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       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       break;
  54
  55     default:
  56       THROW_IMPOSSIBLE;
  57   }
  58   XBT_OUT();
  59 }
  60
  61 void SIMIX_synchro_finish(smx_activity_t synchro)
  62 {
  63   XBT_IN("(%p)", synchro.get());
  64   smx_simcall_t simcall = synchro->simcalls.front();
  65   synchro->simcalls.pop_front();
  66
  67   switch (synchro->state) {
  68
  69     case SIMIX_SRC_TIMEOUT:
  70       SMX_EXCEPTION(simcall->issuer, timeout_error, 0, "Synchro's wait timeout");
  71       break;
  72
  73     case SIMIX_FAILED:
  74         simcall->issuer->context->iwannadie = 1;
  75       break;
  76
  77     default:
  78       THROW_IMPOSSIBLE;
  79       break;
  80   }
  81
  82   SIMIX_synchro_stop_waiting(simcall->issuer, simcall);
  83   simcall->issuer->waiting_synchro = nullptr;
  84   SIMIX_simcall_answer(simcall);
  85   XBT_OUT();
  86 }
  87
  88 /******************************** Semaphores **********************************/
  89 /** @brief Initialize a semaphore */
  90 smx_sem_t SIMIX_sem_init(unsigned int value)
  91 {
  92   XBT_IN("(%u)",value);
  93   smx_sem_t sem = new s_smx_sem_t;
  94   sem->value = value;
  95   XBT_OUT();
  96   return sem;
  97 }
  98
  99 /** @brief Destroys a semaphore */
 100 void SIMIX_sem_destroy(smx_sem_t sem)
 101 {
 102   XBT_IN("(%p)",sem);
 103   XBT_DEBUG("Destroy semaphore %p", sem);
 104   if (sem != nullptr) {
 105     xbt_assert(sem->sleeping.empty(), "Cannot destroy semaphore since someone is still using it");
 106     delete sem;
 107   }
 108   XBT_OUT();
 109 }
 110
 111 /** @brief release the semaphore
 112  *
 113  * Unlock a process waiting on the semaphore.
 114  * If no one was blocked, the semaphore capacity is increased by 1.
 115  */
 116 void SIMIX_sem_release(smx_sem_t sem)
 117 {
 118   XBT_IN("(%p)",sem);
 119   XBT_DEBUG("Sem release semaphore %p", sem);
 120   if (not sem->sleeping.empty()) {
 121     auto& proc = sem->sleeping.front();
 122     sem->sleeping.pop_front();
 123     proc.waiting_synchro = nullptr;
 124     SIMIX_simcall_answer(&proc.simcall);
 125   } else {
 126     sem->value++;
 127   }
 128   XBT_OUT();
 129 }
 130
 131 /** @brief Returns true if acquiring this semaphore would block */
 132 int SIMIX_sem_would_block(smx_sem_t sem)
 133 {
 134   XBT_IN("(%p)",sem);
 135   XBT_OUT();
 136   return (sem->value <= 0);
 137 }
 138
 139 /** @brief Returns the current capacity of the semaphore */
 140 int SIMIX_sem_get_capacity(smx_sem_t sem)
 141 {
 142   XBT_IN("(%p)",sem);
 143   XBT_OUT();
 144   return sem->value;
 145 }
 146
 147 static void _SIMIX_sem_wait(smx_sem_t sem, double timeout, smx_actor_t issuer,
 148                             smx_simcall_t simcall)
 149 {
 150   XBT_IN("(%p, %f, %p, %p)",sem,timeout,issuer,simcall);
 151   smx_activity_t synchro = nullptr;
 152
 153   XBT_DEBUG("Wait semaphore %p (timeout:%f)", sem, timeout);
 154   if (sem->value <= 0) {
 155     synchro = SIMIX_synchro_wait(issuer->host, timeout);
 156     synchro->simcalls.push_front(simcall);
 157     issuer->waiting_synchro = synchro;
 158     sem->sleeping.push_back(*issuer);
 159   } else {
 160     sem->value--;
 161     SIMIX_simcall_answer(simcall);
 162   }
 163   XBT_OUT();
 164 }
 165
 166 /**
 167  * \brief Handles a sem acquire simcall without timeout.
 168  */
 169 void simcall_HANDLER_sem_acquire(smx_simcall_t simcall, smx_sem_t sem)
 170 {
 171   XBT_IN("(%p)",simcall);
 172   _SIMIX_sem_wait(sem, -1, simcall->issuer, simcall);
 173   XBT_OUT();
 174 }
 175
 176 /**
 177  * \brief Handles a sem acquire simcall with timeout.
 178  */
 179 void simcall_HANDLER_sem_acquire_timeout(smx_simcall_t simcall, smx_sem_t sem, double timeout)
 180 {
 181   XBT_IN("(%p)",simcall);
 182   _SIMIX_sem_wait(sem, timeout, simcall->issuer, simcall);
 183   XBT_OUT();
 184 }