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 9315CC33CB1 for ; Thu, 16 Jan 2020 16:30:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6913D206D9 for ; Thu, 16 Jan 2020 16:30:18 +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="H47NxRoD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726928AbgAPQaO (ORCPT ); Thu, 16 Jan 2020 11:30:14 -0500 Received: from mail-io1-f67.google.com ([209.85.166.67]:36973 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726343AbgAPQaO (ORCPT ); Thu, 16 Jan 2020 11:30:14 -0500 Received: by mail-io1-f67.google.com with SMTP id k24so22482560ioc.4 for ; Thu, 16 Jan 2020 08:30:13 -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=H0bxqq0C3ucXX8MRGglR7r12WdoPHtKKYN7fgSSxWGg=; b=H47NxRoDGlb9Xpk4hjnN3H5DX7/Y1nbHyooHSImAb/AuO91aQIFGkz5nukb3XJkFYv BCFJyRRwBEvzIYF9AfRc017mTLM9IhRny0GJr56Y/gybwsRwRQazXNKIwX42+sabdsLN X15X0BmyV6CSB6B1Y0jZ+xf0YMqxWgjogXUFVL8Y/KYiCwDz/+nV1XbCa9yYeU5MGCF8 1T/UCC0X3pKY1oTWAPH2ZIvS3UdDEDvlcCzKmPNCOh3XoAgA/FTwnS5EKMetkIv9+Apq 4JLhhIixxGEdCxKBIoAswpIjhjOkbeNcYmx9Vs77+dnLXnWv+kDj2QCiqbAPzVmQcn8D 0Mwg== 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=H0bxqq0C3ucXX8MRGglR7r12WdoPHtKKYN7fgSSxWGg=; b=C6o6VReyoQUtM/LWLj2hwafzXEd9GjlJoRSOCiVi2w6Pxf4jzUbcgxZOj8H9cHWJfr 6n2cR5rIeM8NKlYQssx/PMJLmHGVS3Vu5eKHFhRZEhq/UcpvfzoHkp+ue3fl+rU5M+e/ BD2+TJf8kSW/eAnYr4d1zMKq8zdg0ahNfh1ozNZTI+9vcooikChR+2FJP8NBGRFSTRtt b0EHnhTDizAgFidfPXF8ZdAhmhNd6YQmFJFXx39nnJYdUjUbmzHQyC5LurqgbpoC4Mna 2Mvda+qqJAUbdFlyIdafziVZB4ZhwVMNto92aUkyUjQs9XFsunT+Fr1XIEy05i96dpo5 fJUA== X-Gm-Message-State: APjAAAWD5DEn814HOA2T3Q3FvMDW2SBYdqWy9ayfpSIohrVg2KpGhcj6 ptpy2DimW91KRZuJEdY3uK+FlQ== X-Google-Smtp-Source: APXvYqzhcTFfeK/8XtYJhf0WKLmiMNNTbsufwyWfMiIHFkki4IrO43BdrOKgAlrWUXZCft53+JVmMg== X-Received: by 2002:a05:6602:1d1:: with SMTP id w17mr26645700iot.239.1579192213396; Thu, 16 Jan 2020 08:30:13 -0800 (PST) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id l22sm7113816ilh.37.2020.01.16.08.30.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 16 Jan 2020 08:30:13 -0800 (PST) Subject: Re: [PATCH] io_uring: wakeup threads waiting for EPOLLOUT events To: Stefano Garzarella Cc: Alexander Viro , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20200116134946.184711-1-sgarzare@redhat.com> <2d2dda92-3c50-ee62-5ffe-0589d4c8fc0d@kernel.dk> <20200116155557.mwjc7vu33xespiag@steredhat> <5723453a-9326-e954-978e-910b8b495b38@kernel.dk> <20200116162630.6r3xc55kdyyq5tvz@steredhat> From: Jens Axboe Message-ID: Date: Thu, 16 Jan 2020 09:30:12 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20200116162630.6r3xc55kdyyq5tvz@steredhat> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 1/16/20 9:26 AM, Stefano Garzarella wrote: >> Since the use case is mostly single submitter, unless you're doing >> something funky or unusual, you're not going to be needing POLLOUT ever. > > The case that I had in mind was with kernel side polling enabled and > a single submitter that can use epoll() to wait free slots in the SQ > ring. (I don't have a test, maybe I can write one...) Right, I think that's the only use case where it makes sense, because you have someone else draining the sq side for you. A test case would indeed be nice, liburing has a good arsenal of test cases and this would be a good addition! -- Jens Axboe