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/mc/checker/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 process.
25 * If there are no process sleeping, no action is done.
27 void ConditionVariableImpl::signal()
29 XBT_DEBUG("Signal condition %p", this);
31 /* If there are processes waiting for the condition choose one and try
32 to make it acquire the mutex */
33 if (not sleeping_.empty()) {
34 auto& proc = sleeping_.front();
35 sleeping_.pop_front();
37 /* Destroy waiter's synchronization */
38 proc.waiting_synchro_ = nullptr;
40 /* Now transform the cond wait simcall into a mutex lock one */
41 smx_simcall_t simcall = &proc.simcall_;
42 // FIXME? using here the MC observer to solve a problem not related to MC
43 const auto* observer = dynamic_cast<mc::ConditionWaitSimcall*>(simcall->observer_);
44 xbt_assert(observer != nullptr);
45 observer->get_mutex()->lock(simcall->issuer_);
51 * @brief Broadcasts a condition.
53 * Signal ALL processes waiting on a condition.
54 * If there are no process waiting, no action is done.
56 void ConditionVariableImpl::broadcast()
58 XBT_DEBUG("Broadcast condition %p", this);
60 /* Signal the condition until nobody is waiting on it */
61 while (not sleeping_.empty())
65 void ConditionVariableImpl::wait(smx_mutex_t mutex, double timeout, actor::ActorImpl* issuer)
67 XBT_DEBUG("Wait condition %p", this);
68 xbt_assert(std::isfinite(timeout), "timeout is not finite!");
70 /* If there is a mutex unlock it */
71 if (mutex != nullptr) {
72 xbt_assert(mutex->get_owner() == issuer,
73 "Actor %s cannot wait on ConditionVariable %p since it does not own the provided mutex %p",
74 issuer->get_cname(), this, mutex);
76 mutex->unlock(issuer);
79 RawImplPtr synchro(new RawImpl([this, issuer]() {
80 this->remove_sleeping_actor(*issuer);
81 auto* observer = dynamic_cast<mc::ConditionWaitSimcall*>(issuer->simcall_.observer_);
82 xbt_assert(observer != nullptr);
83 observer->set_result(true);
85 synchro->set_host(issuer->get_host()).set_timeout(timeout).start();
86 synchro->register_simcall(&issuer->simcall_);
87 sleeping_.push_back(*issuer);
90 // boost::intrusive_ptr<ConditionVariableImpl> support:
91 void intrusive_ptr_add_ref(simgrid::kernel::activity::ConditionVariableImpl* cond)
93 cond->refcount_.fetch_add(1, std::memory_order_relaxed);
96 void intrusive_ptr_release(simgrid::kernel::activity::ConditionVariableImpl* cond)
98 if (cond->refcount_.fetch_sub(1, std::memory_order_release) == 1) {
99 std::atomic_thread_fence(std::memory_order_acquire);
100 xbt_assert(cond->sleeping_.empty(), "Cannot destroy conditional since someone is still using it");
104 } // namespace activity
105 } // namespace kernel
106 } // namespace simgrid