On Wed, Dec 12, 2018 at 03:14:30PM +1100, Paul Mackerras wrote: > We have observed that live migration of radix guests tends to converge > slowly and sometimes doesn't converge at all. This appears to be due > largely to the fact that if the host is using transparent huge pages, > page dirtiness only gets tracked with a 2MB granularity for the parts > of the guest memory that are mapped using 2MB pages. The fix is to > break down the mappings in the partition-scoped page tables to 64k > pages (or 4k pages if 4k is the system page size). This is > accomplished by flushing the partition-scoped page tables when turning > dirty page tracking on or off, and by only inserting small-page PTEs > into the partition-scoped page tables while dirty page tracking is > enabled. > > Paul. Series applied to my kvm-ppc-next branch. Paul.
