/* 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
#include "portable.h"
#include "context_private.h"
-#include "xbt/error.h"
+#include "xbt/log.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) */
-
-#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
+#include "xbt/xbt_thread.h"
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_ctx, xbt, "Context");
+
+#define VOIRP(expr) DEBUG1(" {" #expr " = %p }", expr)
static xbt_context_t current_context = NULL;
static xbt_context_t init_context = NULL;
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); */
-
- if (context) {
- if(context->save==NULL) {
-/* WARNING("**** Yielding to somebody else ****"); */
-/* WARNING("Saving current_context value (%p) to context(%p)->save",current_context,context); */
- context->save = current_context ;
-/* WARNING("current_context becomes context(%p) ",context); */
- current_context = context ;
-/* WARNING("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); */
- } else {
- xbt_context_t old_context = context->save ;
-/* WARNING("**** Back ! ****"); */
-/* WARNING("Setting current_context (%p) to context(%p)->save",current_context,context); */
- current_context = context->save ;
-/* WARNING("Setting context(%p)->save to NULL",context); */
- context->save = NULL ;
-/* WARNING("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); */
- }
- }
-
- return;
+ xbt_assert0(current_context,"You have to call context_init() first.");
+
+ DEBUG2("--------- current_context (%p) is yielding to context(%p) ---------",current_context,context);
+
+ #ifdef CONTEXT_THREADS
+ if (context){
+ xbt_context_t self = current_context;
+ DEBUG0("**** Locking ****");
+ xbt_mutex_lock(context->mutex);
+ DEBUG0("**** Updating current_context ****");
+ current_context = context;
+ DEBUG0("**** Releasing the prisonner ****");
+ xbt_thcond_signal(context->cond);
+ DEBUG0("**** Going to jail ****");
+ xbt_thcond_wait(context->cond, context->mutex);
+ DEBUG0("**** Unlocking ****");
+ xbt_mutex_unlock(context->mutex);
+ DEBUG0("**** Updating current_context ****");
+ current_context = self;
+ }
+ #else /* use SUSv2 contexts */
+ if(current_context)
+ VOIRP(current_context->save);
+
+ VOIRP(context);
+
+ if(context)
+ VOIRP(context->save);
+
+ if (context){
+
+ int return_value = 0;
+
+ if(context->save==NULL){
+
+ DEBUG0("**** Yielding to somebody else ****");
+ 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 ;
+ DEBUG0("**** Back ! ****");
+ 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
+ return;
}
static void xbt_context_destroy(xbt_context_t context)
{
- xbt_free(context);
-
- return;
+ if (!context) return;
+#ifdef CONTEXT_THREADS
+ xbt_free(context->thread);
+ xbt_mutex_destroy(context->mutex);
+ xbt_thcond_destroy(context->cond);
+
+ context->thread = NULL;
+ context->mutex = NULL;
+ context->cond = NULL;
+#endif
+
+ if(context->exception)
+ free(context->exception);
+
+ free(context);
+ return;
}
-
-void xbt_context_init(void)
+
+static void __context_exit(xbt_context_t context ,int value)
{
- 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);
- }
+ int i;
+ DEBUG0("Freeing arguments");
+ for(i=0;i<context->argc; i++)
+ if(context->argv[i])
+ free(context->argv[i]);
+
+ if(context->argv)
+ free(context->argv);
+
+ if(context->cleanup_func){
+ DEBUG0("Calling cleanup function");
+ context->cleanup_func(context->cleanup_arg);
+ }
+
+ 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");
+ DEBUG0("Yielding");
+
+ #ifdef CONTEXT_THREADS
+ DEBUG0("**** Locking ****");
+ xbt_mutex_lock(context->mutex);
+ DEBUG0("**** Updating current_context ****");
+ current_context = context;
+ DEBUG0("**** Releasing the prisonner ****");
+ xbt_thcond_signal(context->cond);
+ DEBUG0("**** Unlocking ****");
+ xbt_mutex_unlock(context->mutex);
+ DEBUG0("**** Exiting ****");
+ xbt_thread_exit(0);
+ #else
+ __xbt_context_yield(context);
+ #endif
+ xbt_assert0(0,"You can't be here!");
}
-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 = (xbt_context_t)c;
+
+ #ifdef CONTEXT_THREADS
+ context->thread = xbt_thread_self();
+
+ DEBUG2("**[%p:%p]** Lock ****",context,(void*)xbt_thread_self());
