/*
- * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
/** \file sched.c Paraslash's scheduling functions. */
-#include <dirent.h> /* readdir() */
+#include <regex.h>
#include <assert.h>
#include <sys/time.h>
#include "list.h"
#include "sched.h"
#include "string.h"
+#include "time.h"
#include "error.h"
static struct list_head pre_select_list, post_select_list;
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)
+static void unregister_task(struct task *t)
{
if (!initialized)
return;
- PARA_INFO_LOG("unregistering %s (%p)\n", t->status, 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);
- if (t->error >= 0)
- t->error = -E_TASK_KILLED;
-};
-
+}
static void sched_preselect(struct sched *s)
{
struct task *t, *tmp;
list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
- if (t->error >= 0)
+ if (t->pre_select)
t->pre_select(s, t);
// PARA_INFO_LOG("%s \n", t->status);
if (t->error >= 0)
}
}
+//#define SCHED_DEBUG 1
+static inline void call_post_select(struct sched *s, struct task *t)
+{
+#ifndef SCHED_DEBUG
+ 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);
+ tv_diff(&t1, &t2, &diff);
+ pst = tv2ms(&diff);
+ if (pst > 50)
+ PARA_WARNING_LOG("%s: post_select time: %lums\n",
+ t->status, pst);
+#endif
+}
+
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) {
if (t->error >= 0)
- t->post_select(s, t);
+ call_post_select(s, t);
// PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
if (t->error >= 0)
continue;
if (!initialized)
return -E_NOT_INITIALIZED;
- gettimeofday(now, NULL);
+ if (!s->select_function)
+ s->select_function = para_select;
again:
FD_ZERO(&s->rfds);
FD_ZERO(&s->wfds);
- s->timeout = s->default_timeout;
+ s->select_timeout = s->default_timeout;
s->max_fileno = -1;
+ gettimeofday(now, NULL);
sched_preselect(s);
if (list_empty(&pre_select_list) && list_empty(&post_select_list))
return 0;
- ret = para_select(s->max_fileno + 1, &s->rfds, &s->wfds, &s->timeout);
+ 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);
sched_post_select(s);
if (list_empty(&pre_select_list) && list_empty(&post_select_list))
goto again;
}
-/**
+/*
* Initialize the paraslash scheduler.
*/
static void init_sched(void)
INIT_LIST_HEAD(&pre_select_list);
INIT_LIST_HEAD(&post_select_list);
initialized = 1;
-};
+}
/**
* Add a task to the scheduler.
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_DEBUG_LOG("post_select: %p\n", &t->post_select);
list_add_tail(&t->post_select_node, &post_select_list);
}
}
if (!initialized)
return;
- list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
+ list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
+ t->error = -E_SCHED_SHUTDOWN;
unregister_task(t);
- list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
+ }
+ list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
+ t->error = -E_SCHED_SHUTDOWN;
unregister_task(t);
+ }
initialized = 0;
-};
+}
/**
* Get the list of all registered tasks.
*
* \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.
- * The result ist dynamically allocated and must be freed by the caller.
+ * Each entry of the list contains an identifier which is simply a hex number.
+ * The result is dynamically allocated and must be freed by the caller.
*/
char *get_task_list(void)
{
}
/**
- * Simulate an error for the given task.
+ * Set the select timeout to the minimal possible value.
*
- * \param id The task identifier.
+ * \param s Pointer to the scheduler struct.
*
- * Find the task identified by \a id, set the tasks' error value to
- * \p -E_TASK_KILLED and unregister the task.
+ * This causes the next select() call to return immediately.
+ */
+void sched_min_delay(struct sched *s)
+{
+ s->select_timeout.tv_sec = 0;
+ s->select_timeout.tv_usec = 1;
+}
+
+/**
+ * Impose an upper bound for the timeout of the next select() call.
+ *
+ * \param to Maximal allowed timeout.
+ * \param s Pointer to the scheduler struct.
*
- * \return Positive on success, negative on errors (e.g. if \a id does not
- * correspond to a registered task).
+ * If the current scheduler timeout is already smaller than \a to, this
+ * function does nothing. Otherwise the timeout for the next select() call is
+ * set to the given value.
+ *
+ * \sa sched_request_timeout_ms().
*/
-int kill_task(char *id)
+void sched_request_timeout(struct timeval *to, struct sched *s)
{
- struct task *t, *tmp;
- char buf[20];
+ if (tv_diff(&s->select_timeout, to, NULL) > 0)
+ s->select_timeout = *to;
+}
- 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->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->error = -E_TASK_KILLED;
- return 1;
- }
- return -E_NO_SUCH_TASK;
+/**
+ * Force the next select() call to return before the given amount of milliseconds.
+ *
+ * \param ms The maximal allowed timeout in milliseconds.
+ * \param s Pointer to the scheduler struct.
+ *
+ * Like sched_request_timeout() this imposes an upper bound on the timeout
+ * value for the next select() call.
+ */
+void sched_request_timeout_ms(long unsigned ms, struct sched *s)
+{
+ struct timeval tv;
+ ms2tv(ms, &tv);
+ sched_request_timeout(&tv, s);
+}
+
+/**
+ * Force the next select() call to return before the given future time.
+ *
+ * \param barrier Absolute time before select() should return.
+ * \param s Pointer to the scheduler struct.
+ *
+ * If \a barrier is in the past, this function does nothing.
+ *
+ * \sa sched_request_barrier_or_min_delay().
+ */
+void sched_request_barrier(struct timeval *barrier, struct sched *s)
+{
+ struct timeval diff;
+
+ if (tv_diff(now, barrier, &diff) > 0)
+ return;
+ sched_request_timeout(&diff, s);
+}
+
+/**
+ * Force the next select() call to return before the given time.
+ *
+ * \param barrier Absolute time before select() should return.
+ * \param s Pointer to the scheduler struct.
+ *
+ * If \a barrier is in the past, this function requests a minimal timeout.
+ *
+ * \sa sched_min_delay(), sched_request_barrier().
+ */
+void sched_request_barrier_or_min_delay(struct timeval *barrier, struct sched *s)
+{
+ struct timeval diff;
+
+ if (tv_diff(now, barrier, &diff) > 0)
+ return sched_min_delay(s);
+ sched_request_timeout(&diff, s);
}
projects / paraslash.git / blobdiff