From patchwork Wed Sep 26 07:26:53 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Coquelin X-Patchwork-Id: 45353 Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id ADEC37CE2; Wed, 26 Sep 2018 09:27:17 +0200 (CEST) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 898B85F2D for ; Wed, 26 Sep 2018 09:27:16 +0200 (CEST) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 823DA285B0; Wed, 26 Sep 2018 07:27:15 +0000 (UTC) Received: from localhost.localdomain (ovpn-112-32.ams2.redhat.com [10.36.112.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id CECE060BE1; Wed, 26 Sep 2018 07:27:07 +0000 (UTC) From: Maxime Coquelin To: dev@dpdk.org, tiwei.bie@intel.com, zhihong.wang@intel.com, jfreimann@redhat.com Cc: dgilbert@redhat.com, Maxime Coquelin Date: Wed, 26 Sep 2018 09:26:53 +0200 Message-Id: <20180926072705.22641-1-maxime.coquelin@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 26 Sep 2018 07:27:15 +0000 (UTC) Subject: [dpdk-dev] [PATCH 00/12] vhost: add postcopy live-migration support X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" This first non-RFC version disables the postcopy feature by default and introduces a new flag passed at registration time to enable it. Vhost PMD adds a new postcopy-support option to enable this flag. Also, the instabilities are now fixed, they were caused by the wrong memory region VA being returned to the master. With classic live-migration, the VM runs on source while its content is being migrated to destination. When pages already migrated to destination are dirtied by the source, they get copied until both source and destination memory converge. At that time, the source is stopped and destination is started. With postcopy live-migration, the VM is started on destination before all the memory has been migrated. When the VM tries to access a page that haven't been migrated yet, a pagefault is triggered, handled by userfaultfd which pauses the thread. A Qemu thread in charge of postcopy request the source for the missing page. Once received and mapped, the paused thread gets resumed. Userfaultfd supports handling faults from a different process, and Qemu supports postcopy with vhost-user backends since v2.12. One problem encountered with classic live-migration for VMs relying on vhost-user backends is that when the traffic is high (e.g. PVP), it happens that it never converges as pages gets dirtied at a faster rate than they are copied to the destination. It is expected this problem sould be solved with using postcopy, as rings memory and buffers will be copied once, when destination will pagefault on them. Note that it will certainly require a rebase to apply on top of Nikolay's vhost-user message handling rework. Steps to test postcopy: 1. Run DPDK's Testpmd application on source: ./install/bin/testpmd -m 512 --file-prefix=src -l 0,2 -n 4 \ --vdev 'net_vhost0,iface=/tmp/vu-src' -- --portmask=1 -i \ --rxq=1 --txq=1 --nb-cores=1 --eth-peer=0,52:54:00:11:22:12 \ --no-mlockall 2. Run DPDK's Testpmd application on destination: ./install/bin/testpmd -m 512 --file-prefix=dst -l 0,2 -n 4 \ --vdev 'net_vhost0,iface=/tmp/vu-dst,postcopy-support=1' -- --portmask=1 -i \ --rxq=1 --txq=1 --nb-cores=1 --eth-peer=0,52:54:00:11:22:12 \ --no-mlockall 3. Launch VM on source: ./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 3G -smp 2 -cpu host \ -object memory-backend-file,id=mem,size=3G,mem-path=/dev/shm,share=on \ -numa node,memdev=mem -mem-prealloc \ -chardev socket,id=char0,path=/tmp/vu-src \ -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \ -device virtio-net-pci,netdev=mynet1 /home/virt/rhel7.6-1-clone.qcow2 \ -net none -vnc :0 -monitor stdio 4. Launch VM on destination: ./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 3G -smp 2 -cpu host \ -object memory-backend-file,id=mem,size=3G,mem-path=/dev/shm,share=on \ -numa node,memdev=mem -mem-prealloc \ -chardev socket,id=char0,path=/tmp/vu-dst \ -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \ -device virtio-net-pci,netdev=mynet1 /home/virt/rhel7.6-1-clone.qcow2 \ -net none -vnc :1 -monitor stdio -incoming tcp::8888 5. In both testpmd prompts, start flooding the virtio-net device: testpmd> set fwd txonly testpmd> start 6. In destination's Qemu monitor, enable postcopy: (qemu) migrate_set_capability postcopy-ram on 7. In source's Qemu monitor, enable postcopy and launch migration: (qemu) migrate_set_capability postcopy-ram on (qemu) migrate -d tcp:0:8888 (qemu) migrate_start_postcopy Maxime Coquelin (12): vhost: define postcopy protocol flag vhost: add number of fds to vhost-user messages and use it vhost: enable fds passing when sending vhost-user messages vhost: introduce postcopy's advise message vhost: add support for postcopy's listen message vhost: register new regions with userfaultfd vhost: avoid useless VhostUserMemory copy vhost: send userfault range addresses back to qemu vhost: add support to postcopy's end request vhost: enable postcopy protocol feature vhost: add flag to enable postcopy live-migration net/vhost: add parameter to enable postcopy migration support doc/guides/nics/vhost.rst | 5 + doc/guides/prog_guide/vhost_lib.rst | 8 ++ drivers/net/vhost/rte_eth_vhost.c | 13 ++ lib/librte_vhost/rte_vhost.h | 5 + lib/librte_vhost/socket.c | 32 ++++- lib/librte_vhost/vhost.h | 3 + lib/librte_vhost/vhost_user.c | 205 ++++++++++++++++++++++++---- lib/librte_vhost/vhost_user.h | 12 +- 8 files changed, 246 insertions(+), 37 deletions(-)