X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/28800061ff3b3913fc2e1cfbdc9d15211cf3a3f2..3de9bd297b49c6d0b62a18b21aef156da297dea7:/src/xbt/context.c

diff --git a/src/xbt/context.c b/src/xbt/context.c
index 6ee172610e..bc16f82279 100644
--- a/src/xbt/context.c
+++ b/src/xbt/context.c
@@ -3,7 +3,7 @@
 /* a fast and simple context switching library                              */
 
 /* Copyright (c) 2004 Arnaud Legrand.                                       */
-/* Copyright (c) 2004 Martin Quinson.                                       */
+/* Copyright (c) 2004, 2005 Martin Quinson.                                 */
 /* All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
@@ -14,106 +14,119 @@
 #include "xbt/error.h"
 #include "xbt/dynar.h"
 #include "gras_config.h"
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(context, xbt, "Context");
 
-/* #define WARNING(format, ...) (fprintf(stderr, "[%s , %s : %d] ", __FILE__, __FUNCTION__, __LINE__),\ */
-/*                               fprintf(stderr, format, ## __VA_ARGS__), \ */
-/*                               fprintf(stderr, "\n")) */
-/* #define VOIRP(expr) WARNING("  {" #expr " = %p }", expr) */
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(context, xbt, "Context");
 
-#ifndef HAVE_UCONTEXT_H
-/* don't want to play with conditional compilation in automake tonight, sorry.
-   include directly the c file from here when needed. */
-# include "context_win32.c" 
-#endif
+#define VOIRP(expr) DEBUG1("  {" #expr " = %p }", expr)
 
 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;
 
+#ifndef USE_PTHREADS /* USE_PTHREADS and USE_CONTEXT are exclusive */
+# ifndef HAVE_UCONTEXT_H
+/* don't want to play with conditional compilation in automake tonight, sorry.
+   include directly the c file from here when needed. */
+#  include "context_win32.c" 
+# endif
+#endif
+
 static void __xbt_context_yield(xbt_context_t context)
 {
   int return_value = 0;
 
   xbt_assert0(current_context,"You have to call context_init() first.");
   
-/*   WARNING("--------- current_context (%p) is yielding to context(%p) ---------",current_context,context); */
-/*   VOIRP(current_context); */
-/*   if(current_context) VOIRP(current_context->save); */
-/*   VOIRP(context); */
-/*   if(context) VOIRP(context->save); */
+  DEBUG2("--------- current_context (%p) is yielding to context(%p) ---------",
+	 current_context,context);
+
+#ifdef USE_PTHREADS
+  if (context) {
+    xbt_context_t self = current_context;
+    DEBUG0("**** Locking ****");
+    pthread_mutex_lock(&(context->mutex));
+    DEBUG0("**** Updating current_context ****");
+    current_context = context;
+    DEBUG0("**** Releasing the prisonner ****");
+    pthread_cond_signal(&(context->cond));
+    DEBUG0("**** Going to jail ****");
+    pthread_cond_wait(&(context->cond), &(context->mutex));
+    DEBUG0("**** Unlocking ****");
+    pthread_mutex_unlock(&(context->mutex));
+    DEBUG0("**** Updating current_context ****");
+    current_context = self;
+  }
+#else
+  if(current_context)
+    VOIRP(current_context->save);
 
+  VOIRP(context);
+  if(context) VOIRP(context->save);
   if (context) {
     if(context->save==NULL) {
-/*       WARNING("**** Yielding to somebody else ****"); */
-/*       WARNING("Saving current_context value (%p) to context(%p)->save",current_context,context); */
+      DEBUG0("**** Yielding to somebody else ****");
+      DEBUG2("Saving current_context value (%p) to context(%p)->save",current_context,context);
       context->save = current_context ;
-/*       WARNING("current_context becomes  context(%p) ",context); */
+      DEBUG1("current_context becomes  context(%p) ",context);
       current_context = context ;
-/*       WARNING("Current position memorized (context->save). Jumping to context (%p)",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");
-/*       WARNING("I am (%p). Coming back\n",context); */
+      DEBUG1("I am (%p). Coming back\n",context);
     } else {
       xbt_context_t old_context = context->save ;
-/*       WARNING("**** Back ! ****"); */
-/*       WARNING("Setting current_context (%p) to context(%p)->save",current_context,context); */
+      DEBUG0("**** Back ! ****");
+      DEBUG2("Setting current_context (%p) to context(%p)->save",current_context,context);
       current_context = context->save ;
-/*       WARNING("Setting context(%p)->save to NULL",context); */
+      DEBUG1("Setting context(%p)->save to NULL",context);
       context->save = NULL ;
-/*       WARNING("Current position memorized (%p). Jumping to context (%p)",context,old_context); */
+      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");
-/*       WARNING("I am (%p). Coming back\n",context); */
+      DEBUG1("I am (%p). Coming back\n",context);
     }
   }
-
+#endif
   return;
 }
 
 static void xbt_context_destroy(xbt_context_t context)
 {
-  xbt_free(context);
-
+#ifdef USE_PTHREADS
+  xbt_free(context->thread);
+  pthread_mutex_destroy(&(context->mutex));
+  pthread_cond_destroy(&(context->cond));
+#endif
+  free(context);
   return;
 }
 
-void xbt_context_init(void)
-{
-  if(!current_context) {
-    current_context = init_context = xbt_new0(s_xbt_context_t,1);
-    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);
-  }
-}
-
-void xbt_context_empty_trash(void)
-{
-  xbt_context_t context=NULL;
-
-  while((context=xbt_swag_extract(context_to_destroy)))
-    xbt_context_destroy(context);
-}
-
 static void *__context_wrapper(void *c)
 {
   xbt_context_t context = c;
   int i;
 
