From: mquinson <mquinson@48e7efb5-ca39-0410-a469-dd3cf9ba447f>
Date: Fri, 16 Mar 2007 10:34:50 +0000 (+0000)
Subject: use two conditions during the thread creation phase to make sure that it is *really... 
X-Git-Tag: v3.3~2072
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/c8c1bbfc07873fbd9f987e3b2499dc19ec02c2fa?ds=sidebyside

use two conditions during the thread creation phase to make sure that it is *really* impossible to signal the condition and get our own signal the line after. The pthread lib under linux works just fine on such a borderline case, but it may not be the case of any thread implementation. Namly, our xbt_thread implem for windows is not that permissive. It could be possible to make our implem more robust, but it is ways easier to make our user code less demanding


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@3287 48e7efb5-ca39-0410-a469-dd3cf9ba447f
---

diff --git a/src/xbt/context.c b/src/xbt/context.c
index 9b3dd1111a..f80d0d812b 100644
--- a/src/xbt/context.c
+++ b/src/xbt/context.c
@@ -33,6 +33,8 @@ 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;
+static xbt_mutex_t creation_mutex;
+static xbt_thcond_t creation_cond;
 
 static void __context_exit(xbt_context_t context ,int value);
 static void __xbt_context_yield(xbt_context_t context)
@@ -182,12 +184,14 @@ __context_wrapper(void* c) {
 	context->thread = xbt_thread_self();
         
 	DEBUG2("**[%p:%p]** Lock ****",context,(void*)xbt_thread_self());
-	xbt_mutex_lock(context->mutex);
+	xbt_mutex_lock(creation_mutex);
 	
-	DEBUG2("**[%p:%p]** Releasing the prisonner ****",context,(void*)xbt_thread_self());
-	xbt_thcond_signal(context->cond);
+	DEBUG2("**[%p:%p]** Releasing the creator ****",context,(void*)xbt_thread_self());
+	xbt_thcond_signal(creation_cond);
+	xbt_mutex_unlock(creation_mutex);
 	
 	DEBUG2("**[%p:%p]** Going to Jail ****",context,(void*)xbt_thread_self());
+	xbt_mutex_lock(context->mutex);
 	xbt_thcond_wait(context->cond, context->mutex);
 	
 	DEBUG2("**[%p:%p]** Unlocking ****",context,(void*)xbt_thread_self());
@@ -244,6 +248,8 @@ void xbt_context_init(void)
 		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);
+	        creation_mutex = xbt_mutex_init();
+	        creation_cond = xbt_thcond_init();
 	}
 }
 
@@ -272,16 +278,16 @@ void xbt_context_start(xbt_context_t context)
 	#ifdef CONTEXT_THREADS
 	/* Launch the thread */
 	DEBUG1("**[%p]** Locking ****",context);
-	xbt_mutex_lock(context->mutex);
+	xbt_mutex_lock(creation_mutex);
    
 	DEBUG1("**[%p]** Thread create ****",context);
         context->thread = xbt_thread_create(__context_wrapper, context);   
 	DEBUG2("**[%p]** Thread created : %p ****",context,context->thread);
    
 	DEBUG1("**[%p]** Going to jail ****",context);
-	xbt_thcond_wait(context->cond, context->mutex);
+	xbt_thcond_wait(creation_cond, creation_mutex);
 	DEBUG1("**[%p]** Unlocking ****",context);
-	xbt_mutex_unlock(context->mutex);
+	xbt_mutex_unlock(creation_mutex);
 	#else
 	makecontext (&(context->uc), (void (*) (void)) __context_wrapper,1, context);
 	#endif
@@ -313,7 +319,7 @@ xbt_context_t xbt_context_new(xbt_context_function_t code,
 	res->mutex = xbt_mutex_init();
         res->cond = xbt_thcond_init();
 	#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->uc.uc_link = &(current_context->uc); */
@@ -382,6 +388,8 @@ void xbt_context_exit(void) {
 	xbt_swag_free(context_living);
 	
 	init_context = current_context = NULL ;
+	xbt_mutex_destroy(creation_mutex);
+	xbt_thcond_destroy(creation_cond);   
 }
 
 /**