Re: [Qemu-devel] [RFC V2 10/10] cpus: reclaim allocated vCPU objects

[Gu Zheng <guz.fnst@cn.fujitsu.com>]

Hi Bharata,

On 09/11/2014 08:37 PM, Bharata B Rao wrote:

> On Thu, Sep 11, 2014 at 3:23 PM, Gu Zheng <guz.fnst@cn.fujitsu.com> wrote:
>> On 09/11/2014 05:35 PM, Bharata B Rao wrote:
>>
>>> On Thu, Aug 28, 2014 at 9:06 AM, Gu Zheng <guz.fnst@cn.fujitsu.com> wrote:
>>>> After ACPI get a signal to eject a vCPU, the vCPU must be
>>>> removed from CPU list，before the vCPU really removed,  then
>>>> release the all related vCPU objects.
>>>> But we do not close KVM vcpu fd, just record it into a list, in
>>>> order to reuse it.
>>>
>>> After I add and delete a CPU, "info cpus" from monitor still lists the
>>> removed CPU. Is this expected ?
>>
>> No, you can not see the removed cpu from QEMU (e.g. monitor) or guest side,
>> but from the kernel side it is still there, just no one uses it any more.
> 
> I am trying your patches, but still see the removed CPU after deletion.
> 
> (qemu) info cpus
> * CPU #0: pc=0xffffffff8100b82c (halted) thread_id=7812
>   CPU #1: pc=0xffffffff8100b82c (halted) thread_id=7813
>   CPU #2: pc=0xffffffff8100b82c (halted) thread_id=7814
>   CPU #3: pc=0xffffffff8100b82c (halted) thread_id=7815
>   CPU #4: pc=0xffffffff8100b82c (halted) thread_id=7816
>   CPU #5: pc=0xffffffff8100b82c (halted) thread_id=7817
>   CPU #6: pc=0xffffffff8100b82c (halted) thread_id=7818
>   CPU #7: pc=0xffffffff8100b82c (halted) thread_id=7819
> (qemu) device_add qemu64-x86_64-cpu,id=cpu8
> (qemu) info cpus
> * CPU #0: pc=0xffffffff8100b82c (halted) thread_id=7812
>   CPU #1: pc=0xffffffff8100b82c (halted) thread_id=7813
>   CPU #2: pc=0xffffffff8100b82c (halted) thread_id=7814
>   CPU #3: pc=0xffffffff8100b82c (halted) thread_id=7815
>   CPU #4: pc=0xffffffff8100b82c (halted) thread_id=7816
>   CPU #5: pc=0xffffffff8100b82c (halted) thread_id=7817
>   CPU #6: pc=0xffffffff8100b82c (halted) thread_id=7818
>   CPU #7: pc=0xffffffff8100b82c (halted) thread_id=7819
>   CPU #8: pc=0xffffffff8100b82c (halted) thread_id=8041
> (qemu) device_del cpu8
> (qemu) info cpus
> * CPU #0: pc=0xffffffff8100b82c (halted) thread_id=7812
>   CPU #1: pc=0xffffffff8100b82c (halted) thread_id=7813
>   CPU #2: pc=0xffffffff8100b82c (halted) thread_id=7814
>   CPU #3: pc=0xffffffff8100b82c (halted) thread_id=7815
>   CPU #4: pc=0xffffffff8100b82c (halted) thread_id=7816
>   CPU #5: pc=0xffffffff8100b82c (halted) thread_id=7817
>   CPU #6: pc=0xffffffff8100b82c (halted) thread_id=7818
>   CPU #7: pc=0xffffffff8100b82c (halted) thread_id=7819
>   CPU #8: pc=0xffffffff81031722 (halted) thread_id=8041
> 
> I applied your patchset on commit 69f87f713069f1f70, may be I should
> try with latest QEMU ?

Is guest os enabled acpi cpu hotplug? What's the guest's cpu info?
Please try latest QEMU, and any feedback is welcome.

Thanks,
Gu

> 
> Regards,
> Bharata.
> .
>