[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]
Subject: Re: [PATCH v25 0/2] Virtio-balloon: support free page reporting
On 02/02/2018 03:15 AM, Michael S. Tsirkin wrote:
On Thu, Jan 25, 2018 at 05:14:04PM +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. The second feature enables the optimization of the 1st round memory transfer - the hypervisor can skip the transfer of guest free pages in the 1st round. 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 next round if they are used and written.Could you post performance numbers please?
Yes, it was posted here https://lkml.org/lkml/2018/1/25/698I just changed the host side to poll the vq so that we don't need kick in the driver, it works pretty well. I'll test a little bit more and post out a new version with new performance numbers attached in the cover letter.
Best, Wei
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]