/*
- * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2014 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
#include <regex.h>
#include <assert.h>
-#include <sys/time.h>
-#include <stdbool.h>
#include "para.h"
#include "ipc.h"
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)
-{
- assert(t->error < 0);
- PARA_INFO_LOG("unregistering %s (%s)\n", t->status,
- para_strerror(-t->error));
- if (t->pre_select)
- list_del(&t->pre_select_node);
- if (t->post_select)
- list_del(&t->post_select_node);
-}
-
static inline bool timeout_is_zero(struct sched *s)
{
struct timeval *tv = &s->select_timeout;
static void sched_preselect(struct sched *s)
{
struct task *t, *tmp;
- list_for_each_entry_safe(t, tmp, &s->pre_select_list, pre_select_node) {
- if (t->error < 0) {
- unregister_task(t);
- continue;
- }
- if (!t->pre_select)
+
+ list_for_each_entry_safe(t, tmp, &s->task_list, node) {
+ if (t->error < 0)
continue;
- t->pre_select(s, t);
- if (timeout_is_zero(s))
- break;
+ if (t->notification != 0)
+ sched_min_delay(s);
+ if (t->pre_select)
+ t->pre_select(s, t);
}
}
static inline void call_post_select(struct sched *s, struct task *t)
{
#ifndef SCHED_DEBUG
- t->post_select(s, t);
+ t->error = t->post_select(s, t);
#else
struct timeval t1, t2, diff;
unsigned long pst;
- gettimeofday(&t1, NULL);
- t->post_select(s, t);
- gettimeofday(&t2, NULL);
+ clock_get_realtime(&t1);
+ t->error = t->post_select(s, t);
+ clock_get_realtime(&t2);
tv_diff(&t1, &t2, &diff);
pst = tv2ms(&diff);
if (pst > 50)
{
struct task *t, *tmp;
- list_for_each_entry_safe(t, tmp, &s->post_select_list, post_select_node) {
- if (t->error >= 0)
- call_post_select(s, t);
-// PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
- if (t->error >= 0)
- continue;
- /*
- * We have to check whether the list is empty because the call
- * to ->post_select() might have called sched_shutdown(). In
- * this case t has been unregistered already, so we must not
- * unregister it again.
- */
- if (list_empty(&s->post_select_list))
- return;
- unregister_task(t);
+ list_for_each_entry_safe(t, tmp, &s->task_list, node) {
+ call_post_select(s, t);
+ t->notification = 0;
+ if (t->error < 0)
+ list_del(&t->node);
}
}
/**
- * The core function for all paraslash programs.
+ * The core function of all paraslash programs.
*
* \param s Pointer to the scheduler struct.
*
* 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.
*
- * \return Zero if no more tasks are left in either of the two lists, negative
- * if para_select returned an error.
+ * \return Zero if no more tasks are left in the task list, negative if the
+ * select function returned an error.
*
- * \sa task, now.
+ * \sa \ref task, \ref now.
*/
int schedule(struct sched *s)
{
FD_ZERO(&s->wfds);
s->select_timeout = s->default_timeout;
s->max_fileno = -1;
- gettimeofday(now, NULL);
+ clock_get_realtime(now);
sched_preselect(s);
- if (list_empty(&s->pre_select_list) && list_empty(&s->post_select_list))
- return 0;
- if (!timeout_is_zero(s)) {
- ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds,
- &s->select_timeout);
- if (ret < 0)
- return ret;
- if (ret == 0) {
- /*
- * APUE: Be careful not to check the descriptor sets on return
- * unless the return value is greater than zero. The return
- * state of the descriptor sets is implementation dependent if
- * either a signal is caught or the timer expires.
- */
- FD_ZERO(&s->rfds);
- FD_ZERO(&s->wfds);
- }
- gettimeofday(now, NULL);
- } else {
+ ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds,
+ &s->select_timeout);
+ if (ret < 0)
+ return ret;
+ if (ret == 0) {
+ /*
+ * APUE: Be careful not to check the descriptor sets on return
+ * unless the return value is greater than zero. The return
+ * state of the descriptor sets is implementation dependent if
+ * either a signal is caught or the timer expires.
+ */
FD_ZERO(&s->rfds);
FD_ZERO(&s->wfds);
}
+ clock_get_realtime(now);
sched_post_select(s);
- if (list_empty(&s->pre_select_list) && list_empty(&s->post_select_list))
+ if (list_empty(&s->task_list))
return 0;
goto again;
}
* \param t The task to add.
