/*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <mutex>
#include <pthread.h>
-namespace {
-
-using folly::EventBase;
-
-class FunctionLoopCallback : public EventBase::LoopCallback {
- public:
- explicit FunctionLoopCallback(EventBase::Func&& function)
- : function_(std::move(function)) {}
-
- void runLoopCallback() noexcept override {
- function_();
- delete this;
- }
-
- private:
- EventBase::Func function_;
-};
-}
-
namespace folly {
/*
}
};
-/*
- * EventBase::CobTimeout methods
- */
-
-void EventBase::CobTimeout::timeoutExpired() noexcept {
- // For now, we just swallow any exceptions that the callback threw.
- try {
- cob_();
- } catch (const std::exception& ex) {
- LOG(ERROR) << "EventBase::runAfterDelay() callback threw "
- << typeid(ex).name() << " exception: " << ex.what();
- } catch (...) {
- LOG(ERROR) << "EventBase::runAfterDelay() callback threw non-exception "
- << "type";
- }
-
- // The CobTimeout object was allocated on the heap by runAfterDelay(),
- // so delete it now that the it has fired.
- delete this;
-}
-
-
// The interface used to libevent is not thread-safe. Calls to
// event_init() and event_base_free() directly modify an internal
// global 'current_base', so a mutex is required to protect this.
, queue_(nullptr)
, fnRunner_(nullptr)
, maxLatency_(0)
- , avgLoopTime_(2000000)
+ , avgLoopTime_(std::chrono::milliseconds(2000000))
, maxLatencyLoopTime_(avgLoopTime_)
, enableTimeMeasurement_(enableTimeMeasurement)
- , nextLoopCnt_(-40) // Early wrap-around so bugs will manifest soon
+ , nextLoopCnt_(uint64_t(-40)) // Early wrap-around so bugs will manifest soon
, latestLoopCnt_(nextLoopCnt_)
, startWork_(0)
, observer_(nullptr)
, queue_(nullptr)
, fnRunner_(nullptr)
, maxLatency_(0)
- , avgLoopTime_(2000000)
+ , avgLoopTime_(std::chrono::milliseconds(2000000))
, maxLatencyLoopTime_(avgLoopTime_)
, enableTimeMeasurement_(enableTimeMeasurement)
- , nextLoopCnt_(-40) // Early wrap-around so bugs will manifest soon
+ , nextLoopCnt_(uint64_t(-40)) // Early wrap-around so bugs will manifest soon
, latestLoopCnt_(nextLoopCnt_)
, startWork_(0)
, observer_(nullptr)
// Keep looping until all keep-alive handles are released. Each keep-alive
// handle signals that some external code will still schedule some work on
// this EventBase (so it's not safe to destroy it).
- while (!loopKeepAlive_.unique()) {
+ while (loopKeepAliveCount() > 0) {
applyLoopKeepAlive();
loopOnce();
}
callback->runLoopCallback();
}
- // Delete any unfired callback objects, so that we don't leak memory
- // (Note that we don't fire them. The caller is responsible for cleaning up
- // its own data structures if it destroys the EventBase with unfired events
- // remaining.)
- while (!pendingCobTimeouts_.empty()) {
- CobTimeout* timeout = &pendingCobTimeouts_.front();
- delete timeout;
- }
+ clearCobTimeouts();
- while (!runBeforeLoopCallbacks_.empty()) {
- delete &runBeforeLoopCallbacks_.front();
- }
+ DCHECK_EQ(0, runBeforeLoopCallbacks_.size());
- (void) runLoopCallbacks(false);
+ (void)runLoopCallbacks();
if (!fnRunner_->consumeUntilDrained()) {
LOG(ERROR) << "~EventBase(): Unable to drain notification queue";
event_base_free(evb_);
}
- while (!runAfterDrainCallbacks_.empty()) {
- LoopCallback* callback = &runAfterDrainCallbacks_.front();
- runAfterDrainCallbacks_.pop_front();
- callback->runLoopCallback();
- }
-
{
std::lock_guard<std::mutex> lock(localStorageMutex_);
for (auto storage : localStorageToDtor_) {
VLOG(5) << "EventBase(): Destroyed.";
}
-int EventBase::getNotificationQueueSize() const {
+size_t EventBase::getNotificationQueueSize() const {
return queue_->size();
}
// Set smoothing coefficient for loop load average; input is # of milliseconds
// for exp(-1) decay.
