X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/a03bd071f7ec12cf9dd65b0e912fd3f84d29c880..06688d73948ce9a162626ecb422345f0c5acd7a4:/src/simix/smx_synchro.c

diff --git a/src/simix/smx_synchro.c b/src/simix/smx_synchro.c
index 46bb6b6b60..1cd37ed82f 100644
--- a/src/simix/smx_synchro.c
+++ b/src/simix/smx_synchro.c
@@ -1,7 +1,5 @@
-/* 	$Id$	 */
-
-/* Copyright (c) 2007 Arnaud Legrand, Bruno Donnassolo.
-   All rights reserved.                                          */
+/* Copyright (c) 2007, 2008, 2009, 2010. 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. */
@@ -51,12 +49,12 @@ void SIMIX_mutex_lock(smx_mutex_t mutex)
     xbt_swag_insert(self, mutex->sleeping);
     self->mutex = mutex;
     /* wait for some process make the unlock and wake up me from mutex->sleeping */
-    SIMIX_context_yield();
+    SIMIX_process_yield();
     self->mutex = NULL;
 
     /* verify if the process was suspended */
     while (self->suspended) {
-      SIMIX_context_yield();
+      SIMIX_process_yield();
     }
 
     mutex->refcount = 1;
@@ -74,7 +72,7 @@ void SIMIX_mutex_lock(smx_mutex_t mutex)
  * \param mutex The mutex
  * \return 1 - mutex free, 0 - mutex used
  */
-int SIMIX_mutex_trylock(smx_mutex_t mutex)
+XBT_INLINE int SIMIX_mutex_trylock(smx_mutex_t mutex)
 {
   xbt_assert0((mutex != NULL), "Invalid parameters");
 
@@ -115,7 +113,7 @@ void SIMIX_mutex_unlock(smx_mutex_t mutex)
  * Destroys and frees the mutex's memory. 
  * \param mutex A mutex
  */
-void SIMIX_mutex_destroy(smx_mutex_t mutex)
+XBT_INLINE void SIMIX_mutex_destroy(smx_mutex_t mutex)
 {
   if (mutex == NULL)
     return;
@@ -131,7 +129,8 @@ void SIMIX_mutex_destroy(smx_mutex_t mutex)
 /**
  * \brief Initialize a condition.
  *
- * Allocs and creates the data for the condition. It have to be called before the utilisation of the condition.
+ * Allocates and creates the data for the condition.
+ * It have to be called before the use of the condition.
  * \return A condition
  */
 smx_cond_t SIMIX_cond_init()
@@ -176,29 +175,33 @@ void SIMIX_cond_signal(smx_cond_t cond)
 void SIMIX_cond_wait(smx_cond_t cond, smx_mutex_t mutex)
 {
   smx_action_t act_sleep;
-  xbt_assert0((mutex != NULL), "Invalid parameters");
 
   DEBUG1("Wait condition %p", cond);
-  cond->mutex = mutex;
 
-  SIMIX_mutex_unlock(mutex);
-  /* always create an action null in case there is a host failure */
-/*   if (xbt_fifo_size(cond->actions) == 0) { */
+  /* If there is a mutex unlock it */
+  if (mutex != NULL) {
+    cond->mutex = mutex;
+    SIMIX_mutex_unlock(mutex);
+  }
+
+  /* Always create an action null in case there is a host failure */
   act_sleep = SIMIX_action_sleep(SIMIX_host_self(), -1);
+  SIMIX_action_set_name(act_sleep, bprintf("Wait condition %p", cond));
+  SIMIX_process_self()->waiting_action = act_sleep;
   SIMIX_register_action_to_condition(act_sleep, cond);
   __SIMIX_cond_wait(cond);
+  SIMIX_process_self()->waiting_action = NULL;
   SIMIX_unregister_action_to_condition(act_sleep, cond);
   SIMIX_action_destroy(act_sleep);
-/*   } else { */
-/*     __SIMIX_cond_wait(cond); */
-/*   } */
-  /* get the mutex again */
-  SIMIX_mutex_lock(cond->mutex);
+
+  /* get the mutex again if necessary */
+  if (mutex != NULL)
+    SIMIX_mutex_lock(cond->mutex);
 
