Re: generate random numbers

[George Dunlap <george.dunlap@eu.citrix.com>]

Did you look at timer.c, line 184, to find out what the BUG is?
 -George

michele.paolino wrote:
> Following George's advices I have rewrited my scheduler. But now 
> serial console's log report me a bug in a function of timer.c
>
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) Xen BUG at timer.c:184
> (XEN) ****************************************
>
> This is caused by cpumask_raise_softirq() in my wake() function. What 
> can I do?
>
> Michele
>
> On Thu, Feb 25, 2010 at 10:25 PM, George Dunlap 
> <george.dunlap@eu.citrix.com <mailto:george.dunlap@eu.citrix.com>> wrote:
>
>     The problem is that you're choosing a random vcpu to run, without
>     considering whether it *wants* to run or not.  In this case,
>     you're running a vcpu before it's even been completely set up yet
>     (write_cr3 is failing because the guest *has* no cr3 ready yet).
>
>     The normal way schedulers deal with this is to keep one list of
>     all vcpus (or all domains), and another list with "runnable"
>     vcpus.  You can keep track of which vcpus are runnable with the
>     vcpu_wake() callback and by using vcpu_runnable() in schedule().
>
>     At very least, your loop in schedule should check vcpu_runnable()
>     before selecting it.
>
>     -George
>
>
>     michele.paolino wrote:
>
>         Here's my random scheduler. It works until I start a virtual
>         machine (error file attached is the serial console's log).
>         In xen call trace there isn't any of my functions.
>         To generate random numbers I'm using the hash (MD5) of NOW()
>         function.
>         I would also Know why at boot time there are two calls at
>         vcpu_init function for vcpu with id = 0 ??
>
>         Thanks
>         Michele
>
>
>