On Sun, 05.06.16 13:03, Ben-melech, Shiran ([email protected]) wrote:
> I've added mutex locks over all the sd functions using the bus as well
> as around the event loop.
>
> This is how i run the event loop inside the pthread:
>
> while (sd_event_get_state(event) != SD_EVENT_FINISHED) {
>
> pthread_mutex_lock (&lock);
> sd_event_run(event, 1000);
>
> pthread_mutex_unlock (&lock);
> if (r < 0) {
> sd_eve
> nt_get_exit_code(event, &r);
> syslog(LOG_ERR, "%s: Error
> sd_event_run with code %d", __FUNCTION__, r);
>
> return NULL;
> }
> sched_yield();
> }
>
> This did solve the seg faults and deadlocks but the callbacks are missed and
> never called. In addition the execution is extremely slow since the event
> loop is catching the lock most of the time.
You have to lock around all functions of sd-event you call. That
includes sd_event_get_state() and sd_event_get_exit_code().
If you want to unlock the mutex while sd-event is waiting for events,
I'd recommend using sd_event_get_fd() and poll()ing on the returned fd
instead of ever calling sd_event_run() or sd_event_wait().
But the rule is really: if you want to access the same sd_event object
from multiple threads, you have to comprehensively lock around it.
Lennart
--
Lennart Poettering, Red Hat
_______________________________________________
systemd-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/systemd-devel
