Re: [Xen-devel] [PATCH 04/18] xen/arm: While a domain is suspended put its watchdogs on pause

[Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>]

Hi Jan,

On Mon, Nov 12, 2018 at 4:23 PM Jan Beulich <JBeulich@xxxxxxxx> wrote:
>
> >>> On 12.11.18 at 16:17, <mirela.simonovic@xxxxxxxxxx> wrote:
> > Hi Jan,
> >
> > On Mon, Nov 12, 2018 at 12:47 PM Jan Beulich <JBeulich@xxxxxxxx> wrote:
> >>
> >> >>> On 12.11.18 at 12:30, <mirela.simonovic@xxxxxxxxxx> wrote:
> >> > --- a/xen/include/xen/timer.h
> >> > +++ b/xen/include/xen/timer.h
> >> > @@ -18,6 +18,9 @@ struct timer {
> >> >      /* System time expiry value (nanoseconds since boot). */
> >> >      s_time_t expires;
> >> >
> >> > +    /* Suspend timestamp value (nanoseconds since boot). */
> >> > +    s_time_t suspended;
> >>
> >> I can't see how this becomes a universally useful field, so I
> >> don't think it belongs here. For your purpose deriving a new
> >> structure containing struct timer and this one field should
> >> work.
> >
> > Each 'expires' value needs to be coupled with 'suspended' value to be
> > able to deal with watchdogs when suspending a domain. This is specific
> > to a watchdog.
> > If we add a derived structure to contain this field we still need to
> > associate such a structure with each watchdog of a domain, which is
> > also domain generic info and requires a lot more (in my opinion
> > unnecessary) changes. Please let me know if I misinterpreted your
> > proposal.
>
> You add the field to all timer instances, yet you need it only for
> very few. Why not have a struct watchdog_timer, and use it
> for struct domain's watchdog_timer[]? I'm afraid I don't see the
> difficulties you appear to see.
>

Thanks, now it's clear. We need to change the type for watchdog_timer
to be the derived structure of timer that additionally contains
'suspended' variable. That makes sense, we'll do so.

Thanks,
Mirela

> Jan
>
>

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel