hi,
El Sat, 10 Feb 2007 18:37:34 -0600
"Curran, Dominic" <dcurran@xxxxxx> ha escrit:
> >
> > > Hello. I have written a netfilter kernel module and I want some
> > > code to run periodically, ie a function in the module should run
> > > every 5 seconds.
> > >
> > > I have researched and implemented a kernel work queue however this
> > > does not have the capability of being periodic from my assessment.
> > > Can anyone point me in the right direction?
> > >
> >
> > i've read all messages in this thread and seems the only way
> > proposed is using timers...
> >
> > i've implemented a very similar kernel module, using netfilter to
> track
> > connections, and i created a kernel tread that detect inactivity in
> > a loop, and sleeping for a while in between.
> >
> > this solutions will work for you? :)
> >
> > or maybe i'm doing a very ugly thing? :(
> >
>
> The original poster asked for code to run periodically. From that I
> assumed he meant every X number of jiffies.
> Using timers will give him pretty good accuracy in that respect.
>
> What mechanism are you using to sleep and wake yourself up within your
> thread ?
i'm using schedule_timeout, because i need to verify if some connections
are expired, but i don't care it it's a fixed time between verifications
>
> If you are using schedule() to sleep and then testing if > X jiffies
> has passed then this will also work.
> e.g.
> while( !exit )
> {
> start = jiffies;
> do {
> schedule();
> } while( jiffies - start < X );
>
> do_work_here();
> }
my code looks like:
for (;;)
{
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(X);
set_current_state(TASK_RUNNING);
if (signal_pending(current))
break;
do_work_here();
}
>
> However I would suggest that you may not get the same accuracy as
> using timers. When you call schedule() you have no control over how
> long it will be before your thread gets scheduled back in.
> If you don't care about accuracy then that probably not a problem.
yes, i don't care about accuracy...
>
> Your method of using a thread benefits from being able to block (wait)
> in that context. You cannot block in a timer context.
i know, i'm doing some data cleanups, that probably would sleep in some
situacions
topi
> dom
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