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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 4E818C433DB for ; Mon, 11 Jan 2021 05:24:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C54322482 for ; Mon, 11 Jan 2021 05:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725536AbhAKFYL (ORCPT ); Mon, 11 Jan 2021 00:24:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725379AbhAKFYK (ORCPT ); Mon, 11 Jan 2021 00:24:10 -0500 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BF84C061786 for ; Sun, 10 Jan 2021 21:23:30 -0800 (PST) Received: by mail-wr1-x433.google.com with SMTP id t30so15052599wrb.0 for ; Sun, 10 Jan 2021 21:23:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:references:from:autocrypt:subject:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=WfKvOqoIQHIS9+tDlH8Ku/AZv1yv6HKg3EV+OPk+uO0=; b=XaQmi1129H2hBXf66nnkS7AwOBMS0gPrvy3gzZy/GMnWGaWg2NbFmCONre95JWuMND s6wuG/jCIW93PJDS7/zkhVb9v20v4fpowTtRAtLmybcBvVv6vIiYOeAPNyqC6wDIJt3X klFAYkaNv0Ps0nbFbPazATEgBq25nlHqayuTxIiFEpvel5N9ehnWP9fsAn5bWHOxG9X3 K2MMsHfbxfsnm/j27sh6TJDtW2VBm0/hYiRTeVvaXph99p7e2Imm66BpFZiNAWOgU9OS zeAbA3o5qCefKESKTukvFM2D6fjlbdgGXa+kL+jWdTbV7yLYgnPiIcltMDXDLJP9ghf+ eYNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:references:from:autocrypt:subject:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=WfKvOqoIQHIS9+tDlH8Ku/AZv1yv6HKg3EV+OPk+uO0=; b=emc56JWNWIa8EbUWJI3B+j1o1rE0WCsVY0yZwqZgkSrQFol5pr1sIJL6QcoDur0tAY ZLVUEt3hOcmQeL6yBbg8l3pg1OvF2dazFnDZVURx3KiOpD3njyQP0ghkEB8+0jfQmOl6 u5Ez41ymof4dTmFW6NQOLGpfVndrLg6iUZrAtCsejepdgcYQWefAhM2k7FW9uA/FtLrO /bhipVH7ryweGpquwMHkqpQQ8Hs6WoBKkLVpherpLL69ErE6CLJH9Xnh4ydm8lbBAGz2 Entws5cbDjtJglC1ZQ94Kb6yY9sHLMgURVu9FBPMB9XWQAN/NlAcGtTZRGsFlqaWEXeg BHfw== X-Gm-Message-State: AOAM533aDg7GQytS4/FNiR7ftshDp9kKlCROJAX+qKEvDI0RJgn6Diiu ZLMQOjHBHt0n5erm07UA4tb2UnOXYOY= X-Google-Smtp-Source: ABdhPJz8FWBnpoWKold9or/lW6w6xQYv9NFmzcNgh1oqgmncb98wUwHEXPpxaQGtNSNwp6IlsqHPKw== X-Received: by 2002:adf:9cca:: with SMTP id h10mr14480553wre.77.1610342608988; Sun, 10 Jan 2021 21:23:28 -0800 (PST) Received: from [192.168.8.119] ([85.255.237.6]) by smtp.gmail.com with ESMTPSA id z15sm23177353wrv.67.2021.01.10.21.23.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 10 Jan 2021 21:23:28 -0800 (PST) To: Bijan Mottahedeh , axboe@kernel.dk, io-uring@vger.kernel.org References: <1607379352-68109-1-git-send-email-bijan.mottahedeh@oracle.com> <1607379352-68109-14-git-send-email-bijan.mottahedeh@oracle.com> <2070b1b5-2931-7782-305f-c578b3b24567@oracle.com> <074644d5-f299-3b70-9d86-bf4ed59d9674@oracle.com> From: Pavel Begunkov Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Subject: Re: [PATCH v2 13/13] io_uring: support buffer registration sharing Message-ID: <4c9d62d8-efc5-1cd6-e73c-9efd3b694950@gmail.com> Date: Mon, 11 Jan 2021 05:19:55 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <074644d5-f299-3b70-9d86-bf4ed59d9674@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org > The intended use case for buffer registration is: > > - a group of processes attach a shmem segment > - one process registers the buffers in the shmem segment and shares it > - other processes attach that registration > > For this case, it seems that there is really no need to wait for the attached processes to get rid of the their references since the shmem segment (and thus the registered buffers) will persist anyway until the last attached process goes away.  So the last unregister could quiesce all references and get rid of the shared buf_data. > > I'm not sure how useful the non-shmem use case would be anyway. > > Would it makes sense to restrict the scope of this feature? I have to say I like that generic resources thing, makes it easier to extend in the future. e.g. pre-allocating dma mappings, structs like bios, etc. I didn't think it through properly but it also looks that with refnodes it would be much easier to do sharing in the end, if not possible vs impossible. -- Pavel Begunkov