src/simix/smx_synchro.cpp

   1 /* Copyright (c) 2007-2018. 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 "smx_private.hpp"
   7 #include "src/kernel/activity/ConditionVariableImpl.hpp"
   8 #include "src/kernel/activity/MutexImpl.hpp"
   9 #include "src/kernel/activity/SynchroRaw.hpp"
  10 #include "src/simix/smx_synchro_private.hpp"
  11 #include "src/surf/cpu_interface.hpp"
  12 #include <xbt/ex.hpp>
  13
  14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_synchro, simix, "SIMIX Synchronization (mutex, semaphores and conditions)");
  15
  16 /***************************** Raw synchronization *********************************/
  17
  18 smx_activity_t SIMIX_synchro_wait(sg_host_t smx_host, double timeout)
  19 {
  20   XBT_IN("(%p, %f)",smx_host,timeout);
  21
  22   simgrid::kernel::activity::RawImplPtr sync =
  23       simgrid::kernel::activity::RawImplPtr(new simgrid::kernel::activity::RawImpl());
  24   sync->sleep                          = smx_host->pimpl_cpu->sleep(timeout);
  25   sync->sleep->set_data(sync.get());
  26   XBT_OUT();
  27   return sync;
  28 }
  29
  30 void SIMIX_synchro_stop_waiting(smx_actor_t process, smx_simcall_t simcall)
  31 {
  32   XBT_IN("(%p, %p)",process,simcall);
  33   switch (simcall->call) {
  34
  35     case SIMCALL_MUTEX_LOCK:
  36       simgrid::xbt::intrusive_erase(simcall_mutex_lock__get__mutex(simcall)->sleeping, *process);
  37       break;
  38
  39     case SIMCALL_COND_WAIT:
  40       simgrid::xbt::intrusive_erase(simcall_cond_wait__get__cond(simcall)->sleeping, *process);
  41       break;
  42
  43     case SIMCALL_COND_WAIT_TIMEOUT:
  44       simgrid::xbt::intrusive_erase(simcall_cond_wait_timeout__get__cond(simcall)->sleeping, *process);
  45       simcall_cond_wait_timeout__set__result(simcall, 1); // signal a timeout
  46       break;
  47
  48     case SIMCALL_SEM_ACQUIRE:
  49       simgrid::xbt::intrusive_erase(simcall_sem_acquire__get__sem(simcall)->sleeping, *process);
  50       break;
  51
  52     case SIMCALL_SEM_ACQUIRE_TIMEOUT:
  53       simgrid::xbt::intrusive_erase(simcall_sem_acquire_timeout__get__sem(simcall)->sleeping, *process);
  54       simcall_sem_acquire_timeout__set__result(simcall, 1); // signal a timeout
  55       break;
  56
  57     default:
  58       THROW_IMPOSSIBLE;
  59   }
  60   XBT_OUT();
  61 }
  62
  63 void SIMIX_synchro_finish(smx_activity_t synchro)
  64 {
  65   XBT_IN("(%p)", synchro.get());
  66   smx_simcall_t simcall = synchro->simcalls_.front();
  67   synchro->simcalls_.pop_front();
  68
  69   if (synchro->state_ != SIMIX_SRC_TIMEOUT) {
  70     if (synchro->state_ == SIMIX_FAILED)
  71       simcall->issuer->context_->iwannadie = 1;
  72     else
  73       THROW_IMPOSSIBLE;
  74   }
  75
  76   SIMIX_synchro_stop_waiting(simcall->issuer, simcall);
  77   simcall->issuer->waiting_synchro = nullptr;
  78   SIMIX_simcall_answer(simcall);
  79   XBT_OUT();
  80 }
  81
  82 /******************************** Semaphores **********************************/
  83 /** @brief Initialize a semaphore */
  84 smx_sem_t SIMIX_sem_init(unsigned int value)
  85 {
  86   XBT_IN("(%u)",value);
  87   smx_sem_t sem = new s_smx_sem_t;
  88   sem->value = value;
  89   XBT_OUT();
  90   return sem;
  91 }
  92
  93 /** @brief Destroys a semaphore */
  94 void SIMIX_sem_destroy(smx_sem_t sem)
  95 {
  96   XBT_IN("(%p)",sem);
  97   XBT_DEBUG("Destroy semaphore %p", sem);
  98   if (sem != nullptr) {
  99     xbt_assert(sem->sleeping.empty(), "Cannot destroy semaphore since someone is still using it");
 100     delete sem;
 101   }
 102   XBT_OUT();
 103 }
 104
 105 /** @brief release the semaphore
 106  *
 107  * Unlock a process waiting on the semaphore.
 108  * If no one was blocked, the semaphore capacity is increased by 1.
 109  */
 110 void SIMIX_sem_release(smx_sem_t sem)
 111 {
 112   XBT_IN("(%p)",sem);
 113   XBT_DEBUG("Sem release semaphore %p", sem);
 114   if (not sem->sleeping.empty()) {
 115     auto& proc = sem->sleeping.front();
 116     sem->sleeping.pop_front();
 117     proc.waiting_synchro = nullptr;
 118     SIMIX_simcall_answer(&proc.simcall);
 119   } else {
 120     sem->value++;
 121   }
 122   XBT_OUT();
 123 }
 124
 125 /** @brief Returns true if acquiring this semaphore would block */
 126 int SIMIX_sem_would_block(smx_sem_t sem)
 127 {
 128   XBT_IN("(%p)",sem);
 129   XBT_OUT();
 130   return (sem->value <= 0);
 131 }
 132
 133 /** @brief Returns the current capacity of the semaphore */
 134 int SIMIX_sem_get_capacity(smx_sem_t sem)
 135 {
 136   XBT_IN("(%p)",sem);
 137   XBT_OUT();
 138   return sem->value;
 139 }
 140
 141 static void _SIMIX_sem_wait(smx_sem_t sem, double timeout, smx_actor_t issuer,
 142                             smx_simcall_t simcall)
 143 {
 144   XBT_IN("(%p, %f, %p, %p)",sem,timeout,issuer,simcall);
 145   smx_activity_t synchro = nullptr;
 146
 147   XBT_DEBUG("Wait semaphore %p (timeout:%f)", sem, timeout);
 148   if (sem->value <= 0) {
 149     synchro = SIMIX_synchro_wait(issuer->host_, timeout);
 150     synchro->simcalls_.push_front(simcall);
 151     issuer->waiting_synchro = synchro;
 152     sem->sleeping.push_back(*issuer);
 153   } else {
 154     sem->value--;
 155     SIMIX_simcall_answer(simcall);
 156   }
 157   XBT_OUT();
 158 }
 159
 160 /**
 161  * \brief Handles a sem acquire simcall without timeout.
 162  */
 163 void simcall_HANDLER_sem_acquire(smx_simcall_t simcall, smx_sem_t sem)
 164 {
 165   XBT_IN("(%p)",simcall);
 166   _SIMIX_sem_wait(sem, -1, simcall->issuer, simcall);
 167   XBT_OUT();
 168 }
 169
 170 /**
 171  * \brief Handles a sem acquire simcall with timeout.
 172  */
 173 void simcall_HANDLER_sem_acquire_timeout(smx_simcall_t simcall, smx_sem_t sem, double timeout)
 174 {
 175   XBT_IN("(%p)",simcall);
 176   simcall_sem_acquire_timeout__set__result(simcall, 0); // default result, will be set to 1 on timeout
 177   _SIMIX_sem_wait(sem, timeout, simcall->issuer, simcall);
 178   XBT_OUT();
 179 }