WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] xenbus stress testing

> 
> On Fri, Feb 18, Paul Durrant wrote:
> 
> > How do you propose to lock against another VM updating a counter in shared
> memory?
> 
> I thought xenstore uses the same ringbuffer as defined by
> DEFINE_RING_TYPES(). But reading the code in
> include/xen/interface/io/xs_wire.h shows it has its own logic.
> 
> And reading further in xenpaging code, which I had in mind while I wrote
> the mail, shows there is a separate spinlock.
> 
> I can imagine that even if a lock exists, a VM crashing while holding
> the lock can stall all other VMs. So its probably not the best idea.
> 

It's also inefficient when a perfectly good lock free method exists.

James
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel