X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/645feae364d69d74fbed1325a905f7db436240d2..933643df9146f8e7e114736d08c0b1547d075d98:/src/xbt/context.c

diff --git a/src/xbt/context.c b/src/xbt/context.c
index 9d313f5c83..136411cf09 100644
--- a/src/xbt/context.c
+++ b/src/xbt/context.c
@@ -24,32 +24,7 @@ static xbt_context_t current_context = NULL;
 static xbt_context_t init_context = NULL;
 static xbt_swag_t context_to_destroy = NULL;
 static xbt_swag_t context_living = NULL;
-#ifdef CONTEXT_THREADS
-static xbt_os_mutex_t creation_mutex;
-static xbt_os_cond_t creation_cond;
-static xbt_os_mutex_t master_mutex;
-static xbt_os_cond_t master_cond;
-
-#ifdef WIN32
-static DWORD __current_thread_id = 0;
-#else
-static pthread_t __current_thread_id;
-#endif
 
-static int
-is_main_thread(void);
-
-static int
-is_main_thread(void)
-{
-	#ifdef WIN32
-	return (GetCurrentThreadId() == __current_thread_id) ? 1 : 0;
-	#else
-	return (pthread_self() == __current_thread_id) ? 1 : 0;
-	#endif
-}
-
-#endif
 
 
 /********************/
@@ -58,19 +33,43 @@ is_main_thread(void)
 #ifndef CONTEXT_THREADS
 /* callback: context fetching (used only with ucontext, os_thread deal with it
                                for us otherwise) */
-static ex_ctx_t *_context_ex_ctx(void) {
+static ex_ctx_t *_context_ex_ctx(void)
+{
   return current_context->exception;
 }
 
 /* callback: termination */
-static void _context_ex_terminate(xbt_ex_t * e) {
+static void _context_ex_terminate(xbt_ex_t * e)
+{
   xbt_ex_display(e);
 
   abort();
   /* FIXME: there should be a configuration variable to 
      choose to kill everyone or only this one */
 }
-#endif 
+#endif
+
+#ifdef CONTEXT_THREADS
+
+static void 
+schedule(xbt_context_t c);
+
+static void 
+yield(xbt_context_t c);
+
+static void 
+schedule(xbt_context_t c) 
+{
+	xbt_os_sem_release(c->begin);	
+	xbt_os_sem_acquire(c->end);	
+}
+
+static void yield(xbt_context_t c) 
+{
+  	xbt_os_sem_release(c->end);		
+ 	xbt_os_sem_acquire(c->begin);
+}
+#endif
 
 /** \name Functions 
  *  \ingroup XBT_context
@@ -80,78 +79,56 @@ static void _context_ex_terminate(xbt_ex_t * e) {
  *
  * \warning It has to be called before using any other function of this module.
  */
-void 
-xbt_context_init(void)
+void xbt_context_init(void)
 {
-	if (!current_context) 
-	{
-		current_context = init_context = xbt_new0(s_xbt_context_t, 1);
-		DEBUG1("Init Context (%p)", init_context);
-		init_context->iwannadie = 0; /* useless but makes valgrind happy */
-		context_to_destroy = xbt_swag_new(xbt_swag_offset(*current_context, hookup));
-		context_living =  xbt_swag_new(xbt_swag_offset(*current_context, hookup));
-		xbt_swag_insert(init_context, context_living);
-		
-		#ifdef CONTEXT_THREADS
-		  /* only used during the creation of the processes */
-		  creation_mutex = xbt_os_mutex_init();
-		  creation_cond = xbt_os_cond_init();
-
-		  /* used to schedule/unschedule the processes */
-		  master_mutex = xbt_os_mutex_init();
-		  master_cond = xbt_os_cond_init();
-
-		  #ifdef WIN32
-		    __current_thread_id = GetCurrentThreadId();
-		  #else
-		    __current_thread_id = pthread_self();
-		  #endif
-		#else
-		  init_context->exception = xbt_new(ex_ctx_t, 1);
-		  XBT_CTX_INITIALIZE(init_context->exception);
-		  __xbt_ex_ctx = _context_ex_ctx;
-		  __xbt_ex_terminate = _context_ex_terminate;
-		#endif
-	}
+  if (!current_context) {
+    current_context = init_context = xbt_new0(s_xbt_context_t, 1);
+    DEBUG1("Init Context (%p)", init_context);
+    init_context->iwannadie = 0;        /* useless but makes valgrind happy */
+    context_to_destroy =
+      xbt_swag_new(xbt_swag_offset(*current_context, hookup));
+    context_living = xbt_swag_new(xbt_swag_offset(*current_context, hookup));
+    xbt_swag_insert(init_context, context_living);
+    
+    #ifndef CONTEXT_THREADS
+    init_context->exception = xbt_new(ex_ctx_t, 1);
+    XBT_CTX_INITIALIZE(init_context->exception);
+    __xbt_ex_ctx = _context_ex_ctx;
+    __xbt_ex_terminate = _context_ex_terminate;
+#endif
+  }
 }
 
