X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.c;h=9976a11d2aa315f78ff88072c0a27d84ed35e58d;hp=6b893d33c9ccb2b07c65fcb8fd02ac168d7bc6f8;hb=335730538150250f32c0df0b184fb494e2bb0df3;hpb=c075e867311c77dfb7171241597e613290d1f62b diff --git a/sched.c b/sched.c index 6b893d33..9976a11d 100644 --- a/sched.c +++ b/sched.c @@ -1,24 +1,15 @@ /* - * Copyright (C) 2006 Andre Noll + * Copyright (C) 2006-2008 Andre Noll * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. + * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file sched.c paraslash's scheduling functions */ +#include /* readdir() */ +#include #include + #include "para.h" #include "ipc.h" #include "fd.h" @@ -27,31 +18,41 @@ #include "string.h" #include "error.h" -/** - * The scheduler manages two lists of tasks. The pre_select list contains - * pointers to functions that are called before calling select() from the main - * loop. Similarly, \a post_select_list is a list of function pointers each of - * which is called after the select call. - */ -struct list_head pre_select_list, post_select_list; +static struct list_head pre_select_list, post_select_list; +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. + */ +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); +}; + + 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); // PARA_INFO_LOG("%s \n", t->status); - if (t->ret > 0) + if (t->error >= 0) continue; - if (!t->event_handler) - continue; - t->event_handler(t); - goto again; + unregister_task(t); } } @@ -62,16 +63,18 @@ static void sched_post_select(struct sched *s) list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { 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); + unregister_task(t); } } /** * the core function for all paraslash programs * - * Short and sweet. It updates the global \a now pointer, calls all registered + * \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 * the fd sets of \a s. Next, it calls para_select() and makes the result available * to the registered tasks by calling their post_select hook. @@ -81,9 +84,12 @@ 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; gettimeofday(now, NULL); again: FD_ZERO(&s->rfds); @@ -91,10 +97,9 @@ 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; + ret = para_select(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)) @@ -102,6 +107,17 @@ again: goto again; } +/** + * initialize the paraslash scheduler + */ +static void init_sched(void) +{ + 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 * @@ -114,58 +130,37 @@ again: */ void register_task(struct task *t) { + if (!initialized) + init_sched(); PARA_INFO_LOG("registering %s (%p)\n", t->status, t); if (t->pre_select) { PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select); - 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); - list_add(&t->post_select_node, &post_select_list); + list_add_tail(&t->post_select_node, &post_select_list); } } -/** - * 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. - */ -void unregister_task(struct task *t) -{ - 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); -}; - -/** - * initialize the paraslash scheduler - */ -void init_sched(void) -{ - INIT_LIST_HEAD(&pre_select_list); - INIT_LIST_HEAD(&post_select_list); -}; - /** * 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) { struct task *t, *tmp; + if (!initialized) + 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; }; /** @@ -181,6 +176,9 @@ char *get_task_list(void) { struct task *t, *tmp; char *msg = NULL; + + if (!initialized) + return NULL; list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) { char *tmp_msg; tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status); @@ -204,32 +202,33 @@ char *get_task_list(void) * * \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 sucess, negative if \a id does not correspond to a - * registered task. + * \return Positive on success, negative on errors (e.g. if \a id does not + * correspond to a registered task). */ int kill_task(char *id) { struct task *t, *tmp; char buf[20]; + + if (!initialized) + return -E_NOT_INITIALIZED; list_for_each_entry_safe(t, tmp, &pre_select_list, pre_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; + unregister_task(t); 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; + unregister_task(t); return 1; } return -E_NO_SUCH_TASK;