Re: /proc/xen/xenbus supports watch?

[Christian Limpach <christian.limpach@gmail.com>]

On 9/9/05, Rusty Russell <rusty@rustcorp.com.au> wrote:
> On Thu, 2005-09-08 at 11:38 +0100, Christian Limpach wrote:
> > On 9/8/05, NAHieu <nahieu@gmail.com> wrote:
> > > Anybody (Christian?) could please tell me if we can get the support
> > > for registering watch with /proc/xen/xenbus? (..OK, I know that we
> > > will change it this /proc stuff to a device soon)
> > >
> > > So far we can only do read/write/rm. I really miss the xen watch feature.
> 
> At the moment, the xenbus device is a simple hack which grabs the lock
> on all store communication on open, and drops it on close.  It's not
> really a general mechanism for tools in domUs to communicate with the
> store.

Could we reduce the time we hold the lock to from before we call
xb_write until both data->bytes_left and data->awaiting_reply are 0
again?  I think this would work except for transactions, how do you
feel about supporting multiple transactions per connection?  Should we
at least extend the interface now so that we can add concurrent
transaction support later, i.e. transaction start returning a handle
and all operations taking a handle argument?

    christian