 /** 
  * This function kill all existing context and free all the memory
  * that has been allocated in this module.
  */
-void 
-xbt_context_exit(void)
+void xbt_context_exit(void)
 {
-	xbt_context_t context = NULL;
-
-	xbt_context_empty_trash();
-	
-	while ((context = xbt_swag_extract(context_living))) 
-	{
-		if (context != init_context) 
-		{
-			xbt_context_kill(context);
-		}
-	}
-	
-	#ifdef CONTEXT_THREADS
-	  xbt_os_mutex_destroy(creation_mutex);
-	  xbt_os_cond_destroy(creation_cond);
-	  xbt_os_mutex_destroy(master_mutex);
-	  xbt_os_cond_destroy(master_cond);
-	#else   
-	  free(init_context->exception);
-	#endif
-	
-	free(init_context);
-	init_context = current_context = NULL;
-
-	xbt_context_empty_trash();
-	xbt_swag_free(context_to_destroy);
-	xbt_swag_free(context_living);
+  xbt_context_t context = NULL;
+
+  xbt_context_empty_trash();
+
+  while ((context = xbt_swag_extract(context_living))) {
+    if (context != init_context) {
+      xbt_context_kill(context);
+    }
+  }
+
+#ifndef CONTEXT_THREADS
+  free(init_context->exception);
+#endif
+
+  free(init_context);
+  init_context = current_context = NULL;
+
+  xbt_context_empty_trash();
+  xbt_swag_free(context_to_destroy);
+  xbt_swag_free(context_living);
 
 }
 
+
 /*******************************/
 /* Object creation/destruction */
 /*******************************/
@@ -166,56 +143,57 @@ xbt_context_exit(void)
  * \param argc first argument of function \a code
  * \param argv seconde argument of function \a code
  */
-xbt_context_t 
-xbt_context_new(	const char *name,
-					xbt_main_func_t code,
-					void_f_pvoid_t startup_func,
-					void *startup_arg,
-					void_f_pvoid_t cleanup_func,
-					void *cleanup_arg, 
-					int argc, 
-					char *argv[]
-)
+xbt_context_t
+xbt_context_new(const char *name,
+                xbt_main_func_t code,
+                void_f_pvoid_t startup_func,
+                void *startup_arg,
+                void_f_pvoid_t cleanup_func,
+                void *cleanup_arg, int argc, char *argv[]
+  )
 {
-	xbt_context_t res = NULL;
+  xbt_context_t res = NULL;
 
-	res = xbt_new0(s_xbt_context_t, 1);
+  res = xbt_new0(s_xbt_context_t, 1);
 
-	res->code = code;
-	res->name = xbt_strdup(name);
+  res->code = code;
+  res->name = xbt_strdup(name);
 
-	#ifdef CONTEXT_THREADS
-	  res->mutex = xbt_os_mutex_init();
-	  res->cond = xbt_os_cond_init();
-	#else
+#ifdef CONTEXT_THREADS
+  /* 
+   * initialize the semaphores used to schedule/yield 
+   * the process associated to the newly created context 
+   */
+  res->begin = xbt_os_sem_init(0);
+  res->end = xbt_os_sem_init(0);
+#else
 