-/*   msg_global->current_process = process; */
+#ifdef USE_PTHREADS
+  DEBUG0("**** Lock ****");
+  pthread_mutex_lock(&(context->mutex));
+  DEBUG0("**** Releasing the prisonner ****");
+  pthread_cond_signal(&(context->cond));
+  DEBUG0("**** Going to Jail ****");
+  pthread_cond_wait(&(context->cond), &(context->mutex));
+  DEBUG0("**** Unlocking ****");
+  pthread_mutex_unlock(&(context->mutex));
+#endif
 
   if(context->startup_func)
     context->startup_func(context->startup_arg);
 
-  /*  WARNING("Calling the main function"); */
-  /*   xbt_context_yield(context); */
+   DEBUG0("Calling the main function");
   (context->code) (context->argc,context->argv);
 
   for(i=0;i<context->argc; i++) 
-    if(context->argv[i]) xbt_free(context->argv[i]);
-  if(context->argv) xbt_free(context->argv);
+    if(context->argv[i]) free(context->argv[i]);
+  if(context->argv) free(context->argv);
 
   if(context->cleanup_func)
     context->cleanup_func(context->cleanup_arg);
@@ -126,16 +139,74 @@ static void *__context_wrapper(void *c)
   return NULL;
 }
 
-void xbt_context_start(xbt_context_t context) 
+/** \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)
 {
-/*   xbt_fifo_insert(msg_global->process, process); */
-/*   xbt_fifo_insert(msg_global->process_to_run, process); */
+  if(!current_context) {
+    current_context = init_context = xbt_new0(s_xbt_context_t,1);
+    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);
+  }
+}
 
+/** Garbage collection
+ *
+ * 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)
+{
+  xbt_context_t context=NULL;
+
+  while((context=xbt_swag_extract(context_to_destroy)))
+    xbt_context_destroy(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 USE_PTHREADS
+  /* Launch the thread */
+  DEBUG0("**** Locking ****");
+  pthread_mutex_lock(&(context->mutex));
+  DEBUG0("**** Pthread create ****");
+  xbt_assert0(!pthread_create(context->thread, NULL, __context_wrapper, context),
+	      "Unable to create a thread.");
+  DEBUG0("**** Going to jail ****");
+  pthread_cond_wait(&(context->cond), &(context->mutex));
+  DEBUG0("**** Unlocking ****");
+  pthread_mutex_unlock(&(context->mutex));  
+#else
   makecontext (&(context->uc), (void (*) (void)) __context_wrapper,
 	       1, context);
+#endif
   return;
 }
 
+/** 
+ * \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_context_function_t code, 
 			      void_f_pvoid_t startup_func, void *startup_arg,
 			      void_f_pvoid_t cleanup_func, void *cleanup_arg,
@@ -145,18 +216,24 @@ xbt_context_t xbt_context_new(xbt_context_function_t code,
 
   res = xbt_new0(s_xbt_context_t,1);
 
-  xbt_assert0(getcontext(&(res->uc))==0,"Error in context saving.");
-
   res->code = code;
+#ifdef USE_PTHREADS
+  res->thread = xbt_new0(pthread_t,1);
+  xbt_assert0(!pthread_mutex_init(&(res->mutex), NULL), "Mutex initialization error");
+  xbt_assert0(!pthread_cond_init(&(res->cond), NULL), "Condition initialization error");
+#else
+  /* FIXME: strerror is not thread safe */
+  xbt_assert2(getcontext(&(res->uc))==0,"Error in context saving: %d (%s)", errno, strerror(errno));
   res->uc.uc_link = NULL;
-  res->argc = argc;
-  res->argv = argv;
-/*   res->uc.uc_link = &(current_context->uc); */
+  /*   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 = res->stack;
   res->uc.uc_stack.ss_size = STACK_SIZE;
+#endif
+  res->argc = argc;
+  res->argv = argv;
   res->startup_func = startup_func;
   res->startup_arg = startup_arg;
   res->cleanup_func = cleanup_func;
@@ -167,12 +244,23 @@ xbt_context_t xbt_context_new(xbt_context_function_t code,
   return res;
 }
 
-
+/** 
+ * Calling this function makes the current context yield. The context
+ * that scheduled it returns from xbt_context_schedule as if nothing
+ * had happened.
+ */
 void xbt_context_yield(void)
 {
   __xbt_context_yield(current_context);
 }
 
+/** 
+ * \param context the winner
+ *
+ * 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.
+ */
 void xbt_context_schedule(xbt_context_t context)
 {
   xbt_assert0((current_context==init_context),
@@ -180,6 +268,10 @@ void xbt_context_schedule(xbt_context_t context)
   __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;
 
@@ -194,14 +286,19 @@ void xbt_context_exit(void) {
   init_context = current_context = NULL ;
 }
 
+/** 
+ * \param context poor victim
+ *
+ * This function simply kills \a context... scarry isn't it ?
+ */
 void xbt_context_free(xbt_context_t context)
 {
   int i ;
 
   xbt_swag_remove(context, context_living);  
   for(i=0;i<context->argc; i++) 
-    if(context->argv[i]) xbt_free(context->argv[i]);
-  if(context->argv) xbt_free(context->argv);
+    if(context->argv[i]) free(context->argv[i]);
+  if(context->argv) free(context->argv);
   
   if(context->cleanup_func)
     context->cleanup_func(context->cleanup_arg);
@@ -209,3 +306,4 @@ void xbt_context_free(xbt_context_t context)
 
   return;
 }
+/* @} */