[systemd-devel] [PATCH 1/2] Add sd_event_loop_timeout to sd_event

[Didier Roche]

Le 04/02/2015 18:20, Lennart Poettering a écrit :
> On Wed, 04.02.15 17:40, Didier Roche (didrocks at ubuntu.com) wrote:
>
>> Le 04/02/2015 17:10, Lennart Poettering a écrit :
>>> On Wed, 04.02.15 17:05, Didier Roche (didrocks at ubuntu.com) wrote:
>>>
>>>> Hey,
>>>>
>>>> I rewrote a version of this patch including the feedback on the list. As per
>>>> IRC discussion, (and after giving up the busy loop for a rewrite with
>>>> epool), I did rebase it again on sd_event.
>>>>
>>>> I'm only proposing there up for review the 2 first patches (without plymouth
>>>> communication, cancel support, i18n, man pages and the service and socket)
>>>> so that I don't have to rebase all other 10 patches on a moving
>>>> ground.
>>> Tom just added support for installing timer events with a NULL
>>> callback, that trigger event loop exit. I kinda prefer that solution
>>> over a new call sd_event_loop() with timeout.
>>>
>>>       sd_event_add_time(event, NULL, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + 5 * USEC_PER_SEC, NULL, NULL);
>> So, it means that I need to reset it after any received activity, is that
>> ok? (as this will be really frequent as each clients in parallel can send a
>> message each 50ms). The goal is to have a global "inactivity" timeout.
>>
>> I didn't see a way to cancel this event source though?
> Oh, I see, you actually want a real idle logic, not just a normal
> timer.
>
> So far, for daemons like timedated, localed and so on, we are using an
> idle logic that is implemented in bus_event_loop_with_idle() in
> src/libsystemd/sd-bus/bus-util.c. It does considerably more than what
> you need (since it contains all the magic to racefully do exit-on-idle
> for bus services so that no bus messages are lost).
>
> I think the best would be to take inspiration from that code, isolate
> there basic minimum out of it, without all the dbus logic, and then
> stick that in your C file.
>
> We can generalize such exit-on-idle logic one day, somewhere between
> sd-bus and sd-event, but that requires considerabe design work, so
> that we find a generic solution that works for you and also covers
> this dbus case without hacks. For now it's hence better if you just
> take inspiration from bus_event_loop_with_idle(), drop all the
> bus-specific bits, and stick it in your .c code...

Making sense.

Done and fixed. Thanks a lot
Cheers,
Didier