Re: [Xen-devel] why xenstore-* hangs if xenstored is not started

[Vincent Hanquez <vincent.hanquez@xxxxxxxxxxxxx>]

On 22/06/10 08:58, Yu Zhiguo wrote:
> Hi,
>
> Vincent Hanquez wrote:
>
> > That's the common behavior of task stuck in a kernel operation (ps aux
> > will show the task at D, and /proc/<pid>/wchan will tell you exactly
> > where it's blocked in the kernel).
> >
> > the write is going to wait for a xenstored reply in kernel mode since by
> > default the xenstore-* tools use the kernel xenstore page to communicate
> > with xenstored.
> >
> > The unix socket operations doesn't have this "problems" (xenstore-* -s)
> Thanks~~
> I confirmed the task is at D+ and there are no this "problem" if use option -s.
> But I think S+ is better than D+...
I don't think it's very easy to have interruptible sleep here, it would 
change radically the protocol. the kernel xenstored page need to be 
handled "atomically" since requests and their replied cannot be 
intertwined. Maybe a timeout would be the one requiring the less change ?
--
Vincent

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