Re: [Qemu-devel] [PATCH 8/8] [PATCH RFC v2] s390-qemu: cpu hotplug - Treat S390 cpus as devices

["Jason J. Herne" <jjherne@linux.vnet.ibm.com>]

On 07/30/2013 03:24 AM, Igor Mammedov wrote:
> On Mon, 29 Jul 2013 15:41:57 -0400
> "Jason J. Herne" <jjherne@linux.vnet.ibm.com> wrote:
>
>> On 06/08/2013 09:11 PM, Andreas Färber wrote:
>>>>    if (tcg_enabled() && !inited) {
>>>>>           inited = true;
>>>>>           s390x_translate_init();
>>>>>       }
>>>>> +
>>>>> +    smp_cpus += 1;
>>> Won't we need some form of locking?
>>>
>>> If we fiddle with a global CPU counter, we should do so in qom/cpu.c,
>>> not just in s390x code.
>>>
>>
>> I've redesigned a lot of this to make it simpler and less intrusive.
>> I'm almost ready to post the next revision but I'm hung up on this one
>> thing.
>>
>> I moved the smp_cpu increment to qom/cpu.c : cpu_common_realizefn.
>> However this seems to break the user mode target because smp_cpus does
>> not exist.  I tried wrapping the increment in a #ifndef CONFIG_USER_ONLY
>> statement but it seems to have no effect.  I think the reason for that
>> is because CONFIG_USER_ONLY is added to config-target.h which is not
>> actually generated until after we compile qom/cpu.c.
>>
>> ...
>>     CC    qom/object.o
>>     CC    qom/container.o
>>     CC    qom/qom-qobject.o
>>     CC    qom/cpu.o
>>     CC    hw/core/qdev.o
>>     CC    hw/core/qdev-properties.o
>>     CC    hw/core/irq.o
>>     GEN   s390x-linux-user/config-target.h
>>     CC    s390x-linux-user/exec.o
>> ...
>>
>> Is there another place I should put the increment?
>
> Could you just use current number of cpus instead of smp_cpus increment?
>

Is there an easier way of getting the count besides this?

int cpu_count = 0;
for (cpu = first_cpu; cpu != NULL; cpu = cpu->next_cpu) {
     cpu_count++;
}




-- 
-- Jason J. Herne (jjherne@linux.vnet.ibm.com)