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 3FB44C33CB6 for ; Thu, 16 Jan 2020 17:03:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1285E2077B for ; Thu, 16 Jan 2020 17:03:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TSFHdajr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388264AbgAPRDu (ORCPT ); Thu, 16 Jan 2020 12:03:50 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:56567 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388618AbgAPRDt (ORCPT ); Thu, 16 Jan 2020 12:03:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579194228; 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=TSFHdajr3i8d2RRlrZkNp2G7Kodwu8Oi00WJtyzD5DkC+PiyKtIzt0etf3nLLsi2M+JBO/ K092JorT4BiBsxJjEi8ua9Km3HVoYGpEYeBzj0VHECLpi7KPzCQEZGevePycYV92dRPmNz JUD++pJvf20OFhkpqY+D37jV9osWLy4= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-346-8Wzr5IoUMsCea6d2zcRGzQ-1; Thu, 16 Jan 2020 12:03:46 -0500 X-MC-Unique: 8Wzr5IoUMsCea6d2zcRGzQ-1 Received: by mail-wr1-f69.google.com with SMTP id z14so9568184wrs.4 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=thTOgDYGL2LN2KjWzFdjjfiNq2s+5M2Dc5WUNqV9dpQIv3FkTif/cCFOucSMQq9w+O l+06ytZN2QhDxFNAChaSgzNRV0UHXLe47zoNXsS5ABaH55oLOnbpIh4pInQ8YQtRkxqj H4JhFH33YmsAx0HDpF9Pd4XBjLD/V69A4W4emJbUxq8rOKzxusgQLvs1quXcgtovVP2d HDK81GmZHlxy2v5ye9bszxzBpkkxiEtaBiFuthh9QGnvel9+1laxjqfA00K9c1M5E1Sq F266NUjJc1ce3fj1sjGkICIt73Y/rsQ61TciTXPrMl3MXDOI0LB9KlXvxbjBcGqU1oI4 dF+g== X-Gm-Message-State: APjAAAVYrq/hP0Am/nMiPTpVrV7xLC7YFtaUAk9RUXfrFhOH01CyJ7uQ YUdcEEpAnfEbFkFk7Ua9IZD2nu9urtHT4XF+CrV7HlDov43XkJNgxjzBViG0FcEKdARlaCd8pJy 9TxCpcYbGqjGVf2tTuAq5xRYc9Q== X-Received: by 2002:adf:ce87:: with SMTP id r7mr4222756wrn.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: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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