X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/3f617f15b3e35f4212d1ba8c1ea62f20057e9714..dfe761f4bc8d35a74c3da5fabe99630c0788001f:/src/xbt/context.c diff --git a/src/xbt/context.c b/src/xbt/context.c index 93f7b9c248..4f4edcaf46 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 @@ -11,135 +11,489 @@ #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"); +#include "xbt/xbt_os_thread.h" +#include "xbt/ex_interface.h" -#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 +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_dynar_t context_to_destroy = NULL; +static xbt_context_t init_context = NULL; +static xbt_swag_t context_to_destroy = NULL; +static xbt_swag_t context_living = NULL; + + + +/********************/ +/* 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) +{ + return current_context->exception; +} + +/* 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 + + +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 + */ +/* @{ */ +/** 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 = xbt_new0(s_xbt_context_t,1); - context_to_destroy = xbt_dynar_new(sizeof(xbt_context_t),xbt_free); + 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 } } -void xbt_context_empty_trash(void) +/** + * This function kill all existing context and free all the memory + * that has been allocated in this module. + */ +void xbt_context_exit(void) { - xbt_dynar_reset(context_to_destroy); + xbt_context_t context = NULL; + + 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 + + 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 *__context_wrapper(void *c) + +/*******************************/ +/* 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[] + ) +{ + xbt_context_t res = NULL; + + res = xbt_new0(s_xbt_context_t, 1); + + res->code = code; + res->name = xbt_strdup(name); + +#ifdef CONTEXT_THREADS + /* + * 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)); + 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->exception = xbt_new(ex_ctx_t, 1); + XBT_CTX_INITIALIZE(res->exception); +#endif /* CONTEXT_THREADS or not */ + + res->iwannadie = 0; /* useless but makes valgrind happy */ + + 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; + + xbt_swag_insert(res, context_living); + + return res; +} + +/* 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) { - xbt_context_t context = c; int i; -/* msg_global->current_process = process; */ + if (!context) + return; - /* WARNING("Calling the main function"); */ - (context->code) (context->argc,context->argv); + DEBUG1("Freeing %p", context); + free(context->name); - for(i=0;iargc; i++) - if(context->argv[i]) xbt_free(context->argv[i]); - if(context->argv) xbt_free(context->argv); + DEBUG0("Freeing arguments"); - xbt_dynar_push(context_to_destroy, &context); + for (i = 0; i < context->argc; i++) + if (context->argv[i]) + free(context->argv[i]); - xbt_context_yield(context); + if (context->argv) + free(context->argv); - return NULL; +#ifdef CONTEXT_THREADS + DEBUG1("\t joining %p", (void *) context->thread); + + xbt_os_thread_join(context->thread, NULL); + + /* 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 + if (context->exception) + free(context->exception); +#endif + + free(context); } -void xbt_context_start(xbt_context_t 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();*/ + + /* signal its starting to the maestro and wait to start its job*/ + unschedule(context); + +#endif -/* TBX_FIFO_insert(msg_global->process, process); */ -/* TBX_FIFO_insert(msg_global->process_to_run, process); */ + if (context->startup_func) + context->startup_func(context->startup_arg); - /* WARNING("Assigning __MSG_process_launcher to context (%p)",context); */ - makecontext (&(context->uc), (void (*) (void)) __context_wrapper, - 1, context); + DEBUG0("Calling the main function"); - return; + xbt_context_stop((context->code) (context->argc, context->argv)); + return NULL; +} +/** + * \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 + /* 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_wait(context->end); +#else + makecontext(&(context->uc), (void (*)(void)) __context_wrapper, 1, context); +#endif } -xbt_context_t xbt_context_new(xbt_context_function_t code, - int argc, char *argv[]) +/* Stops current context: calls user's cleanup function, kills os thread, and yields back to maestro */ +static void xbt_context_stop(int retvalue) { - xbt_context_t res = NULL; + DEBUG1("--------- %p is exiting ---------", current_context); + + if (current_context->cleanup_func) { + DEBUG0("Calling cleanup function"); + current_context->cleanup_func(current_context->cleanup_arg); + } - res = xbt_new0(s_xbt_context_t,1); + DEBUG0("Putting context in the to_destroy set"); + xbt_swag_remove(current_context, context_living); + xbt_swag_insert(current_context, context_to_destroy); - /* WARNING("Initializing context (%p)",res); */ + DEBUG0("Yielding"); - xbt_assert0(getcontext(&(res->uc))==0,"Error in context saving."); +#ifdef CONTEXT_THREADS + /* 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(current_context); +#endif + THROW_IMPOSSIBLE; +} - /* VOIRP(res->uc); */ - res->code = code; - res->uc.uc_link = &(current_context->uc); /* FIXME LATER */ - /* WARNING : when this context is over, the current_context (i.e. the - father), is awaken... May result in bugs later.*/ - res->uc.uc_stack.ss_sp = res->stack; - res->uc.uc_stack.ss_size = STACK_SIZE; - return res; + + +/** 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; + + DEBUG1("Emptying trashbin (%d contexts to free)", + xbt_swag_size(context_to_destroy)); + + while ((context = xbt_swag_extract(context_to_destroy))) + xbt_context_free(context); } -static void xbt_context_destroy(xbt_context_t context) -{ - xbt_free(context); - - return; -} - -void xbt_context_yield(xbt_context_t context) -{ - - xbt_assert0(current_context,"You have to call context_init() first."); - - /* __MSG_context_init(); */ - /* fprintf(stderr,"\n"); */ - /* 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) { -/* m_process_t self = msg_global->current_process; */ - 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 ; - context->uc.uc_link = &(current_context->uc); - /* WARNING("current_context becomes context(%p) ",context); */ - current_context = context ; - /* WARNING("Current position memorized (context->save). Jumping to context (%p)",context); */ - if(!swapcontext (&(context->save->uc), &(context->uc))) - xbt_assert0(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",current_context,context); */ - context->save = NULL ; - /* WARNING("Current position memorized (%p). Jumping to context (%p)",context,old_context); */ - if(!swapcontext (&(context->uc), &(old_context->uc)) ) - xbt_assert0(0,"Context swapping failure"); - /* WARNING("I am (%p). Coming back\n",context); */ - } -/* msg_global->current_process = self; */ +/*********************/ +/* context switching */ +/*********************/ + +static void __xbt_context_yield(xbt_context_t context) +{ + 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); + } + +#ifdef CONTEXT_THREADS + + 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); + VOIRP(current_context->save); + + VOIRP(context); + VOIRP(context->save); + + 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 - 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) +{ + __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. + * + * 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!"); + __xbt_context_yield(context); +} + + +/** + * \param context poor victim + * + * This function simply kills \a context... scarry isn't it ? + */ +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); +} + +/* 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;} + +/* @} */