From patchwork Sat Aug 5 02:38:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: ~hyman X-Patchwork-Id: 1819727 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RLygn0YN6z1yYC for ; Thu, 10 Aug 2023 17:08:21 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qTzlO-0005PC-De; Thu, 10 Aug 2023 03:07:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qTzlK-0005O9-Uy for qemu-devel@nongnu.org; Thu, 10 Aug 2023 03:07:14 -0400 Received: from mail-b.sr.ht ([173.195.146.151]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qTzlH-0004oI-WA for qemu-devel@nongnu.org; Thu, 10 Aug 2023 03:07:14 -0400 Authentication-Results: mail-b.sr.ht; dkim=none Received: from git.sr.ht (unknown [173.195.146.142]) by mail-b.sr.ht (Postfix) with ESMTPSA id 406E411EF58; Thu, 10 Aug 2023 07:07:10 +0000 (UTC) From: ~hyman Date: Sat, 05 Aug 2023 10:38:11 +0800 Subject: [PATCH QEMU v2 2/3] virtio-blk-pci: introduce auto-num-queues property MIME-Version: 1.0 Message-ID: <169165122958.4096.6557269987206106594-2@git.sr.ht> X-Mailer: git.sr.ht In-Reply-To: <169165122958.4096.6557269987206106594-0@git.sr.ht> To: qemu-devel Cc: Raphael Norwitz , "Michael S. Tsirkin" , Kevin Wolf , Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , Fam Zheng , yong.huang@smartx.com Received-SPF: pass client-ip=173.195.146.151; envelope-from=outgoing@sr.ht; helo=mail-b.sr.ht X-Spam_score_int: 15 X-Spam_score: 1.5 X-Spam_bar: + X-Spam_report: (1.5 / 5.0 requ) BAYES_00=-1.9, DATE_IN_PAST_96_XX=3.405, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: ~hyman Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Hyman Huang(黄勇) Commit "9445e1e15 virtio-blk-pci: default num_queues to -smp N" implment sizing the number of virtio-blk-pci request virtqueues to match the number of vCPUs automatically. Which improves IO preformance remarkably. To enable this feature for the existing VMs, the cloud platform may migrate VMs from the source hypervisor (num_queues is set to 1 by default) to the destination hypervisor (num_queues is set to -smp N) lively. The different num-queues for virtio-blk-pci devices between the source side and the destination side will result in migration failure due to loading vmstate incorrectly on the destination side. To provide a smooth upgrade solution, introduce the auto-num-queues property for the virtio-blk-pci device. This allows upper APPs, e.g., libvirt, to recognize the hypervisor's capability of allocating the virtqueues automatically by probing the virtio-blk-pci.auto-num-queues property. Basing on which, upper APPs can ensure to allocate the same num-queues on the destination side in case of migration failure. Signed-off-by: Hyman Huang(黄勇) --- hw/block/virtio-blk.c | 1 + hw/virtio/virtio-blk-pci.c | 9 ++++++++- include/hw/virtio/virtio-blk.h | 5 +++++ 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 39e7f23fab..9e498ca64a 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1716,6 +1716,7 @@ static Property virtio_blk_properties[] = { #endif DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, true), + DEFINE_PROP_BOOL("auto-num-queues", VirtIOBlock, auto_num_queues, true), DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, VIRTIO_BLK_AUTO_NUM_QUEUES), DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 256), diff --git a/hw/virtio/virtio-blk-pci.c b/hw/virtio/virtio-blk-pci.c index 9743bee965..4b6b4c4933 100644 --- a/hw/virtio/virtio-blk-pci.c +++ b/hw/virtio/virtio-blk-pci.c @@ -54,7 +54,14 @@ static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) VirtIOBlkConf *conf = &dev->vdev.conf; if (conf->num_queues == VIRTIO_BLK_AUTO_NUM_QUEUES) { - conf->num_queues = virtio_pci_optimal_num_queues(0); + /* + * Allocate virtqueues automatically only if auto_num_queues + * property set true. + */ + if (dev->vdev.auto_num_queues) + conf->num_queues = virtio_pci_optimal_num_queues(0); + else + conf->num_queues = 1; } if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) { diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index dafec432ce..dab6d7c70c 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -65,6 +65,11 @@ struct VirtIOBlock { uint64_t host_features; size_t config_size; BlockRAMRegistrar blk_ram_registrar; + /* + * Set to true if virtqueues allow to be allocated to + * match the number of virtual CPUs automatically. + */ + bool auto_num_queues; }; typedef struct VirtIOBlockReq {