-	  xbt_assert2(getcontext(&(res->uc)) == 0,
-	  "Error in context saving: %d (%s)", errno, strerror(errno));
-	  res->uc.uc_link = NULL;
-	  /*   res->uc.uc_link = &(current_context->uc); */
-	  /* WARNING : when this context is over, the current_context (i.e. the 
-	  father), is awaken... Theorically, the wrapper should prevent using 
-	  this feature. */
-	  res->uc.uc_stack.ss_sp = pth_skaddr_makecontext(res->stack, STACK_SIZE);
-	  res->uc.uc_stack.ss_size =
-	  pth_sksize_makecontext(res->stack, STACK_SIZE);
+  xbt_assert2(getcontext(&(res->uc)) == 0,
+              "Error in context saving: %d (%s)", errno, strerror(errno));
+  res->uc.uc_link = NULL;
+  /*   res->uc.uc_link = &(current_context->uc); */
+  /* WARNING : when this context is over, the current_context (i.e. the 
+     father), is awaken... Theorically, the wrapper should prevent using 
+     this feature. */
+  res->uc.uc_stack.ss_sp = pth_skaddr_makecontext(res->stack, STACK_SIZE);
+  res->uc.uc_stack.ss_size = pth_sksize_makecontext(res->stack, STACK_SIZE);
 
-	  res->exception = xbt_new(ex_ctx_t, 1);
-	  XBT_CTX_INITIALIZE(res->exception);
-	#endif				/* CONTEXT_THREADS or not */
+  res->exception = xbt_new(ex_ctx_t, 1);
+  XBT_CTX_INITIALIZE(res->exception);
+#endif /* CONTEXT_THREADS or not */
 
-	res->iwannadie = 0; /* useless but makes valgrind happy */
+  res->iwannadie = 0;           /* useless but makes valgrind happy */
 
-	res->argc = argc;
-	res->argv = argv;
-	res->startup_func = startup_func;
-	res->startup_arg = startup_arg;
-	res->cleanup_func = cleanup_func;
-	res->cleanup_arg = cleanup_arg;
+  res->argc = argc;
+  res->argv = argv;
+  res->startup_func = startup_func;
+  res->startup_arg = startup_arg;
+  res->cleanup_func = cleanup_func;
+  res->cleanup_arg = cleanup_arg;
 
-	xbt_swag_insert(res, context_living);
+  xbt_swag_insert(res, context_living);
 
-	return res;
+  return res;
 }
 
 /* Scenario for the end of a context:
@@ -239,45 +217,45 @@ xbt_context_new(	const char *name,
  *   (same than first case afterward)
  */
 
+
 /* Argument must be stopped first -- runs in maestro context */
-static void 
-xbt_context_free(xbt_context_t context) 
+static void xbt_context_free(xbt_context_t context)
 {
-	int i;
+  int i;
+
+  if (!context)
+    return;
 
-	if (!context)
-		return;
+  DEBUG1("Freeing %p", context);
+  free(context->name);
 
-	DEBUG1("Freeing %p", context);
-	free(context->name);
+  DEBUG0("Freeing arguments");
 
-	DEBUG0("Freeing arguments");
+  for (i = 0; i < context->argc; i++)
+    if (context->argv[i])
+      free(context->argv[i]);
 
-	for (i = 0; i < context->argc; i++)
-		if (context->argv[i])
-			free(context->argv[i]);
-	
-	if (context->argv)
-		free(context->argv);
+  if (context->argv)
+    free(context->argv);
 
-	#ifdef CONTEXT_THREADS
-	  DEBUG1("\t joining %p", (void *) context->thread);
+#ifdef CONTEXT_THREADS
+  DEBUG1("\t joining %p", (void *) context->thread);
 
-	  xbt_os_thread_join(context->thread, NULL);
+  xbt_os_thread_join(context->thread, NULL);
 
-	  xbt_os_mutex_destroy(context->mutex);
-	  xbt_os_cond_destroy(context->cond);
+  /* destroy the semaphore used to schedule/unshedule the process */
+	xbt_os_sem_destroy(context->begin);
+	xbt_os_sem_destroy(context->end);
 
