From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9F07C38A2A for ; Fri, 8 May 2020 12:54:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9A882496A for ; Fri, 8 May 2020 12:54:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942477; bh=5M9/i+sHmIz8sIvRvyAC4vBnfJk2Ljuv92Rsyc2GraY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=t4DIxzcyM01CTIEQNPv6qra9IIwfv6Ajk/Tgvje1seI4cRVmmtJvPN4AOab/hq0QE /aUJsFFHrMqgn97M3+7ESP/BY2BKIrvIGIJ5pq7NGIr0vMPdIlVd1QSGPxAxOUMu6X m4mXr/WnMyIHH+YhNGpJOYKDP+/0s5yljiCp5UbQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730227AbgEHMyh (ORCPT ); Fri, 8 May 2020 08:54:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:36938 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730218AbgEHMye (ORCPT ); Fri, 8 May 2020 08:54:34 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AC4E724958; Fri, 8 May 2020 12:54:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942473; bh=5M9/i+sHmIz8sIvRvyAC4vBnfJk2Ljuv92Rsyc2GraY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UkZuAPeEkdPbt1IwvzJTDI2Bjw3li3dFw6Aipu/CWbpnNV0PjdHbJNyQxfWiGLkgo mi5BXYz4aFc/leDecxmN3lporc0k63RqGLkzjLgOwpeBxEytUE98OwbPzR9frwozT0 2A2sJRr9TZaCQwWVRNb8/ewr6SJXckwhIWkzQO/o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ning Bo , Stefano Garzarella , Jia He , "Michael S. Tsirkin" Subject: [PATCH 5.6 01/49] vhost: vsock: kick send_pkt worker once device is started Date: Fri, 8 May 2020 14:35:18 +0200 Message-Id: <20200508123043.013091973@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123042.775047422@linuxfoundation.org> References: <20200508123042.775047422@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jia He commit 0b841030625cde5f784dd62aec72d6a766faae70 upstream. Ning Bo reported an abnormal 2-second gap when booting Kata container [1]. The unconditional timeout was caused by VSOCK_DEFAULT_CONNECT_TIMEOUT of connecting from the client side. The vhost vsock client tries to connect an initializing virtio vsock server. The abnormal flow looks like: host-userspace vhost vsock guest vsock ============== =========== ============ connect() --------> vhost_transport_send_pkt_work() initializing | vq->private_data==NULL | will not be queued V schedule_timeout(2s) vhost_vsock_start() <--------- device ready set vq->private_data wait for 2s and failed connect() again vq->private_data!=NULL recv connecting pkt Details: 1. Host userspace sends a connect pkt, at that time, guest vsock is under initializing, hence the vhost_vsock_start has not been called. So vq->private_data==NULL, and the pkt is not been queued to send to guest 2. Then it sleeps for 2s 3. After guest vsock finishes initializing, vq->private_data is set 4. When host userspace wakes up after 2s, send connecting pkt again, everything is fine. As suggested by Stefano Garzarella, this fixes it by additional kicking the send_pkt worker in vhost_vsock_start once the virtio device is started. This makes the pending pkt sent again. After this patch, kata-runtime (with vsock enabled) boot time is reduced from 3s to 1s on a ThunderX2 arm64 server. [1] https://github.com/kata-containers/runtime/issues/1917 Reported-by: Ning Bo Suggested-by: Stefano Garzarella Signed-off-by: Jia He Link: https://lore.kernel.org/r/20200501043840.186557-1-justin.he@arm.com Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefano Garzarella Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/vsock.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -543,6 +543,11 @@ static int vhost_vsock_start(struct vhos mutex_unlock(&vq->mutex); } + /* Some packets may have been queued before the device was started, + * let's kick the send worker to send them. + */ + vhost_work_queue(&vsock->dev, &vsock->send_pkt_work); + mutex_unlock(&vsock->dev.mutex); return 0;