-/* Copyright (c) 2019-2021. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2019-2023. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
+#include <simgrid/Exception.hpp>
+#include <simgrid/s4u/Host.hpp>
+
#include "src/kernel/activity/SemaphoreImpl.hpp"
-#include "src/kernel/activity/SynchroRaw.hpp"
+#include "src/kernel/activity/Synchro.hpp"
+#include "src/kernel/actor/SynchroObserver.hpp"
+#include "src/kernel/resource/CpuImpl.hpp"
+
+#include <cmath> // std::isfinite
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_semaphore, simix_synchro, "Semaphore kernel-space implementation");
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(ker_semaphore, ker_synchro, "Semaphore kernel-space implementation");
-namespace simgrid {
-namespace kernel {
-namespace activity {
+namespace simgrid::kernel::activity {
-void SemaphoreImpl::acquire(actor::ActorImpl* issuer, double timeout)
+/* -------- Acquisition -------- */
+
+void SemAcquisitionImpl::wait_for(actor::ActorImpl* issuer, double timeout)
{
+ xbt_assert(std::isfinite(timeout), "timeout is not finite!");
+ xbt_assert(issuer == issuer_, "Cannot wait on acquisitions created by another actor (id %ld)", issuer_->get_pid());
+
XBT_DEBUG("Wait semaphore %p (timeout:%f)", this, timeout);
- if (value_ <= 0) {
- RawImplPtr synchro(new RawImpl());
- synchro->set_host(issuer->get_host()).set_timeout(timeout).start();
- synchro->register_simcall(&issuer->simcall_);
- sleeping_.push_back(*issuer);
+
+ this->register_simcall(&issuer_->simcall_); // Block on that acquisition
+
+ if (granted_) {
+ finish();
+ } else if (timeout > 0) {
+ model_action_ = get_issuer()->get_host()->get_cpu()->sleep(timeout);
+ model_action_->set_activity(this);
+
} else {
- value_--;
- issuer->simcall_answer();
+ // Already in the queue
}
}
-void SemaphoreImpl::release()
+void SemAcquisitionImpl::finish()
{
- XBT_DEBUG("Sem release semaphore %p", this);
+ xbt_assert(simcalls_.size() == 1, "Unexpected number of simcalls waiting: %zu", simcalls_.size());
+ actor::Simcall* simcall = simcalls_.front();
+ simcalls_.pop_front();
- if (not sleeping_.empty()) {
- auto& actor = sleeping_.front();
- sleeping_.pop_front();
- actor.waiting_synchro_ = nullptr;
- actor.simcall_answer();
- } else {
- value_++;
+ if (model_action_ != nullptr) { // A timeout was declared
+ if (model_action_->get_state() == resource::Action::State::FINISHED) { // The timeout elapsed
+ if (granted_) { // but we got the semaphore, just in time!
+ set_state(State::DONE);
+
+ } else { // we have to report that timeout
+ cancel(); // Unregister the acquisition from the semaphore
+
+ /* Return to the englobing simcall that the wait_for timeouted */
+ auto* observer = dynamic_cast<kernel::actor::SemaphoreAcquisitionObserver*>(get_issuer()->simcall_.observer_);
+ xbt_assert(observer != nullptr);
+ observer->set_result(true);
+ }
+ }
+ model_action_->unref();
+ model_action_ = nullptr;
}
+
+ simcall->issuer_->waiting_synchro_ = nullptr;
+ simcall->issuer_->simcall_answer();
+}
+void SemAcquisitionImpl::cancel()
+{
+ /* Remove myself from the list of interested parties */
+ const auto* issuer = get_issuer();
+ auto it = std::find_if(semaphore_->ongoing_acquisitions_.begin(), semaphore_->ongoing_acquisitions_.end(),
+ [issuer](SemAcquisitionImplPtr acqui) { return acqui->get_issuer() == issuer; });
+ xbt_assert(it != semaphore_->ongoing_acquisitions_.end(),
+ "Cannot find myself in the waiting queue that I have to leave");
+ semaphore_->ongoing_acquisitions_.erase(it);
}
-} // namespace activity
-} // namespace kernel
-} // namespace simgrid
+/* -------- Semaphore -------- */
+unsigned SemaphoreImpl::next_id_ = 0;
-// Simcall handlers:
-/**
- * @brief Handles a sem acquire simcall without timeout.
- */
-void simcall_HANDLER_sem_acquire(smx_simcall_t simcall, smx_sem_t sem)
+SemAcquisitionImplPtr SemaphoreImpl::acquire_async(actor::ActorImpl* issuer)
{
- sem->acquire(simcall->issuer_, -1);
-}
+ auto res = SemAcquisitionImplPtr(new kernel::activity::SemAcquisitionImpl(issuer, this), true);
-/**
- * @brief Handles a sem acquire simcall with timeout.
- */
-void simcall_HANDLER_sem_acquire_timeout(smx_simcall_t simcall, smx_sem_t sem, double timeout)
+ if (value_ > 0) {
+ value_--;
+ res->granted_ = true;
+ } else {
+ /* No free token in the semaphore; register the acquisition */
+ ongoing_acquisitions_.push_back(res);
+ }
+ return res;
+}
+void SemaphoreImpl::release()
{
- simcall_sem_acquire_timeout__set__result(simcall, 0); // default result, will be set to 1 on timeout
- sem->acquire(simcall->issuer_, timeout);
+ XBT_DEBUG("Sem release semaphore %p", this);
+
+ if (not ongoing_acquisitions_.empty()) {
+ /* Release the first waiting actor */
+
+ auto acqui = ongoing_acquisitions_.front();
+ ongoing_acquisitions_.pop_front();
+
+ acqui->granted_ = true;
+ if (acqui == acqui->get_issuer()->waiting_synchro_)
+ acqui->finish();
+ // else, the issuer is not blocked on this acquisition so no need to release it
+
+ } else {
+ // nobody's waiting here
+ value_++;
+ }
}
+
+} // namespace simgrid::kernel::activity