-void EventBase::setLoadAvgMsec(uint32_t ms) {
+void EventBase::setLoadAvgMsec(std::chrono::milliseconds ms) {
assert(enableTimeMeasurement_);
- uint64_t us = 1000 * ms;
- if (ms > 0) {
+ std::chrono::microseconds us = std::chrono::milliseconds(ms);
+ if (ms > std::chrono::milliseconds::zero()) {
maxLatencyLoopTime_.setTimeInterval(us);
avgLoopTime_.setTimeInterval(us);
} else {
bool EventBase::loopBody(int flags) {
VLOG(5) << "EventBase(): Starting loop.";
+
+ DCHECK(!invokingLoop_)
+ << "Your code just tried to loop over an event base from inside another "
+ << "event base loop. Since libevent is not reentrant, this leads to "
+ << "undefined behavior in opt builds. Please fix immediately. For the "
+ << "common case of an inner function that needs to do some synchronous "
+ << "computation on an event-base, replace getEventBase() by a new, "
+ << "stack-allocated EvenBase.";
+ invokingLoop_ = true;
+ SCOPE_EXIT {
+ invokingLoop_ = false;
+ };
+
int res = 0;
bool ranLoopCallbacks;
bool blocking = !(flags & EVLOOP_NONBLOCK);
startWork_;
idle = startWork_ - idleStart;
- avgLoopTime_.addSample(idle, busy);
- maxLatencyLoopTime_.addSample(idle, busy);
+ avgLoopTime_.addSample(std::chrono::microseconds(idle),
+ std::chrono::microseconds(busy));
+ maxLatencyLoopTime_.addSample(std::chrono::microseconds(idle),
+ std::chrono::microseconds(busy));
if (observer_) {
if (observerSampleCount_++ == observer_->getSampleRate()) {
return true;
}
+ssize_t EventBase::loopKeepAliveCount() {
+ if (loopKeepAliveCountAtomic_.load(std::memory_order_relaxed)) {
+ loopKeepAliveCount_ +=
+ loopKeepAliveCountAtomic_.exchange(0, std::memory_order_relaxed);
+ }
+ DCHECK_GE(loopKeepAliveCount_, 0);
+ return loopKeepAliveCount_;
+}
+
void EventBase::applyLoopKeepAlive() {
- if (loopKeepAliveActive_ && loopKeepAlive_.unique()) {
+ if (loopKeepAliveActive_ && loopKeepAliveCount() == 0) {
// Restore the notification queue internal flag
fnRunner_->stopConsuming();
fnRunner_->startConsumingInternal(this, queue_.get());
loopKeepAliveActive_ = false;
- } else if (!loopKeepAliveActive_ && !loopKeepAlive_.unique()) {
+ } else if (!loopKeepAliveActive_ && loopKeepAliveCount() > 0) {
// Update the notification queue event to treat it as a normal
// (non-internal) event. The notification queue event always remains
// installed, and the main loop won't exit with it installed.
{
SCOPE_EXIT {
applyLoopKeepAlive();
- loopForeverActive_ = false;
};
- loopForeverActive_ = true;
// Make sure notification queue events are treated as normal events.
- auto loopKeepAlive = loopKeepAlive_;
+ // We can't use loopKeepAlive() here since LoopKeepAlive token can only be
+ // released inside a loop.
+ ++loopKeepAliveCount_;
+ SCOPE_EXIT {
+ --loopKeepAliveCount_;
+ };
ret = loop();
}
}
}
-void EventBase::runAfterDrain(Func cob) {
- auto callback = new FunctionLoopCallback(std::move(cob));
- std::lock_guard<std::mutex> lg(runAfterDrainCallbacksMutex_);
- callback->cancelLoopCallback();
- runAfterDrainCallbacks_.push_back(*callback);
-}
-
void EventBase::runOnDestruction(LoopCallback* callback) {
std::lock_guard<std::mutex> lg(onDestructionCallbacksMutex_);
callback->cancelLoopCallback();
return true;
}
-bool EventBase::runInEventBaseThreadAndWait(Func fn) {
+bool EventBase::runInEventBaseThreadAndWait(FuncRef fn) {
if (inRunningEventBaseThread()) {
LOG(ERROR) << "EventBase " << this << ": Waiting in the event loop is not "
<< "allowed";
return true;
}
-bool EventBase::runImmediatelyOrRunInEventBaseThreadAndWait(Func fn) {
+bool EventBase::runImmediatelyOrRunInEventBaseThreadAndWait(FuncRef fn) {
if (isInEventBaseThread()) {
fn();
return true;
}
}
-void EventBase::runAfterDelay(
- Func cob,
- uint32_t milliseconds,
- TimeoutManager::InternalEnum in) {
- if (!tryRunAfterDelay(std::move(cob), milliseconds, in)) {
- folly::throwSystemError(
- "error in EventBase::runAfterDelay(), failed to schedule timeout");
- }
-}
-
-bool EventBase::tryRunAfterDelay(
- Func cob,
- uint32_t milliseconds,
- TimeoutManager::InternalEnum in) {
- CobTimeout* timeout = new CobTimeout(this, std::move(cob), in);
- if (!timeout->scheduleTimeout(milliseconds)) {
- delete timeout;
- return false;
- }
- pendingCobTimeouts_.push_back(*timeout);
- return true;
-}
-
-bool EventBase::runLoopCallbacks(bool setContext) {
+bool EventBase::runLoopCallbacks() {
if (!loopCallbacks_.empty()) {
bumpHandlingTime();
// Swap the loopCallbacks_ list with a temporary list on our stack.
