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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 D0600C33CAF for ; Thu, 16 Jan 2020 17:03:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A5A532077B for ; Thu, 16 Jan 2020 17:03:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MA7M7xNe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387849AbgAPRDt (ORCPT ); Thu, 16 Jan 2020 12:03:49 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:26607 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388619AbgAPRDs (ORCPT ); Thu, 16 Jan 2020 12:03:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579194227; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=dwuqMFEPkLVf1SB1Qby1DH0sArybWQvfhVUygmsr0E4=; b=MA7M7xNedg4uST0aneGIEwk6MS6vmk+Ir+mla1IMUSZAWFzolUmgsnKf2j04/5xUgYuOrX rDOwcxcDHPPoRqvTi6Hu5XD/Vi7dH99H2Qk2zlgr9+LO7mSN+67roNbQ2TM67R7WIGMPVn m71gRMVJLl+xv5jt4o/8s/I+J4H98ZI= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-402-q09_he4QMyGDOeYFaQaA3g-1; Thu, 16 Jan 2020 12:03:46 -0500 X-MC-Unique: q09_he4QMyGDOeYFaQaA3g-1 Received: by mail-wm1-f71.google.com with SMTP id q206so1417547wme.9 for ; Thu, 16 Jan 2020 09:03:46 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=dwuqMFEPkLVf1SB1Qby1DH0sArybWQvfhVUygmsr0E4=; b=QAhqom3Fj1GdfB80f5GgOFhv1fL6ob6z++1u0g/IqHDTCWHWCmTv8bkyD8Fpwwtl9h vH7uxV0GEjMgy6I62+Az62i6vzj1dUl08Qd45uJJrL43gCoOrQfbymrGuYSl411/xCr/ ifs38YnGP/RBdm7yFqVKX4RtOQ52LwF9u2xYLab5jcnyew2GYq7KxSOMTAUKRwj5xvmN 9dJm0937BmgvLilEWP2dqkQ3jD3Hsy32lOYxpEB2hdLHOwn605xiRhRQYhkTdxTLZQz5 Bbys9K07Pr6oqbmsw4jbh4C2MlefBJL3zkKyAvvM7XdnFLCjm1Zdx/PJagwj63FLEtoZ fGOA== X-Gm-Message-State: APjAAAXz6mFU0gbVWaAFnfVqgyhTeC5mbM/PNknaOATh5/aaBuwU9xXV zgPHH/2/ou9BM6nxlMV+/cEdGC0mqTN8yFBwIYL4m89bwp6jssR6CKtaIdoZ1Y3DKH5HY0ZTH4r SX+nP7L3KtJn8BQPqGak= X-Received: by 2002:adf:ce87:: with SMTP id r7mr4222758wrn.245.1579194225147; Thu, 16 Jan 2020 09:03:45 -0800 (PST) X-Google-Smtp-Source: APXvYqwmahambFLYvDPNDfSiuwfj+RNjJ2awrp8kvOtBAw+JLe5Wbrx78e1fRaCj45Q555ccQHKFSw== X-Received: by 2002:adf:ce87:: with SMTP id r7mr4222739wrn.245.1579194224894; Thu, 16 Jan 2020 09:03:44 -0800 (PST) Received: from steredhat (host84-49-dynamic.31-79-r.retail.telecomitalia.it. [79.31.49.84]) by smtp.gmail.com with ESMTPSA id q15sm29985051wrr.11.2020.01.16.09.03.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jan 2020 09:03:44 -0800 (PST) Date: Thu, 16 Jan 2020 18:03:42 +0100 From: Stefano Garzarella To: Jens Axboe Cc: Alexander Viro , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] io_uring: wakeup threads waiting for EPOLLOUT events Message-ID: <20200116170342.4jvkhbbw4x6z3txn@steredhat> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, Jan 16, 2020 at 09:30:12AM -0700, Jens Axboe wrote: > 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! Sure, I'll send a test to liburing for this case! Thanks, Stefano