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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 74FB7C33CB3 for ; Fri, 17 Jan 2020 00:51:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 49B8F20748 for ; Fri, 17 Jan 2020 00:51:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="Mj09KchI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733205AbgAQAvn (ORCPT ); Thu, 16 Jan 2020 19:51:43 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:43243 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733197AbgAQAvn (ORCPT ); Thu, 16 Jan 2020 19:51:43 -0500 Received: by mail-pl1-f194.google.com with SMTP id p27so9103416pli.10 for ; Thu, 16 Jan 2020 16:51:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=rzkCIZyeJNSDUeoW0WDB8K+pRYNo5VpYgzNZyHy++lw=; b=Mj09KchIo1UJC0dxpJ6tTc5JSmvFhWwaMSUlnYQVL2MRTzXFp7fQWkrZ8CGqGFg0OH mY0LixZ82mfeaG8ATkYBdbcO3SDpqeVKjyBXovlIhVQ/SSkzoZmCVi5WWr269yExnBJP uVTFtYm3M5nPXvniklQeotAcoejYmD+P9NlsBliabSreISdc0ZwuqkaAkl837RTeX+TJ 2VszMUnzK6vGi/FAt5ZF5iSaNST5NiP1j4eg7lrgAvgi3JHxtzstj98Kx/jPK+olRFQX dYRQVVT62jCin5QG56eepAXLb5XIjZ60v5sh3ixL/leBvGQ6yfIp9oezS7VwO+qmMmJy SmGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rzkCIZyeJNSDUeoW0WDB8K+pRYNo5VpYgzNZyHy++lw=; b=kQAq6eoKQ5pOCyF29GmEshdVPe7WlcX3mgXWAjQicQsIpAcrxYFeya8lqLTL+0dpwn ix5K7b5IzTPpvPt5oLcmR8EfGUehL5rt0be/nmgUl2Wz6S9l/JAGqVZh14mK6guZwkJ0 1aeypsXV/j6uzjsQ1zumDgPf+izcghO0Wmn1w9nw20aqKuJJOWORMznTMEpgvCpls8QK Je8wrKsDnJRcLHDMgnId0hYlXYmO3sEYkQeSnUV97Byh6fQL9m/wv11Vh5oUbSeb/ceQ qxuWas41oVuQp6Tdi27WWYZjyV/QATKNy757GltfYzGYG/W4MfAurFXAjqBDwEYg5Sit YUVw== X-Gm-Message-State: APjAAAU8mvJCkhF/jaz4eJrweoeQPGF6yLXwwQaGxC4I0TqcRd8epn0x PIZ5O+7MqlS7NASi7699/KcBE5qXXfI= X-Google-Smtp-Source: APXvYqxENfIB4K5OnJQQzypWRzHGjGvL0brA93ricVch/BwLGlMnTSwlaK9+A+6cJqfN6VEobmovDw== X-Received: by 2002:a17:902:8f8e:: with SMTP id z14mr27512057plo.195.1579222302225; Thu, 16 Jan 2020 16:51:42 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.145]) by smtp.gmail.com with ESMTPSA id g11sm25868383pgd.26.2020.01.16.16.51.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 16 Jan 2020 16:51:41 -0800 (PST) Subject: Re: [PATCHSET v2 0/6] io_uring: add support for open/close To: Colin Walters , Stefan Metzmacher , io-uring@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org References: <20200107170034.16165-1-axboe@kernel.dk> <4adb30f4-2ab3-6029-bc94-c72736b9004a@kernel.dk> <4dffd58e-5602-62d5-d1af-343c4a091ed9@samba.org> <9a407238-5505-c446-80b7-086646dd15be@kernel.dk> <1e8a9e98-67f8-4e2f-8185-040b9979bc1a@www.fastmail.com> From: Jens Axboe Message-ID: <18c5a50e-cd7b-cb7f-c159-322486550e8f@kernel.dk> Date: Thu, 16 Jan 2020 17:51:40 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <1e8a9e98-67f8-4e2f-8185-040b9979bc1a@www.fastmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 1/16/20 5:44 PM, Colin Walters wrote: > > > On Thu, Jan 16, 2020, at 5:50 PM, Stefan Metzmacher wrote: >> >> The client can compound a chain with open, getinfo, read, close >> getinfo, read and close get an file handle of -1 and implicitly >> get the fd generated/used in the previous request. > > Sounds similar to https://capnproto.org/rpc.html too. Never heard of it, but I don't see how you can do any of this in an efficient manner without kernel support. Unless it's just wrapping the communication in its own protocol and using that as the basis for the on-wire part. It has "infinitely faster" in a yellow sticker, so it must work :-) > But that seems most valuable in a situation with nontrivial latency. Which is basically what Stefan is looking at, over the network open, read, close etc is pretty nondeterministic. But even for local storage, being able to setup a bundle like that and have it automagically work makes for easier programming and more efficient communication with the kernel. -- Jens Axboe