Subject: Re: port-xen/29775: Cannot use a vnode disk for domU
To: None <port-xen-maintainer@netbsd.org, gnats-admin@netbsd.org,>
From: Jason Thorpe <thorpej@shagadelic.org>
List: netbsd-bugs
Date: 03/24/2005 00:53:02
The following reply was made to PR port-xen/29775; it has been noted by GNATS.

From: Jason Thorpe <thorpej@shagadelic.org>
To: tech-kern@NetBSD.org
Cc: port-xen-maintainer@NetBSD.org, gnats-admin@NetBSD.org,
	netbsd-bugs@NetBSD.org, gnats-bugs@NetBSD.org
Subject: Re: port-xen/29775: Cannot use a vnode disk for domU
Date: Wed, 23 Mar 2005 16:52:53 -0800

 On Mar 23, 2005, at 1:12 PM, Manuel Bouyer wrote:
 
 > This means that I/O on the vnd block device expect to be called from
 > a process context, while the xbd backend calls it from interrupt  
 > context.
 > And obvious way to fix this would be to add a kernel thread to the  
 > xbd backend
 > to do this. But maybe this needs a closer look:
 
 This is really a known problem.  The vnd driver needs to be rewritten  
 badly.  It needs to queue up requests and defer everything to a  
 kthread that actually does the work.
 
 -- thorpej