RE: List of Processes

["manish regmi" <manish_regmi@xxxxxxxxxxx>]

> Regarding acquiring a lock:  I realize this may be a stupid question,
> but how does one go about doing this?  Can you provide a short code
> example?
>
> Thanks

> > one small doubt, shouldn't we be acquiring a lock while iterating over
> > all the tasks ?
> >
> > anupam
> >
> > > for_each_task(p)
> > > {
> > > ...
> > > }
> > >
> > > You will each task's descriptor on p on each loop. The first one will 
> > be
> > > that of init. You will automatically break from loop when you finish
> > > traverse through all tasks.
> > > Actually a circular list.
> No, Lock is unnecessary here,
> we are not manipulating the list, just following the link.
> Lock is necessary if you add or remove from the list.
>
> regards manish

Sorry,
It was incorrect. You need a lock.
But only a read lock.

For that purpose we have a tasklist_lock defined in sched.h

The implementationm will be,

read_lock(&tasklist_lock);
for_each_task(p)
{
.....
}
read_unlock(&tasklist_lock);

regards manish

_________________________________________________________________
Help STOP SPAM with the new MSN 8 and get 2 months FREE*  
http://join.msn.com/?page=features/junkmail


--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/