lkml.org 
[lkml]   [2010]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH] [RFC] timerfd: add TFD_NOTIFY_CLOCK_SET to watch for clock changes
    From
    Date
    On Tue, 2010-11-23 at 23:43 +0100, Lennart Poettering wrote:
    > On Tue, 23.11.10 19:22, Alexander Shishkin (virtuoso@slind.org) wrote:
    >
    > > Certain userspace applications (like "clock" desktop applets or cron or
    > > systemd) might want to be notified when some other application changes
    > > the system time. There are several known to me reasons for this:
    > > - avoiding periodic wakeups to poll time changes;
    > > - rearming CLOCK_REALTIME timers when said changes happen;
    > > - changing system timekeeping policy for system-wide time management
    > > programs;
    > > - keeping guest applications/operating systems running in emulators
    > > up to date.
    > >
    > > This is another attempt to approach notifying userspace about system
    > > clock changes. The other one is using an eventfd and a syscall [1]. In
    > > the course of discussing the necessity of a syscall for this kind of
    > > notifications, it was suggested that this functionality can be achieved
    > > via timers [2] (and timerfd in particular [3]). This idea got quite
    > > some support [4], [5], [6] and some vague criticism [7], so I decided
    > > to try and go a bit further with it.
    >
    > I agree with Kay, this is pretty much exactly what we want for
    > systemd. (Assuming that the time jump due to system suspend is
    > propagated to userspace like any other time jump with this path).

    A "Tested-by: Lennart Poettering <mzxreary@0pointer.de>" would be
    helpful, I think.

    > So yeah, I'd be very happy if this could be merged.

    Hmm, and question about why exactly the timerfd interface is a bad way
    to go was ignored.

    --
    Best Regards,
    Artem Bityutskiy (Артём Битюцкий)

    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2010-11-24 09:09    [W:0.024 / U:62.692 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site