-/*
- * Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
/** \file sched.c Paraslash's scheduling functions. */
* The possible states of a task.
*
* In addition to the states listed here, a task may also enter zombie state.
- * This happens when its ->post_select function returns negative, the ->status
+ * This happens when its ->post_monitor function returns negative, the ->status
* field is then set to this return value. Such tasks are not scheduled any
- * more (i.e. ->pre_select() and ->post_select() are no longer called), but
+ * more (i.e. ->pre_monitor() and ->post_monitor() are no longer called), but
* they stay on the scheduler task list until \ref task_reap() or
* \ref sched_shutdown() is called.
*/
static struct timeval now_struct;
const struct timeval *now = &now_struct;
-static void sched_preselect(struct sched *s)
+static void sched_pre_monitor(struct sched *s)
{
struct task *t, *tmp;
continue;
if (t->notification != 0)
sched_min_delay(s);
- if (t->info.pre_select)
- t->info.pre_select(s, t->info.context);
+ if (t->info.pre_monitor)
+ t->info.pre_monitor(s, t->info.context);
}
}
static void unlink_and_free_task(struct task *t)
{
- PARA_INFO_LOG("freeing task %s\n", t->name);
+ PARA_INFO_LOG("freeing task %s (%s)\n", t->name, t->status < 0?
+ para_strerror(-t->status) :
+ (t->status == TS_DEAD? "[dead]" : "[running]"));
+
list_del(&t->node);
free(t->name);
free(t);
}
//#define SCHED_DEBUG 1
-static inline void call_post_select(struct sched *s, struct task *t)
+static inline void call_post_monitor(struct sched *s, struct task *t)
{
int ret;
#ifndef SCHED_DEBUG
- ret = t->info.post_select(s, t->info.context);
+ ret = t->info.post_monitor(s, t->info.context);
#else
struct timeval t1, t2, diff;
unsigned long pst;
clock_get_realtime(&t1);
- ret = t->info.post_select(s, t->info.context);
+ ret = t->info.post_monitor(s, t->info.context);
clock_get_realtime(&t2);
tv_diff(&t1, &t2, &diff);
pst = tv2ms(&diff);
if (pst > 50)
- PARA_WARNING_LOG("%s: post_select time: %lums\n",
+ PARA_WARNING_LOG("%s: post_monitor time: %lums\n",
t->name, pst);
#endif
t->status = ret < 0? ret : TS_RUNNING;
}
-static unsigned sched_post_select(struct sched *s)
+static unsigned sched_post_monitor(struct sched *s)
{
struct task *t, *tmp;
unsigned num_running_tasks = 0;
if (t->status == TS_DEAD) /* task has been reaped */
unlink_and_free_task(t);
else if (t->status == TS_RUNNING) {
- call_post_select(s, t); /* sets t->status */
+ call_post_monitor(s, t); /* sets t->status */
t->notification = 0;
if (t->status == TS_RUNNING)
num_running_tasks++;
* \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.
+ * pre_monitor 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_monitor hook.
*
* \return Zero if no more tasks are left in the task list, negative if the
* select function returned an error.
again:
FD_ZERO(&s->rfds);
FD_ZERO(&s->wfds);
- s->select_timeout = s->default_timeout;
+ s->timeout = s->default_timeout;
s->max_fileno = -1;
clock_get_realtime(&now_struct);
- sched_preselect(s);
+ sched_pre_monitor(s);
ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds,
- &s->select_timeout);
+ s->timeout);
if (ret < 0)
return ret;
if (ret == 0) {
FD_ZERO(&s->wfds);
}
clock_get_realtime(&now_struct);
- num_running_tasks = sched_post_select(s);
+ num_running_tasks = sched_post_monitor(s);
if (num_running_tasks == 0)
return 0;
goto again;
* \param tptr Identifies the task to reap.
*
* This function is similar to wait(2) in that it returns information about a
- * terminated task and allows to release the resources associated with the
+ * terminated task which allows releasing the resources associated with the
* task. Until this function is called, the terminated task remains in a zombie
* state.
