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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 3734FC433B4 for ; Thu, 15 Apr 2021 14:18:08 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DD27B6113D for ; Thu, 15 Apr 2021 14:18:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD27B6113D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id A67DF40129; Thu, 15 Apr 2021 14:18:07 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id b11B-YTGZMww; Thu, 15 Apr 2021 14:18:07 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp2.osuosl.org (Postfix) with ESMTP id 60F344021C; Thu, 15 Apr 2021 14:18:06 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2E119C000C; Thu, 15 Apr 2021 14:18:06 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [IPv6:2605:bc80:3010::138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 7B966C000A for ; Thu, 15 Apr 2021 14:18:05 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 661C084719 for ; Thu, 15 Apr 2021 14:18:05 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp1.osuosl.org (amavisd-new); dkim=pass (1024-bit key) header.d=redhat.com Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id CdknReooU1zU for ; Thu, 15 Apr 2021 14:18:00 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp1.osuosl.org (Postfix) with ESMTPS id E5FD78473D for ; Thu, 15 Apr 2021 14:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618496278; 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: in-reply-to:in-reply-to:references:references; bh=IOewNMfPKKreZaktQJpTbBLLtYdk3yANsE5YR8AZsrE=; b=KXSgGbCegOEB8+S8PQg6Q9BiIdiDhoxkQATj9FDdYGC3QeFRsarGybnicop9QwVNifkk1O qjBtGh1+1W+3XrAvyITku+Kh+fbKvEqSGsGn95917QJaDF7meAB/7IW8iuwUTX3T0bfUu2 QCicWAMMr7VT3rA/6kd43yWqpoVdo6Q= 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-130-zPBktbWMNaCxZdXJ3ywBsA-1; Thu, 15 Apr 2021 10:17:55 -0400 X-MC-Unique: zPBktbWMNaCxZdXJ3ywBsA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5981D801814; Thu, 15 Apr 2021 14:17:52 +0000 (UTC) Received: from localhost (ovpn-114-209.ams2.redhat.com [10.36.114.209]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4D7495D723; Thu, 15 Apr 2021 14:17:47 +0000 (UTC) Date: Thu, 15 Apr 2021 15:17:47 +0100 From: Stefan Hajnoczi To: Yongji Xie Subject: Re: Re: Re: [PATCH v6 10/10] Documentation: Add documentation for VDUSE Message-ID: References: <20210331080519.172-1-xieyongji@bytedance.com> <20210331080519.172-11-xieyongji@bytedance.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Cc: Jens Axboe , Jonathan Corbet , kvm@vger.kernel.org, "Michael S. Tsirkin" , netdev@vger.kernel.org, Randy Dunlap , Matthew Wilcox , virtualization@lists.linux-foundation.org, Christoph Hellwig , Christian Brauner , bcrl@kvack.org, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, Dan Carpenter , Mika =?iso-8859-1?Q?Penttil=E4?= X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============3882930713040546328==" Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" --===============3882930713040546328== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="MPbHG8vrrTTLxD+q" Content-Disposition: inline --MPbHG8vrrTTLxD+q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 15, 2021 at 04:33:27PM +0800, Yongji Xie wrote: > On Thu, Apr 15, 2021 at 3:19 PM Stefan Hajnoczi wro= te: > > On Thu, Apr 15, 2021 at 01:38:37PM +0800, Yongji Xie wrote: > > > On Wed, Apr 14, 2021 at 10:15 PM Stefan Hajnoczi wrote: > > > > On Wed, Mar 31, 2021 at 04:05:19PM +0800, Xie Yongji wrote: > > It's not obvious to me that there is a fundamental difference between > > the two approaches in terms of performance. > > > > > On the other > > > hand, we can handle the virtqueue in a unified way for both vhost-vdpa > > > case and virtio-vdpa case. Otherwise, userspace daemon needs to know > > > which iova ranges need to be accessed with pread(2)/pwrite(2). And in > > > the future, we might be able to avoid bouncing in some cases. > > > > Ah, I see. So bounce buffers are not used for vhost-vdpa? > > >=20 > Yes. Okay, in that case I understand why mmap is used and it's nice to keep virtio-vpda and vhost-vdpa unified. Thanks! Stefan --MPbHG8vrrTTLxD+q Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmB4SwsACgkQnKSrs4Gr c8iNcgf/SlAcQNeAhYZD3E8EAxA7kj75HWb2bs314xQK1UuM8yPecd9e468z8oN6 e0lS0+RDTiPjrV+Nlpgs6+xVqLAjatBXGWiauZeed+q6kMlAlt9OiZApRG3/AACc spwkoFaL9mPKBS5lAaGAEiJqd3ZjA1EpKbXq8klSFDVYLXkfD8qyxxsAUlREsH6t s0yoJqiZlLqcDPcfPw4aCEOZteP3MNSinotRCHDDQ6X0cDpcqCyInpClclxd507Z fxz/hu7w1vEbPIGcp6O5VsaUolPr74X0HS4lkDRN32vh8OkDnGsoDiNQg0sduQ5u FV/ND4nsUIUTsXxlBnLOcX2Cj1V4/w== =wUKZ -----END PGP SIGNATURE----- --MPbHG8vrrTTLxD+q-- --===============3882930713040546328== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization --===============3882930713040546328==--