Re: [Qemu-devel] [PATCH] Merge NBD client/server int qemu-nbd

[Anthony Liguori]

Laurent Vivier wrote:
> Le samedi 14 juin 2008 à 12:35 -0700, Avi Kivity a écrit :
>   
> > Laurent Vivier wrote:
> >
> >   
> >
> >     
> > > > It is udev that creates the devices, based on events it receives from 
> > > > the kernel.  Calling udevsettle after the kernel instructs udev to 
> > > > create the device files will wait until they are actually created.
> > > >     
> > > >         
> > > Yes, I agree but the kernel events are generated by the open(), so I
> > > think I can't use this to know if I can use open(). 
> > >
> > > I've used udevmonitor to see what happen:
> > > - without open() -> no events
> > > - whith open() whithout sleep() -> no events
> > > -> open() + sleep() -> events generated by the partition creation.
> > >
> > > So, what do I miss ?
> > >   
> > >       
> > For this, it seems like sleep() generates the events, which is a little 
> > unlikely.  I suggest re-checking this.
> >     
>
> re-checked, no events with sleep() only.
>
> events generated with sleep() + open() are:
>   

I imagine the sleep() is causing another task to be scheduled (probably 
the server) which is what ends up generating the event.

Regards,

Anthony Liguori