*
/*
* With list_for_each_entry_safe() it is only safe to remove the
* _current_ list item. Since we are being called from the loop in
- * schedule() via some task's ->post_select() function, freeing the
+ * schedule() via some task's ->post_monitor() function, freeing the
* given task here would result in use-after-free bugs in schedule().
* So we only set the task status to TS_DEAD which tells schedule() to
* free the task in the next iteration of its loop.
{
struct task *t = para_malloc(sizeof(*t));
- assert(info->post_select);
+ assert(info->post_monitor);
if (!s->task_list.next)
- INIT_LIST_HEAD(&s->task_list);
+ init_list_head(&s->task_list);
t->info = *info;
t->name = para_strdup(info->name);
* \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
+ * task_get_notification() in their post_monitor 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
+ * If the scheduler detects during its pre_monitor loop that at least one task
+ * has been notified, the loop terminates, and the post_monitor methods of all
* taks are immediately called again.
*
- * The notification for a task is reset after the call to its post_select
+ * The notification for a task is reset after the call to its post_monitor
* method.
*
* \sa \ref task_get_notification().
*
* \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.
+ * calling this function from their post_monitor method.
*
* \sa \ref task_notify().
*/
*/
void sched_min_delay(struct sched *s)
{
- s->select_timeout.tv_sec = s->select_timeout.tv_usec = 0;
+ s->timeout = 0;
}
/**
* function does nothing. Otherwise the timeout for the next select() call is
* set to the given value.
*
- * \sa sched_request_timeout_ms().
+ * \sa \ref sched_request_timeout_ms().
*/
void sched_request_timeout(struct timeval *to, struct sched *s)
{
- if (tv_diff(&s->select_timeout, to, NULL) > 0)
- s->select_timeout = *to;
+ long unsigned ms = tv2ms(to);
+ if (s->timeout > ms)
+ s->timeout = ms;
}
/**
* \return If \a barrier is in the past, this function does nothing and returns
* zero. Otherwise it returns one.
*
- * \sa sched_request_barrier_or_min_delay().
+ * \sa \ref sched_request_barrier_or_min_delay().
*/
int sched_request_barrier(struct timeval *barrier, struct sched *s)
{
* \return If \a barrier is in the past, this function requests a minimal
* timeout and returns zero. Otherwise it returns one.
*
- * \sa sched_min_delay(), sched_request_barrier().
+ * \sa \ref sched_min_delay(), \ref sched_request_barrier().
*/
int sched_request_barrier_or_min_delay(struct timeval *barrier, struct sched *s)
{
sched_request_timeout(&diff, s);
return 1;
}
+
+static void sched_fd_set(int fd, fd_set *fds, int *max_fileno)
+{
+ assert(fd >= 0 && fd < FD_SETSIZE);
+#if 0
+ {
+ int flags = fcntl(fd, F_GETFL);
+ if (!(flags & O_NONBLOCK)) {
+ PARA_EMERG_LOG("fd %d is a blocking file descriptor\n", fd);
+ exit(EXIT_FAILURE);
+ }
+ }
+#endif
+ FD_SET(fd, fds);
+ *max_fileno = PARA_MAX(*max_fileno, fd);
+}
+
+/**
+ * Instruct the scheduler to monitor an fd for readiness for reading.
+ *
+ * \param fd The file descriptor.
+ * \param s The scheduler.
+ *
+ * \sa \ref sched_monitor_writefd().
+ */
+void sched_monitor_readfd(int fd, struct sched *s)
+{
+ sched_fd_set(fd, &s->rfds, &s->max_fileno);
+}
+
+/**
+ * Instruct the scheduler to monitor an fd for readiness for writing.
+ *
+ * \param fd The file descriptor.
+ * \param s The scheduler.
+ *
+ * \sa \ref sched_monitor_readfd().
+ */
+void sched_monitor_writefd(int fd, struct sched *s)
+{
+ sched_fd_set(fd, &s->wfds, &s->max_fileno);
+}
projects / paraslash.git / blobdiff