+ xbt_mutex_lock(context->mutex);
+
+ DEBUG2("**[%p:%p]** Releasing the prisonner ****",context,(void*)xbt_thread_self());
+ xbt_thcond_signal(context->cond);
+
+ DEBUG2("**[%p:%p]** Going to Jail ****",context,(void*)xbt_thread_self());
+ xbt_thcond_wait(context->cond, context->mutex);
+
+ DEBUG2("**[%p:%p]** Unlocking ****",context,(void*)xbt_thread_self());
+ xbt_mutex_unlock(context->mutex);
+
+ #endif
+
+ if(context->startup_func)
+ context->startup_func(context->startup_arg);
+
+ DEBUG0("Calling the main function");
+
+ __context_exit(context, (context->code) (context->argc,context->argv));
+ return NULL;
}
-static void *__context_wrapper(void *c)
+/* callback: context fetching */
+static ex_ctx_t *__context_ex_ctx(void)
{
- xbt_context_t context = c;
- int i;
-
-/* msg_global->current_process = process; */
-
- if(context->startup_func)
- context->startup_func(context->startup_arg);
-
- /* WARNING("Calling the main function"); */
- /* xbt_context_yield(context); */
- (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);
+ return current_context->exception;
+}
- if(context->cleanup_func)
- context->cleanup_func(context->cleanup_arg);
+/* 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 this
+ if(current_context!=init_context)
+ __context_exit(current_context, e->value);
+ else
+ abort();
+ */
+}
- xbt_swag_remove(context, context_living);
- xbt_swag_insert(context, context_to_destroy);
+/** \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);
+
+ 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);
+ }
+}
- __xbt_context_yield(context);
- xbt_assert0(0,"You're cannot be here!");
- return NULL;
+/** 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)
{
-/* xbt_fifo_insert(msg_global->process, process); */
-/* xbt_fifo_insert(msg_global->process_to_run, process); */
-
- makecontext (&(context->uc), (void (*) (void)) __context_wrapper,
- 1, context);
- return;
+ #ifdef CONTEXT_THREADS
+ /* Launch the thread */
+ DEBUG1("**[%p]** Locking ****",context);
+ xbt_mutex_lock(context->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);
+ DEBUG1("**[%p]** Unlocking ****",context);
+ xbt_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,
int argc, char *argv[])
{
- xbt_context_t res = NULL;
-
- res = xbt_new0(s_xbt_context_t,1);
-
- xbt_assert0(getcontext(&(res->uc))==0,"Error in context saving.");
-
- res->code = code;
- res->uc.uc_link = NULL;
- res->argc = argc;
- res->argv = argv;
-/* 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;
- 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);
-
- return res;
+ xbt_context_t res = NULL;
+
+ res = xbt_new0(s_xbt_context_t,1);
+
+ res->code = code;
+ #ifdef CONTEXT_THREADS
+ 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); */
+ /* 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 */
+
+ 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);
+
+ xbt_swag_insert(res, context_living);
+
+ 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);
+ __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),
- "You are not supposed to run this function here!");
- __xbt_context_yield(context);
+ DEBUG1("Scheduling %p",context);
+ xbt_assert0((current_context==init_context),"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();
- xbt_swag_free(context_to_destroy);
-
- while((context=xbt_swag_extract(context_living)))
- xbt_context_free(context);
-
- xbt_swag_free(context_living);
-
- init_context = current_context = NULL ;
+ xbt_context_t context=NULL;
+
+ xbt_context_empty_trash();
+ xbt_swag_free(context_to_destroy);
+
+ while((context=xbt_swag_extract(context_living))) {
+ xbt_context_free(context);
+ }
+
+ xbt_swag_free(context_living);
+
+ 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->cleanup_func)
- context->cleanup_func(context->cleanup_arg);
- xbt_context_destroy(context);
-
- return;
+ int i ;
+
+
+ xbt_swag_remove(context, context_living);
+
+ for(i=0;i<context->argc; i++)
+ if(context->argv[i])
+ free(context->argv[i]);
+
+ if(context->argv)
+ free(context->argv);
+
+ if(context->cleanup_func)
+ context->cleanup_func(context->cleanup_arg);
+
+ xbt_context_destroy(context);
+
+ return;
}
+/* @} */
