Re: [PATCH v1] KVM: stats: Add VM stat for the cumulative number of dirtied pages

On 12/08/21 01:37, Jing Zhang wrote:
> A per VM stat dirty_pages is added to record the number of dirtied pages
> in the life cycle of a VM.
> The growth rate of this stat is a good indicator during the process of
> live migrations. The exact number of dirty pages at the moment doesn't
> matter. That's why we define dirty_pages as a cumulative counter instead
> of an instantaneous one.

Why not make it a per-CPU stat?  mark_page_dirty_in_slot can use 
kvm_get_running_vcpu() and skip the logging in the rare case it's NULL.

Paolo