From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-3131-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [66.179.20.138]) by lists.oasis-open.org (Postfix) with ESMTP id 334255818039 for ; Fri, 2 Feb 2018 04:46:25 -0800 (PST) Message-ID: <5A745E27.7070002@intel.com> Date: Fri, 02 Feb 2018 20:48:39 +0800 From: Wei Wang MIME-Version: 1.0 References: <1516871646-22741-1-git-send-email-wei.w.wang@intel.com> <20180201211525-mutt-send-email-mst@kernel.org> In-Reply-To: <20180201211525-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: [virtio-dev] Re: [PATCH v25 0/2] Virtio-balloon: support free page reporting To: "Michael S. Tsirkin" 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, pbonzini@redhat.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com List-ID: 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/2018/1/25/698 I 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 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org