From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Wang Subject: Re: [PATCH v37 0/3] Virtio-balloon: support free page reporting Date: Thu, 25 Oct 2018 18:18:53 +0800 Message-ID: <5BD1988D.7010606@intel.com> References: <1535333539-32420-1-git-send-email-wei.w.wang@intel.com> <20181024205759-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org, dgilbert@redhat.com, torvalds@linux-foundation.org, pbonzini@redhat.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com, peterx@redhat.com, quintela@redhat.com To: "Michael S. Tsirkin" Return-path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: <20181024205759-mutt-send-email-mst@kernel.org> List-Id: kvm.vger.kernel.org On 10/25/2018 08:58 AM, Michael S. Tsirkin wrote: > On Mon, Aug 27, 2018 at 09:32:16AM +0800, Wei Wang wrote: >> 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 host. It can be used to accelerate virtual machine (VM) live >> migration. 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 have the hypervisor 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. > OK so it will be in linux-next. Now can I trouble you for a virtio spec > patch with the description please? No problem, I'll start to patch the spec. Thanks! Best, Wei