Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration

[Juan Quintela]

Paolo Bonzini <address@hidden> wrote:
> On 02/11/2015 08:36, Liang Li wrote:
>> The patch 3ea3b7fa9af067982f34b of kvm introduces a lazy collapsing
>> of small sptes into large sptes mechanism, which intend to solve the
>> performance drop issue if live migration fails or is canceled. The
>> rmap will be scanned in the KVM_SET_USER_MEMORY_REGION ioctl context
>> when dirty logging is stopped so as to drop the small sptes, scanning
>> the rmap and drop the small sptes is a time consuming operation which
>> will take dozens of milliseconds, the actual time depends on VM's
>> memory size. For a VM with 8GB RAM, it will take about 30ms.
>
> I'm okay with these patches.  Juan, can they be included in 2.5?

Applied, thanks.

>
> However, the KVM patch is a regression too.  Wanpeng, can you look into
> doing the collapsing from a work item?
>
> Thanks,
>
> Paolo