1 /* Copyright (c) 2007-2018. 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 "src/kernel/activity/MutexImpl.hpp"
8 #include "src/kernel/activity/SynchroRaw.hpp"
9 #include "src/simix/smx_synchro_private.hpp"
12 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(ConditionVariable, simix_synchro, "Condition variables");
14 static void _SIMIX_cond_wait(smx_cond_t cond, smx_mutex_t mutex, double timeout, smx_actor_t issuer,
15 smx_simcall_t simcall);
17 /********************************* Condition **********************************/
20 * \brief Handle a condition waiting simcall without timeouts
22 void simcall_HANDLER_cond_wait(smx_simcall_t simcall, smx_cond_t cond, smx_mutex_t mutex)
24 XBT_IN("(%p)", simcall);
25 smx_actor_t issuer = simcall->issuer;
27 _SIMIX_cond_wait(cond, mutex, -1, issuer, simcall);
32 * \brief Handle a condition waiting simcall with timeouts
34 void simcall_HANDLER_cond_wait_timeout(smx_simcall_t simcall, smx_cond_t cond, smx_mutex_t mutex, double timeout)
36 XBT_IN("(%p)", simcall);
37 smx_actor_t issuer = simcall->issuer;
39 _SIMIX_cond_wait(cond, mutex, timeout, issuer, simcall);
43 static void _SIMIX_cond_wait(smx_cond_t cond, smx_mutex_t mutex, double timeout, smx_actor_t issuer,
44 smx_simcall_t simcall)
46 XBT_IN("(%p, %p, %f, %p,%p)", cond, mutex, timeout, issuer, simcall);
47 smx_activity_t synchro = nullptr;
49 XBT_DEBUG("Wait condition %p", cond);
51 /* If there is a mutex unlock it */
52 /* FIXME: what happens if the issuer is not the owner of the mutex? */
53 if (mutex != nullptr) {
55 mutex->unlock(issuer);
58 synchro = SIMIX_synchro_wait(issuer->host, timeout);
59 synchro->simcalls.push_front(simcall);
60 issuer->waiting_synchro = synchro;
61 cond->sleeping.push_back(*simcall->issuer);
69 ConditionVariableImpl::ConditionVariableImpl() : cond_(this) {}
70 ConditionVariableImpl::~ConditionVariableImpl() = default;
73 * \brief Signalizes a condition.
75 * Signalizes a condition and wakes up a sleeping process.
76 * If there are no process sleeping, no action is done.
78 void ConditionVariableImpl::signal()
80 XBT_DEBUG("Signal condition %p", this);
82 /* If there are processes waiting for the condition choose one and try
83 to make it acquire the mutex */
84 if (not sleeping.empty()) {
85 auto& proc = sleeping.front();
88 /* Destroy waiter's synchronization */
89 proc.waiting_synchro = nullptr;
91 /* Now transform the cond wait simcall into a mutex lock one */
92 smx_simcall_t simcall = &proc.simcall;
93 smx_mutex_t simcall_mutex;
94 if (simcall->call == SIMCALL_COND_WAIT)
95 simcall_mutex = simcall_cond_wait__get__mutex(simcall);
97 simcall_mutex = simcall_cond_wait_timeout__get__mutex(simcall);
98 simcall->call = SIMCALL_MUTEX_LOCK;
100 simcall_HANDLER_mutex_lock(simcall, simcall_mutex);
106 * \brief Broadcasts a condition.
108 * Signal ALL processes waiting on a condition.
109 * If there are no process waiting, no action is done.
111 void ConditionVariableImpl::broadcast()
113 XBT_DEBUG("Broadcast condition %p", this);
115 /* Signal the condition until nobody is waiting on it */
116 while (not sleeping.empty())
120 // boost::intrusive_ptr<ConditionVariableImpl> support:
121 void intrusive_ptr_add_ref(simgrid::kernel::activity::ConditionVariableImpl* cond)
123 cond->refcount_.fetch_add(1, std::memory_order_relaxed);
126 void intrusive_ptr_release(simgrid::kernel::activity::ConditionVariableImpl* cond)
128 if (cond->refcount_.fetch_sub(1, std::memory_order_release) == 1) {
129 std::atomic_thread_fence(std::memory_order_acquire);
130 xbt_assert(cond->sleeping.empty(), "Cannot destroy conditional since someone is still using it");
134 } // namespace activity
135 } // namespace kernel