* \param s The scheduler instance to add the task to.
*
- * If the pre_select pointer of \a t is not \p NULL, it is added to
- * the pre_select list of the scheduler. Same goes for post_select.
- *
* \sa task::pre_select, task::post_select
*/
void register_task(struct sched *s, struct task *t)
{
PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
- if (!s->pre_select_list.next)
- INIT_LIST_HEAD(&s->pre_select_list);
- if (!s->post_select_list.next)
- INIT_LIST_HEAD(&s->post_select_list);
- if (t->pre_select) {
- PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
- list_add_tail(&t->pre_select_node, &s->pre_select_list);
- }
- if (t->post_select) {
- PARA_DEBUG_LOG("post_select: %p\n", &t->post_select);
- list_add_tail(&t->post_select_node, &s->post_select_list);
- }
-}
-
-/**
- * Unregister all tasks.
- *
- * This will cause \a schedule() to return immediately because both the
- * \a pre_select_list and the \a post_select_list are empty. This function
- * must be called from the post_select (rather than the pre_select) method.
- */
-void sched_shutdown(struct sched *s)
-{
- struct task *t, *tmp;
-
- list_for_each_entry_safe(t, tmp, &s->pre_select_list, pre_select_node) {
- t->error = -E_SCHED_SHUTDOWN;
- unregister_task(t);
- }
- list_for_each_entry_safe(t, tmp, &s->post_select_list, post_select_node) {
- t->error = -E_SCHED_SHUTDOWN;
- unregister_task(t);
- }
+ assert(t->post_select);
+ t->notification = 0;
+ if (!s->task_list.next)
+ INIT_LIST_HEAD(&s->task_list);
+ list_add_tail(&t->node, &s->task_list);
}
/**
* Get the list of all registered tasks.
*
+ * \param s The scheduler instance to get the task list from.
+ *
* \return The task list.
*
* Each entry of the list contains an identifier which is simply a hex number.
struct task *t, *tmp;
char *msg = NULL;
- list_for_each_entry_safe(t, tmp, &s->pre_select_list, pre_select_node) {
+ list_for_each_entry_safe(t, tmp, &s->task_list, node) {
char *tmp_msg;
- tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status);
+ tmp_msg = make_message("%s%p\t%s\n", msg? msg : "", t, t->status);
free(msg);
msg = tmp_msg;
}
- list_for_each_entry_safe(t, tmp, &s->post_select_list, post_select_node) {
- char *tmp_msg;
-// if (t->pre_select)
-// continue;
- tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status);
- free(msg);
- msg = tmp_msg;
- }
- //PARA_DEBUG_LOG("task list:\n%s", msg);
return msg;
}
+/**
+ * Set the notification value of a task.
+ *
+ * \param t The task to notify.
+ * \param err A positive error code.
+ *
+ * Tasks which honor notifications are supposed to call \ref
+ * task_get_notification() in their post_select function and act on the
+ * returned notification value.
+ *
+ * If the scheduler detects during its pre_select loop that at least one task
+ * has been notified, the loop terminates, and the post_select methods of all
+ * taks are immediately called again.
+ *
+ * The notification for a task is reset after the call to its post_select
+ * method.
+ *
+ * \sa \ref task_get_notification().
+ */
+void task_notify(struct task *t, int err)
+{
+ assert(err > 0);
+ if (t->notification == -err) /* ignore subsequent notifications */
+ return;
+ PARA_INFO_LOG("notifying task %s: %s\n", t->status, para_strerror(err));
+ t->notification = -err;
+}
+
+/**
+ * Return the notification value of a task.
+ *
+ * \param t The task to get the notification value from.
+ *
+ * \return The notification value. If this is negative, the task has been
+ * notified by another task. Tasks are supposed to check for notifications by
+ * calling this function from their post_select method.
+ *
+ * \sa \ref task_notify().
+ */
+int task_get_notification(struct task *t)
+{
+ return t->notification;
+}
+
+/**
+ * Set the notification value of all tasks of a scheduler instance.
+ *
+ * \param s The scheduler instance whose tasks should be notified.
+ * \param err A positive error code.
+ *
+ * This simply iterates over all existing tasks of \a s and sets each
+ * task's notification value to \p -err.
+ */
+void task_notify_all(struct sched *s, int err)
+{
+ struct task *t;
+
+ list_for_each_entry(t, &s->task_list, node)
+ task_notify(t, err);
+}
+
/**
* Set the select timeout to the minimal possible value.
*
projects / paraslash.git / blobdiff