1 /* Copyright (c) 2007-2023. 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/MutexImpl.hpp"
7 #include "src/kernel/activity/Synchro.hpp"
9 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(ker_mutex, ker_synchro, "Mutex kernel-space implementation");
11 namespace simgrid::kernel::activity {
13 /* -------- Acquisition -------- */
15 bool MutexAcquisitionImpl::test(actor::ActorImpl*)
17 return mutex_->owner_ == issuer_;
19 void MutexAcquisitionImpl::wait_for(actor::ActorImpl* issuer, double timeout)
21 xbt_assert(mutex_->owner_ != nullptr); // it was locked either by someone else or by me during the lock_async
22 xbt_assert(issuer == issuer_, "Cannot wait on acquisitions created by another actor (id %ld)", issuer_->get_pid());
23 xbt_assert(timeout < 0, "Timeouts on mutex acquisitions are not implemented yet.");
25 this->register_simcall(&issuer_->simcall_); // Block on that acquisition
27 if (mutex_->get_owner() == issuer_) { // I'm the owner
30 // Already in the queue
34 void MutexAcquisitionImpl::finish()
36 xbt_assert(simcalls_.size() == 1, "Unexpected number of simcalls waiting: %zu", simcalls_.size());
37 actor::Simcall* simcall = simcalls_.front();
38 simcalls_.pop_front();
40 simcall->issuer_->waiting_synchro_ = nullptr;
41 simcall->issuer_->simcall_answer();
44 /* -------- Mutex -------- */
46 unsigned MutexImpl::next_id_ = 0;
48 MutexAcquisitionImplPtr MutexImpl::lock_async(actor::ActorImpl* issuer)
50 /* If the mutex is recursive */
52 if (owner_ == issuer) {
54 auto res = MutexAcquisitionImplPtr(new kernel::activity::MutexAcquisitionImpl(issuer, this), true);
57 } else if (owner_ == nullptr) { // Free
60 auto res = MutexAcquisitionImplPtr(new kernel::activity::MutexAcquisitionImpl(issuer, this), true);
65 for (auto acq : ongoing_acquisitions_)
66 if (acq->get_issuer() == issuer) {
67 acq->recursive_depth_++;
71 // Not yet in the ongoing acquisition list. Get in there
72 auto res = MutexAcquisitionImplPtr(new kernel::activity::MutexAcquisitionImpl(issuer, this), true);
73 ongoing_acquisitions_.push_back(res);
77 // Non-recursive mutex
78 auto res = MutexAcquisitionImplPtr(new kernel::activity::MutexAcquisitionImpl(issuer, this), true);
79 if (owner_ == nullptr) { // Lock is free, take it
83 } else { // Somebody is using the mutex; register the acquisition
84 ongoing_acquisitions_.push_back(res);
89 /** Tries to lock the mutex for a actor
91 * @param issuer the actor that tries to acquire the mutex
92 * @return whether we managed to lock the mutex
94 bool MutexImpl::try_lock(actor::ActorImpl* issuer)
96 if (owner_ == issuer && is_recursive_) {
100 if (owner_ != nullptr)
107 /** Unlock a mutex for a actor
109 * Unlocks the mutex and gives it to a actor waiting for it.
110 * If the unlocker is not the owner of the mutex nothing happens.
111 * If there are no actor waiting, it sets the mutex as free.
113 void MutexImpl::unlock(actor::ActorImpl* issuer)
115 XBT_IN("(%p, %p)", this, issuer);
116 xbt_assert(issuer == owner_, "Cannot release that mutex: you're not the owner. %s is (pid:%ld).",
117 owner_ != nullptr ? owner_->get_cname() : "(nobody)", owner_ != nullptr ? owner_->get_pid() : -1);
121 if (recursive_depth > 0) // Still owning the lock
125 if (not ongoing_acquisitions_.empty()) {
126 /* Give the ownership to the first waiting actor */
127 auto acq = ongoing_acquisitions_.front();
128 ongoing_acquisitions_.pop_front();
130 owner_ = acq->get_issuer();
132 recursive_depth = acq->recursive_depth_;
133 if (acq == owner_->waiting_synchro_)
135 // else, the issuer is not blocked on this acquisition so no need to release it
138 /* nobody to wake up */
144 } // namespace simgrid::kernel::activity