X-Git-Url: http://bilbo.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/554255fe3f311a54df171d31a4a27f4004840f59..8c6bbb14f44b8daed5ea43d80880c6bf2155118b:/src/kernel/activity/SemaphoreImpl.cpp

diff --git a/src/kernel/activity/SemaphoreImpl.cpp b/src/kernel/activity/SemaphoreImpl.cpp
index fb13608087..2bb639663d 100644
--- a/src/kernel/activity/SemaphoreImpl.cpp
+++ b/src/kernel/activity/SemaphoreImpl.cpp
@@ -1,66 +1,120 @@
-/* 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/actor/SimcallObserver.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::kernel::activity {
 
-namespace simgrid {
-namespace kernel {
-namespace activity {
+/* -------- Acquisition -------- */
 
-void SemaphoreImpl::acquire(actor::ActorImpl* issuer, double timeout)
+void SemAcquisitionImpl::wait_for(actor::ActorImpl* issuer, double timeout)
 {
-  XBT_DEBUG("Wait semaphore %p (timeout:%f)", this, 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);
+
+  this->register_simcall(&issuer_->simcall_); // Block on that acquisition
+
+  if (granted_) {
+    post();
+  } else if (timeout > 0) {
+    model_action_ = get_issuer()->get_host()->get_cpu()->sleep(timeout);
+    model_action_->set_activity(this);
 
-  if (value_ <= 0) {
-    RawImplPtr synchro(new RawImpl([this, issuer]() {
-      this->remove_sleeping_actor(*issuer);
-      auto* observer = dynamic_cast<kernel::actor::SemAcquireSimcall*>(issuer->simcall_.observer_);
-      xbt_assert(observer != nullptr);
-      observer->set_result(true);
-    }));
-    synchro->set_host(issuer->get_host()).set_timeout(timeout).start();
-    synchro->register_simcall(&issuer->simcall_);
-    sleeping_.push_back(*issuer);
   } else {
-    value_--;
-    issuer->simcall_answer();
+    // Already in the queue
   }
 }
-void SemaphoreImpl::release()
+void SemAcquisitionImpl::post()
 {
-  XBT_DEBUG("Sem release semaphore %p", this);
+  finish();
+}
+void SemAcquisitionImpl::finish()
+{
+  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;
   }
-}
 
-/** Increase the refcount for this semaphore */
-SemaphoreImpl* SemaphoreImpl::ref()
+  simcall->issuer_->waiting_synchro_ = nullptr;
+  simcall->issuer_->simcall_answer();
+}
+void SemAcquisitionImpl::cancel()
 {
-  intrusive_ptr_add_ref(this);
-  return this;
+  /* Remove myself from the list of interested parties */
+  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);
 }
 
-/** Decrease the refcount for this mutex */
-void SemaphoreImpl::unref()
+/* -------- Semaphore -------- */
+unsigned SemaphoreImpl::next_id_ = 0;
+
+SemAcquisitionImplPtr SemaphoreImpl::acquire_async(actor::ActorImpl* issuer)
+{
+  auto res = SemAcquisitionImplPtr(new kernel::activity::SemAcquisitionImpl(issuer, this), true);
+
+  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()
 {
-  intrusive_ptr_release(this);
+  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->post();
+    // else, the issuer is not blocked on this acquisition so no need to release it
+
+  } else {
+    // nobody's waiting here
+    value_++;
+  }
 }
 
-} // namespace activity
-} // namespace kernel
-} // namespace simgrid
+} // namespace simgrid::kernel::activity