-	  context->thread = NULL;
-	  context->mutex = NULL;
-	  context->cond = NULL;
-	#else
-	  if (context->exception)
-	  free(context->exception);
-	#endif
+  context->thread = NULL;
+  context->begin = NULL;
+  context->end = NULL;
+#else
+  if (context->exception)
+    free(context->exception);
+#endif
 
-	free(context);
-	return;
+  free(context);
 }
 
 /************************/
@@ -286,38 +264,26 @@ xbt_context_free(xbt_context_t context)
 static void xbt_context_stop(int retvalue);
 static void __xbt_context_yield(xbt_context_t context);
 
-static void *
-__context_wrapper(void *c)
+static void *__context_wrapper(void *c)
 {
-	xbt_context_t context = current_context;
+  xbt_context_t context = current_context;
 
-	#ifdef CONTEXT_THREADS
-	  context = (xbt_context_t) c;
-	  context->thread = xbt_os_thread_self();
-
-	  DEBUG3("**[ctx:%p;self:%p]** Lock creation_mutex %p ****", context,(void *) xbt_os_thread_self(), creation_mutex);
-	  xbt_os_mutex_lock(creation_mutex);
-	  xbt_os_mutex_lock(context->mutex);
-
-	  DEBUG4("**[ctx:%p;self:%p]** Releasing the creator (creation_cond %p,%p) ****",context, (void *) xbt_os_thread_self(), creation_cond,creation_mutex);
-	  xbt_os_cond_signal(creation_cond);
-	  xbt_os_mutex_unlock(creation_mutex);
-
-	  DEBUG4("**[ctx:%p;self:%p]** Going to Jail on lock %p and cond %p ****",context, (void *) xbt_os_thread_self(), context->mutex,context->cond);
-	  xbt_os_cond_wait(context->cond, context->mutex);
+#ifdef CONTEXT_THREADS
+  context = (xbt_context_t) c;
+  /*context->thread = xbt_os_thread_self();*/
 
-	  DEBUG3("**[ctx:%p;self:%p]** Unlocking individual %p ****",context, (void *) xbt_os_thread_self(), context->mutex);
-	  xbt_os_mutex_unlock(context->mutex);
+  /* signal its starting to the maestro and wait to start its job*/
+  yield(context);
 
-	#endif
+#endif
 
-	if (context->startup_func)
-		context->startup_func(context->startup_arg);
+  if (context->startup_func)
+    context->startup_func(context->startup_arg);
 
-	DEBUG0("Calling the main function");
+  DEBUG0("Calling the main function");
 
-	xbt_context_stop((context->code) (context->argc, context->argv));
-	return NULL;
+  xbt_context_stop((context->code) (context->argc, context->argv));
+  return NULL;
 }
 /** 
  * \param context the context to start
@@ -325,66 +291,44 @@ __context_wrapper(void *c)
  * Calling this function prepares \a context to be run. It will 
    however run effectively only when calling #xbt_context_schedule
  */
-void 
-xbt_context_start(xbt_context_t context)
+void xbt_context_start(xbt_context_t context)
 {
-	#ifdef CONTEXT_THREADS
-	/* Launch the thread */
-
-	  DEBUG3("**[ctx:%p;self:%p]** Locking creation_mutex %p ****", context,
-	  xbt_os_thread_self(), creation_mutex);
-	  xbt_os_mutex_lock(creation_mutex);
-
-	  DEBUG2("**[ctx:%p;self:%p]** Thread create ****", context,xbt_os_thread_self());
-	  context->thread = xbt_os_thread_create(context->name,__context_wrapper, context);
-	  DEBUG3("**[ctx:%p;self:%p]** Thread created : %p ****", context,xbt_os_thread_self(), context->thread);
-
-	  DEBUG4("**[ctx:%p;self:%p]** Going to jail on creation_cond/mutex (%p,%p) ****",context, xbt_os_thread_self(), creation_cond, creation_mutex);
-	  xbt_os_cond_wait(creation_cond, creation_mutex);
-	  DEBUG3("**[ctx:%p;self:%p]** Unlocking creation %p ****", context,xbt_os_thread_self(), creation_mutex);
-	  xbt_os_mutex_unlock(creation_mutex);
-	#else
-	  makecontext(&(context->uc), (void (*)(void)) __context_wrapper, 1, context);
-	#endif
+#ifdef CONTEXT_THREADS
+  /* create the process and start it */
+  context->thread = xbt_os_thread_create(context->name,__context_wrapper, context);
+  	
+  /* wait the starting of the newly created process */
+  xbt_os_sem_acquire(context->end);
+#else
+  makecontext(&(context->uc), (void (*)(void)) __context_wrapper, 1, context);
+#endif
 }
 
 /* Stops current context: calls user's cleanup function, kills os thread, and yields back to maestro */
-static void 
-xbt_context_stop(int retvalue) 
+static void xbt_context_stop(int retvalue)
 {
-	DEBUG1("--------- %p is exiting ---------", current_context);
-
-	if (current_context->cleanup_func) 
-	{
-		DEBUG0("Calling cleanup function");
-		current_context->cleanup_func(current_context->cleanup_arg);
-	}
-
-	DEBUG0("Putting context in the to_destroy set");
-	xbt_swag_remove(current_context, context_living);
-	xbt_swag_insert(current_context, context_to_destroy);
+  DEBUG1("--------- %p is exiting ---------", current_context);
 
-	DEBUG0("Yielding");
+  if (current_context->cleanup_func) {
+    DEBUG0("Calling cleanup function");
+    current_context->cleanup_func(current_context->cleanup_arg);
+  }
 
-	#ifdef CONTEXT_THREADS
-	  /* a java thread has called this function
-			 * - update the current context
-			 * - signal the condition of the main thread
-			 * - wait on its condition
-			 * - restore thr current contex
-			 */
+  DEBUG0("Putting context in the to_destroy set");
+  xbt_swag_remove(current_context, context_living);
+  xbt_swag_insert(current_context, context_to_destroy);
 
-			xbt_os_mutex_lock(master_mutex);
-			xbt_os_cond_signal(master_cond);
-			xbt_os_mutex_unlock(master_mutex);
-			xbt_os_thread_exit(NULL);	/* We should provide return value in case other wants it */
-		
-			
-	#else
-	  __xbt_context_yield(current_context);
-	#endif
+  DEBUG0("Yielding");
 
-	xbt_assert0(0, "You can't be here!");
+#ifdef CONTEXT_THREADS
+  /* signal to the maestro that it has finished */
+	xbt_os_sem_release(current_context->end);
+	/* exit*/
+	xbt_os_thread_exit(NULL);	/* We should provide return value in case other wants it */
+#else
+  __xbt_context_yield(current_context);
+#endif
+  THROW_IMPOSSIBLE;
 }
 
 
@@ -394,135 +338,111 @@ xbt_context_stop(int retvalue)
  * Should be called some time to time to free the memory allocated for contexts
  * that have finished executing their main functions.
  */
-void 
-xbt_context_empty_trash(void)
+void xbt_context_empty_trash(void)
 {
-	xbt_context_t context = NULL;
-	DEBUG1("Emptying trashbin (%d contexts to free)",xbt_swag_size(context_to_destroy));
-	
-	while ((context = xbt_swag_extract(context_to_destroy)))
-		xbt_context_free(context);
+  xbt_context_t context = NULL;
+
+  DEBUG1("Emptying trashbin (%d contexts to free)",
+         xbt_swag_size(context_to_destroy));
+
+  while ((context = xbt_swag_extract(context_to_destroy)))
+    xbt_context_free(context);
 }
 
 /*********************/
 /* context switching */
 /*********************/
 
-static void 
-__xbt_context_yield(xbt_context_t context)
+static void __xbt_context_yield(xbt_context_t context)
 {
-	#ifdef CONTEXT_THREADS
-	  xbt_context_t self;
-	#endif  
-	
-	  xbt_assert0(current_context, "You have to call context_init() first.");	
-	xbt_assert0(context,"Invalid argument");
-
-	if (current_context == context) 
-	{
-		DEBUG1("--------- current_context (%p) is yielding back to maestro ---------",context);
-	} 
-	else 
-	{
-		DEBUG2("--------- current_context (%p) is yielding to context(%p) ---------",current_context, context);
-	}
+  xbt_assert0(current_context, "You have to call context_init() first.");
+  xbt_assert0(context, "Invalid argument");
+
+  if (current_context == context) {
+    DEBUG1
+      ("--------- current_context (%p) is yielding back to maestro ---------",
+       context);
+  } else {
+    DEBUG2
+      ("--------- current_context (%p) is yielding to context(%p) ---------",
+       current_context, context);
+  }
+
+#ifdef CONTEXT_THREADS
 