   return;
 }
 
-xbt_fifo_t SIMIX_cond_get_actions(smx_cond_t cond)
+XBT_INLINE xbt_fifo_t SIMIX_cond_get_actions(smx_cond_t cond)
 {
   xbt_assert0((cond != NULL), "Invalid parameters");
   return cond->actions;
@@ -213,13 +216,12 @@ void __SIMIX_cond_wait(smx_cond_t cond)
 
   self->cond = cond;
   xbt_swag_insert(self, cond->sleeping);
-  SIMIX_context_yield();
+  SIMIX_process_yield();
   self->cond = NULL;
   while (self->suspended) {
-    SIMIX_context_yield();
+    SIMIX_process_yield();
   }
   return;
-
 }
 
 /**
@@ -233,33 +235,40 @@ void __SIMIX_cond_wait(smx_cond_t cond)
 void SIMIX_cond_wait_timeout(smx_cond_t cond, smx_mutex_t mutex,
                              double max_duration)
 {
-
   smx_action_t act_sleep;
-  xbt_assert0((mutex != NULL), "Invalid parameters");
 
   DEBUG1("Timed wait condition %p", cond);
-  cond->mutex = mutex;
 
-  SIMIX_mutex_unlock(mutex);
+  /* If there is a mutex unlock it */
+  if (mutex != NULL) {
+    cond->mutex = mutex;
+    SIMIX_mutex_unlock(mutex);
+  }
+
   if (max_duration >= 0) {
     act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
+    SIMIX_action_set_name(act_sleep,
+                          bprintf
+                          ("Timed wait condition %p (max_duration:%f)",
+                           cond, max_duration));
     SIMIX_register_action_to_condition(act_sleep, cond);
+    SIMIX_process_self()->waiting_action = act_sleep;
     __SIMIX_cond_wait(cond);
+    SIMIX_process_self()->waiting_action = NULL;
     SIMIX_unregister_action_to_condition(act_sleep, cond);
     if (SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
       SIMIX_action_destroy(act_sleep);
-      THROW0(timeout_error, 0, "Condition timeout");
+      THROW1(timeout_error, 0, "Condition timeout after %f", max_duration);
     } else {
       SIMIX_action_destroy(act_sleep);
     }
 
   } else
-    __SIMIX_cond_wait(cond);
-
-  /* get the mutex again */
-  SIMIX_mutex_lock(cond->mutex);
+    SIMIX_cond_wait(cond, NULL);
 
-  return;
+  /* get the mutex again if necessary */
+  if (mutex != NULL)
+    SIMIX_mutex_lock(cond->mutex);
 }
 
 /**
@@ -280,8 +289,6 @@ void SIMIX_cond_broadcast(smx_cond_t cond)
     xbt_swag_remove(proc, cond->sleeping);
     xbt_swag_insert(proc, simix_global->process_to_run);
   }
-
-  return;
 }
 
