Re: [Xen-devel] Some question to changeset 17962

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 09/03/2009 09:25, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:

>> For (b), Xen itself has okay semantics -- the most recent
>> caller to set the
>> suspend_evtchn always wins. How tools make use of that policy
>> is up to them
>> -- since we can only have one save process per domain at a time, it all
>> works out fine. 
> 
> Are there any special reason that not the first caller hold it (which is more
> nature IMO), and the later caller will failed?

The only reason I can think is if the xc_save process fails and exit()s and
then we want to continue execution of the domain and maybe try xc_save again
later. Then the first registered evtchn won't be cleaned up and we would
like to overwrite it when we next try xc_save.

Arguably we should make the kernel evtchn driver aware of suspend evtchns
and clean them up on process destruction. Then we could tighten up Xen's
checking. But... It's all kind of a hassle for hardly any reward!

 -- Keir



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