-	#ifdef CONTEXT_THREADS
+  if(current_context != init_context && !context->iwannadie)
+	{/* it's a process and it doesn't wants to die (xbt_context_yield()) */
 		
-	  self = current_context;
-	
-	  if(is_main_thread())
-	  {
-			/* the main thread has called this function
-			 * - update the current context
-			 * - signal the condition of the process to run
-			 * - wait on its condition
-			 * - restore thr current contex
-			 */
-
-			xbt_os_mutex_lock(master_mutex);
-			xbt_os_mutex_lock(context->mutex);
-			
-			/* update the current context */
-			current_context = context;
-			xbt_os_cond_signal(context->cond);
-			xbt_os_mutex_unlock(context->mutex);
-			
-			xbt_os_cond_wait(master_cond, master_mutex);
-			xbt_os_mutex_unlock(master_mutex);
-			/* retore the current context */
-			current_context = self;
-			
-		}
-		else
-		{
-			/* a java thread has called this function
-			 * - update the current context
-			 * - signal the condition of the main thread
-			 * - wait on its condition
-			 * - restore thr current contex
-			 */
-
-			xbt_os_mutex_lock(master_mutex);
-			xbt_os_mutex_lock(context->mutex);
-			/* update the current context */
-			current_context = context;
-			xbt_os_cond_signal(master_cond);
-			xbt_os_mutex_unlock(master_mutex);
-			xbt_os_cond_wait(context->cond, context->mutex);
-			xbt_os_mutex_unlock(context->mutex);
-			/* retore the current context */
-			current_context = self;
-		}
-
-	#else				/* use SUSv2 contexts */
-	  VOIRP(current_context);
-	  VOIRP(current_context->save);
-
-	  VOIRP(context);
-	  VOIRP(context->save);
-
-	  int return_value = 0;
-
-	if (context->save == NULL) 
-	{
-	  xbt_assert(context == current_context);
-	  DEBUG1("[%p] **** Yielding to somebody else ****", current_context);
-	  DEBUG2("Saving current_context value (%p) to context(%p)->save",current_context, context);
-	  context->save = current_context;
-	DEBUG1("current_context becomes  context(%p) ", context);
-	current_context = context;
-	DEBUG1
-	("Current position memorized (context->save). Jumping to context (%p)",
-	context);
-	return_value = swapcontext(&(context->save->uc), &(context->uc));
-	xbt_assert0((return_value == 0), "Context swapping failure");
-	DEBUG1("I am (%p). Coming back\n", context);
-	} else {
-	xbt_context_t old_context = context->save;
-	DEBUG1("[%p] **** Back ! ****", context);
-	DEBUG2("Setting current_context (%p) to context(%p)->save",
-	current_context, context);
-	current_context = context->save;
-	DEBUG1("Setting context(%p)->save to NULL", context);
-	context->save = NULL;
-	DEBUG2("Current position memorized (%p). Jumping to context (%p)",
-	context, old_context);
-	return_value = swapcontext(&(context->uc), &(old_context->uc));
-	xbt_assert0((return_value == 0), "Context swapping failure");
-	DEBUG1("I am (%p). Coming back\n", context);
-	}
-	#endif
-	
-	if (current_context->iwannadie)
-		xbt_context_stop(1);
+		/* save the current context */
+		xbt_context_t self = current_context;
 
-	return;
-}
+		/* update the current context to this context */
+		current_context = context;
+		
+		/* yield itself */
+		yield(context);
+		
+		/* restore the current context to the previously saved context */
+		current_context = self;
+	}
+	else
+	{ /* maestro wants to schedule a process or a process wants to die (xbt_context_schedule() or xbt_context_kill())*/
+		
+		/* save the current context */
+		xbt_context_t self = current_context;
+		
+		/* update the current context */
+		current_context = context;
 
