X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/caffa65a64dc6c71dbd7ec60af00ec0da51073a9..797980252c46782a2b6afdc729088af5acff79bf:/src/xbt/context.c

diff --git a/src/xbt/context.c b/src/xbt/context.c
index 96476aa082..136411cf09 100644
--- a/src/xbt/context.c
+++ b/src/xbt/context.c
@@ -16,18 +16,6 @@
 #include "xbt/xbt_os_thread.h"
 #include "xbt/ex_interface.h"
 
-#ifdef CONTEXT_THREADS
- /* This file (context.c) is only loaded in libsimgrid, not libgras.
-  * xbt_os_thread is only loaded in libgras explicitly, and we need it in 
-  *    libsimgrid, but only when it is the backend used to implement the 
-  *    xbt_context. So, do load it on need.
-  */
-#include "xbt/xbt_os_thread.c"
-#else
-/* if not, load stubs so that all symbols get resolved anyway */
-#include "xbt/xbt_os_thread_stubs.c"
-#endif
-
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_ctx, xbt, "Context");
 
 #define VOIRP(expr) DEBUG1("  {" #expr " = %p }", expr)
@@ -36,128 +24,213 @@ 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;
-#endif
 
-static void __context_exit(xbt_context_t context, int value);
-static void __xbt_context_yield(xbt_context_t context)
+
+
+/********************/
+/* Module init/exit */
+/********************/
+#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)
 {
-  xbt_assert0(current_context, "You have to call context_init() first.");
+  return current_context->exception;
+}
 
-  DEBUG2
-      ("--------- current_context (%p) is yielding to context(%p) ---------",
-       current_context, context);
+/* callback: termination */
+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
 
 #ifdef CONTEXT_THREADS
-  if (context) {
-    xbt_context_t self = current_context;
-    DEBUG2("[%p] **** Locking ctx %p ****", self, context);
-    xbt_os_mutex_lock(context->mutex);
-    DEBUG1("[%p] **** Updating current_context ****", self);
-    current_context = context;
-    DEBUG1("[%p] **** Releasing the prisonner ****", self);
-    xbt_os_cond_signal(context->cond);
-    DEBUG3("[%p] **** Going to jail on individual %p/%p ****", self,
-	   context->cond, context->mutex);
-    xbt_os_cond_wait(context->cond, context->mutex);
-    DEBUG2("[%p] **** Unlocking individual %p ****", self, context->mutex);
-    xbt_os_mutex_unlock(context->mutex);
-    DEBUG1("[%p] **** Updating current_context ****", self);
-    current_context = self;
+
+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
+ */
+/* @{ */
+/** Context module initialization
+ *
+ * \warning It has to be called before using any other function of this module.
+ */
+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);
+    
+    #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
   }
-#else				/* use SUSv2 contexts */
-  if (current_context)
-    VOIRP(current_context->save);
+}
 
-  VOIRP(context);
+/** 
+ * This function kill all existing context and free all the memory
+ * that has been allocated in this module.
+ */
+void xbt_context_exit(void)
+{
+  xbt_context_t context = NULL;
 
-  if (context)
-    VOIRP(context->save);
-
-  if (context) {
-
-    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);
+  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
-  if (current_context->iwannadie)
-    __context_exit(current_context, 1);
 
-  return;
+  free(init_context);
+  init_context = current_context = NULL;
+
+  xbt_context_empty_trash();
+  xbt_swag_free(context_to_destroy);
+  xbt_swag_free(context_living);
+
 }
 
-static void xbt_context_free(xbt_context_t context)
+
+/*******************************/
+/* Object creation/destruction */
+/*******************************/
+/** 
+ * \param code a main function
+ * \param startup_func a function to call when running the context for
+ *      the first time and just before the main function \a code
+ * \param startup_arg the argument passed to the previous function (\a startup_func)
+ * \param cleanup_func a function to call when running the context, just after 
+        the termination of the main function \a code
+ * \param cleanup_arg the argument passed to the previous function (\a cleanup_func)
+ * \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[]
+  )
 {
-  if (!context)
-    return;
-  DEBUG1("Freeing %p", context);
+  xbt_context_t res = NULL;
+
+  res = xbt_new0(s_xbt_context_t, 1);
+
+  res->code = code;
+  res->name = xbt_strdup(name);
+
 #ifdef CONTEXT_THREADS
-  /*DEBUG1("\t joining %p",(void *)context->thread->t); */
-  DEBUG1("\t joining %p", (void *) context->thread);
+  /* 
+   * 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_os_thread_join(context->thread, NULL);
+  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);
 
