On Friday, July 20, 2018 8:52 PM, Michael S. Tsirkin wrote: > On Fri, Jul 20, 2018 at 04:33:00PM +0800, Wei Wang wrote: > > This patch series is separated from the previous "Virtio-balloon > > Enhancement" series. The new feature, > VIRTIO_BALLOON_F_FREE_PAGE_HINT, > > implemented by this series enables the virtio-balloon driver to report > > hints of guest free pages to the host. It can be used to accelerate > > live migration of VMs. Here is an introduction of this usage: > > > > Live migration needs to transfer the VM's memory from the source > > machine to the destination round by round. For the 1st round, all the > > VM's memory is transferred. From the 2nd round, only the pieces of > > memory that were written by the guest (after the 1st round) are > > transferred. One method that is popularly used by the hypervisor to > > track which part of memory is written is to write-protect all the guest > memory. > > > > This feature enables the optimization by skipping the transfer of > > guest free pages during VM live migration. It is not concerned that > > the memory pages are used after they are given to the hypervisor as a > > hint of the free pages, because they will be tracked by the hypervisor > > and transferred in the subsequent round if they are used and written. > > > > * Tests > > - Test Environment > > Host: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz > > Guest: 8G RAM, 4 vCPU > > Migration setup: migrate_set_speed 100G, migrate_set_downtime 2 > > second > > Can we split out patches 1 and 2? They seem appropriate for this release ... Sounds good to me. I'm not sure if there would be comments on the first 2 patches. If no, can you just take them here? Or you need me to repost them separately? Best, Wei
