Re: [Xen-devel] Sched_op hypercall small questions

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.09.11 at 10:31, Daniel Castro <evil.dani@xxxxxxxxx> wrote:
> On Tue, Sep 20, 2011 at 4:33 PM, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>>>> Daniel Castro  09/20/11 8:18 AM >>>
>>>On Tue, Sep 20, 2011 at 2:41 PM, Keir Fraser  wrote:
>>>> On 19/09/2011 22:21, "Daniel Castro"  wrote:
>>>>
>>>>> Greetings all.
>>>>>
>>>>> Some small question regarding schedule poll operation hypercall.
>>>>>
>>>>> 1. struct sched_poll poll.timeout is measured in what unit of time?
>>>>> Secs, ms? ns?
>>>>
>>>> It is an absolute system time (rather than a duration), in nanoseconds.
>>>
>>>really an absolute system time?
>>>
>>>When the timeout is set and the timeout is reached, the system behaves
>>>like if the event had been received? i.e the bit is changed?
>>
>> No, the bit would remain unset - the poll times out then, it doesn't
>> "complete".
> 
> My Guest VM would get stuck on the hypercall call, like if it was an
> infinite loop?

I'm not following. Of course, if you blindly and constantly re-issue the
hypercall, then you'd be stuck in a loop. Allowing to prevent that is
what the timeout is for.

> And once the timeout occurs or the event get delivered, then the
> hypercall would return, right?

Yes.

Jan


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