-  DEBUG1("\t mutex_destroy %p", (void *) context->mutex);
-  xbt_os_mutex_destroy(context->mutex);
-  DEBUG1("\t cond_destroy %p", (void *) context->cond);
-  xbt_os_cond_destroy(context->cond);
+  res->exception = xbt_new(ex_ctx_t, 1);
+  XBT_CTX_INITIALIZE(res->exception);
+#endif /* CONTEXT_THREADS or not */
 
-  context->thread = NULL;
-  context->mutex = NULL;
-  context->cond = NULL;
-#endif
+  res->iwannadie = 0;           /* useless but makes valgrind happy */
 
-  if (context->exception)
-    free(context->exception);
+  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;
 
-  free(context);
-  return;
+  xbt_swag_insert(res, context_living);
+
+  return res;
 }
 
-static void __context_exit(xbt_context_t context, int value)
+/* Scenario for the end of a context:
+ * 
+ * CASE 1: death after end of function
+ *   __context_wrapper, called by os thread, calls xbt_context_stop after user code stops
+ *   xbt_context_stop calls user cleanup_func if any (in context settings),
+ *                    add current to trashbin
+ *                    yields back to maestro (destroy os thread on need)
+ *   From time to time, maestro calls xbt_context_empty_trash, 
+ *       which maps xbt_context_free on the content
+ *   xbt_context_free frees some more memory, 
+ *                    joins os thread
+ * 
+ * CASE 2: brutal death
+ *   xbt_context_kill (from any context)
+ *                    set context->wannadie to 1
+ *                    yields to the context
+ *   the context is awaken in the middle of __yield. 
+ *   At the end of it, it checks that wannadie == 1, and call xbt_context_stop
+ *   (same than first case afterward)
+ */
+
+
+/* Argument must be stopped first -- runs in maestro context */
+static void xbt_context_free(xbt_context_t context)
 {
   int i;
 
-  DEBUG1("--------- %p is exiting ---------", context);
+  if (!context)
+    return;
 
-  DEBUG0("Calling cleanup functions");
-  if (context->cleanup_func) {
-    DEBUG0("Calling cleanup function");
-    context->cleanup_func(context->cleanup_arg);
-  }
+  DEBUG1("Freeing %p", context);
+  free(context->name);
 
   DEBUG0("Freeing arguments");
+
   for (i = 0; i < context->argc; i++)
     if (context->argv[i])
       free(context->argv[i]);
@@ -165,59 +238,42 @@ static void __context_exit(xbt_context_t context, int value)
   if (context->argv)
     free(context->argv);
 
-  DEBUG0("Putting context in the to_destroy set");
-  xbt_swag_remove(context, context_living);
-  xbt_swag_insert(context, context_to_destroy);
-  DEBUG0("Context put in the to_destroy set");
+#ifdef CONTEXT_THREADS
+  DEBUG1("\t joining %p", (void *) context->thread);
 
-  DEBUG0("Yielding");
+  xbt_os_thread_join(context->thread, NULL);
 
-#ifdef CONTEXT_THREADS
-  DEBUG2("[%p] **** Locking %p ****", context, context->mutex);
-  xbt_os_mutex_lock(context->mutex);
-/* 	DEBUG1("[%p] **** Updating current_context ****"); */
-/* 	current_context = context; */
-  DEBUG1("[%p] **** Releasing the prisonner ****", context);
-  xbt_os_cond_signal(context->cond);
-  DEBUG2("[%p] **** Unlocking individual %p ****", context,
-	 context->mutex);
-  xbt_os_mutex_unlock(context->mutex);
-  DEBUG1("[%p] **** Exiting ****", context);
-  xbt_os_thread_exit(NULL);	// We should provide return value in case other wants it
+  /* 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->begin = NULL;
+  context->end = NULL;
 #else
-  __xbt_context_yield(context);
+  if (context->exception)
+    free(context->exception);
 #endif
-  xbt_assert0(0, "You can't be here!");
+
+  free(context);
 }
 
+/************************/
+/* Start/stop a context */
+/************************/
+static void xbt_context_stop(int retvalue);
+static void __xbt_context_yield(xbt_context_t context);
+
 static void *__context_wrapper(void *c)
 {
   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);
+  /*context->thread = xbt_os_thread_self();*/
 
-  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);
-
-  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
 
@@ -226,60 +282,57 @@ static void *__context_wrapper(void *c)
 
   DEBUG0("Calling the main function");
 
-  __context_exit(context, (context->code) (context->argc, context->argv));
+  xbt_context_stop((context->code) (context->argc, context->argv));
   return NULL;
 }
-
-/* callback: context fetching */
-static ex_ctx_t *__context_ex_ctx(void)
+/** 
+ * \param context the context to start
+ * 
+ * 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)
 {
-  return current_context->exception;
+#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
 }
 
