Xen devel - Jun 2007 - redundancy with timer function of balloon driver

hi

Code involved in balloon driver for scanning of xenstore has been
implemented by polling with timer and event notification function.

timer written like this:

init_timer(&balloon_timer);
   balloon_timer.data = 0;
       balloon_timer.function = balloon_alarm;

and other function realted to timer in balloon driver is

mod_timer(&balloon_timer, jiffies + HZ);

but there is no routine i have seen which make the timer activate by adding

add_timer(&balloon_timer) in the balloon driver

so i am assumign that balloon driver works only with event notifiction
in xenstore and the timer code in balloon driver is redundant

please correct me

thanks
TEJ

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

On 6/6/07 08:58, "Tej Parkash" <tejparkash.d@gmail.com> wrote:
> mod_timer(&balloon_timer, jiffies + HZ);
> 
> but there is no routine i have seen which make the timer activate by adding
> 
> add_timer(&balloon_timer) in the balloon driver
mod_timer() activates the timer if it isn''t already active.

 -- Keir


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

> Code involved in balloon driver for scanning of xenstore has been
> implemented by polling with timer and event notification function.
>
> timer written like this:
>
> init_timer(&balloon_timer);
>    balloon_timer.data = 0;
>        balloon_timer.function = balloon_alarm;
>
> and other function realted to timer in balloon driver is
>
> mod_timer(&balloon_timer, jiffies + HZ);
>
> but there is no routine i have seen which make the timer activate by adding
>
> add_timer(&balloon_timer) in the balloon driver
Hi there,

From the comments in linux-2.6.18/kernel/timer.c::mod_timer():

 * mod_timer is a more efficient way to update the expire field of an
 * active timer (if the timer is inactive it will be activated)

So I guess the mod_timer call is also having the effect of activating the 
timer without using add_timer.  Does this sound right to you?

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel