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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 5F53CC43387 for ; Mon, 7 Jan 2019 06:58:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33339206C0 for ; Mon, 7 Jan 2019 06:58:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726504AbfAGG6T (ORCPT ); Mon, 7 Jan 2019 01:58:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36066 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725777AbfAGG6T (ORCPT ); Mon, 7 Jan 2019 01:58:19 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0CC7374EE1; Mon, 7 Jan 2019 06:58:19 +0000 (UTC) Received: from [10.72.12.209] (ovpn-12-209.pek2.redhat.com [10.72.12.209]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4D48A106222B; Mon, 7 Jan 2019 06:58:11 +0000 (UTC) Subject: Re: [RFC PATCH V3 0/5] Hi: To: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net References: <20181229124656.3900-1-jasowang@redhat.com> <20190104163516-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <68727e1b-1d51-0596-29c3-931475dd5dab@redhat.com> Date: Mon, 7 Jan 2019 14:58:08 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190104163516-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 07 Jan 2019 06:58:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/1/5 上午5:41, Michael S. Tsirkin wrote: > On Sat, Dec 29, 2018 at 08:46:51PM +0800, Jason Wang wrote: >> This series tries to access virtqueue metadata through kernel virtual >> address instead of copy_user() friends since they had too much >> overheads like checks, spec barriers or even hardware feature >> toggling. > > I think it's a reasonable approach. > However I need to look at whether and which mmu notifiers are invoked before > writeback. Do you know? I don't know but just looking at the MMU notifier ops definition, there's no such callback if my understanding is correct. Thanks > >> Test shows about 24% improvement on TX PPS. It should benefit other >> cases as well. >> >> Changes from V2: >> - fix buggy range overlapping check >> - tear down MMU notifier during vhost ioctl to make sure invalidation >> request can read metadata userspace address and vq size without >> holding vq mutex. >> Changes from V1: >> - instead of pinning pages, use MMU notifier to invalidate vmaps and >> remap duing metadata prefetch >> - fix build warning on MIPS >> >> Jason Wang (5): >> vhost: generalize adding used elem >> vhost: fine grain userspace memory accessors >> vhost: rename vq_iotlb_prefetch() to vq_meta_prefetch() >> vhost: introduce helpers to get the size of metadata area >> vhost: access vq metadata through kernel virtual address >> >> drivers/vhost/net.c | 4 +- >> drivers/vhost/vhost.c | 416 +++++++++++++++++++++++++++++++++++++----- >> drivers/vhost/vhost.h | 15 +- >> 3 files changed, 384 insertions(+), 51 deletions(-) >> >> -- >> 2.17.1