1 /* Copyright (c) 2007-2021. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "src/kernel/activity/ConditionVariableImpl.hpp"
7 #include "simgrid/Exception.hpp"
8 #include "src/kernel/activity/MutexImpl.hpp"
9 #include "src/kernel/activity/SynchroRaw.hpp"
10 #include "src/kernel/actor/SimcallObserver.hpp"
11 #include <cmath> // std::isfinite
13 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_condition, simix_synchro, "Condition variables");
15 /********************************* Condition **********************************/
22 * @brief Signalizes a condition.
24 * Signalizes a condition and wakes up a sleeping actor.
25 * If there are no actor sleeping, no action is done.
27 void ConditionVariableImpl::signal()
29 XBT_DEBUG("Signal condition %p", this);
31 /* If there are actors waiting for the condition choose one and try to make it acquire the mutex */
32 if (not sleeping_.empty()) {
33 auto& proc = sleeping_.front();
34 sleeping_.pop_front();
36 /* Destroy waiter's synchronization */
37 proc.waiting_synchro_ = nullptr;
39 /* Now transform the cond wait simcall into a mutex lock one */
40 smx_simcall_t simcall = &proc.simcall_;
41 const auto* observer = dynamic_cast<kernel::actor::ConditionWaitSimcall*>(simcall->observer_);
42 xbt_assert(observer != nullptr);
43 observer->get_mutex()->lock(simcall->issuer_);
49 * @brief Broadcasts a condition.
51 * Signal ALL actors waiting on a condition.
52 * If there are no actor waiting, no action is done.
54 void ConditionVariableImpl::broadcast()
56 XBT_DEBUG("Broadcast condition %p", this);
58 /* Signal the condition until nobody is waiting on it */
59 while (not sleeping_.empty())
63 void ConditionVariableImpl::wait(smx_mutex_t mutex, double timeout, actor::ActorImpl* issuer)
65 XBT_DEBUG("Wait condition %p", this);
66 xbt_assert(std::isfinite(timeout), "timeout is not finite!");
68 /* If there is a mutex unlock it */
69 if (mutex != nullptr) {
70 xbt_assert(mutex->get_owner() == issuer,
71 "Actor %s cannot wait on ConditionVariable %p since it does not own the provided mutex %p",
72 issuer->get_cname(), this, mutex);
74 mutex->unlock(issuer);
77 RawImplPtr synchro(new RawImpl([this, issuer]() {
78 this->remove_sleeping_actor(*issuer);
79 auto* observer = dynamic_cast<kernel::actor::ConditionWaitSimcall*>(issuer->simcall_.observer_);
80 xbt_assert(observer != nullptr);
81 observer->set_result(true);
83 synchro->set_host(issuer->get_host()).set_timeout(timeout).start();
84 synchro->register_simcall(&issuer->simcall_);
85 sleeping_.push_back(*issuer);
88 // boost::intrusive_ptr<ConditionVariableImpl> support:
89 void intrusive_ptr_add_ref(ConditionVariableImpl* cond)
91 cond->refcount_.fetch_add(1, std::memory_order_relaxed);
94 void intrusive_ptr_release(ConditionVariableImpl* cond)
96 if (cond->refcount_.fetch_sub(1, std::memory_order_release) == 1) {
97 std::atomic_thread_fence(std::memory_order_acquire);
98 xbt_assert(cond->sleeping_.empty(), "Cannot destroy conditional since someone is still using it");
102 } // namespace activity
103 } // namespace kernel
104 } // namespace simgrid