver* FiberManager::getObserver() {
166 void FiberManager::setPreemptRunner(InlineFunctionRunner* preemptRunner) {
167 preemptRunner_ = preemptRunner;
170 void FiberManager::doFibersPoolResizing() {
171 while (fibersAllocated_ > maxFibersActiveLastPeriod_ &&
172 fibersPoolSize_ > options_.maxFibersPoolSize) {
173 auto fiber = &fibersPool_.front();
174 assert(fiber != nullptr);
175 fibersPool_.pop_front();
181 maxFibersActiveLastPeriod_ = fibersActive_;
184 void FiberManager::FibersPoolResizer::operator()() {
185 fiberManager_.doFibersPoolResizing();
186 fiberManager_.timeoutManager_->registerTimeout(
188 std::chrono::milliseconds(
189 fiberManager_.options_.fibersPoolResizePeriodMs));
192 #ifdef FOLLY_SANITIZE_ADDRESS
194 void FiberManager::registerStartSwitchStackWithAsan(
195 void** saveFakeStack,
196 const void* stackBottom,
198 // Check if we can find a fiber enter function and call it if we find one
199 static AsanStartSwitchStackFuncPtr fn = getStartSwitchStackFunc();
201 LOG(FATAL) << "The version of ASAN in use doesn't support fibers";
203 fn(saveFakeStack, stackBottom, stackSize);
207 void FiberManager::registerFinishSwitchStackWithAsan(
209 const void** saveStackBottom,
210 size_t* saveStackSize) {
211 // Check if we can find a fiber exit function and call it if we find one
212 static AsanFinishSwitchStackFuncPtr fn = getFinishSwitchStackFunc();
214 LOG(FATAL) << "The version of ASAN in use doesn't support fibers";
216 fn(saveFakeStack, saveStackBottom, saveStackSize);
220 void FiberManager::unpoisonFiberStack(const Fiber* fiber) {
221 auto stack = fiber->getStack();
223 // Check if we can find a fiber enter function and call it if we find one
224 static AsanUnpoisonMemoryRegionFuncPtr fn = getUnpoisonMemoryRegionFunc();
226 LOG(FATAL) << "This version of ASAN doesn't support memory unpoisoning";
228 fn(stack.first, stack.second);
232 static AsanStartSwitchStackFuncPtr getStartSwitchStackFunc() {
233 AsanStartSwitchStackFuncPtr fn{nullptr};
235 // Check whether weak reference points to statically linked enter function
236 if (nullptr != (fn = &::__sanitizer_start_switch_fiber_weak)) {
240 // Check whether we can find a dynamically linked enter function
241 if (nullptr != (fn = (AsanStartSwitchStackFuncPtr)dlsym(
242 RTLD_DEFAULT, "__sanitizer_start_switch_fiber"))) {
246 // Couldn't find the function at all
250 static AsanFinishSwitchStackFuncPtr getFinishSwitchStackFunc() {
251 AsanFinishSwitchStackFuncPtr fn{nullptr};
253 // Check whether weak reference points to statically linked exit function
254 if (nullptr != (fn = &::__sanitizer_finish_switch_fiber_weak)) {
258 // Check whether we can find a dynamically linked exit function
259 if (nullptr != (fn = (AsanFinishSwitchStackFuncPtr)dlsym(
260 RTLD_DEFAULT, "__sanitizer_finish_switch_fiber"))) {
264 // Couldn't find the function at all
268 static AsanUnpoisonMemoryRegionFuncPtr getUnpoisonMemoryRegionFunc() {
269 AsanUnpoisonMemoryRegionFuncPtr fn{nullptr};
271 // Check whether weak reference points to statically linked unpoison function
272 if (nullptr != (fn = &::__asan_unpoison_memory_region_weak)) {
276 // Check whether we can find a dynamically linked unpoison function
277 if (nullptr != (fn = (AsanUnpoisonMemoryRegionFuncPtr)dlsym(
278 RTLD_DEFAULT, "__asan_unpoison_memory_region"))) {
282 // Couldn't find the function at all
286 #endif // FOLLY_SANITIZE_ADDRESS
291 // SIGSTKSZ (8 kB on our architectures) isn't always enough for
292 // folly::symbolizer, so allocate 32 kB.
293 constexpr size_t kAltStackSize = folly::constexpr_max(SIGSTKSZ, 32 * 1024);
295 bool hasAlternateStack() {
297 sigaltstack(nullptr, &ss);
298 return !(ss.ss_flags & SS_DISABLE);
301 int setAlternateStack(char* sp, size_t size) {
306 return sigaltstack(&ss, nullptr);
309 int unsetAlternateStack() {
311 ss.ss_flags = SS_DISABLE;
312 return sigaltstack(&ss, nullptr);
315 class ScopedAlternateSignalStack {
317 ScopedAlternateSignalStack() {
318 if (hasAlternateStack()) {
322 stack_ = folly::make_unique<AltStackBuffer>();
324 setAlternateStack(stack_->data(), stack_->size());
327 ~ScopedAlternateSignalStack() {
329 unsetAlternateStack();
334 using AltStackBuffer = std::array<char, kAltStackSize>;
335 std::unique_ptr<AltStackBuffer> stack_;
339 void FiberManager::registerAlternateSignalStack() {
340 static folly::SingletonThreadLocal<ScopedAlternateSignalStack> singleton;
343 alternateSignalStackRegistered_ = true;