cl_status_t
cl_timer_start(IN cl_timer_t * const p_timer, IN const uint32_t time_ms)
{
struct timeval curtime;
cl_list_item_t *p_list_item;
uint32_t delta_time = time_ms;
CL_ASSERT(p_timer);
CL_ASSERT(p_timer->state == CL_INITIALIZED);
pthread_mutex_lock(&gp_timer_prov->mutex);
/* Signal the timer provider thread to wake up. */
pthread_cond_signal(&gp_timer_prov->cond);
/* Remove the timer from the queue if currently queued. */
if (p_timer->timer_state == CL_TIMER_QUEUED)
cl_qlist_remove_item(&gp_timer_prov->queue,
&p_timer->list_item);
/* Get the current time */
#ifndef timerclear
#define timerclear(tvp) (tvp)->tv_sec = (time_t)0, (tvp)->tv_usec = 0L
#endif
timerclear(&curtime);
gettimeofday(&curtime, NULL);
/* do not do 0 wait ! */
/* if (delta_time < 1000.0) {delta_time = 1000;} */
/* Calculate the timeout. */
p_timer->timeout.tv_sec = curtime.tv_sec + (delta_time / 1000);
p_timer->timeout.tv_nsec =
(curtime.tv_usec + ((delta_time % 1000) * 1000)) * 1000;
/* Add the timer to the queue. */
if (cl_is_qlist_empty(&gp_timer_prov->queue)) {
/* The timer list is empty. Add to the head. */
cl_qlist_insert_head(&gp_timer_prov->queue,
&p_timer->list_item);
} else {
/* Find the correct insertion place in the list for the timer. */
p_list_item = cl_qlist_find_from_tail(&gp_timer_prov->queue,
__cl_timer_find, p_timer);
/* Insert the timer. */
cl_qlist_insert_next(&gp_timer_prov->queue, p_list_item,
&p_timer->list_item);
}
/* Set the state. */
p_timer->timer_state = CL_TIMER_QUEUED;
pthread_mutex_unlock(&gp_timer_prov->mutex);
return (CL_SUCCESS);
}
static void __cl_event_wheel_callback(IN void *context)
{
cl_event_wheel_t *p_event_wheel = (cl_event_wheel_t *) context;
cl_list_item_t *p_list_item, *p_prev_event_list_item;
cl_list_item_t *p_list_next_item;
cl_event_wheel_reg_info_t *p_event;
uint64_t current_time;
uint64_t next_aging_time;
uint32_t new_timeout;
cl_status_t cl_status;
/* might be during closing ... */
if (p_event_wheel->closing)
return;
current_time = cl_get_time_stamp();
if (NULL != p_event_wheel->p_external_lock)
/* Take care of the order of acquiring locks to avoid the deadlock!
* The external lock goes first.
*/
cl_spinlock_acquire(p_event_wheel->p_external_lock);
cl_spinlock_acquire(&p_event_wheel->lock);
p_list_item = cl_qlist_head(&p_event_wheel->events_wheel);
if (p_list_item == cl_qlist_end(&p_event_wheel->events_wheel))
/* the list is empty - nothing to do */
goto Exit;
/* we found such an item. get the p_event */
p_event =
PARENT_STRUCT(p_list_item, cl_event_wheel_reg_info_t, list_item);
while (p_event->aging_time <= current_time) {
/* this object has aged - invoke it's callback */
if (p_event->pfn_aged_callback)
next_aging_time =
p_event->pfn_aged_callback(p_event->key,
p_event->num_regs,
p_event->context);
else
next_aging_time = 0;
/* point to the next object in the wheel */
p_list_next_item = cl_qlist_next(p_list_item);
/* We need to retire the event if the next aging time passed */
if (next_aging_time < current_time) {
/* remove it from the map */
cl_qmap_remove_item(&p_event_wheel->events_map,
&(p_event->map_item));
/* pop p_event from the wheel */
cl_qlist_remove_head(&p_event_wheel->events_wheel);
/* delete the event info object - allocated by cl_event_wheel_reg */
free(p_event);
} else {
/* update the required aging time */
p_event->aging_time = next_aging_time;
p_event->num_regs++;
/* do not remove from the map - but remove from the list head and
place in the correct position */
/* pop p_event from the wheel */
cl_qlist_remove_head(&p_event_wheel->events_wheel);
/* find the event that ages just before */
p_prev_event_list_item =
cl_qlist_find_from_tail(&p_event_wheel->
events_wheel,
__event_will_age_before,
&p_event->aging_time);
/* insert just after */
cl_qlist_insert_next(&p_event_wheel->events_wheel,
p_prev_event_list_item,
&p_event->list_item);
/* as we have modified the list - restart from first item: */
p_list_next_item =
cl_qlist_head(&p_event_wheel->events_wheel);
}
/* advance to next event */
p_list_item = p_list_next_item;
if (p_list_item == cl_qlist_end(&p_event_wheel->events_wheel))
/* the list is empty - nothing to do */
break;
/* get the p_event */
p_event =