while (!currentCallbacks.empty()) {
LoopCallback* callback = ¤tCallbacks.front();
currentCallbacks.pop_front();
- if (setContext) {
- RequestContext::setContext(callback->context_);
- }
+ folly::RequestContextScopeGuard rctx(callback->context_);
callback->runLoopCallback();
}
fnRunner_->startConsumingInternal(this, queue_.get());
}
-void EventBase::SmoothLoopTime::setTimeInterval(uint64_t timeInterval) {
- expCoeff_ = -1.0/timeInterval;
+void EventBase::SmoothLoopTime::setTimeInterval(
+ std::chrono::microseconds timeInterval) {
+ expCoeff_ = -1.0 / timeInterval.count();
VLOG(11) << "expCoeff_ " << expCoeff_ << " " << __PRETTY_FUNCTION__;
}
value_ = value;
}
-void EventBase::SmoothLoopTime::addSample(int64_t idle, int64_t busy) {
- /*
- * Position at which the busy sample is considered to be taken.
- * (Allows to quickly skew our average without editing much code)
- */
- enum BusySamplePosition {
- RIGHT = 0, // busy sample placed at the end of the iteration
- CENTER = 1, // busy sample placed at the middle point of the iteration
- LEFT = 2, // busy sample placed at the beginning of the iteration
- };
+void EventBase::SmoothLoopTime::addSample(
+ std::chrono::microseconds idle,
+ std::chrono::microseconds busy) {
+ /*
+ * Position at which the busy sample is considered to be taken.
+ * (Allows to quickly skew our average without editing much code)
+ */
+ enum BusySamplePosition {
+ RIGHT = 0, // busy sample placed at the end of the iteration
+ CENTER = 1, // busy sample placed at the middle point of the iteration
+ LEFT = 2, // busy sample placed at the beginning of the iteration
+ };
// See http://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
// and D676020 for more info on this calculation.
- VLOG(11) << "idle " << idle << " oldBusyLeftover_ " << oldBusyLeftover_ <<
- " idle + oldBusyLeftover_ " << idle + oldBusyLeftover_ <<
- " busy " << busy << " " << __PRETTY_FUNCTION__;
+ VLOG(11) << "idle " << idle.count() << " oldBusyLeftover_ "
+ << oldBusyLeftover_.count() << " idle + oldBusyLeftover_ "
+ << (idle + oldBusyLeftover_).count() << " busy " << busy.count()
+ << " " << __PRETTY_FUNCTION__;
idle += oldBusyLeftover_ + busy;
oldBusyLeftover_ = (busy * BusySamplePosition::CENTER) / 2;
idle -= oldBusyLeftover_;
- double coeff = exp(idle * expCoeff_);
+ double coeff = exp(idle.count() * expCoeff_);
value_ *= coeff;
- value_ += (1.0 - coeff) * busy;
+ value_ += (1.0 - coeff) * busy.count();
}
bool EventBase::nothingHandledYet() const noexcept {
assert(isInEventBaseThread());
// Set up the timeval and add the event
struct timeval tv;
- tv.tv_sec = timeout.count() / 1000LL;
- tv.tv_usec = (timeout.count() % 1000LL) * 1000LL;
+ tv.tv_sec = long(timeout.count() / 1000LL);
+ tv.tv_usec = long((timeout.count() % 1000LL) * 1000LL);
struct event* ev = obj->getEvent();
if (event_add(ev, &tv) < 0) {