src/simix/smx_synchro.cpp

   1 /* Copyright (c) 2007-2019. The SimGrid Team. All rights reserved.          */
   2
   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. */
   5
   6 #include "src/kernel/activity/ConditionVariableImpl.hpp"
   7 #include "src/kernel/activity/MutexImpl.hpp"
   8 #include "src/kernel/activity/SynchroRaw.hpp"
   9 #include "src/kernel/context/Context.hpp"
  10 #include "src/simix/smx_synchro_private.hpp"
  11 #include "src/surf/cpu_interface.hpp"
  12
  13 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_synchro, simix, "SIMIX Synchronization (mutex, semaphores and conditions)");
  14
  15 /***************************** Raw synchronization *********************************/
  16
  17 smx_activity_t SIMIX_synchro_wait(sg_host_t smx_host, double timeout)
  18 {
  19   XBT_IN("(%p, %f)",smx_host,timeout);
  20
  21   simgrid::kernel::activity::RawImplPtr sync =
  22       simgrid::kernel::activity::RawImplPtr(new simgrid::kernel::activity::RawImpl());
  23   sync->sleep                          = smx_host->pimpl_cpu->sleep(timeout);
  24   sync->sleep->set_data(sync.get());
  25   XBT_OUT();
  26   return sync;
  27 }
  28
  29 void SIMIX_synchro_stop_waiting(smx_actor_t process, smx_simcall_t simcall)
  30 {
  31   XBT_IN("(%p, %p)",process,simcall);
  32   switch (simcall->call) {
  33
  34     case SIMCALL_MUTEX_LOCK:
  35       simgrid::xbt::intrusive_erase(simcall_mutex_lock__get__mutex(simcall)->sleeping, *process);
  36       break;
  37
  38     case SIMCALL_COND_WAIT:
  39       simgrid::xbt::intrusive_erase(simcall_cond_wait__get__cond(simcall)->sleeping, *process);
  40       break;
  41
  42     case SIMCALL_COND_WAIT_TIMEOUT:
  43       simgrid::xbt::intrusive_erase(simcall_cond_wait_timeout__get__cond(simcall)->sleeping, *process);
  44       simcall_cond_wait_timeout__set__result(simcall, 1); // signal a timeout
  45       break;
  46
  47     case SIMCALL_SEM_ACQUIRE:
  48       simgrid::xbt::intrusive_erase(simcall_sem_acquire__get__sem(simcall)->sleeping, *process);
  49       break;
  50
  51     case SIMCALL_SEM_ACQUIRE_TIMEOUT:
  52       simgrid::xbt::intrusive_erase(simcall_sem_acquire_timeout__get__sem(simcall)->sleeping, *process);
  53       simcall_sem_acquire_timeout__set__result(simcall, 1); // signal a timeout
  54       break;
  55
  56     default:
  57       THROW_IMPOSSIBLE;
  58   }
  59   XBT_OUT();
  60 }
  61
  62 void SIMIX_synchro_finish(smx_activity_t synchro)
  63 {
  64   XBT_IN("(%p)", synchro.get());
  65   smx_simcall_t simcall = synchro->simcalls_.front();
  66   synchro->simcalls_.pop_front();
  67
  68   if (synchro->state_ != SIMIX_SRC_TIMEOUT) {
  69     if (synchro->state_ == SIMIX_FAILED)
  70       simcall->issuer->context_->iwannadie = 1;
  71     else
  72       THROW_IMPOSSIBLE;
  73   }
  74
  75   SIMIX_synchro_stop_waiting(simcall->issuer, simcall);
  76   simcall->issuer->waiting_synchro = nullptr;
  77   SIMIX_simcall_answer(simcall);
  78   XBT_OUT();
  79 }
  80
  81 /******************************** Semaphores **********************************/
  82 /** @brief Initialize a semaphore */
  83 smx_sem_t SIMIX_sem_init(unsigned int value)
  84 {
  85   XBT_IN("(%u)",value);
  86   smx_sem_t sem = new s_smx_sem_t;
  87   sem->value = value;
  88   XBT_OUT();
  89   return sem;
  90 }
  91
  92 /** @brief Destroys a semaphore */
  93 void SIMIX_sem_destroy(smx_sem_t sem)
  94 {
  95   XBT_IN("(%p)",sem);
  96   XBT_DEBUG("Destroy semaphore %p", sem);
  97   if (sem != nullptr) {
  98     xbt_assert(sem->sleeping.empty(), "Cannot destroy semaphore since someone is still using it");
  99     delete sem;
 100   }
 101   XBT_OUT();
 102 }
 103
 104 /** @brief release the semaphore
 105  *
 106  * Unlock a process waiting on the semaphore.
 107  * If no one was blocked, the semaphore capacity is increased by 1.
 108  */
 109 void SIMIX_sem_release(smx_sem_t sem)
 110 {
 111   XBT_IN("(%p)",sem);
 112   XBT_DEBUG("Sem release semaphore %p", sem);
 113   if (not sem->sleeping.empty()) {
 114     auto& proc = sem->sleeping.front();
 115     sem->sleeping.pop_front();
 116     proc.waiting_synchro = nullptr;
 117     SIMIX_simcall_answer(&proc.simcall);
 118   } else {
 119     sem->value++;
 120   }
 121   XBT_OUT();
 122 }
 123
 124 /** @brief Returns true if acquiring this semaphore would block */
 125 int SIMIX_sem_would_block(smx_sem_t sem)
 126 {
 127   XBT_IN("(%p)",sem);
 128   XBT_OUT();
 129   return (sem->value <= 0);
 130 }
 131
 132 /** @brief Returns the current capacity of the semaphore */
 133 int SIMIX_sem_get_capacity(smx_sem_t sem)
 134 {
 135   XBT_IN("(%p)",sem);
 136   XBT_OUT();
 137   return sem->value;
 138 }
 139
 140 static void _SIMIX_sem_wait(smx_sem_t sem, double timeout, smx_actor_t issuer,
 141                             smx_simcall_t simcall)
 142 {
 143   XBT_IN("(%p, %f, %p, %p)",sem,timeout,issuer,simcall);
 144   smx_activity_t synchro = nullptr;
 145
 146   XBT_DEBUG("Wait semaphore %p (timeout:%f)", sem, timeout);
 147   if (sem->value <= 0) {
 148     synchro = SIMIX_synchro_wait(issuer->host_, timeout);
 149     synchro->simcalls_.push_front(simcall);
 150     issuer->waiting_synchro = synchro;
 151     sem->sleeping.push_back(*issuer);
 152   } else {
 153     sem->value--;
 154     SIMIX_simcall_answer(simcall);
 155   }
 156   XBT_OUT();
 157 }
 158
 159 /**
 160  * @brief Handles a sem acquire simcall without timeout.
 161  */
 162 void simcall_HANDLER_sem_acquire(smx_simcall_t simcall, smx_sem_t sem)
 163 {
 164   XBT_IN("(%p)",simcall);
 165   _SIMIX_sem_wait(sem, -1, simcall->issuer, simcall);
 166   XBT_OUT();
 167 }
 168
 169 /**
 170  * @brief Handles a sem acquire simcall with timeout.
 171  */
 172 void simcall_HANDLER_sem_acquire_timeout(smx_simcall_t simcall, smx_sem_t sem, double timeout)
 173 {
 174   XBT_IN("(%p)",simcall);
 175   simcall_sem_acquire_timeout__set__result(simcall, 0); // default result, will be set to 1 on timeout
 176   _SIMIX_sem_wait(sem, timeout, simcall->issuer, simcall);
 177   XBT_OUT();
 178 }