X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.c;h=6f3f1faf8dc29ab8934cd01dd340cc96bb806089;hp=a7660f5972c9f678b6f3a19b7b4398a1e43ae24b;hb=672e27768e31a6eaa6854d4fc75ee6885db9abd8;hpb=2c679eeb8bbc93220f85403eca6e9380dc624a6a diff --git a/sched.c b/sched.c index a7660f59..6f3f1faf 100644 --- a/sched.c +++ b/sched.c @@ -1,10 +1,10 @@ /* - * Copyright (C) 2006-2007 Andre Noll + * Copyright (C) 2006-2009 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ -/** \file sched.c paraslash's scheduling functions */ +/** \file sched.c Paraslash's scheduling functions. */ #include /* readdir() */ #include @@ -24,19 +24,46 @@ static int initialized; static struct timeval now_struct; struct timeval *now = &now_struct; +/** + * Remove a task from the scheduler. + * + * \param t The task to remove. + * + * If the pre_select pointer of \a t is not \p NULL, it is removed from + * the pre_select list of the scheduler. Same goes for \a post_select. + */ +static void unregister_task(struct task *t) +{ + if (!initialized) + return; + PARA_INFO_LOG("unregistering %s (%s)\n", t->status, + t->error <0? para_strerror(-t->error) : "shutdown"); + if (t->pre_select) + list_del(&t->pre_select_node); + if (t->post_select) + list_del(&t->post_select_node); + t->error = -E_TASK_UNREGISTERED; +} + + static void sched_preselect(struct sched *s) { struct task *t, *tmp; -again: list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) { - t->pre_select(s, t); + if (t->error >= 0 && t->pre_select) + t->pre_select(s, t); // PARA_INFO_LOG("%s \n", t->status); - if (t->ret > 0) - continue; - if (!t->event_handler) + if (t->error >= 0) continue; - t->event_handler(t); - goto again; + /* + * We have to check whether the list is empty because the call + * to ->pre_select() might have called sched_shutdown(). In + * this case t has been unregistered already, so we must not + * unregister it again. + */ + if (list_empty(&pre_select_list)) + return; + unregister_task(t); } } @@ -45,18 +72,22 @@ static void sched_post_select(struct sched *s) struct task *t, *tmp; list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { - t->post_select(s, t); + if (t->error >= 0) + t->post_select(s, t); // PARA_INFO_LOG("%s: %d\n", t->status, t->ret); - if (t->ret > 0 || !t->event_handler) + if (t->error >= 0) continue; - t->event_handler(t); + /* nec., see sched_preselect() */ + if (list_empty(&post_select_list)) + return; + unregister_task(t); } } /** - * the core function for all paraslash programs + * The core function for all paraslash programs. * - * \param s pointer to the scheduler struct + * \param s Pointer to the scheduler struct. * * This function updates the global \a now pointer, calls all registered * pre_select hooks which may set the timeout and add any file descriptors to @@ -68,10 +99,14 @@ static void sched_post_select(struct sched *s) * * \sa task, now. */ -int sched(struct sched *s) +int schedule(struct sched *s) { + int ret; + if (!initialized) return -E_NOT_INITIALIZED; + if (!s->select_function) + s->select_function = para_select; gettimeofday(now, NULL); again: FD_ZERO(&s->rfds); @@ -79,10 +114,11 @@ again: s->timeout = s->default_timeout; s->max_fileno = -1; sched_preselect(s); - s->select_ret = para_select(s->max_fileno + 1, &s->rfds, - &s->wfds, &s->timeout); - if (s->select_ret < 0) - return s->select_ret; + if (list_empty(&pre_select_list) && list_empty(&post_select_list)) + return 0; + ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds, &s->timeout); + if (ret < 0) + return ret; gettimeofday(now, NULL); sched_post_select(s); if (list_empty(&pre_select_list) && list_empty(&post_select_list)) @@ -91,18 +127,18 @@ again: } /** - * initialize the paraslash scheduler + * Initialize the paraslash scheduler. */ static void init_sched(void) { - PARA_INFO_LOG("%s", "initializing scheduler\n"); + PARA_INFO_LOG("initializing scheduler\n"); INIT_LIST_HEAD(&pre_select_list); INIT_LIST_HEAD(&post_select_list); initialized = 1; -}; +} /** - * add a task to the scheduler + * Add a task to the scheduler. * * \param t the task to add * @@ -118,37 +154,18 @@ void register_task(struct task *t) PARA_INFO_LOG("registering %s (%p)\n", t->status, t); if (t->pre_select) { PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select); - para_list_add(&t->pre_select_node, &pre_select_list); + list_add_tail(&t->pre_select_node, &pre_select_list); } if (t->post_select) { - PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select); - para_list_add(&t->post_select_node, &post_select_list); + PARA_DEBUG_LOG("post_select: %p\n", &t->post_select); + list_add_tail(&t->post_select_node, &post_select_list); } } /** - * remove a task from the scheduler - * - * \param t the task to remove + * Unregister all tasks. * - * If the pre_select pointer of \a t is not \p NULL, it is removed from - * the pre_select list of the scheduler. Same goes for \a post_select. - */ -void unregister_task(struct task *t) -{ - if (!initialized) - return; - PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t); - if (t->pre_select) - list_del(&t->pre_select_node); - if (t->post_select) - list_del(&t->post_select_node); -}; - -/** - * unregister all tasks - * - * This will cause \a sched() to return immediately because both the + * This will cause \a schedule() to return immediately because both the * \a pre_select_list and the \a post_select_list are empty. */ void sched_shutdown(void) @@ -159,16 +176,15 @@ void sched_shutdown(void) return; list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) unregister_task(t); - /* remove tasks which do not have a pre_select hook */ list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) unregister_task(t); initialized = 0; -}; +} /** - * get the list of all registered tasks. + * Get the list of all registered tasks. * - * \return the task list + * \return The task list. * * Each entry of the list contains an identifier which is simply a hex number * that may be used in \a kill_task() to terminate the task. @@ -200,12 +216,12 @@ char *get_task_list(void) } /** - * simulate an error for the given task + * Simulate an error for the given task. * - * \param id the task identifier + * \param id The task identifier. * - * Find the task identified by \a id, set the tasks' return value to - * \p -E_TASK_KILLED and call the event handler of the task. + * Find the task identified by \a id, set the tasks' error value to + * \p -E_TASK_KILLED and unregister the task. * * \return Positive on success, negative on errors (e.g. if \a id does not * correspond to a registered task). @@ -221,18 +237,14 @@ int kill_task(char *id) sprintf(buf, "%p", t); if (strcmp(id, buf)) continue; - t->ret = -E_TASK_KILLED; - if (t->event_handler) - t->event_handler(t); + t->error = -E_TASK_KILLED; return 1; } list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { sprintf(buf, "%p", t); if (strcmp(id, buf)) continue; - t->ret = -E_TASK_KILLED; - if (t->event_handler) - t->event_handler(t); + t->error = -E_TASK_KILLED; return 1; } return -E_NO_SUCH_TASK;