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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 AB7E3C433B4 for ; Fri, 21 May 2021 06:41:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 893EE611AB for ; Fri, 21 May 2021 06:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233237AbhEUGmi (ORCPT ); Fri, 21 May 2021 02:42:38 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:3644 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233394AbhEUGjW (ORCPT ); Fri, 21 May 2021 02:39:22 -0400 Received: from dggems701-chm.china.huawei.com (unknown [172.30.72.59]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4FmcLM4xKxzmXTd; Fri, 21 May 2021 14:35:39 +0800 (CST) Received: from dggpemm500022.china.huawei.com (7.185.36.162) by dggems701-chm.china.huawei.com (10.3.19.178) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 21 May 2021 14:37:56 +0800 Received: from [10.174.187.155] (10.174.187.155) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 21 May 2021 14:37:56 +0800 Subject: Re: [RFC PATCH v3 4/8] vfio/type1: Pre-map more pages than requested in the IOPF handling To: Alex Williamson CC: Cornelia Huck , Will Deacon , "Robin Murphy" , Joerg Roedel , "Jean-Philippe Brucker" , Eric Auger , , , , , , Kevin Tian , Lu Baolu , , Christoph Hellwig , Jonathan Cameron , "Barry Song" , , References: <20210409034420.1799-1-lushenming@huawei.com> <20210409034420.1799-5-lushenming@huawei.com> <20210518125826.7ba38b78.alex.williamson@redhat.com> From: Shenming Lu Message-ID: Date: Fri, 21 May 2021 14:37:55 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: <20210518125826.7ba38b78.alex.williamson@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.187.155] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500022.china.huawei.com (7.185.36.162) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/5/19 2:58, Alex Williamson wrote: > On Fri, 9 Apr 2021 11:44:16 +0800 > Shenming Lu wrote: > >> To optimize for fewer page fault handlings, we can pre-map more pages >> than requested at once. >> >> Note that IOPF_PREMAP_LEN is just an arbitrary value for now, which we >> could try further tuning. > > I'd prefer that the series introduced full end-to-end functionality > before trying to improve performance. The pre-map value seems > arbitrary here and as noted in the previous patch, the IOMMU API does > not guarantee unmaps of ranges smaller than the original mapping. This > would need to map with single page granularity in order to guarantee > page granularity at the mmu notifier when the IOMMU supports > superpages. Thanks, Yeah, I will drop this patch in the current stage. Thanks, Shenming > > Alex > > . >