 /**
@@ -330,3 +337,242 @@ void SIMIX_cond_display_info(smx_cond_t cond)
     }
   }
 }
+
+/* ************************** Semaphores ************************************** */
+#define SMX_SEM_NOLIMIT 99999
+/** @brief Initialize a semaphore */
+smx_sem_t SIMIX_sem_init(int capacity)
+{
+  smx_sem_t sem = xbt_new0(s_smx_sem_t, 1);
+
+  sem->sleeping = xbt_fifo_new();
+  sem->actions = xbt_fifo_new();
+  sem->capacity = capacity;
+  return sem;
+}
+
+/** @brief Destroys a semaphore */
+void SIMIX_sem_destroy(smx_sem_t sem)
+{
+  smx_action_t action = NULL;
+  DEBUG1("Destroy semaphore %p", sem);
+  if (sem == NULL)
+    return;
+
+  xbt_assert0(xbt_fifo_size(sem->sleeping) == 0,
+              "Cannot destroy semaphore since someone is still using it");
+  xbt_fifo_free(sem->sleeping);
+
+  DEBUG1("%d actions registered", xbt_fifo_size(sem->actions));
+  while ((action = xbt_fifo_pop(sem->actions)))
+    SIMIX_unregister_action_to_semaphore(action, sem);
+
+  xbt_fifo_free(sem->actions);
+  xbt_free(sem);
+}
+
+/** @brief release the semaphore
+ *
+ * The first locked process on this semaphore is unlocked.
+ * If no one was blocked, the semaphore capacity is increased by 1.
+ * */
+void SIMIX_sem_release(smx_sem_t sem)
+{
+  smx_process_t proc;
+
+  if (sem->capacity != SMX_SEM_NOLIMIT) {
+    sem->capacity++;
+  }
+  DEBUG1("Sem release semaphore %p", sem);
+  if ((proc = xbt_fifo_shift(sem->sleeping)) != NULL) {
+    xbt_swag_insert(proc, simix_global->process_to_run);
+  }
+}
+
+/** @brief make sure the semaphore will never be blocking again
+ *
+ * This function is not really in the semaphore spirit. It makes
+ * sure that the semaphore will never be blocking anymore.
+ *
+ * Releasing and acquiring the semaphore after calling this
+ * function is a noop. Such "broken" semaphores are useful to
+ * implement something between condition variables (with broadcast)
+ * and semaphore (with memory). It's like a semaphore signaled for ever.
+ *
+ * There is no way to reset the semaphore to a more regular state afterward.
+ * */
+void SIMIX_sem_release_forever(smx_sem_t sem)
+{
+  smx_process_t proc;
+
+  sem->capacity = SMX_SEM_NOLIMIT;
+  DEBUG1("Broadcast semaphore %p", sem);
+  while ((proc = xbt_fifo_shift(sem->sleeping)) != NULL) {
+    xbt_swag_insert(proc, simix_global->process_to_run);
+  }
+}
+
+/**
+ * \brief Low level wait on a semaphore
+ *
+ * This function does not test the capacity of the semaphore and direcly locks
+ * the calling process on the semaphore (until someone call SIMIX_sem_release()
+ * on this semaphore). Do not call this function if you did not attach any action
+ * to this semaphore to be awaken. Note also that you may miss host failure if you
+ * do not attach a dummy action beforehand. SIMIX_sem_acquire does all these
+ * things for you so you it may be preferable to use.
+ */
+void SIMIX_sem_block_onto(smx_sem_t sem)
+{
+  smx_process_t self = SIMIX_process_self();
+
+  /* process status */
+  self->sem = sem;
+  xbt_fifo_push(sem->sleeping, self);
+  SIMIX_process_yield();
+  self->sem = NULL;
+  while (self->suspended)
+    SIMIX_process_yield();
+}
+
+/** @brief Returns true if acquiring this semaphore would block */
+XBT_INLINE int SIMIX_sem_would_block(smx_sem_t sem)
+{
+  return (sem->capacity <= 0);
+}
+
+/** @brief Returns the current capacity of the semaphore
+ *
+ * If it's negative, that's the amount of processes locked on the semaphore
+ */
+int SIMIX_sem_get_capacity(smx_sem_t sem)
+{
+  return sem->capacity;
+}
+
+/**
+ * \brief Waits on a semaphore
+ *
+ * If the capacity>0, decrease the capacity.
+ *
+ * If capacity==0, locks the current process
+ * until someone call SIMIX_sem_release() on this semaphore
+ */
+void SIMIX_sem_acquire(smx_sem_t sem)
+{
+  SIMIX_sem_acquire_timeout(sem, -1);
+}
+
+/**
+ * \brief Tries to acquire a semaphore before a timeout
+ *
+ * Same behavior of #SIMIX_sem_acquire, but waits a maximum time and throws an timeout_error if it happens.
