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=-6.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 51F11C433E0 for ; Fri, 25 Dec 2020 07:00:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EA39F22AAA for ; Fri, 25 Dec 2020 07:00:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA39F22AAA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 53D476B00EA; Fri, 25 Dec 2020 02:00:05 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4EE6E6B00EB; Fri, 25 Dec 2020 02:00:05 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 403C36B00EC; Fri, 25 Dec 2020 02:00:05 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id 2B8B06B00EA for ; Fri, 25 Dec 2020 02:00:05 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id EC9B3363D for ; Fri, 25 Dec 2020 07:00:04 +0000 (UTC) X-FDA: 77630905128.05.cast46_1204e5827477 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id D19A01802C51F for ; Fri, 25 Dec 2020 07:00:04 +0000 (UTC) X-HE-Tag: cast46_1204e5827477 X-Filterd-Recvd-Size: 3616 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Fri, 25 Dec 2020 07:00:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608879603; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FXXaFNVTGUVp9lrtyUaIa3Klg2oiiWfo9NKoxtJtuRE=; b=KZ+WXm0k5yWvhKSQPX5vEU1jXcBqfIMn2yzP+klggmxH4QXsNNpt5yn44N8ESEEh5D/Ro8 sqDlpEQSVj/2ilU0Ul9GIpe9dqIlhQ2gqd9jic4dQ0JVfhi93ReIvFiEGPhQuSkpabA/No Rfd7vXWrNCUIEEiPS1bKqRx852LPTwc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-583-GcigxxwTOgOrBiQwDAAu7g-1; Fri, 25 Dec 2020 02:00:00 -0500 X-MC-Unique: GcigxxwTOgOrBiQwDAAu7g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7D7CB180A093; Fri, 25 Dec 2020 06:59:58 +0000 (UTC) Received: from [10.72.12.97] (ovpn-12-97.pek2.redhat.com [10.72.12.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id CD6625D9CC; Fri, 25 Dec 2020 06:59:22 +0000 (UTC) Subject: Re: [RFC v2 06/13] vduse: Introduce VDUSE - vDPA Device in Userspace To: Yongji Xie Cc: "Michael S. Tsirkin" , Stefan Hajnoczi , sgarzare@redhat.com, Parav Pandit , akpm@linux-foundation.org, Randy Dunlap , Matthew Wilcox , viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20201222145221.711-1-xieyongji@bytedance.com> <20201222145221.711-7-xieyongji@bytedance.com> <468be90d-1d98-c819-5492-32a2152d2e36@redhat.com> <26ea3a3d-b06b-6256-7243-8ca9eae61bce@redhat.com> From: Jason Wang Message-ID: Date: Fri, 25 Dec 2020 14:59:21 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2020/12/24 =E4=B8=8B=E5=8D=884:34, Yongji Xie wrote: >> Yes, the disadvantage is the performance. But it should be simpler (I >> guess) and we know it can succeed. >> > Yes, another advantage is that we can support the VM using anonymous me= mory. Exactly. > >>> I think I can try this in v3. And the >>> MMU-based IOMMU implementation can be a future optimization in the >>> virtio-vdpa case. What's your opinion? >> Maybe I was wrong, but I think we can try as what has been proposed he= re >> first and use shadow virtqueue as backup plan if we fail. >> > OK, I will continue to work on this proposal. Thanks >