-/* callback: termination */
-static void __context_ex_terminate(xbt_ex_t * e)
+/* Stops current context: calls user's cleanup function, kills os thread, and yields back to maestro */
+static void xbt_context_stop(int retvalue)
 {
-  xbt_ex_display(e);
+  DEBUG1("--------- %p is exiting ---------", current_context);
 
-  abort();
-  /* FIXME: there should be a configuration variable to choose this
-     if(current_context!=init_context) 
-     __context_exit(current_context, e->value);
-     else
-     abort();
-   */
-}
+  if (current_context->cleanup_func) {
+    DEBUG0("Calling cleanup function");
+    current_context->cleanup_func(current_context->cleanup_arg);
+  }
 
-/** \name Functions 
- *  \ingroup XBT_context
- */
-/* @{ */
-/** Context module initialization
- *
- * \warning It has to be called before using any other function of this module.
- */
-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);
+  DEBUG0("Putting context in the to_destroy set");
+  xbt_swag_remove(current_context, context_living);
+  xbt_swag_insert(current_context, context_to_destroy);
+
+  DEBUG0("Yielding");
 
-    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;
-    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
-    creation_mutex = xbt_os_mutex_init();
-    creation_cond = xbt_os_cond_init();
+  /* 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;
 }
 
+
+
 /** Garbage collection
  *
  * Should be called some time to time to free the memory allocated for contexts
@@ -288,103 +341,116 @@ void xbt_context_init(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));
+         xbt_swag_size(context_to_destroy));
+
   while ((context = xbt_swag_extract(context_to_destroy)))
     xbt_context_free(context);
 }
 
-/** 
- * \param context the context to start
- * 
- * 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)
-{
-#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_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
-  return;
-}
+/*********************/
+/* context switching */
+/*********************/
 
-/** 
- * \param code a main function
- * \param startup_func a function to call when running the context for
- *      the first time and just before the main function \a code
- * \param startup_arg the argument passed to the previous function (\a startup_func)
- * \param cleanup_func a function to call when running the context, just after 
-        the termination of the main function \a code
- * \param cleanup_arg the argument passed to the previous function (\a cleanup_func)
- * \param argc first argument of function \a code
- * \param argv seconde argument of function \a code
- */
-xbt_context_t xbt_context_new(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[])
+static void __xbt_context_yield(xbt_context_t context)
 {
-  xbt_context_t res = NULL;
-
-  res = xbt_new0(s_xbt_context_t, 1);
+  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);
+  }
 
-  res->code = code;
 #ifdef CONTEXT_THREADS
-  res->mutex = xbt_os_mutex_init();
-  res->cond = xbt_os_cond_init();
-#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);
-#endif				/* CONTEXT_THREADS or not */
+  if(current_context != init_context && !context->iwannadie)
+	{/* it's a process and it doesn't wants to die (xbt_context_yield()) */
+		
+		/* save the current context */
+		xbt_context_t self = current_context;
+
+		/* 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);
 
-  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->exception = xbt_new(ex_ctx_t, 1);
-  XBT_CTX_INITIALIZE(res->exception);
+  VOIRP(context);
+  VOIRP(context->save);
 
-  xbt_swag_insert(res, context_living);
+  int return_value = 0;
 
-  return res;
+  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
  * that scheduled it returns from xbt_context_schedule as if nothing
  * had happened.
+ * 
+ * Only the processes can call this function, giving back the control
+ * to the maestro
  */
 void xbt_context_yield(void)
 {
@@ -397,42 +463,17 @@ void xbt_context_yield(void)
  * Calling this function blocks the current context and schedule \a context.  
  * When \a context will call xbt_context_yield, it will return
  * to this function as if nothing had happened.
+ * 
+ * Only the maestro can call this function to run a given process.
  */
 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!");
+              "You are not supposed to run this function here!");
   __xbt_context_yield(context);
 }
 
-/** 
- * This function kill all existing context and free all the memory
- * that has been allocated in this module.
- */
-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);
-    }
-  }
-  free(init_context->exception);
-  free(init_context);
-  init_context = current_context = NULL;
-
-  xbt_context_empty_trash();
-  xbt_swag_free(context_to_destroy);
-  xbt_swag_free(context_living);
-
-#ifdef CONTEXT_THREADS
-  xbt_os_mutex_destroy(creation_mutex);
-  xbt_os_cond_destroy(creation_cond);
-#endif
-}
 
 /** 
  * \param context poor victim
@@ -444,44 +485,16 @@ 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;
-}
-
-/* @} */
-
-/* Stub of the stuff to interact with JAVA threads; not used in native lib */
-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;
-}
+/* 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_jenv(xbt_context_t context,void* je){}
+void* xbt_context_get_jenv(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;
-}
+/* @} */