Re: [PATCH] xen: add steal_clock support on x86

[Juergen Gross]

On 18/05/16 16:46, Boris Ostrovsky wrote:
> On 05/18/2016 08:15 AM, Juergen Gross wrote:
>>  }
>>  
>> +void __init xen_time_setup_guest(void)
>> +{
>> +	pv_time_ops.steal_clock = xen_steal_clock;
>> +
>> +	static_key_slow_inc(&paravirt_steal_enabled);
>> +	/*
>> +	 * We can't set paravirt_steal_rq_enabled as this would require the
>> +	 * capability to read another cpu's runstate info.
>> +	 */
>> +}
> 
> Won't we be accounting for stolen cycles twice now --- once from
> steal_account_process_tick()->steal_clock() and second time from
> do_stolen_accounting()?

Uuh, yes.

I guess I should rip do_stolen_accounting() out, too? It is a
Xen-specific hack, so I guess nobody will cry. Maybe it would be a
good idea to select CONFIG_PARAVIRT_TIME_ACCOUNTING for XEN then?


Juergen