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
+
/********************/
#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
+
+
+static void
+schedule(xbt_context_t c);
+
+static void
+unschedule(xbt_context_t c);
+
+
+static void
+schedule(xbt_context_t c)
+{
+ xbt_os_sem_post(c->begin);
+ xbt_os_sem_wait(c->end);
+}
+
+static void unschedule(xbt_context_t c)
+{
+ xbt_os_sem_post(c->end);
+ xbt_os_sem_wait(c->begin);
+}
/** \name Functions
* \ingroup XBT_context
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 */
+ 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_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();
-#else
+
+ #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_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);
-#else
+
+#ifndef CONTEXT_THREADS
free(init_context->exception);
#endif
+
free(init_context);
init_context = current_context = NULL;
}
+
/*******************************/
/* Object creation/destruction */
/*******************************/
* \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;
res->code = code;
res->name = xbt_strdup(name);
+
#ifdef CONTEXT_THREADS
- res->mutex = xbt_os_mutex_init();
- res->cond = xbt_os_cond_init();
+ /*
+ * initialize the semaphores used to schedule/unschedule
+ * the process associated to the newly created context
+ */
+ res->begin = xbt_os_sem_init(0,0);
+ res->end = xbt_os_sem_init(0,0);
#else
xbt_assert2(getcontext(&(res->uc)) == 0,
- "Error in context saving: %d (%s)", errno, strerror(errno));
+ "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->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 */
+#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;
return res;
}
-static void xbt_context_free(xbt_context_t context) {
+/* 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;
+
if (!context)
return;
+
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]);
+
+ if (context->argv)
+ free(context->argv);
+
#ifdef CONTEXT_THREADS
- /*DEBUG1("\t joining %p",(void *)context->thread->t); */
DEBUG1("\t joining %p", (void *) context->thread);
xbt_os_thread_join(context->thread, NULL);
- 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);
+ /* 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;
+ context->begin = NULL;
+ context->end = NULL;
#else
if (context->exception)
free(context->exception);
#endif
-
+
free(context);
- return;
}
/************************/
/* Start/stop a context */
/************************/
-static void xbt_context_stop(xbt_context_t context, int value);
+static void xbt_context_stop(int retvalue);
+static void __xbt_context_yield(xbt_context_t context);
static void *__context_wrapper(void *c)
{
#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*/
+ unschedule(context);
#endif
DEBUG0("Calling the main function");
- xbt_context_stop(context, (context->code) (context->argc, context->argv));
+ xbt_context_stop((context->code) (context->argc, context->argv));
return NULL;
}
/**
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());
+ /* create the process and start it */
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);
+
+ /* wait the starting of the newly created process */
+ xbt_os_sem_wait(context->end);
#else
- makecontext(&(context->uc), (void (*)(void)) __context_wrapper, 1,
- context);
+ makecontext(&(context->uc), (void (*)(void)) __context_wrapper, 1, context);
#endif
- return;
}
-static void xbt_context_stop(xbt_context_t context, int value)
+/* Stops current context: calls user's cleanup function, kills os thread, and yields back to maestro */
+static void xbt_context_stop(int retvalue)
{
- int i;
+ DEBUG1("--------- %p is exiting ---------", current_context);
- DEBUG1("--------- %p is exiting ---------", context);
-
- DEBUG0("Calling cleanup functions");
- if (context->cleanup_func) {
+ if (current_context->cleanup_func) {
DEBUG0("Calling cleanup function");
- context->cleanup_func(context->cleanup_arg);
+ current_context->cleanup_func(current_context->cleanup_arg);
}
- DEBUG0("Freeing arguments");
- for (i = 0; i < context->argc; i++)
- if (context->argv[i])
- free(context->argv[i]);
-
- 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");
+ xbt_swag_remove(current_context, context_living);
+ xbt_swag_insert(current_context, context_to_destroy);
DEBUG0("Yielding");
#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
+ /* signal to the maestro that it has finished */
+ xbt_os_sem_post(current_context->end);
+ /* exit*/
+ xbt_os_thread_exit(NULL); /* We should provide return value in case other wants it */
#else
- __xbt_context_yield(context);
+ __xbt_context_yield(current_context);
#endif
- xbt_assert0(0, "You can't be here!");
+ THROW_IMPOSSIBLE;
}
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);
}
static void __xbt_context_yield(xbt_context_t context)
{
xbt_assert0(current_context, "You have to call context_init() first.");
-
- DEBUG2
+ 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
- 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;
- }
-#else /* use SUSv2 contexts */
+
+ 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 */
+ unschedule(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);
- if (current_context)
- VOIRP(current_context->save);
+ VOIRP(current_context->save);
VOIRP(context);
+ VOIRP(context->save);
- 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);
+ 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(current_context, 1);
- return;
+ 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)
{
* 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);
}
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;}
