Re: [Qemu-devel] [PATCH v2 1/9] cpus: Reclaim vCPU objects

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Thu, Nov 19, 2015 at 10:10:06AM -0500, Matthew Rosato wrote:
> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
> 
> In order to deal well with the kvm vcpus (which can not be removed without any
> protection), we do not close KVM vcpu fd, just record and mark it as stopped
> into a list, so that we can reuse it for the appending cpu hot-add request if
> possible. It is also the approach that kvm guys suggested:
> https://www.mail-archive.com/kvm@vger.kernel.org/msg102839.html
> 
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
>                [Explicit CPU_REMOVE() from qemu_kvm/tcg_destroy_vcpu()
>                 isn't needed as it is done from cpu_exec_exit()]

I didn't look very closely but the patch that removes cpu from the list
from cpu_exec_exit() isn't part of this series. The above change requires

https://lists.gnu.org/archive/html/qemu-devel/2015-08/msg00656.html

I have just cleaned that patch a bit and will be posting early next
week with another patch that does CPU vmstate unregistration too from
cpu_exec_exit(). I think since we do vmstate registration from cpu_exec_init()
it makes sense to do unregistration from cpu_exec_exit() instead of
archs doing it themselves. I had a version of this at

https://lists.gnu.org/archive/html/qemu-devel/2015-08/msg00649.html

With the above patch, you woudn't need 7/9 in this series.

Regards,
Bharata.