+		/* schedule the process associated with this context */
+		schedule(context);
 
+		/* restore the current context to the previously saved context */
+		current_context = self;
+	}
 
+#else /* use SUSv2 contexts */
+  VOIRP(current_context);
+  VOIRP(current_context->save);
+
+  VOIRP(context);
+  VOIRP(context->save);
+
+  int return_value = 0;
+
+  if (context->save == NULL) {
+    DEBUG1("[%p] **** Yielding to somebody else ****", current_context);
+    DEBUG2("Saving current_context value (%p) to context(%p)->save",
+           current_context, context);
+    context->save = current_context;
+    DEBUG1("current_context becomes  context(%p) ", context);
+    current_context = context;
+    DEBUG1
+      ("Current position memorized (context->save). Jumping to context (%p)",
+       context);
+    return_value = swapcontext(&(context->save->uc), &(context->uc));
+    xbt_assert0((return_value == 0), "Context swapping failure");
+    DEBUG1("I am (%p). Coming back\n", context);
+  } else {
+    xbt_context_t old_context = context->save;
+
+    DEBUG1("[%p] **** Back ! ****", context);
+    DEBUG2("Setting current_context (%p) to context(%p)->save",
+           current_context, context);
+    current_context = context->save;
+    DEBUG1("Setting context(%p)->save to NULL", context);
+    context->save = NULL;
+    DEBUG2("Current position memorized (%p). Jumping to context (%p)",
+           context, old_context);
+    return_value = swapcontext(&(context->uc), &(old_context->uc));
+    xbt_assert0((return_value == 0), "Context swapping failure");
+    DEBUG1("I am (%p). Coming back\n", context);
+  }
+#endif
 
+  if (current_context->iwannadie)
+    xbt_context_stop(1);
+}
 
 /** 
  * Calling this function makes the current context yield. The context
@@ -532,8 +452,7 @@ __xbt_context_yield(xbt_context_t context)
  * Only the processes can call this function, giving back the control
  * to the maestro
  */
-void 
-xbt_context_yield(void)
+void xbt_context_yield(void)
 {
   __xbt_context_yield(current_context);
 }
@@ -547,11 +466,11 @@ xbt_context_yield(void)
  * 
  * Only the maestro can call this function to run a given process.
  */
-void 
-xbt_context_schedule(xbt_context_t context)
+void xbt_context_schedule(xbt_context_t context)
 {
   DEBUG1("Scheduling %p", context);
-  xbt_assert0((current_context == init_context),"You are not supposed to run this function here!");
+  xbt_assert0((current_context == init_context),
+              "You are not supposed to run this function here!");
   __xbt_context_yield(context);
 }
 
@@ -561,27 +480,20 @@ xbt_context_schedule(xbt_context_t context)
  *
  * This function simply kills \a context... scarry isn't it ?
  */
-void 
-xbt_context_kill(xbt_context_t context)
+void xbt_context_kill(xbt_context_t context)
 {
   DEBUG1("Killing %p", context);
 
   context->iwannadie = 1;
-  
+
   DEBUG1("Scheduling %p", context);
   __xbt_context_yield(context);
   DEBUG1("End of Scheduling %p", context);
-
-  return;
 }
 
 /* Java cruft I'm gonna kill in the next cleanup round */
 void  xbt_context_set_jprocess(xbt_context_t context, void *jp){}
 void* xbt_context_get_jprocess(xbt_context_t context){return NULL;}
-void  xbt_context_set_jmutex(xbt_context_t context,void *jm){}
-void* xbt_context_get_jmutex(xbt_context_t context){return NULL;}
-void  xbt_context_set_jcond(xbt_context_t context,void *jc){}
-void* xbt_context_get_jcond(xbt_context_t context){return NULL;}
 void  xbt_context_set_jenv(xbt_context_t context,void* je){}
 void* xbt_context_get_jenv(xbt_context_t context){return NULL;}