PARENT_STRUCT(p_list_item, cl_event_wheel_reg_info_t,
list_item);
}
/* We need to restart the timer only if the list is not empty now */
if (p_list_item != cl_qlist_end(&p_event_wheel->events_wheel)) {
/* get the p_event */
p_event =
PARENT_STRUCT(p_list_item, cl_event_wheel_reg_info_t,
list_item);
/* start the timer to the timeout [msec] */
new_timeout =
(uint32_t) ((p_event->aging_time - current_time + 500) / 1000);
CL_DBG("__cl_event_wheel_callback: Restart timer in: "
"%u [msec]\n", new_timeout);
cl_status = cl_timer_start(&p_event_wheel->timer, new_timeout);
if (cl_status != CL_SUCCESS) {
CL_DBG("__cl_event_wheel_callback : ERR 6200: "
"Failed to start timer\n");
}
}
/* release the lock */
Exit:
cl_spinlock_release(&p_event_wheel->lock);
if (NULL != p_event_wheel->p_external_lock)
cl_spinlock_release(p_event_wheel->p_external_lock);
}
cl_status_t cl_event_wheel_reg(IN cl_event_wheel_t * const p_event_wheel,
IN const uint64_t key,
IN const uint64_t aging_time_usec,
IN cl_pfn_event_aged_cb_t pfn_callback,
IN void *const context)
{
cl_event_wheel_reg_info_t *p_event;
uint64_t timeout;
uint32_t to;
cl_status_t cl_status = CL_SUCCESS;
cl_list_item_t *prev_event_list_item;
cl_map_item_t *p_map_item;
/* Get the lock on the manager */
cl_spinlock_acquire(&(p_event_wheel->lock));
cl_event_wheel_dump(p_event_wheel);
/* Make sure such a key does not exists */
p_map_item = cl_qmap_get(&p_event_wheel->events_map, key);
if (p_map_item != cl_qmap_end(&p_event_wheel->events_map)) {
CL_DBG("cl_event_wheel_reg: Already exists key:0x%"
PRIx64 "\n", key);
/* already there - remove it from the list as it is getting a new time */
p_event =
PARENT_STRUCT(p_map_item, cl_event_wheel_reg_info_t,
map_item);
/* remove the item from the qlist */
cl_qlist_remove_item(&p_event_wheel->events_wheel,
&p_event->list_item);
/* and the qmap */
cl_qmap_remove_item(&p_event_wheel->events_map,
&p_event->map_item);
} else {
/* make a new one */
p_event = (cl_event_wheel_reg_info_t *)
malloc(sizeof(cl_event_wheel_reg_info_t));
p_event->num_regs = 0;
}
p_event->key = key;
p_event->aging_time = aging_time_usec;
p_event->pfn_aged_callback = pfn_callback;
p_event->context = context;
p_event->num_regs++;
CL_DBG("cl_event_wheel_reg: Registering event key:0x%" PRIx64
" aging in %u [msec]\n", p_event->key,
(uint32_t) ((p_event->aging_time - cl_get_time_stamp()) / 1000));
/* If the list is empty - need to start the timer */
if (cl_is_qlist_empty(&p_event_wheel->events_wheel)) {
/* Edward Bortnikov 03/29/2003
* ++TBD Consider moving the timer manipulation behind the list manipulation.
*/
/* calculate the new timeout */
timeout =
(p_event->aging_time - cl_get_time_stamp() + 500) / 1000;
/* stop the timer if it is running */
/* Edward Bortnikov 03/29/2003
* Don't call cl_timer_stop() because it spins forever.
* cl_timer_start() will invoke cl_timer_stop() by itself.
*
* The problematic scenario is when __cl_event_wheel_callback()
* is in race condition with this code. It sets timer.in_timer_cb
* to TRUE and then blocks on p_event_wheel->lock. Following this,
* the call to cl_timer_stop() hangs. Following this, the whole system
* enters into a deadlock.
*
* cl_timer_stop(&p_event_wheel->timer);
*/
/* The timeout for the cl_timer_start should be given as uint32_t.
if there is an overflow - warn about it. */
to = (uint32_t) timeout;
if (timeout > (uint32_t) timeout) {
to = 0xffffffff; /* max 32 bit timer */
CL_DBG("cl_event_wheel_reg: timeout requested is "
"too large. Using timeout: %u\n", to);
}
/* start the timer to the timeout [msec] */
cl_status = cl_timer_start(&p_event_wheel->timer, to);
if (cl_status != CL_SUCCESS) {
CL_DBG("cl_event_wheel_reg : ERR 6203: "
"Failed to start timer\n");
goto Exit;
}
}
/* insert the object to the qlist and the qmap */
/* BUT WE MUST INSERT IT IN A SORTED MANNER */
prev_event_list_item =
cl_qlist_find_from_tail(&p_event_wheel->events_wheel,
__event_will_age_before,
&p_event->aging_time);
cl_qlist_insert_next(&p_event_wheel->events_wheel,
prev_event_list_item, &p_event->list_item);
cl_qmap_insert(&p_event_wheel->events_map, key, &(p_event->map_item));
Exit:
cl_spinlock_release(&p_event_wheel->lock);
return cl_status;
}