+ */
+void SIMIX_sem_acquire_timeout(smx_sem_t sem, double max_duration)
+{
+  smx_action_t act_sleep;
+
+  DEBUG2("Wait semaphore %p (timeout:%f)", sem, max_duration);
+
+  if (sem->capacity == SMX_SEM_NOLIMIT) {
+    DEBUG1("semaphore %p wide open", sem);
+    return;                     /* don't even decrease it if wide open */
+  }
+
+  /* If capacity sufficient, decrease it */
+  if (sem->capacity > 0) {
+    DEBUG1("semaphore %p has enough capacity", sem);
+    sem->capacity--;
+    return;
+  }
+
+  /* Always create an action null in case there is a host failure */
+  act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
+  SIMIX_action_set_name(act_sleep,
+                        bprintf("Locked in semaphore %p (max_duration:%f)",
+                                sem, max_duration));
+  SIMIX_process_self()->waiting_action = act_sleep;
+  SIMIX_register_action_to_semaphore(act_sleep, sem);
+  SIMIX_sem_block_onto(sem);
+  SIMIX_process_self()->waiting_action = NULL;
+  SIMIX_unregister_action_to_semaphore(act_sleep, sem);
+  if (max_duration >= 0
+      && SIMIX_action_get_state(act_sleep) == SURF_ACTION_DONE) {
+    SIMIX_action_destroy(act_sleep);
+    THROW1(timeout_error, 0, "Semaphore acquire timeouted after %f",
+           max_duration);
+  } else {
+    if (sem->capacity != SMX_SEM_NOLIMIT) {
+      /* Take the released token */
+      sem->capacity--;
+    }
+    SIMIX_action_destroy(act_sleep);
+  }
+  DEBUG1("End of Wait on semaphore %p", sem);
+}
+
+/**
+ * \brief Blocks on a set of semaphore
+ *
+ * If any of the semaphores has some more capacity, it gets decreased.
+ * If not, blocks until the capacity of one of the semaphores becomes more friendly.
+ *
+ * \return the rank in the dynar of the semaphore which just got locked from the set
+ */
+unsigned int SIMIX_sem_acquire_any(xbt_dynar_t sems)
+{
+  smx_sem_t sem;
+  unsigned int counter, result = -1;
+  smx_action_t act_sleep;
+  smx_process_t self = SIMIX_process_self();
+
+  xbt_assert0(xbt_dynar_length(sems),
+              "I refuse to commit sucide by locking on an **empty** set of semaphores!!");
+  DEBUG2("Wait on semaphore set %p (containing %ld semaphores)", sems,
+         xbt_dynar_length(sems));
+
+  xbt_dynar_foreach(sems, counter, sem) {
+    if (!SIMIX_sem_would_block(sem)) {
+      DEBUG1("Semaphore %p wouldn't block; get it without waiting", sem);
+      SIMIX_sem_acquire(sem);
+      return counter;
+    }
+  }
+
+  /* Always create an action null in case there is a host failure */
+  act_sleep = SIMIX_action_sleep(SIMIX_host_self(), -1);
+  SIMIX_action_set_name(act_sleep, bprintf("Locked in semaphore %p", sem));
+  self->waiting_action = act_sleep;
+  SIMIX_register_action_to_semaphore(act_sleep,
+                                     xbt_dynar_get_as(sems, 0, smx_sem_t));
+
+  /* Get listed as member of all the provided semaphores */
+  self->sem = (smx_sem_t) sems; /* FIXME: we pass a pointer to dynar where a pointer to sem is expected... */
+  xbt_dynar_foreach(sems, counter, sem) {
+    xbt_fifo_push(sem->sleeping, self);
+  }
+  SIMIX_process_yield();
+  self->sem = NULL;
+  while (self->suspended)
+    SIMIX_process_yield();
+
+  /* at least one of the semaphore unsuspended us -- great, let's search the first one (and get out of the others) */
+  xbt_dynar_foreach(sems, counter, sem) {
+    if (!xbt_fifo_remove(sem->sleeping, self) && result == -1) {
+      if (sem->capacity != SMX_SEM_NOLIMIT) {
+        /* Take the released token */
+        sem->capacity--;
+      }
+      result = counter;
+    }
+  }
+  xbt_assert0(result != -1, "Cannot find which semaphore unlocked me!");
+
+  /* Destroy the waiting action */
+  self->waiting_action = NULL;
+  SIMIX_unregister_action_to_semaphore(act_sleep,
+                                       xbt_dynar_get_as(sems, 0,
+                                                        smx_sem_t));
+  SIMIX_action_destroy(act_sleep);
+  return result;
+}