X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/090cf2282f07bf598ff25bf0740e35268b20b699..dbba6b3b12961ab6482a948f76c1a4989530bf2e:/src/simix/smx_synchro.c

diff --git a/src/simix/smx_synchro.c b/src/simix/smx_synchro.c
index 42d67bc080..8cee3bc822 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. */
@@ -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;
@@ -203,7 +201,7 @@ void SIMIX_cond_wait(smx_cond_t cond, smx_mutex_t 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;
@@ -351,21 +349,18 @@ smx_sem_t SIMIX_sem_init(int capacity) {
 }
 /** @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_fifo_item_t item = NULL;
-  smx_action_t action = NULL;
-
   xbt_assert0(xbt_swag_size(sem->sleeping) == 0,
       "Cannot destroy semaphore since someone is still using it");
   xbt_swag_free(sem->sleeping);
 
   DEBUG1("%d actions registered", xbt_fifo_size(sem->actions));
-  xbt_fifo_foreach(sem->actions, item, action, smx_action_t) {
+  while((action=xbt_fifo_pop(sem->actions)))
     SIMIX_unregister_action_to_semaphore(action, sem);
-  }
 
   xbt_fifo_free(sem->actions);
   xbt_free(sem);
@@ -377,6 +372,7 @@ void SIMIX_sem_destroy(smx_sem_t sem) {
  * If no one was blocked, the semaphore capacity is increased by 1.
  * */
 void SIMIX_sem_release(smx_sem_t sem) {
+	DEBUG1("Sem release semaphore %p", sem);
   if (xbt_swag_size(sem->sleeping) >= 1) {
     smx_process_t proc = xbt_swag_extract(sem->sleeping);
     xbt_swag_insert(proc, simix_global->process_to_run);
@@ -405,9 +401,20 @@ void SIMIX_sem_release_forever(smx_sem_t sem) {
     xbt_swag_remove(proc, sem->sleeping);
     xbt_swag_insert(proc, simix_global->process_to_run);
   }
+  sem->capacity = SMX_SEM_NOLIMIT;
 }
 
-static inline void SIMIX_sem_block_onto(smx_sem_t sem) {
+/**
+ * \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 */
@@ -420,8 +427,16 @@ static inline void SIMIX_sem_block_onto(smx_sem_t sem) {
 }
 
 /** @brief Returns true if acquiring this semaphore would block */
-int SIMIX_sem_would_block(smx_sem_t sem) {
-  return (sem->capacity>0);
+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;
 }
 
 /**
@@ -437,15 +452,19 @@ void SIMIX_sem_acquire(smx_sem_t sem) {
 
   DEBUG1("Wait semaphore %p", sem);
 
-  if (sem->capacity == SMX_SEM_NOLIMIT)
+  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;
   }
 
+  sem->capacity--;
   /* 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));
@@ -455,6 +474,8 @@ void SIMIX_sem_acquire(smx_sem_t sem) {
   SIMIX_process_self()->waiting_action = NULL;
   SIMIX_unregister_action_to_semaphore(act_sleep, sem);
   SIMIX_action_destroy(act_sleep);
+  DEBUG1("End of Wait on semaphore %p", sem);
+  sem->capacity++;
 }
 /**
  * \brief Tries to acquire a semaphore before a timeout
@@ -476,6 +497,7 @@ void SIMIX_sem_acquire_timeout(smx_sem_t sem, double max_duration) {
   }
 
   if (max_duration >= 0) {
+    sem->capacity--;
     act_sleep = SIMIX_action_sleep(SIMIX_host_self(), max_duration);
     SIMIX_action_set_name(act_sleep,bprintf("Timed wait semaphore %p (max_duration:%f)", sem,max_duration));
     SIMIX_register_action_to_semaphore(act_sleep, sem);
@@ -489,6 +511,7 @@ void SIMIX_sem_acquire_timeout(smx_sem_t sem, double max_duration) {
     } else {
       SIMIX_action_destroy(act_sleep);
     }
+    sem->capacity++;
 
   } else
     SIMIX_sem_acquire(sem);
@@ -509,12 +532,14 @@ unsigned int SIMIX_sem_acquire_any(xbt_dynar_t sems) {
 
   xbt_assert0(xbt_dynar_length(sems),
       "I refuse to commit sucide by locking on an **empty** set of semaphores!!");
-  DEBUG1("Wait on semaphore set %p", sems);
+  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))
+    if (!SIMIX_sem_would_block(sem)) {
+      DEBUG1("Semaphore %p wouldn't block; get it without waiting",sem);
       SIMIX_sem_acquire(sem);
-    return counter;
+      return counter;
+    }
   }
 
   /* Always create an action null in case there is a host failure */
@@ -529,11 +554,11 @@ unsigned int SIMIX_sem_acquire_any(xbt_dynar_t sems) {
     xbt_swag_insert(self, sem->sleeping);
   }
   SIMIX_process_yield();
+  self->sem = NULL;
   while (self->suspended)
     SIMIX_process_yield();
 
   /* one of the semaphore unsuspended us -- great, let's search which one (and get out of the others) */
-  self->sem = NULL;
   xbt_dynar_foreach(sems,counter,sem) {
     if (xbt_swag_belongs(self,sem->sleeping))
       xbt_swag_remove(self,sem->sleeping);